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Smartphone-based cough detection predicts asthma control – description of a novel, scalable digital biomarker
... There are scenarios when experts or participants can provide labelled data; however, it can become labor-intensive or time-consuming to label every observation. For example, a supervised learning algorithm trained to classify human sounds can be used to automatically annotate and quantify hours of coughs [124] and instances of crying [125]. These algorithms can also be used to differentiate between clinical populations and control participants [95] to identify known clinical population subtypes [23] or classify a clinical event (such as a seizure or tremor) [126]. ...
Background: Central nervous system (CNS) disorders benefit from ongoing monitoring to assess disease progression and treatment efficacy. Mobile health (mHealth) technologies offer a means for the remote and continuous symptom monitoring of patients. Machine Learning (ML) techniques can process and engineer mHealth data into a precise and multidimensional biomarker of disease activity. Objective: This narrative literature review aims to provide an overview of the current landscape of biomarker development using mHealth technologies and ML. Additionally, it proposes recommendations to ensure the accuracy, reliability, and interpretability of these biomarkers. Methods: This review extracted relevant publications from databases such as PubMed, IEEE, and CTTI. The ML methods employed across the selected publications were then extracted, aggregated, and reviewed. Results: This review synthesized and presented the diverse approaches of 66 publications that address creating mHealth-based biomarkers using ML. The reviewed publications provide a foundation for effective biomarker development and offer recommendations for creating representative, reproducible, and interpretable biomarkers for future clinical trials. Conclusion: mHealth-based and ML-derived biomarkers have great potential for the remote monitoring of CNS disorders. However, further research and standardization of study designs are needed to advance this field. With continued innovation, mHealth-based biomarkers hold promise for improving the monitoring of CNS disorders.
Résumé
Applications mobiles, spiromètres connectés, inhalateurs connectés, bracelets connectés, montres connectées, stéthoscopes connectés, capteurs de qualité de l’air connectés : les outils connectés sont en plein essor dans l’asthme. Ils rendent possible des systèmes de télésurveillance avancés, associant collecte continue de données depuis le domicile du patient et intervention précoce des professionnels de santé. La première partie de cette revue reprend les arguments théoriques en faveur de l’utilisation de ces outils connectés pour la télésurveillance des patients asthmatiques. Dans une seconde partie, les différents types d’outils connectés développés dans l’asthme sont détaillés et illustrés par des exemples. La troisième partie s’attache à présenter les résultats des essais randomisés ayant comparé l’utilisation de systèmes de télésurveillance intégrant des outils connectés à une prise en charge plus classique. Les limites à l’utilisation des outils connectés au sein de tels systèmes sont abordées dans la quatrième partie. Enfin, la cinquième partie présente les perspectives liées à l’utilisation d’écosystèmes numériques dans l’asthme et à la possibilité d’obtenir des systèmes de décision algorithmiques autonomes pour l’adaptation des prises en charge des patients.
Introduction:
The nature of nocturnal cough is largely unknown. It might be a valid marker for asthma control but very few studies characterized it as a basis for better defining its role and its use as clinical marker. This study investigated prevalence and characteristics of nocturnal cough in asthmatics over the course of four weeks.
Methods:
In two centers, 94 adult patients with physician-diagnosed asthma were recruited. Patient-reported outcomes and nocturnal sensor data were collected by a smartphone with a chat-based study app.
Results:
Patients coughed in 53% of 2212 nights (range: 0-345 coughs/night). Median coughs per hour were 0 (IQR 0-1). Nocturnal cough rates showed considerable inter-individual variance. The highest counts were measured in the first 30 min in bed (4.5-fold higher than rest of night). Eighty-six percent of coughs were part of a cough cluster. Clusters consisted of a median of two coughs (IQR 2-4). Nocturnal cough was persistent within patient.
Conclusion:
To the best of the authors' knowledge, this study is the first to describe prevalence and characteristics of nocturnal cough in asthma over a period of one month, demonstrating that it was a prevalent symptom with large variance between patients and high persistence within patients. Cough events in asthmatics were 4.5 times more frequent within the first 30 min in bed indicating a potential role of positional change, and not more frequent during the early morning hours. An important next step will investigate the association between nocturnal cough and asthma control.
Background: Asthma is one of the most prevalent chronic respiratory diseases. Despite increased investment in treatment, little
progress has been made in the early recognition and treatment of asthma exacerbations over the last decade. Nocturnal cough
monitoring may provide an opportunity to identify patients at risk for imminent exacerbations. Recently developed approaches
enable smartphone-based cough monitoring. These approaches, however, have not undergone longitudinal overnight testing nor
have they been specifically evaluated in the context of asthma. Also, the problem of distinguishing partner coughs from patient
coughs when two or more people are sleeping in the same room using contact-free audio recordings remains unsolved.
