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Chapter 16: identifying and quantifying heterogeneity
... For this study, its result was 30.6959 and its p-value corresponded to 0.0456, which indicates that there was significant heterogeneity among the meta-analyzed studies. τ 2 : Corresponds to an estimate of the variance of the true effect sizes among the meta-analyzed studies [42,43]. In this case, the estimated τ was 2. The restricted maximum likelihood method was used, which was located at 0.0501 [43]. ...
... τ 2 : Corresponds to an estimate of the variance of the true effect sizes among the meta-analyzed studies [42,43]. In this case, the estimated τ was 2. The restricted maximum likelihood method was used, which was located at 0.0501 [43]. ...
... In this case, its result was 37.68%. This heterogeneity indicator can be low (up to 25%), moderate (up to 50%), and high (up to 75%) [43]. In this sense, heterogeneity had a variability of 37.68%, i.e., it as considered moderate. ...
The aim of this study was to establish the relationship between different polymorphisms in drug transporter and metabolizer genes and resistance to imatinib in chronic myeloid leukemia (CML). For this purpose, an exhaustive search was carried out in the Scopus, Web of Science, and PubMed databases using different combinations of keywords with different inclusion and exclusion criteria. The meta-analysis included nine studies that met the established criteria. The results of the study showed that the polymorphic variants AG and GG of CYP3A5*3 are associated with response to treatment, presenting a significantly lower risk with resistance to imatinib. Likewise, the variants T1236C and G2677T/A of the ABCB1 gene show a significant association with treatment efficacy. In addition, the genetic polymorphism 1236T, homozygous CC of the MDR1 gene, significantly influences the increased risk of cytogenetic relapse and the polymorphic variant 361G>A GA of the SLCO1A2 gene significantly affects the complete molecular response.
... Very preterm birth is defined by a gestational age (GA) of less than 32 weeks, and extremely preterm birth by a GA of less than 28 weeks. 1 2 This degree of prematurity is the leading cause of neonatal mortality and morbidity due to a combination of organ immaturity and iatrogenic injury. 1 2 Preterm birth is always the result of a pathological process, which may not only contribute to early delivery but may also adversely impact neonatal outcomes. [3][4][5][6] The pathogenic pathways leading to very and extremely preterm birth can be clustered into two main groups: (1) intrauterine infection/inflammation and (2) dysfunctional placentation. [3][4][5][6] The first group is related to histological chorioamnionitis and placental microbial invasion, whereas the second group is associated with hypertensive disorders of pregnancy (HDP), and the entity identified as fetal indication/intrauterine growth restriction (IUGR). ...
... [3][4][5][6] The pathogenic pathways leading to very and extremely preterm birth can be clustered into two main groups: (1) intrauterine infection/inflammation and (2) dysfunctional placentation. [3][4][5][6] The first group is related to histological chorioamnionitis and placental microbial invasion, whereas the second group is associated with hypertensive disorders of pregnancy (HDP), and the entity identified as fetal indication/intrauterine growth restriction (IUGR). [3][4][5][6] Characterisation of these two groups provides strong rationale for establishing each as a distinct endotype that impacts the risk and outcome of prematurity. ...
... [3][4][5][6] The first group is related to histological chorioamnionitis and placental microbial invasion, whereas the second group is associated with hypertensive disorders of pregnancy (HDP), and the entity identified as fetal indication/intrauterine growth restriction (IUGR). [3][4][5][6] Characterisation of these two groups provides strong rationale for establishing each as a distinct endotype that impacts the risk and outcome of prematurity. The term endotype was coined by Anderson to cluster asthmatic patients not only by their clinical characteristics but also by the pathophysiological features of the disease. ...
Background
Antenatal pathological conditions are key in the pathogenesis of bronchopulmonary dysplasia (BPD). Pathophysiological pathways or endotypes leading to prematurity and perinatal lung injury can be clustered into two groups: infection and dysfunctional placentation, which include hypertensive disorders of pregnancy (HDP) and intrauterine growth restriction (IUGR). We conducted a systematic review of observational studies exploring the association between the dysfunctional placentation endotype and BPD.
Methods
MEDLINE, Embase and Web of Science databases were searched up to February 2020 for studies reporting data on the diagnosis of HDP, IUGR or small for gestational age (SGA) and BPD risk. BPD was classified as BPD28 (supplemental oxygen on day 28), BPD36 (oxygen at 36 weeks postmenstrual age), severe BPD (≥ 30% oxygen or mechanical ventilation), BPD36/death and BPD-associated pulmonary hypertension.
Results
Of 6319 studies screened, 211 (347 963 infants) were included. Meta-analysis showed an association between SGA/IUGR and BPD36 (OR 1.56, 95% CI 1.37 to 1.79), severe BPD (OR 1.82, 95% CI 1.36 to 2.29) and BPD/death (OR 1.91, 95% CI 1.55 to 2.37). Exposure to HDP was not associated with BPD but was associated with decreased odds of BPD/death (OR 0.77, 95% CI 0.64 to 0.94). Both HDP (OR 1.41, 95% CI 1.10 to 1.80) and SGA/IUGR (OR 2.37, 95% CI 1.86 to 3.02) were associated with BPD-associated pulmonary hypertension.
Conclusion
When placental vascular dysfunction is accompanied by fetal growth restriction or being born SGA, it is associated with an increased risk of developing BPD and pulmonary hypertension. The placental dysfunction endotype of prematurity is strongly associated with the vascular phenotype of BPD.
Prospero registration number
Review protocol was registered in PROSPERO database (ID=CRD42018086877).
... Considering the differences in the design of research methods and sources of research data used in the target literature, it was extremely necessary to test the heterogeneity of the studied literature. In this study, Q value and I 2 were used to test the heterogeneity of the studies [62], and the results of the test are shown in Table 4. As can be seen from the table, the Q test had a p-value < 0.001 and Q-value > degrees of freedom (df). ...
... The test results showed that the I 2 value was 95.625%, indicating that 95.625% and 4.375% of the observed variance in this study were caused by the true number of variances and random errors in the effect sizes, respectively. According to [62], an I 2 value in the 75-100% range would indicate a high degree of heterogeneity in this study, and a τ 2 value of 0.047 would indicate a 3.7% variance between studies. In summary, the authors of this study adopted a random effects model for analysis to cope with the heterogeneity between studies. ...
Worsening environmental problems have created more and more challenges for green development, and the government is often seen as an important guide in turning this situation around. A government generally enacts green development through green development behavior, but previous research has not revealed the mechanism of this behavior. In addition, the multi-agent interaction between the government and green development behavior also needs to be explored. Based on an integrated theoretical model, the authors of this study adopted a meta-analysis method to analyze 18 high-quality published pieces from 6 mainstream databases and described the mechanism of government green development behavior in exploring and thinking about multi-agent interactions. In addition, the authors of this study explored differences in the roles of central and local government green development behaviors and the moderating role of regional heterogeneity. The research results showed that: (1) Enterprise economic behavior, enterprise environmental behavior, enterprise social behavior, and public participation are all significantly positively affected by government green development behavior; (2) local government green development actions have stronger effects than central government actions; (3) regional heterogeneity moderates the effect of government green development behavior. Furthermore, the authors of this study propose relevant countermeasures and suggestions from the government’s point of view. This research provides a theoretical and practical reference for governments to better improve their environmental systems and environmental supervision.
... Study heterogeneity for each parameter was assessed using the Cochran Q test, I 2 , and τ 2 statistics. 16 A two-tail value of p < 0.05 was used. Table, Supplemental Digital Content 2, which shows the summary of the studies on unconventional perfusion flaps in experimental animal models identified in the systematic review and included in the meta-analysis. ...
... The authors tried to partially circumvent this problem by using random effects models for estimating population parameters. 16 Another major potential caveat of this study was the effect of publication bias. The latter bias reflects the observation that positive results are more likely to be published compared with neutral or negative ones. ...
Background:
Unconventional perfusion flaps offer multiple potential advantages compared with traditional flaps. Although there are numerous experimental articles on unconventional perfusion flaps, the multiple animal species involved, the myriad vascular constructions used, and the frequently conflicting data reported make synthesis of this information challenging. The main aim of this study was to perform a systematic review and meta-analysis of the literature on the experimental use of unconventional perfusion flaps, to identify the best experimental models proposed and to estimate their global survival rate.
Methods:
The authors performed a systematic review and meta-analysis of all articles written in English, French, Italian, Spanish, and Portuguese on the experimental use of unconventional perfusion flaps and indexed to PubMed from 1981 until February 1, 2017.
Results:
A total of 68 studies were found, corresponding to 86 optimized experimental models and 1073 unconventional perfusion flaps. The overall unconventional perfusion flap survival rate was 90.8 percent (95 percent CI, 86.9 to 93.6 percent; p < 0.001). The estimated proportion of experimental unconventional perfusion flaps presenting complete survival or nearly complete survival was 74.4 percent (95 percent CI, 62.1 to 83.7 percent; p < 0.001). The most commonly reported animal species in the literature were the rabbit (57.1 percent), the rat (26.4 percent), and the dog (14.3 percent). No significant differences were found in survival rates among these species, or among the diverse vascular patterns used.
Conclusion:
These data do not differ significantly from those reported regarding the use of unconventional perfusion flaps in human medicine, suggesting that rabbit, rat, and canine experimental unconventional perfusion flap models may adequately mimic the clinical application of unconventional perfusion flaps.
... To combine the city-specific results estimated from the first-stage modeling, we performed a meta-analysis based on a random-effect model (Borenstein et al. 2009;Viechtbauer 2010). To investigate the heterogeneity, we calculated I 2 and tested the uncertainty of the heterogeneity using a chi-squared test for Cochran's Q statistic (Borenstein et al. 2009;Higgins et al. 2003). ...