Objective: The objective of this study was to evaluate the automatic recognition and segmentation of nocturnal asthmatic coughs
and cough epochs in smartphone-based audio recordings that were collected in the field. We also aimed to distinguish partner
coughs from patient coughs in contact-free audio recordings by classifying coughs based on sex.
Methods: We used a convolutional neural network model that we had developed in previous work for automated cough
recognition. We further used techniques (such as ensemble learning, minibatch balancing, and thresholding) to address the
imbalance in the data set. We evaluated the classifier in a classification task and a segmentation task. The cough-recognition
classifier served as the basis for the cough-segmentation classifier from continuous audio recordings. We compared automated
cough and cough-epoch counts to human-annotated cough and cough-epoch counts. We employed Gaussian mixture models to
build a classifier for cough and cough-epoch signals based on sex.
Results: We recorded audio data from 94 adults with asthma (overall: mean 43 years; SD 16 years; female: 54/94, 57%; male
40/94, 43%). Audio data were recorded by each participant in their everyday environment using a smartphone placed next to
their bed; recordings were made over a period of 28 nights. Out of 704,697 sounds, we identified 30,304 sounds as coughs. A
total of 26,166 coughs occurred without a 2-second pause between coughs, yielding 8238 cough epochs. The ensemble classifier
performed well with a Matthews correlation coefficient of 92% in a pure classification task and achieved comparable cough
counts to that of human annotators in the segmentation of coughing. The count difference between automated and human-annotated coughs was a mean –0.1 (95% CI –12.11, 11.91) coughs. The count difference between automated and human-annotated cough
epochs was a mean 0.24 (95% CI –3.67, 4.15) cough epochs. The Gaussian mixture model cough epoch–based sex classification
performed best yielding an accuracy of 83%.
Conclusions: Our study showed longitudinal nocturnal cough and cough-epoch recognition from nightly recorded
smartphone-based audio from adults with asthma. The model distinguishes partner cough from patient cough in contact-free
recordings by identifying cough and cough-epoch signals that correspond to the sex of the patient. This research represents a step
towards enabling passive and scalable cough monitoring for adults with asthma.
Ubiquitous mobile devices have the potential to reduce the financial burden of healthcare systems by providing scalable and cost-efficient health monitoring applications. Coughing is a symptom associated with prevalent pulmonary diseases, and bears great potential for being exploited by monitoring applications. Prior research has shown the feasibility of cough detection by smartphone-based audio recordings, but it is still open as to whether current detection models generalize well to a variety of mobile devices to ensure scalability. We first conducted a lab study with 43 subjects and recorded 6737 cough samples and 8854 control sounds by 5 different recording devices. We then reimplemented two approaches from prior work and investigated their performance in two different scenarios across devices. We propose an efficient convolutional neural network architecture and an ensemble based classifier to reduce the cross-device discrepancy. Our approach produced mean accuracies in the range [85.9%, 90.9%], showing consistency across devices (SD = [1.5%, 2.7%]) and outperforming prior learning algorithms. Thus, our proposal is a step towards cost-efficient, ubiquitous, scalable and device-agnostic cough detection.
Introduction: Nocturnal cough is a burdensome asthma symptom. However, knowledge about the prevalence of nocturnal cough in asthma is limited. Furthermore, prior research has shown that nocturnal cough and impaired sleep quality are associated with asthma control, but the association between these two symptoms remains unclear. This study further investigates the potential of these symptoms as markers for asthma control and the accuracy of automated, smartphone-based passive monitoring for nocturnal cough detection and sleep quality assessment.
Methods and analysis: The study is a multicentre, longitudinal observational study with two stages. Sensor and questionnaire data of 94 individuals with asthma will be recorded for 28 nights by means of a smartphone. On the first and the last study day, a participant’s asthma will be clinically assessed, including spirometry and fractionated exhaled nitric oxide levels. Asthma control will be assessed by the Asthma Control Test and sleep quality by means of the Pittsburgh Sleep Quality Index. In addition, nocturnal coughs from smartphone microphone recordings will be labelled and counted by human annotators. Relatively unrestrictive eligibility criteria for study participation are set to support external validity of study results. Analysis of the first stage is concerned with the prevalence and trends of nocturnal cough and the accuracies of smartphone-based automated detection of nocturnal cough and sleep quality. In the second stage, patient-reported asthma control will be predicted in a mixed effects regression model with nocturnal cough frequencies and sleep quality of past nights as the main predictors.