... To combine the city-specific results estimated from the first-stage modeling, we performed a meta-analysis based on a random-effect model (Borenstein et al. 2009;Viechtbauer 2010). To investigate the heterogeneity, we calculated I 2 and tested the uncertainty of the heterogeneity using a chi-squared test for Cochran's Q statistic (Borenstein et al. 2009;Higgins et al. 2003). ...
Background:
There is growing evidence suggesting an association between air pollution and suicide. However, previous findings varied depending on the type of air pollutant and study location.
Objectives:
We examined the association between air pollutants and suicide in 10 large cities in South Korea, Japan, and Taiwan.
Methods:
We used a two-stage meta-analysis. First, we conducted a time-stratified case-crossover analysis to estimate the short-term association between nitrogen dioxide (NO2), sulfur dioxide (SO2), and particulate matter [aerodynamic diameter ≤10μm (PM10), aerodynamic diameter ≤2.5μm (PM2.5), and PM10-2.5] and suicide, adjusted for weather factors, day-of-week, long-term time trends, and season. Then, we conducted a meta-analysis to combine the city-specific effect estimates forNO2,SO2, and PM10across 10 cities and for PM2.5and PM10-2.5across 3 cities. We first fitted single-pollutant models, followed by two-pollutant models to examine the robustness of the associations.
Results:
Higher risk of suicide was associated with higher levels ofNO2,SO2, PM10, and PM10-2.5over multiple days. The combined relative risks (RRs) were 1.019 forNO2(95% confidence interval [CI]: 0.999, 1.039), 1.020 forSO2(95% CI: 1.005, 1.036), 1.016 for PM10(95% CI: 1.004, 1.029), and 1.019 for PM10-2.5(95% CI: 1.005, 1.033) per interquartile range (IQR) increase in the 0-1 d average level of each pollutant. We found no evidence of an association for PM2.5. Some of the associations, particularly forSO2andNO2, were attenuated after adjusting for a second pollutant.
Conclusions:
Our findings suggest that higher levels of air pollution may be associated with suicide, and further research is merited to understand the underlying mechanisms. https://doi.org/10.1289/EHP2223.
... Heterogeneity, or variability among studies, is a common challenge in meta-analysis. Differences in study design, populations, interventions and outcomes can contribute to heterogeneity, complicating the interpretation of results [45]. Statistical methods, such as meta-regression and subgroup analyses, are used to address heterogeneity. ...
Given the plethora of studies today that focus on the same topic, clinicians and other healthcare professionals increasingly rely on meta-analysis to aid in their evidence-based decision-making. This research method, which combines data from multiple studies to produce a single, more precise estimate of effect size, is invaluable for synthesizing evidence, resolving inconsistencies and guiding clinical practice and public health policies. Especially in disease prevention and control, meta-analysis has emerged as a critical tool. Meta-analysis is particularly valuable in assessing the effectiveness of preventive interventions such as vaccines, lifestyle modifications and screening programs. It provides robust evidence that supports the implementation of effective preventive measures and the discontinuation of ineffective or harmful ones. Furthermore, meta-analysis provides evidence to develop clinical practice guidelines, ensuring patients receive evidence-based treatments. In addition, public health policies aimed at disease prevention and control often rely on evidence from meta-analyses, which provide the data needed to justify and design large-scale public health initiatives. This comprehensive review delves into the role of meta-analysis in disease prevention and control, exploring its advantages, applications, challenges and overall impact on guiding clinical practice and public health policies. Through case studies and an examination of future directions, this paper underscores the pivotal role of meta-analysis in disease prevention and control.
... Network heterogeneity was quantified and categorized using I 2 statistics, as described in Chapter 10.10 of the Cochrane handbook, and the τ, estimated using the maximum likelihood approach. 29,30 Transitivity was evaluated by testing for inconsistency using the node splitting approach. 31 When the transitivity within the network was violated (p < 0:05), the study causing the inconsistency was identified and examined on possible explanations for the violation. ...
Background
Randomized controlled trials are considered the gold standard in regulatory decision making, as observational studies are known to have important methodological limitations. However, real‐world evidence may be helpful in specific situations. This review investigates how the effect estimates obtained from randomized controlled trials compare to those obtained from observational studies, using drug therapy for relapsing–remitting multiple sclerosis as an example.
Study Design and Setting
A systematic review of randomized controlled trials and observational studies was conducted. The primary outcome was the annualized relapse rate. Using (network) meta‐analysis together with posterior predictive distributions, the drug‐specific rate ratios from the network of randomized controlled trials were compared with those from the network of observational studies.
Results
Effect estimates from 26 observational studies showed greater magnitudes and were less precise compared to estimates obtained from 21 randomized controlled trials. Twenty of the 28 treatment comparisons between designs had similar rate ratios. Seven inconsistencies in observed rate ratios could be attributed to two specific disease‐modifying therapies.
Conclusion
In this case study, estimates from observational studies predominantly agreed with estimates from randomized controlled trials given their posterior predictive distributions. Multiple observational studies together may therefore supplement additional pivotal randomized controlled trials in relapsing–remitting multiple sclerosis, for instance facilitating the extrapolation of trial results to the broader patient population.
... Clinical, methodological, and statistical heterogeneity was considered. Heterogeneity was assessed by Q-statistic and corresponding p-value, and the I 2 statistic and corresponding 95% confidence interval [23]. Heterogeneity was considered low, moderate, substantial and considerable if I 2 ranged between <40%; 30e60%; 50e90% and >75% respectively [24]. ...
Background:
Patients require vascular access for medical treatments, diagnostic procedures and symptom management. Current failure rates of peripheral intravascular catheters (PIVCs) are unacceptably high (40-50%). This systematic review aimed to determine the effect of different PIVC materials and designs on the incidence of PIVC failure.
Methods:
A systematic search was conducted in November 2022 using CINAHL, PubMed, EMBASE and Cochrane Central Register of Controlled Trials databases. Randomised controlled trials that compared PIVC novel PIVC material/design and standard material/design were included. The primary outcome was all causes of PIVC failure, any reason for device removal due to cessation of device function; and secondary outcomes included individual PIVC complications and infection (local or systemic), and dwell times. Quality appraisal was conducted using the Cochrane risk of bias tool. A meta-analysis was performed using random effects model.
Results:
Seven randomised controlled trials were eligible for inclusion. In meta-analysis, the impact of material and design on PIVC failure in the studies favoured the intervention arms (RR 0.71, 95% CI 0.57-0.89), however there was substantial heterogeneity (I2 = 81%, 95% CI 61-91%). Through subgroup analyses, a significant difference on PIVC failure favoured the closed system over the open system (RR 0.85, 95% CI 0.73 to 0.99; I2 = 23%, 95% CI 0-90%).
Conclusion:
Catheter material and design can impact PIVC outcome. Conclusive recommendations are limited due to the small number of studies and inconsistent reporting of clinical outcomes. Further rigorous research of PIVC types is necessary to improve clinical practice and device selection pathways should reflect the resulting evidence.
... We need to calculate effect size calculations to make this comparison. The below formulas from (Borenstein et al., 2009) are used for calculation of the Effect Size g and its standard deviation SE g : ...
Is there a statistical difference between Naive Bayes and Random Forest in terms of recall, f-measure, and precision for predicting software defects? By utilizing systematic literature review and meta-analysis, we are answering this question. We conducted a systematic literature review by establishing criteria to search and choose papers, resulting in five studies. After that, using the meta-data and forest-plots of five chosen papers, we conducted a meta-analysis to compare the two models. The results have shown that there is no significant statistical evidence that Naive Bayes perform differently from Random Forest in terms of recall, f-measure, and precision.
... It is assumed that the actual effect size of this study is consistent with the expected effect size, i.e., there is no heterogeneity. The Q statistics reflects the difference between the actual and expected effect sizes, and I 2 reflects the proportion of the total effect size that is heterogeneous [88]. Therefore, this study used the Q statistics and I 2 to identify and quantify the heterogeneity of the study, and the test results are presented in Table 4. ...
Enterprise green innovation behavior is necessary for the transformation of enterprises and the enhancement of green development. However, the inconsistency of existing studies on the behavioral mechanism has not been effectively addressed. The purpose of this paper is to reveal a mechanism for enterprise green innovation behavior, taking the coevolutionary theory. Based on the coevolution theory model, this study screened 16 high-quality studies covering 11 countries and regions with 5471 independent samples from six major databases (Web of Science Core Collection (SCIE & SSCI), Science Direct, Springer Link, Wiley, Taylor & Francis, and Sage journals). The included literature was coded and tested. Meta-analysis was used to clarify the direction and intensity of the behavioral antecedent and outcome variables to explore the mechanism of enterprise green innovation behavior. Furthermore, this study also explores the moderating effect of regional heterogeneity on behavior. The results are as follows: (1) The economic, political, social, and technological environments significantly and positively influence enterprise green innovation behavior. (2) Enterprises’ green innovation behavior significantly and positively influences environmental performance. (3) Regional heterogeneity can moderate the effects of enterprise green innovation behavior and antecedent and consequence variables. Then, this study proposes countermeasures based on government and enterprise perspectives. This study provides both theoretical and empirical referents for enterprises to better adopt green innovation behaviors and enhance their green development.
... The heterogeneity will be assessed visually through the forest plot, and the I² will be reported 25 . Confidence intervals of 95% (95%CI) will be calculated for I², and the hypothesis of statistical heterogeneity will be rejected when the lower limit of 95%CI include the value of 0% 26 . ...
Exergame, a type of enjoyable active video game that combines physical exertion and game is a technological innovation that has generated important information for the health field. In the cardiovascular area, exergames have been used to manage blood pressure in adults with some positive results. Despite this, in primary studies, it is possible to identify that participants dropout of the exergames interventions, but no synthesis of evidence has been produced so far to explore that. The aims of this review are i) to estimate the pooled rate of dropouts in controlled trials assessing the effects of exergame-based interventions on resting blood pressure in adults and older people; ii) to compare dropout rates between exergame and controls groups, and iii) to investigate the intervention characteristics associate with dropout rates. Inclusion criteria: Randomized controlled trials (RCTs) or quasi-RCTs (≥ 4 weeks) assessing the effects of exergame-based interventions on resting blood pressure in adults aged ≥ 18 years old. Without restriction to language, date of the publication, and intervention setting. Literature searches will be conducted using PubMed, Scopus, SPORTDiscus, Cumulative Index of Nursing and Allied Health Literature, Web of Science, Cochrane Central Register of Controlled Trials, and Scientific Electronic Library Online. The quality of the RCTs will be assessed using Cochrane’s risk of bias tool. A descriptive narrative synthesis and a random-effects model meta-analysis of the pooled event rate (prevalence) will be provided (p < 0.05). This protocol is registered with PROSPERO: CRD42020199547.
... A P value <0.1 in the Cochran's Q test was considered statistically significant [31]. An I 2 value ≤25% represented low heterogeneity, 25-49% moderate heterogeneity, and ≥50% high heterogeneity [32]. To explore potential sources of heterogeneity, subgroup analyses were conducted by sex (female or male), geographic area (Asian or non-Asian countries), risk of bias (moderate to high or low), adjustment for obesity (yes or no), and adjustment for Helicobacter pylori infection (yes or no). ...
This systematic review and meta-analysis examined associations between serum levels of haemoglobin A1c (HbA1c) and glucose and the risk of gastric cancer.
MEDLINE, Embase, and Cochrane Library were searched for studies examining associations between serum levels of HbA1c or glucose and the risk of gastric cancer. Inclusion of studies, quality assessment, and data extraction were conducted independently by two authors. Pooled hazard ratios (HR) with 95% confidence intervals (CI) were synthesised using random-effects models. Cochran’s Q test and I² statistic were used to assess heterogeneity.
Among 3473 identified studies, 12 were included. Of these, 5 studies examined HbA1c levels and 7 studies examined serum glucose levels. Serum HbA1c levels >6% were associated with an increased risk of gastric cancer (HR 1.36, 95% CI 1.06–1.74). When compared with the lowest glucose categories, the highest glucose categories were associated with a borderline increased risk of gastric cancer (HR 1.11, 95% CI 0.98–1.26). In subgroup analyses, studies that adjusted for Helicobacter pylori infection indicated stronger associations between elevated HbA1c levels and gastric cancer (HR 2.08, 95% CI 1.46–2.98) than those without such adjustment (HR 1.10, 95% CI 0.91–1.32).
Long-standing poor glycaemic control may increase the risk of gastric cancer.
PROSPERO CRD42020157453.
... We need to calculate effect size calculations to make this comparison. The below formulas from [23] are used for calculation of the Effect Size g and its standard deviation SE g : ...
... When Q values indicated significant heterogeneity, subgroup analyses on categorical variables and meta-regression on continuous measures examined possible moderators. I-square values of 25%, 50%, and 75% represented low, moderate, and high level of observed heterogeneity, respectively (Borenstein et al., 2009a). ...
Numerous investigators have tested contentions that angry faces capture early attention more completely than happy faces do in the context of other faces. However, syntheses of studies on early event‐related potentials related to the anger superiority hypothesis have yet to be conducted, particularly in relation to the N200 posterior‐contralateral (N2pc) component which provides a reliable electrophysiological index related to orienting of attention suitable for testing this hypothesis. Fifteen samples (N = 534) from 13 studies featuring the assessment of N2pc amplitudes during exposure to angry‐neutral and/or happy‐neutral facial expression arrays were included for meta‐analysis. Moderating effects of study design features and sample characteristics on effect size variability were also assessed. N2pc amplitudes elicited by affectively valenced expressions (angry and happy) were significantly more pronounced than those elicited by neutral expressions. However, the mean effect size difference between angry and happy expressions was ns. N2pc effect sizes were moderated by sample age, number of trials, and nature of facial images used (schematic vs. real) with larger effect sizes observed when samples were comparatively younger, more task trials were presented and schematic face arrays were used. N2pc results did not support anger superiority hypothesis. Instead, attentional resources allocated to angry versus happy facial expressions were similar in early stages of processing. As such, possible adaptive advantages of biases in orienting toward both anger and happy expressions warrant consideration in revisions of related theory.
... Heterogeneity may suggest that different populations were included in the meta-analysis (Engels, Schmid, Terrin, Olkin, & Lau, 2000). In addition to the τ 2 statistic, that represents an absolute value of the variance of the true effect sizes (Borenstein, Hedges, Higgins, & Rothstein, 2009), we also used the I 2 statistic to estimate the percentage of real differences in effect sizes (true heterogeneity). In the current study, the degree of heterogeneity was interpreted as low (I 2 ≈ 25%), moderate (I 2 ≈ 50%) or high (I 2 ≈ 75%), according to the benchmarks provided by Higgins, Thompson, Deeks, and Altman (2003). ...
A previous meta-analysis demonstrated short-term memory (STM) and working memory (WM) dysfunction in patients with Parkinson’s disease (PD). However, considerable research on the topic that calls into question the extent of such impairments in PD has since been published. The aim of the present quantitative review was to provide the largest statistical overview on STM and WM dysfunction in Parkinson’s disease (PD), while simultaneously providing novel insights on moderating factors of effect size heterogeneity in PD. The systematic literature search in PubMed, PsycINFO, PsycArticles, Scopus and Web of Science databases allowed us to estimate 350 effect sizes from 145 empirical studies that reported STM and WM scores for patients with PD against healthy controls. The outcomes indicated general dysfunction in the visuospatial domain and poor verbal WM in PD. Subgroup analyses suggested that mild cognitive impairment is associated with STM and WM difficulties in PD. Furthermore, meta-regression analyses revealed that disease duration accounted for more than 80% of the visuospatial STM effect size variance (β = 0.136, p < .001, R2 = .8272), larger daily levodopa equivalent dose was associated with WM dysfunction (verbal: β = -0.001, p = .016, R2 = .1812; visuospatial: β = 0.003, p = .069, R2 = .2340), and years of education partially explained the verbal STM effect size variance (β = -0.027, p = .040, R2 = .1171). Collectively, these findings advance our understanding of underlying factors that influence STM and WM functioning in PD, while at the same time providing novel directions for future research.
... Heterogeneity between studies is inevitable when performing a clinical meta-analysis, as such studies integrate information from institutions with different treatment schemes and patient characteristics. However, heterogeneity among studies is not an obstacle for conducting meta-analyses; rather, it is a subject that should be rigorously interpreted and clinically analyzed with statistical analysis, such as subgroup comparison or metaregression [27]. Meta-analyses of radiation oncology studies in particular require an understanding and interpretation of heterogeneity. ...
Meta-analyses have been conventionally performed to extract the firmest conclusions from randomized controlled trials while minimizing the risk of bias. However, the field of oncology does not always allow for collecting the best evidence. Radiation oncology is a discipline where intractable or rare diseases are commonly encountered; hence, more practical data suitable for detailed clinical evaluations are needed. This review discusses new viewpoints regarding meta-analyses by pointing out heterogeneities among clinical studies and issues related to analyzing observational studies, thus clarifying the practical utility of meta-analyses in radiation oncology. Limitations of previous systematic reviews or meta-analyses are also assessed to suggest future directions.
... The heterogeneity between studies was evaluated using the I 2 and τ 2 tests. A p-value < 0.05 was considered statistically significant, and I 2 ≥ 50% indicates the existence of significant heterogeneity, while τ 2 equal to zero or close to zero indicates that there is no variance between studies [52][53][54]. The publication bias of the selected studies was assessed using Begg's funnel plot and Egger's test [55]. ...
Medical device-associated infections (MDAI) are a critical problem due to the increasing usage of medical devices in the aging population. The inhibition of biofilm formation through the use of probiotics has received attention from the medical field in the last years. However, this sparse knowledge has not been properly reviewed, so that successful strategies for biofilm management can be developed. This study aims to summarize the relevant literature about the effect of probiotics and their metabolites on biofilm formation in medical devices using a PRISMA-oriented (Preferred Reporting Items for Systematic reviews and Meta-Analyses) systematic search and meta-analysis. This approach revealed that the use of probiotics and their products is a promising strategy to hinder biofilm growth by a broad spectrum of pathogenic microorganisms. The meta-analysis showed a pooled effect estimate for the proportion of biofilm reduction of 70% for biosurfactants, 76% for cell-free supernatants (CFS), 77% for probiotic cells and 88% for exopolysaccharides (EPS). This review also highlights the need to properly analyze and report data, as well as the importance of standardizing the in vitro culture conditions to facilitate the comparison between studies. This is essential to increase the predictive value of the studies and translate their findings into clinical applications.
... The I 2 statistics was used to assess the heterogeneity among the studies, with values of <25, 25-75, and >75% interpreted as low, moderate and high heterogeneity, respectively (Higgins et al., 2003;Higgins, 2008). Heterogeneity was assessed in line with a low chi-squares' p-value (Higgins et al., 2003;Higgins, 2008) and a high Tau 2 value (Borenstein et al., 2009). ...
The aim of this meta-analysis was to evaluate the effects of complex training (CT) on sprint, jump, and change of direction (COD) ability among soccer players. After an electronic search, 10 peer-reviewed articles were considered in the meta-analysis. The athletes included in this meta-analysis were amateur to professional level male soccer players (age range, 14–23 years). These studies incorporated CT in soccer players who were compared to a control group. Significant moderate to large improvements were observed in the CT group [sprint: standard mean difference (SMD) = 0.92–1.91; jump: SMD = 0.96–1.58; COD: SMD = 0.97–1.49] when compared to control groups. Subgroup analysis were also conducted based on age, duration, and competitive level. The beneficial effects of CT were greater in players <18 vs. ≥18 years (linear sprinting; SMD = 2.01 vs. −0.13), after ≥8 vs. <8 weeks (jumping and COD; SMD = 1.55–2.01 vs. 0.31–0.64, respectively) and among professional vs. amateur players (linear sprinting and with COD; SMD = 1.53–1.58 vs. 0.08–0.63, respectively). In conclusion, regular soccer training programs may be supplemented with CT to improve sprint, jump, and COD performance. A longer duration of CT (≥8 weeks) seems to be optimal in improving the physical abilities of soccer players. Professional players and <18 years players may benefit more from CT program.