Ethics and dissemination: The study was reviewed and approved by the ethics commission responsible for research involving humans in eastern Switzerland (BASEC ID: 2017–01872). All study data will be anonymised on study termination. Results will be published in medical and technical peer-reviewed journals.
Background:
Cough is a key symptom in patients with cystic fibrosis (CF) and primary ciliary dyskinesia (PCD).
Objective:
The study objectives were to test whether cough is related to parameters reflecting their disease severity and whether CF and PCD differ in cough frequency.
Methods:
In this prospective observational study, we used a microphone-based monitoring system (LEOSound® Monitor) to count the coughs in healthy subjects (HS) and in stable patients with CF and PCD (25 subjects per group) on 2 consecutive nights.
Results:
The median number of coughs/h in the HS, CF, and PCD groups was 0.0, 1.3, and 0.5 on the first night and 0.0, 2.3, and 0.2 on the second night, respectively. Patients with CF and PCD coughed more than HS (p < 0.001 and p = 0.009, respectively) and CF patients coughed more than PCD patients (p = 0.023). A multivariable mixed model analysis revealed forced expiratory volume in 1 s as an independent risk factor for increased cough frequency in patients. The reliability for repeated measurements was higher for cough epochs/h than for coughs/h (intraclass correlation coefficient: 0.75 and 0.49, respectively).
Conclusions:
Patients with CF cough more than patients with PCD. The cough frequency in CF and PCD is associated with parameters reflecting disease severity. Cough frequency is a possible endpoint in clinical trials and cough epochs/h may be more useful than coughs/h.
Background
The Global Burden of Diseases, Injuries, and Risk Factors Study 2017 (GBD 2017) includes a comprehensive assessment of incidence, prevalence, and years lived with disability (YLDs) for 354 causes in 195 countries and territories from 1990 to 2017. Previous GBD studies have shown how the decline of mortality rates from 1990 to 2016 has led to an increase in life expectancy, an ageing global population, and an expansion of the non-fatal burden of disease and injury. These studies have also shown how a substantial portion of the world's population experiences non-fatal health loss with considerable heterogeneity among different causes, locations, ages, and sexes. Ongoing objectives of the GBD study include increasing the level of estimation detail, improving analytical strategies, and increasing the amount of high-quality data.
Methods
We estimated incidence and prevalence for 354 diseases and injuries and 3484 sequelae. We used an updated and extensive body of literature studies, survey data, surveillance data, inpatient admission records, outpatient visit records, and health insurance claims, and additionally used results from cause of death models to inform estimates using a total of 68 781 data sources. Newly available clinical data from India, Iran, Japan, Jordan, Nepal, China, Brazil, Norway, and Italy were incorporated, as well as updated claims data from the USA and new claims data from Taiwan (province of China) and Singapore. We used DisMod-MR 2.1, a Bayesian meta-regression tool, as the main method of estimation, ensuring consistency between rates of incidence, prevalence, remission, and cause of death for each condition. YLDs were estimated as the product of a prevalence estimate and a disability weight for health states of each mutually exclusive sequela, adjusted for comorbidity. We updated the Socio-demographic Index (SDI), a summary development indicator of income per capita, years of schooling, and total fertility rate. Additionally, we calculated differences between male and female YLDs to identify divergent trends across sexes. GBD 2017 complies with the Guidelines for Accurate and Transparent Health Estimates Reporting.
Findings
Globally, for females, the causes with the greatest age-standardised prevalence were oral disorders, headache disorders, and haemoglobinopathies and haemolytic anaemias in both 1990 and 2017. For males, the causes with the greatest age-standardised prevalence were oral disorders, headache disorders, and tuberculosis including latent tuberculosis infection in both 1990 and 2017. In terms of YLDs, low back pain, headache disorders, and dietary iron deficiency were the leading Level 3 causes of YLD counts in 1990, whereas low back pain, headache disorders, and depressive disorders were the leading causes in 2017 for both sexes combined. All-cause age-standardised YLD rates decreased by 3·9% (95% uncertainty interval [UI] 3·1–4·6) from 1990 to 2017; however, the all-age YLD rate increased by 7·2% (6·0–8·4) while the total sum of global YLDs increased from 562 million (421–723) to 853 million (642–1100). The increases for males and females were similar, with increases in all-age YLD rates of 7·9% (6·6–9·2) for males and 6·5% (5·4–7·7) for females. We found significant differences between males and females in terms of age-standardised prevalence estimates for multiple causes. The causes with the greatest relative differences between sexes in 2017 included substance use disorders (3018 cases [95% UI 2782–3252] per 100 000 in males vs s1400 [1279–1524] per 100 000 in females), transport injuries (3322 [3082–3583] vs 2336 [2154–2535]), and self-harm and interpersonal violence (3265 [2943–3630] vs 5643 [5057–6302]).