... To compare scales at the meta-analysis level, we first calculated pooled effect sizes and corresponding DerSimonian and Laird estimate of the variance t 2 within meta-analyses separately for each scale in a first step, and then combined these estimates across meta-analyses using inverse variance random-effects meta-analysis in a second step 17,18 . To allow the pooling of t 2 across metaanalyses, we derived its standard error 19 and calculated its 95% confidence interval (CI) assuming a normal distribution. If the lower bound of the 95% CI of t 2 fell below zero, we truncated it to zero 20 . ...
Objective
To compare assay sensitivity of the Visual Analogue Scale (VAS) for global osteoarthritis pain and the Western Ontario and McMaster University (WOMAC) pain subscale, and the associated between-trial heterogeneity in effect sizes (ES).
Design
We included trials with placebo, sham or non-intervention control that included at least 100 patients with hip or knee osteoarthritis per arm, reporting both VAS and WOMAC pain scores. ES were calculated as between-group difference in means divided by the pooled standard deviation and compared using a paired t-test. ES and τ² as a measure of between-trial heterogeneity were combined using random-effects meta-regression with robust variance estimation to account for the correlation of data within trials and meta-analyses.
Results
Twenty-eight trials with 44 randomized comparisons were included. In 28 comparisons (64%), ES from VAS favoured the intervention more than those from WOMAC pain (P = 0.003). Twenty-six p-values (59%) were smaller according to VAS (P = 0.008). The 44 comparisons contributed to 12 meta-analyses. Eleven meta-analyses (92%) showed larger benefits of interventions according to VAS, with a combined overall difference in ES of −0.08 (95% CI −0.14 to −0.02). τ² was similar for VAS and WOMAC pain (difference in τ², −0.003, 95% CI −0.009 to 0.004).
Conclusion
The VAS for global pain had slightly higher assay sensitivity at trial and meta-analysis levels than the WOMAC pain subscale without relevant increase in between-trial heterogeneity.
... This model accounts for variability between studies as well as within studies. Statistical heterogeneity was assessed by Cochran's Q statistic and by the I 2 statistic, which is derived from Q and describes the proportion of total variation that is due to heterogeneity beyond chance (39). ...
Background: Necrotizing enterocolitis (NEC) is the leading cause of morbidity and mortality from gastrointestinal disease in very and extremely preterm infants. Stem cell therapy has shown some promising protective effects in animal models of intestinal injury, including NEC, but no systematic review has yet evaluated the preclinical evidence of stem cell therapy for NEC prevention or treatment.
Methods: PubMed and EMBASE databases were searched for studies using an animal model of NEC with stem cells or their products. Risk of bias was assessed using the SYRCLE tool. A random-effects model was used to pool odds ratios (OR) and 95% confidence interval (CI).
Results: We screened 953 studies, of which 9 (8 rat, 1 mouse model) met the inclusion criteria. All animal models induced NEC by a combination of hypothermia, hypoxia and formula feeding. Risk of bias was evaluated as unclear on most items for all studies included. Meta-analysis found that both mesenchymal and neural stem cells and stem cell-derived exosomes reduced the incidence of all NEC (OR 0.22, 95% CI 0.16-0.32, k=16), grade 2 NEC (OR 0.41, 95% CI 0.24-0.70, k=16), and grade 3-4 NEC (OR 0.28, 95% CI 0.19-0.42, k=16). K represents the number of independent effect sizes included in each meta-analysis. The effect of the exosomes was similar to that of the stem cells. Stem cells and exosomes also improved 4-day survival (OR 2.89 95% CI 2.07-4.04, k=9), and 7-day survival (OR 3.96 95% CI 2.39-6.55, k=5) after experimental NEC. Meta-analysis also found that stem cells reduced other indicators of intestinal injury.
Conclusion: The data from this meta-analysis suggest that both stem cells and stem cell-derived exosomes prevented NEC in rodent experimental models. However, unclear risk of bias and incomplete reporting underline that poor reporting standards are common and hamper the reliable interpretation of preclinical evidence for stem cell therapy for NEC.
... Q is a measure of weighted sum of squared deviations of each study effect size from the overall mean effect size to provide significance testing (p value ≤ .05) for heterogeneity (Borenstein, Hedges, Higgins and Rothstein, 2009a). I 2 is a measure of relative heterogeneity estimating the percentage of the variability in effect estimates that is due to heterogeneity rather than chance. ...
Impulsivity is a multi-faceted construct that underpins various mental health disorders. Impulsive behavior exacts a substantial health and economic burden, hence the importance of developing specific interventions to target impulsivity. Two forms of non-invasive brain stimulation, namely transcranial direct current stimulation (tDCS) and repetitive transcranial magnetic stimulation (rTMS), have been used to modulate impulsivity. To date, no reviews have systematically examined their effects on modulating impulsivity in people with mental health disorders. We conducted a systematic review and meta-analysis of the literature from AMED, Embase, Medline and PsycINFO databases on the use of rTMS and tDCS to modulate impulsivity in people with mental health disorders. Results from 11 tDCS and 18 rTMS studies indicate that tDCS has a significant, albeit small, effect on modulating impulsivity (g = 0.29; 95% CI, 0.09 to 0.48; p = .004) whereas rTMS has no significant effect on impulsivity (g = -0.08; 95% Cl, -0.35 to 0.19; p = .550). Subgroup analyses identified the key parameters required to enhance the effects of tDCS and rTMS on impulsivity. Gender and stimulation intensity acted as significant moderators for effects of rTMS on impulsivity. There is insufficient evidence to support the use of tDCS or rTMS in clinical practice to reduce impulsivity in people with mental health disorders. The use of standardized non-invasive brain stimulation protocols and outcome measures in patients with the same diagnosis is advised to minimize methodological heterogeneity.
... To evaluate the amount of heterogeneity in the dataset (Table 4) on which the model in Fig. 5 is based, the I 2 statistics was calculated (Hak et al., 2016). The I 2 statistics is a relative measure of the amount of detected variance that reflects real differences in effect sizes (Borenstein et al., 2009). An I 2 statistic of 98.38% was obtained, which indicates that there is a high level of heterogeneity for the variables listed in Table 4. ...
The purpose of this article is to evaluate the main drivers of the sharing economy through an exhaustive weighting and meta-analysis of previous relevant quantitative research articles, obtained using a systematic literature review methodology. The authors analysed 22 quantitative studies from 2008 through. Out of the 249 extracted relationships (independent e dependent variable), the paper identifies the "best" predictors used in theoretical models to study the sharing economy. These include: attitude on intention to share, perceived behavioural control on intention to share, subjective norm on intention to share, economic benefit on attitude, and perceived risk on attitude. Geographically, Germany and the United States of America were found to be the nations with the highest number of respondents. Temporally, an increasing trend in the number of articles on the sharing economy and respondents was observed. The consolidation of the drivers of the sharing economy provides a solid theoretical foundation for the research community to explore existing hypotheses further and test new hypotheses in emerging contexts of the sharing economy. Given the different conceptual theories that have been used to study the sharing economy and their application to different contexts, this study presents the first attempt at advancing knowledge by quantitatively synthesizing findings presented in previous literature.
... This model accounts for variability between studies, as well as within studies. Statistical heterogeneity was assessed by Cochran's Q statistic and by the I 2 statistic, which is derived from Q and describes the proportion of total variation that is due to heterogeneity beyond chance (22). The I 2 statistic was interpreted as per Higgins & Green (23): low (25% ≤ I 2 < 50%), moderate (50% ≤ I 2 < 75%), and high (I 2 ≥ 75%). ...
Epidemiological evidence and animal studies support that intrauterine exposure to tobacco smoke disturbs lung development and has a negative effect in the pulmonary health of the offspring. Individual studies suggest an association between fetal exposure to maternal smoking and risk of developing bronchopulmonary dysplasia (BPD). However, this association has not yet been systematically investigated. We aimed to conduct a systematic review of studies reporting on tobacco smoking during pregnancy as potential risk factor for BPD. PubMed/MEDLINE and EMBASE databases were searched. BPD was defined as requirement of supplemental oxygen on postnatal day 28 (BPD28; all BPD), at the postmenstrual age (PMA) of 36 weeks (BPD36; moderate/severe BPD), or as requirement of more than 30% oxygen and/or positive pressure at 36 weeks PMA (severe BPD). Pooled risk ratios (RR) and 95% confidence intervals (CI) were calculated using a random-effects model. Of 2,894 potentially relevant studies, 33 met the inclusion criteria. The included studies evaluated 171,772 infants and included 30,445 cases of exposure to maternal smoking and 25,340 cases of BPD of any severity. Meta-analysis showed a significant association between tobacco smoking during pregnancy and BPD36 (17 studies, RR 1.126, 95% CI 1.008-1.259, p = 0.036), but could not demonstrate a significant association between tobacco smoking during pregnancy and BPD28 (16 studies, RR 1.021, 95% CI 0.924-1.129, p = 0.681), or severe BPD (3 studies, RR 1.143, 95% CI 0.528-2.478, p = 0.734). In conclusion, our data suggest that tobacco smoking during pregnancy increases the risk of moderate/severe BPD. Our results highlight the detrimental effects of tobacco smoking and reinforce the hypothesis of the involvement of prenatal insults in the etiopathogenesis of BPD.
... 64 The Cochrane Q, which estimates statistical significance; s 2 , which estimates the absolute value of the true variance between studies, but not the proportion of the variance; and I 2 , which estimates the proportion of true variance, but not the absolute value of the variance, were all used to test homogeneity of variance among effect sizes. 65 To show the dispersion of true effect sizes around the mean, prediction intervals for each time point were also calculated. 66 ...
Background:
Patients undergoing surgery in the prone position may be at risk for postoperative vision loss associated with increased intraocular pressure. The purpose of this systematic review and meta-analysis is to estimate the magnitude of the increase in intraocular pressure at specific perioperative time points in adult patients. The research question to be addressed is "What is the magnitude of the increase in intraocular pressure at specific perioperative time points in adults undergoing surgery in the prone position?"
Methods:
Comprehensive search strategies were used to identify nine eligible studies (N = 229). Standardized mean difference effect sizes were calculated for two intraoperative time points.Time points for meta-analysis were selected to achieve the greatest number of comparisons for analysis at each time point. Prediction intervals for each time point were also calculated to show the dispersion of true effect sizes around the mean.
Results:
Meta-analysis showed that intraocular pressure increased significantly between induction of anesthesia and up to 10 minutes of prone position (T1: standardized mean difference [d] = 2.55; P < .001) and continued to increase significantly until the end of the prone position (T2: d = 3.44; P = .002).
Conclusions:
Intraocular pressure increases of this magnitude demonstrate the need for implementing interventions to reduce the risk for postoperative vision loss in patients undergoing surgery in the prone position.
Clinical relevance:
Implementing preoperative ophthalmologic examinations for patients undergoing surgery in the prone position may help to reduce the risk for ocular injury. Intraoperative interventions that can be implemented to reduce or mitigate the increase in intraocular pressure include implementing a 5- to 10-degree reverse Trendelenburg prone position, reducing the amount of time the patient is in the prone position, considering staged procedures, monitoring intraocular pressure, providing periodic position changes or rest periods, preventing pressure on the eye, and administering specific medications or anesthetics.
... The pooled prevalence of HSV-1 and HSV-2 in the Nigerian population with 95% confidence intervals (CI) was estimated using DerSimonian-Laird random-effects models provided ≥1 measure was available. This method accounts for sampling variation and heterogeneity in effect size [22]. The Freeman-Turkey double-arcsine transformation was used for variance stabilization [23]. ...
A source of comprehensive information on the prevalence of herpes simplex virus type 1 and 2 (HSV-1 and HSV-2) can help researchers and policymakers address HSV related burden in the society. At the moment, this is not readily available. This study aims to fill this gap by attempting to estimate the seroprevalence of HSV-1 and HSV-2 infections in Nigeria on the basis of published data. A systematic review and meta-analysis including cross-sectional studies on HSV-1 and HSV-2 in Nigeria was conducted. Electronic databases including PubMed/MEDLINE, CENTRAL, African Journals Online (AJOL), ScienceDirect, WHO-Afro Library, WHO-IRIS and African Index Medicus were searched for English Language publications on HSV-1 and HSV-2. Seven relevant publications were identified. Seroprevalence measures of 3 and 23 for HSV-1 and HSV-2, respectively, were extracted. The pooled mean seroprevalences for HSV-1 and HSV-2 were 74.0% (37.4–99.4%) and 63.4% (56.1–70.4%) respectively. The mean seroprevalence of HSV-1 was higher among females, 82.4% (n = 509, CI, 36.6–100.0%), than males, 54.5% (n = 198, CI, 47.6–61.4%). The mean seroprevalence of HSV-2 were 51.8% (n = 1414, CI: 39.4–64.0%) and 86.5% (n = 162, CI: 80.8–91.3%) among healthy and clinical populations, respectively. The study was limited by the paucity of quality studies, variations in diagnostic methods and high heterogeneity in seroprevalence estimates. In conclusion, the seroprevalence of HSV-1 and HSV-2 remain high in Nigeria. Large and representative national epidemiological surveys covering all regions and specific groups are recommended.
... Moreover, one of the main inter-study differing variables, age, did not affect the efficacy of exercise on the outcome measures. Besides, Q-and I 2 -statistic cannot be used to estimate the magnitude of true dispersion [253]. Fifth, for all outcome measures, the risk of bias assessment indicated highest risk in terms of attrition. ...
We performed a meta-analysis to synthesize evidence on the efficacy and safety of physical exercise as an add-on therapeutic intervention for quality of life (QoL), depressive symptoms and cognition across six chronic brain disorders: Alzheimer’s disease, Huntington’s disease, multiple sclerosis, Parkinson’s disease, schizophrenia and unipolar depression. 122 studies ( = k) (n = 7231) were included. Exercise was superior to treatment as usual in improving QoL (k = 64, n = 4334, ES = 0.40, p < 0.0001), depressive symptoms (k = 60, n = 2909, ES = 0.78, p < 0.0001), the cognitive domains attention and working memory (k = 21, n = 1313, ES = 0.24, p < 0.009), executive functioning (k = 14, n = 977, ES = 0.15, p = 0.013), memory (k = 12, n = 994, ES = 0.12, p = 0.038) and psychomotor speed (k = 16, n = 896, ES = 0.23, p = 0.003). Meta-regression showed a dose–response effect for exercise time (min/week) on depressive symptoms (β = 0.007, p = 0.012). 69% of the studies that reported on safety, found no complications. Exercise is an efficacious and safe add-on therapeutic intervention showing a medium-sized effect on QoL and a large effect on mood in patients with chronic brain disorders, with a positive dose–response correlation. Exercise also improved several cognitive domains with small but significant effects.
... If the study did not report an exact P-value and it was not possible to calculate it, the value for a non-significant result was treated as P > 0.5 and for a significant result as P ≤ 0.05. Heterogeneity was assessed by calculating the Q-statistic [36], T 2 -statistic [37] and I 2 -statistic [32]. In case of high heterogeneity (I 2 > 75%), a subgroup analysis of studies (minimum four per subgroup [38]) was performed taking into account related factors. ...
Aims
The main aim of this study was to assess the relationship between parental attitudes towards children's alcohol use and their child's alcohol use. Secondary aims included assessing the relationship between attitudes reported by parents and those perceived by children, and between perceived parental attitudes and children's alcohol use.
Methods
Meta‐analysis of studies reporting on the associations between parental attitudes towards children's alcohol use and children's self‐reported alcohol use. Published, peer‐reviewed cross‐sectional and longitudinal studies were identified from the following databases up to April 2018: Medline, PsycINFO, EMBASE, Scopus and Web of Science. Quality assessment was performed by using guidelines developed by Hayden, Cote & Bombardier. Pooled effect sizes were calculated by using random‐effects meta‐analyses, if there were at least two studies that could be included per analysis. Of 7471 articles screened, 29 were included comprising data from 16 477 children and 15 229 parents.
Results
Less restrictive parental attitudes towards children's alcohol use were related to higher rates of alcohol use initiation [odds ratio (OR) = 1.45, 95% confidence interval (CI) = 1.17–1.80], alcohol use frequency (OR = 1.52, 95% CI = 1.24–1.86) and drunkenness (OR = 1.58, 95% CI = 1.35–1.85) among children. Less perceived restrictive parental attitudes were related to higher alcohol use frequency (OR = 1.76, 95% CI = 1.29–2.40). Perceived parental attitudes were not clearly related to alcohol use initiation. Parent‐reported attitudes and perceived parental attitudes were weakly positively correlated (r = 0.27, P = ≤ 0.001). The strength of the relationship between parental attitudes and children's alcohol use frequency attenuated with children's age. Study design, sample size, study location and levels of alcohol use frequency did not have a detectable effect on the relationship.
Conclusions
Less restrictive parental attitudes towards children's alcohol use are associated with increases in children's alcohol use onset, alcohol use frequency and drunkenness. Children's perception of less restrictive parental attitudes is associated with children's alcohol use.
... Furthermore, the p value for T does not give any indication of the amount of variability in the true effect size, only the significance. Finally, I 2 indicates what proportion of the observed variation in effect sizes between studies is due to variability in the true effect size [83]. In other words, I 2 tells us what proportion of the observed variability between studies would remain if variability due to sampling error were removed. ...
Background: Ramadan involves one month of fasting from sunrise to sunset. In this meta-analysis, we aimed to determine the effect of Ramadan fasting on weight and body composition. Methods: In May 2018, we searched six databases for publications that measured weight and body composition before and after Ramadan, and that did not attempt to influence physical activity or diet. Results: Data were collected from 70 publications (90 comparison groups, 2947 participants). There was a significant positive correlation between starting body mass index and weight lost during the fasting period. Consistently, there was a significant reduction in fat percentage between pre-Ramadan and post-Ramadan in people with overweight or obesity (−1.46 (95% confidence interval: −2.57 to −0.35) %, p = 0.010), but not in those of normal weight (−0.41 (−1.45 to 0.63) %, p = 0.436). Loss of fat-free mass was also significant between pre-Ramadan and post-Ramadan, but was about 30% less than loss of absolute fat mass. At 2–5 weeks after the end of Ramadan, there was a return towards, or to, pre-Ramadan measurements in weight and body composition. Conclusions: Even with no advice on lifestyle changes, there are consistent—albeit transient—reductions in weight and fat mass with the Ramadan fast, especially in people with overweight or obesity.
... Heterogeneity amongst included studies was quantitatively assessed using the I 2 and tau 2 (T 2 ) statistics. Given that using the I 2 statistic is not precise, an uncertainty interval (UI) was also given (22,23). ...
Background:
The clinical effectiveness of cardiac rehabilitation (CR) on health-related quality of life (HRQOL) is an area that has not been consistently explored. The objective of this systematic review was to evaluate the effectiveness of providing any core component of CR on HRQOL domains.
Methods:
We performed a meta-analysis and meta-regression of randomized controlled trials (RCTs) on the core components of CR. RCTs included adult patients with diagnosed coronary artery disease via angiography, myocardial infarction, angina, or who had undergone coronary revascularization. The Cochrane Library, MEDLINE, EMBASE, CINAHL, SCI-EXPANDED, Psych INFO, and Web of Science were searched from inception to April 27, 2017. Outcomes included overall, physical, emotional, and social HRQOL. Outcomes were reported as standardized mean change (SMC) with 95% confidence intervals (CIs). Effect size changes of 0.2, 0.5, and 0.8 SD units reflect a small, moderate, and large effect, respectively.
Results:
Forty-nine reports of 41 RCTs with 11,747 patients were included. Summary effect sizes were: overall HRQOL SMC, 0.28 (95% CI, 0.05-0.50), physical HRQOL SMC, 0.47 (95% CI, 0.13-0.81), emotional HRQOL SMC, 0.37 (95% CI, -0.02 to 0.77), and social HRQOL SMC, 0.13 (95% CI, -0.06 to 0.32). Meta-regression revealed type of CR intervention and year of publication as positive statistically significant treatment effect modifiers.
Conclusions:
Receiving CR was shown to improve HRQOL, with exercise-, nonexercise-, and psychological-based interventions playing a vital role. Although these improvements in HRQOL were modest they still reflect an incremental benefit compared with receiving usual care.
... Categories with non-overlapping 95% confidence intervals were considered to have significantly different PADR incidence rates. Subgroup heterogeneity was evaluated using the I 2 statistic [23]. The "prospective methods" category was considered by the research team to most closely estimate the true incidence of PADRs in the population as it is known to be the most sensitive event detection method [18][19][20]. ...
Background
Preventable adverse drug reactions (PADRs) in inpatients are associated with harm, including increased length of stay and potential loss of life, and result in elevated costs of care. We conducted an overview of reviews (i.e., a systematic review of systematic reviews) to determine the incidence of PADRs experienced by inpatients. Secondary review objectives were related to assessment of the effects of patient age, setting, and clinical specialty on PADR incidence.
Methods
The protocol was registered in PROSPERO (CRD42016043220). We performed a search of Medline, Embase, and the Cochrane Library, limiting languages of publication to English and French. We included published systematic reviews that reported quantitative data on the incidence of PADRs in patients receiving acute or ambulatory care in a hospital setting. The full texts of all primary studies for which PADR data were reported in the included reviews were obtained and data relevant to review objectives were extracted. Quality of the included reviews was assessed using the AMSTAR-2 tool. Both narrative summaries of findings and meta-analyses of primary study data were undertaken.
Results
Thirteen systematic reviews encompassing 37 unique primary studies were included. Across primary studies, the PADR incidence was highly varied, ranging from 0.006 to 13.3 PADRs per 100 patients, with a pooled incidence estimate of 0.59 PADRs per 100 patients. Substantial heterogeneity was present across both reviews and primary studies with respect to review/study objectives, patient age, hospital setting, medical discipline, definitions and assessment tools used, event detection methods, endpoints of interest, and units of measure. Thirteen primary studies used prospective event detection methods and had a pooled PADR incidence of 3.13 (2.87–3.38) PADRs per 100 patients; however, extreme statistical heterogeneity (I² = 97%) indicated this finding should be considered with caution. Subgroup meta-analyses demonstrated that PADR incidence varied significantly with event detection method (prospective > retrospective > voluntary reporting methods), hospital setting (ICU > wards), and medical discipline (medical > surgical). High statistical heterogeneity (I² > 80%) was present across all analyses, indicating results should be interpreted with caution. Effects of patient age could not be assessed due to poor reporting of age groups used in primary studies.
Discussion
The method of event detection appeared to significantly influence PADR incidence, with prospective methods having the highest reported PADR rate. This finding is in agreement with the background literature. High methodological and statistical heterogeneity across primary studies evaluating adverse drug events reduces the validity of the overall PADR incidence derived from the meta-analyses of the pooled data. Data pooled from studies using only prospective methods of event detection should provide an overall estimate closest to the true PADR incidence; however, our estimate should be considered with caution due to the statistical heterogeneity found in this group of studies. Future studies should employ prospective methods of detection. This review demonstrates that the true overall incidence of PADRs is likely much greater than the overall pooled incidence estimate of 0.59 PADRs per 100 patients obtained when event detection method was not taken into consideration.
... The pooled prevalence of HSV-1 and HSV-2 in the Nigerian population with 95% confidence intervals (CI) was estimated using DerSimonian-Laird random-effects models provided ≥1 measure was available. This method accounts for sampling variation and heterogeneity in effect size [22]. The Freeman-Turkey double-arcsine transformation was used for variance stabilization [23]. ...
Disease outbreaks due to Salmonella spp and Shigella spp have continued to pose serious veterinary and public heath problems. Salmonella is a leading cause of food poisoning in humans, while both are responsible for various diseases of livestock resulting in high morbidity and mortality. This study was carried out to determine the prevalence of Salmonella spp and Shigella spp in free range chickens and turkeys in Nsukka area and to determine the antibiogram profile of the isolates. A total of 150 cloacae samples comprising of 100 from free range chickens and 50 from free range turkeys were collected from various farms and markets in Nsukka metropolis. The samples were subjected to pre-enrichment in buffer peptone water for 20-24 h at 37oC, then to selective enrichment in tetrathionate broth for 22 - 24 h at 37oC. Aliquots of the enrichment broth were screened on plates of Salmonella-Shigella agar and purified on plates of MacConkey agar. Presumptive Salmonella and Shigella colonies were subjected to biochemical assays. Salmonella spp and Shigella spp had a equal prevalence of 5.3%. Salmonella spp and Shigella spp were recovered from 6(6%) and 4(4%) respectively of the 100 free range chickens and 2(4%) and 4(8%) respectively of the 50 free range turkeys. The antimicrobial analyses showed that the isolates were very sensitive to ciprofloxacin (87.5%), while the highest resistance was against septrin (93.8%). This study has shown that free range chickens and turkeys in Nsukka harbor Salmonella spp and Shigella spp. Thus any plan for the control of these pathogens in poultry should not be limited to intensive reared poultry alone but should also include those reared through the free range system.
Keywords: Salmonella spp. Shigella spp, Freerange, Chickens, Turkeys, Antibiogram
... The I 2 statistic, a measure of inconsistency across study findings, was high in the water, sanitation and hygiene analysis (50). This is consistent with the substantial differences among the studies in terms of intervention type and uptake, study methods, settings, populations, pathogens present and transmission pathways dynamics. ...
Objectives:
Safe drinking water, sanitation and hygiene are protective against diarrhoeal disease; a leading cause of child mortality. The main objective was an updated assessment of the impact of unsafe water, sanitation and hygiene (WaSH) on childhood diarrhoeal disease.
Methods:
We undertook a systematic review of articles published between 1970 and February 2016. Study results were combined and analysed using meta-analysis and meta-regression.
Results:
A total of 135 studies met the inclusion criteria. Several water, sanitation and hygiene interventions were associated with lower risk of diarrhoeal morbidity. Point-of-use filter interventions with safe storage reduced diarrhoea risk by 61% (RR=0.39; 95% CI: 0.32, 0.48); piped water to premises of higher quality and continuous availability by 75% and 36% (RR=0.25 (0.09, 0.67) and 0.64 (0.42, 0.98)), respectively compared to a baseline of unimproved drinking water; sanitation interventions by 25% (RR=0.75 (0.63, 0.88)) with evidence for greater reductions when high sanitation coverage is reached; and interventions promoting handwashing with soap by 30% (RR=0.70 (0.64, 0.77)) versus no intervention. Results of the analysis of sanitation and hygiene interventions are sensitive to certain differences in study methods and conditions. Correcting for non-blinding would reduce the associations with diarrhoea to some extent.
Conclusions:
Though evidence is limited, results suggest that household connections of water supply and higher levels of community coverage for sanitation appear particularly impactful which is in line with targets of the Sustainable Development Goals. This article is protected by copyright. All rights reserved.
... This value is computed within subgroups and not pooled across subgroups. Statistical heterogeneity was assessed by Cochran's Q statistic and by the I 2 statistic, which is derived from Q and describes the proportion of total variation that is due to heterogeneity beyond chance [27]. We used the Egger's regression test and funnel plots to assess publication bias. ...
Bronchopulmonary dysplasia (BPD) is the most common complication after preterm birth. Pasteurized donor human milk (DHM) has increasingly become the standard of care for very preterm infants over the use of preterm formula (PF) if the mother's own milk (MOM) is unavailable. Studies have reported beneficial effects of DHM on BPD. We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) and observational studies on the effects of DHM on BPD and other respiratory outcomes. Eighteen studies met the inclusion criteria. Meta-analysis of RCTs could not demonstrate that supplementation of MOM with DHM reduced BPD when compared to PF (three studies, risk ratio (RR) 0.89, 95% confidence interval (CI) 0.60-1.32). However, meta-analysis of observational studies showed that DHM supplementation reduced BPD (8 studies, RR 0.78, 95% CI 0.67-0.90). An exclusive human milk diet reduced the risk of BPD, compared to a diet with PF and/or bovine milk-based fortifier (three studies, RR 0.80, 95% CI 0.68-0.95). Feeding raw MOM, compared to feeding pasteurized MOM, protected against BPD (two studies, RR 0.77, 95% CI 0.62-0.96). In conclusion, our data suggest that DHM protects against BPD in very preterm infants.
... This value is computed within subgroups and not pooled across subgroups. Statistical heterogeneity was assessed by Cochran's Q statistic and by the I 2 statistic, which is derived from Q and describes the proportion of total variation that is due to heterogeneity beyond chance [26]. We used the Egger's regression test and funnel plots to assess publication bias. ...
Bronchopulmonary dysplasia (BPD) is the most common complication after preterm birth. Pasteurized donor human milk (DHM) has increasingly become the standard of care for very preterm infants over the use of preterm formula (PF) if mother's own milk (MOM) is unavailable. Studies have reported beneficial effects of DHM on BPD. We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) and observational studies on the effects of DHM on BPD and other respiratory outcomes. Eighteen studies met the inclusion criteria. Meta-analysis of RCT's could not demonstrate that supplementation of MOM with DHM reduced BPD when compared to PF (3 studies, risk ratio [RR] 0.89, 95% confidence interval [CI] 0.60-1.32). However, meta-analysis of observational studies showed that DHM supplementation reduced BPD (8 studies, RR 0.78, 95% CI 0.67-0.90). An exclusive human milk diet reduced the risk of BPD, compared to a diet with PF and/or bovine milk-based fortifier (3 studies, RR 0.80, 95% CI 0.68-0.95). Feeding raw MOM, compared to feeding pasteurized MOM, protected against BPD (2 studies, RR 0.77, 95% CI 0.62-0.96). In conclusion, our data suggest that DHM protects against BPD in very preterm infants, but pasteurization of human milk reduces the benefit.
Objective
Dramatic changes in state-level cannabis laws (CL) over the past 25 years have shifted societal beliefs throughout the US with unknown implications for youth. In the present study we conducted an updated systematic review and meta-analysis examining estimated effects of medical CL (MCL) and recreational CL (RCL) on past-month cannabis use among US youth.
Method
A systematic review was conducted following PRISMA guidelines followed by a subsequent meta-analysis investigating the associations between state-level cannabis laws (i.e., MCL vs. non-MCL, and RCL vs non-RCL) and past-month cannabis use prevalence among US adolescents and young adults. Supplemental analyses examined age-group effects and design-related factors.
Results
Our search identified 4604 citations, 34 and 30 of which were included in qualitative and quantitative analyses, respectively. Meta-analysis of MCL studies identified no significant association between MCL and change in past-month youth cannabis use (OR 0.981 [95% C.I. 0.960, 1.003]). Meta-analysis of RCL studies showed significantly increased odds of past-month cannabis use (OR 1.134 [95% C.I. 1.116-1.153]). Meta-analysis of more recent studies however showed a significantly increased odds of past-month cannabis use both amongst adolescents and young adults (OR 1.089[95% CI 1.015,1.169], and OR 1.221[95% CI 1.188,1.255], respectively).
Conclusion
Cannabis legalization has complex and heterogenous effects on youth use that may differ across law types. Our meta-analytic results showed modest positive effects of RCL on past-month cannabis use (more so in young adults than in adolescents) and minimal effects of MCL on these outcomes in US youth. Given the shift towards recreational legalization, additional focus on RCL effects is warranted.
Background
To investigate the individual profile of each SGLT2 (sodium‐glucose cotransoporter‐2) inhibitor in patients with different backgrounds.
Methods and Results
This study included 21 placebo‐controlled randomized controlled trials with a total of 96 196 participants, investigating empagliflozin, ertugliflozin, dapagliflozin, canagliflozin, and sotagliflozin. The primary efficacy end point was the composite of cardiovascular death and hospitalizations for heart failure. The secondary efficacy end points were all‐cause death, cardiovascular death, hospitalizations for heart failure, kidney disease progression, and acute kidney injury. We conducted subgroup analyses based on the underlying comorbidities, including diabetes and chronic kidney disease. Safety end points were also assessed among SGLT2 inhibitors in the overall cohort. In the overall cohort, there were no significant differences in the primary efficacy outcome among the SGLT2 inhibitors, while empagliflozin (hazard ratio [HR], 0.70 [95% CI, 0.53–0.92]) and dapagliflozin (HR, 0.73 [95% CI, 0.56–0.96]) were associated with lower risk of acute kidney injury than sotagliflozin. The presence or absence of diabetes did not alter the results. In patients with chronic kidney disease, there were no differences in the efficacy outcomes among SGLT2 inhibitors, while in patients without chronic kidney disease, empagliflozin was associated with lower risk of the primary outcome compared with ertugliflozin (HR, 0.77 [95% CI, 0.60–0.98]). For safety outcomes, no significant differences were observed in amputation, urinary tract infection, genital infection, hypoglycemia, and diabetic ketoacidosis.
Conclusions
The differences in reducing cardiovascular and kidney outcomes as well as safety profiles across SGLT2 inhibitors were not consistently significant, although empagliflozin might be preferred in patients without chronic kidney disease. Further investigations are needed to better understand the mechanism and clinical effectiveness of each SGLT2 inhibitor in certain populations.
Is there a statistical difference between Naive Bayes and Random Forest in terms of recall, f-measure, and precision for predicting software defects? By utilizing systematic literature review and meta-analysis, we are answering this question. We conducted a systematic literature review by establishing criteria to search and choose papers, resulting in five studies. After that, using the meta-data and forest-plots of five chosen papers, we conducted a meta-analysis to compare the two models. The results have shown that there is no significant statistical evidence that Naive Bayes perform differently from Random Forest in terms of recall, f-measure, and precision.KeywordsRandom ForestNaive BayesDefect PredictionSoftware Defect PredictionMeta-analysis
Objectives
Individuals with ADHD struggle with social impairments. The present study aimed to find out the inconsistent results of theory of mind skill in individuals with ADHD.
Methods
The current meta-analysis reviewed 17 empirical studies that compared theory of mind in individuals with and without ADHD based on reading mind from the eyes test (RMET).
Results
Finding from 1620 participants with ADHD and 1249 healthy controls showed a significant impairment in theory of mind in individuals with ADHD (Hedges’ g = 0.66). Moderator analyses indicated that the impaired theory of mind was not affected by age and gender.
Conclusion
These findings describe impaired theory of mind in individuals with ADHD and provide an insight to pay attention to theory of mind in respective clinical assessments and treatments.
Background:
Precise estimates of mortality in Staphylococcus aureus bacteremia (SAB) are important to convey prognosis and guide design of interventional studies.
Objective:
We performed a systematic review and meta-analysis to estimate the all-cause mortality in SAB and to explore how it changed with time.
Data sources:
MEDLINE, Embase, and Cochrane Database of Systematic Reviews from January 1, 1991 to May 7, 2021.
Study eligibility criteria:
Human observational studies on patients with S. aureus bloodstream infection.
Participants:
Patients with a positive blood culture for S. aureus.
Methods:
Two independent reviewers extracted study data and assessed risk of bias using the Newcastle Ottawa Scale. A generalized linear mixed random effects model was used to pool estimates.
Results:
A total of 341 studies were included, which described 536,791 patients. From 2011 onwards, the estimated mortality was 10.4% (95% confidence interval (CI) 9.0%-12.1%) at 7 days, 13.3% (95% CI 11.1%-15.8%) at 2 weeks, 18.1% (95% CI 16.3%-20.0%) at 1 month, 27.0% (95% CI 21.5%-33.3%) at 3 months, and 30.2% (95% CI 22.4%-39.3%) at 1 year. In a meta-regression model of 1-month mortality, methicillin-resistant S. aureus (MRSA) had a higher mortality (adjusted odds ratio (aOR) 1.04 95% CI 1.02-1.06 per 10% increase in MRSA proportion), and compared to prior to 2001, more recent time periods had lower mortality (aORs 0.88 [95% CI 0.75-1.03] for 2001 to 2010; 0.82 [95% CI 0.69-0.97] for 2011 onwards).
Conclusions:
SAB mortality has decreased over the last 3 decades. However, more than 1 in 4 patients will die within 3 months and continuous improvement in care remains necessary.
Registration:
PROSPERO CRD42021253891.
Energy Consumption poses a major constraint in the battery lifetime of mobile devices, data centers and their power-hungry servers. Understanding the difference in energy consumption induced by different implementations of software and systems can equip the engineers with the necessary knowledge to make better design choices early on. Our goal is to study the impact of programming languages on energy consumption. This paper is twofold: a Rapid Review to investigate the available literature and a meta-analysis comparing Python and Java in terms of energy consumption. The review yielded 17 relevant studies and showed that Java, C, C++ are the most-widely studied languages. The meta-analysis of five eligible papers showed a non-significant difference in energy between Python and Java. We anticipate more research in this area to extend our work.
Atypical motor coordination and cognitive processes, such as response inhibition and working memory, have been extensively researched in individuals with attention deficit hyperactivity disorder (ADHD). Oculomotor neural circuits overlap extensively with regions involved in motor planning and cognition, therefore studies of oculomotor function may offer unique insights into motor and cognitive control in ADHD. We performed a series of pairwise meta-analyses based on data from 26 oculomotor studies in ADHD to examine whether there were differences in performance on visually-guided saccade, gap, antisaccade, memory-guided, pursuit eye movements and fixation tasks. These analyses revealed oculomotor disturbances in ADHD, particularly for difficulties relating to saccade inhibition, memorizing visual target locations and initiating antisaccades. There was no evidence for pursuit eye movement disturbances or saccade dysmetria. Investigating oculomotor abnormalities in ADHD may provide insight into top-down cognitive control processes and motor control, and may serve as a promising biomarker in ADHD research and clinical practice.
Complementary and alternative medicine (CAM) encompasses a wide range of different non-mainstream therapies that have been increasingly used for treatment or adjunctive treatment of various ailments with mood disorders and “depressive difficulties” being two of the commonly CAM (self-)medicated conditions. We focus specifically on clinically diagnosed (in line with the standard criteria) depressive disorders, primarily major depressive disorder (MDD), and overview evidence of efficacy/safety of a range of CAM modalities addressing exclusively randomized controlled trials (RCTs) and systematic reviews/meta-analyses of RCTs. The list of addressed CAM interventions is not exhaustive: due to space limitation, addressed are interventions with at least a few conducted RCTs in the specific clinical conditions. We try to provide numerical and meaningful data as much as it is possible and to (a) indicate situations in which the reported data/estimates might have been “too enthusiastic” and (b) warn about heterogeneity of results that, together with other possible limitations (various biases and imprecision), results in uncertainty about the effects.
Background
Therapeutic hypothermia (TH) is a well-established neuroprotective therapy applied in (near) term asphyxiated infants. However, little is known regarding the effects of TH on renal and/or myocardial function.
Objectives
To describe the short- and long-term effects of TH on renal and myocardial function in asphyxiated (near) term neonates.
Methods
An electronic search strategy incorporating MeSH terms and keywords was performed in October 2019 and updated in June 2020 using PubMed and Cochrane databases. Inclusion criteria consisted of a RCT or observational cohort design, intervention with TH in a setting of perinatal asphyxia and available long-term results on renal and myocardial function. We performed a meta-analysis and heterogeneity and sensitivity analyses using a random effects model. Subgroup analysis was performed on the method of cooling.
Results
Of the 107 studies identified on renal function, 9 were included. None of the studies investigated the effects of TH on long-term renal function after perinatal asphyxia. The nine included studies described the effect of TH on the incidence of acute kidney injury (AKI) after perinatal asphyxia. Meta-analysis showed a significant difference between the incidence of AKI in neonates treated with TH compared to the control group (RR = 0.81; 95% CI 0.67–0.98; p = 0.03). No studies were found investigating the long-term effects of TH on myocardial function after neonatal asphyxia. Possible short-term beneficial effects were presented in 4 out of 5 identified studies, as observed by significant reductions in cardiac biomarkers and less findings of myocardial dysfunction on ECG and cardiac ultrasound.
Conclusions
TH in asphyxiated neonates reduces the incidence of AKI, an important risk factor for chronic kidney damage, and thus is potentially renoprotective. No studies were found on the long-term effects of TH on myocardial function. Short-term outcome studies suggest a cardioprotective effect.
The aim of this meta-analysis was to assess the effects of a lifestyle intervention through health education on nutrition, physical activity, and healthy habits on physical and mental health-related quality of life (HRQoL), in adults with metabolic syndrome (MetS). The databases used were PubMed, WOS, and Scopus. The inclusion criteria were: observational, longitudinal and randomized clinical trial (RCT) study designs, adults (both sexes), with at least two criteria of MetS, lifestyle intervention and comparison with a control group, and a measurement of HRQoL with a validated questionnaire. We analyzed the Hedges’ g and SF-36 score. I2 statistics were calculated and possible publication and small study biases were assessed using Egger’s test and funnel plots. Seven RCTs were selected for meta-analysis, based on 637 study participants. Significant improvements were found in the physical dimensions of the HRQoL scores for subjects in the active intervention compared to the group that received general lifestyle information (Hedges’ g 0.61, 95% confidence interval (CI) = 0.31–0.91). Mental health-related quality of life was also significantly improved in the intervention group compared with the control group (Hedges’ g 0.84, 95% CI = 0.64–1.03). In conclusion, our results suggest that, according to the RCTs selected for this meta-analysis, a lifestyle intervention significantly improves HRQoL in all its domains.
Background: The past 30 years have witnessed growing scientific interest regarding theimpact of mindfulness-based interventions (MBIs) on cognitive functions. Several theories propose that habitually exercising mindfulness skills can improve cognitive abilities, but no comprehensive quantitative reviews of the effect of MBIs on global and unique cognitive domains exist to date. Method: This systematic review thus examined the effects of MBI on global cognition and 16 specific accuracy and latency cognitive domains. MBI randomized controlled trials (RCTs) that administered performance-based and subjective cognitive tests pre- and post-treatment were included. Open-trials, non-randomized MBIs, and cross-sectional studies were excluded. Keywords included “mindful*,” AND “alerting” OR “executive attention,” “working memory (WM),” “inhibition,” OR “attentional control.” Robust variance estimation and moderator analyses were conducted. All analyses controlled for presence of reported treatment fidelity. Results: One-hundred RCTs (n = 7,342) met eligibility criteria. MBI had small-to-moderate significant effects on global cognition, executive attention, WM accuracy, inhibition accuracy, shifting accuracy, sustained attention, and subjective attentional control (average g = 0.228–0.675 compared to waitlist or no-treatment; average g = 0.192–0.370 versus active controls). Age, gender, study quality, treatment length, completer analysis, and MBI characteristics moderated a few treatment effects. Treatment effects were stronger for standard mindfulness-based stress reduction and mindfulness-based cognitive therapy (vs. non-standard MBI) and instructor-led (vs. self-guided app) MBIs, as well as participants with heightened psychiatric or medical symptoms compared to healthy controls. Conclusion: MBIs confer notable neuropsychological benefits on some, but not all cognitive domains. Limitations, theoretical, and applied implications are discussed.
Importance
Bronchopulmonary dysplasia (BPD), a chronic lung disease of prematurity, remains one of the major and most common complications of very preterm birth. Insight into factors associated with the pathogenesis of BPD is key to improving its prevention and treatment.
Objective
To perform a systematic review, meta-analysis, and metaregression of clinical studies exploring the association between chorioamnionitis (CA) and BPD in preterm infants.
Data Sources
PubMed and Embase were searched without language restriction (last search, October 1, 2018). Key search terms included bronchopulmonary dysplasia, chorioamnionitis, and risk factors.
Study Selection
Included studies were peer-reviewed studies examining preterm (<37 weeks’ gestation) or very low-birth-weight (<1500 g) infants and reporting primary data that could be used to measure the association between exposure to CA and the development of BPD.
Data Extraction and Synthesis
The Meta-analysis of Observational Studies in Epidemiology (MOOSE) guideline was followed. Data were independently extracted by 2 researchers. A random-effects model was used to calculate odds ratios (ORs) and 95% CIs. Heterogeneity in effect size across studies was studied using multivariate, random-effects metaregression analysis.
Main Outcomes and Measures
The primary outcome was BPD, defined as supplemental oxygen requirement on postnatal day 28 (BPD28) or at the postmenstrual age of 36 weeks (BPD36). Covariates considered as potential confounders included differences between CA-exposed and CA-unexposed infants in gestational age, rates of respiratory distress syndrome (RDS), exposure to antenatal corticosteroids, and rates of early- and late-onset sepsis.
Results
A total of 3170 potentially relevant studies were found, of which 158 met the inclusion criteria (244 096 preterm infants, 20 971 CA cases, and 24 335 BPD cases). Meta-analysis showed that CA exposure was significantly associated with BPD28 (65 studies; OR, 2.32; 95% CI, 1.88-2.86; P < .001; heterogeneity: I² = 84%; P < .001) and BPD36 (108 studies; OR, 1.29; 95% CI, 1.17-1.42; P < .001; heterogeneity: I² = 63%; P < .001). The association between CA and BPD remained significant for both clinical and histologic CA. In addition, significant differences were found between CA-exposed and CA-unexposed infants in gestational age, birth weight, odds of being small for gestational age, exposure to antenatal corticosteroids, and early- and late-onset sepsis. Chorioamnionitis was not significantly associated with RDS (48 studies; OR, 1.10; 95% CI, 0.92-1.34; P = .24; heterogeneity: I² = 90%; P < .001), but multivariate metaregression analysis with backward elimination revealed that a model combining the difference in gestational age and the odds of RDS was associated with 64% of the variance in the association between CA and BPD36 across studies.
Conclusions and Relevance
The results of this study confirm that among preterm infants, exposure to CA is associated with a higher risk of developing BPD, but this association may be modulated by gestational age and risk of RDS.
Objectives:
The impact on diarrhoea of sanitation interventions has been heterogeneous. We hypothesize that this is due to the level of prevailing faecal environmental contamination and propose a Faecal Contamination Index (FAECI) of selected WASH indicators (objective 1). Additionally, we provide estimates of the proportion of the population living in communities above certain sanitation coverage levels (objective 2).
Methods:
Objective 1: Faecal contamination post-intervention was estimated from WASH intervention reports. WASH indicators composing the FAECI included eight water, sanitation and hygiene practice indicators, which were selected for their relevance for health and data availability at study- and country-level. The association between the estimated level of faecal environmental contamination and diarrhoea was examined using meta-regression. Objective 2: A literature search was conducted to identify health-relevant community sanitation coverage thresholds. To estimate total community coverage with basic sanitation in low- and middle-income countries, at relevant thresholds, household surveys with data available at primary sampling unit (PSU)-level were analysed according to the identified thresholds, at country-, regional- and overall level.
Results:
Objective 1: We found a non-linear association between estimated environmental faecal contamination and sanitation interventions' impact on diarrhoeal disease. Diarrhoea reductions were highest at lower faecal contamination levels, and no diarrhoea reduction was found when contamination increased above a certain level. Objective 2: Around 45% of the population lives in communities with more than 75% of coverage with basic sanitation and 24% of the population lives in communities above 95% coverage, respectively.
Conclusions:
High prevailing faecal contamination might explain interventions' poor effectiveness in reducing diarrhoea. The here proposed Faecal Contamination Index is a first attempt to estimate the level of faecal contamination in communities. Much of the world's population currently lives in faecally contaminated environments as indicated by low community sanitation coverage.
The present meta-analysis was conducted to examine how shared book reading affects the English language and literacy skills of young children learning English as a second language. The final analysis included 54 studies of shared reading conducted in the United States. Features of the intervention and child characteristics were tested as potential moderators, and the impact of methodological criteria was examined using sensitivity analyses. Results revealed an overall significant, positive effect of shared reading on English learners’ outcomes. Children’s developmental status moderated this effect, with larger effect sizes found in studies including only typically developing participants than in studies including only participants with developmental disorders. No other significant moderators were identified. The main positive effect was robust to the application of more stringent methodological inclusion criteria. These results support shared book reading as an early educational activity for young English learners.
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