Interpretation
Global all-cause age-standardised YLD rates have improved only slightly over a period spanning nearly three decades. However, the magnitude of the non-fatal disease burden has expanded globally, with increasing numbers of people who have a wide spectrum of conditions. A subset of conditions has remained globally pervasive since 1990, whereas other conditions have displayed more dynamic trends, with different ages, sexes, and geographies across the globe experiencing varying burdens and trends of health loss. This study emphasises how global improvements in premature mortality for select conditions have led to older populations with complex and potentially expensive diseases, yet also highlights global achievements in certain domains of disease and injury.
How can health systems make good use of digital medicine? For healthcare infrastructure, the answer is population measurement, monitoring people to compute status for clustering cohorts. In chronic care, most effective is measuring all the time, to track health status as it gradually changes. Passive monitors run in the background, without additional tasks to activate monitors, especially on mobile phones. At its core, a health system is a “sorting problem”. Each patient entering the system must be effectively sorted into treatment cohorts. Health systems have three primary problems: Case Finding (which persons have which diagnoses), Risk Stratification (which persons are which status), and Care Routing (which persons need which treatments). The issue is then which measures can be continuously monitored at appropriate periodicity. The solutions of population measurement measure vital signs with passive monitors. These are input to predictive analytics to detect clinical values for providing care within health systems. For chronic care, complex vitals must be measured for overall status, such as oxygen saturation or gait speed. This enables healthcare infrastructure to support stratification, with persons placed into current levels of health status. Practical considerations for health systems influence implementation of new infrastructure. Case finding is more likely to be useful in urban settings, with barriers to entry based upon lower incomes. Care routing is more likely to be useful in rural settings, with barriers to entry based upon isolated geographies. Viable healthcare at acceptable quality and affordable cost is now possible for the range of geographies and incomes.
Self-management is an established, effective approach to controlling asthma, recommended in guidelines. However, promotion, uptake and use among patients and health-care professionals remain low. Many barriers and facilitators to effective self-management have been reported, and views and beliefs of patients and health care professionals have been explored in qualitative studies. We conducted a systematic review and thematic synthesis of qualitative research into self-management in patients, carers and health care professionals regarding self-management of asthma, to identify perceived barriers and facilitators associated with reduced effectiveness of asthma self-management interventions. Electronic databases and guidelines were searched systematically for qualitative literature that explored factors relevant to facilitators and barriers to uptake, adherence, or outcomes of self-management in patients with asthma. Thematic synthesis of the 56 included studies identified 11 themes: (1) partnership between patient and health care professional; (2) issues around medication; (3) education about asthma and its management; (4) health beliefs; (5) self-management interventions; (6) co-morbidities (7) mood disorders and anxiety; (8) social support; (9) non-pharmacological methods; (10) access to healthcare; (11) professional factors. From this, perceived barriers and facilitators were identified at the level of individuals with asthma (and carers), and health-care professionals. Future work addressing the concerns and beliefs of adults, adolescents and children (and carers) with asthma, effective communication and partnership, tailored support and education (including for ethnic minorities and at risk groups), and telehealthcare may improve how self-management is recommended by professionals and used by patients. Ultimately, this may achieve better outcomes for people with asthma.
The open source platform MobileCoach (mobile-coach.eu) has been used for various behavioral health interventions in the public health context. However, so far, MobileCoach is limited to text message-based interactions. That is, participants use error-prone and laborious text-input fields and have to bear the SMS costs. Moreover, MobileCoach does not provide a dedicated chat channel for individual requests beyond the processing capabilities of its chatbot. Intervention designers are also limited to text-based self-report data. In this paper, we thus present a mobile chat app with pre-defined answer options, a dedicated chat channel for patients and health professionals and sensor data integration for the MobileCoach platform. Results of a pretest (N = 11) and preliminary findings of a randomized controlled clinical trial (N = 14) with young patients, who participate in an intervention for the treatment of obesity, are promising with respect to the utility of the chat app.
Purpose:
A large number of asthmatic patients, particularly females, present inadequate disease control. Depressive symptoms are reportedly common in asthma and have been related to poor disease control, but the mechanism of this association is still unclear. Poor quality sleep, frequently observed in asthmatics, is also a manifestation of depression and has been related to uncontrolled asthma. This study aimed to investigate the relationship between depressive symptoms, sleep quality, and asthma control.
Methods:
This was a cross-sectional study of 123 women with previous diagnosis of asthma from a reference center in Fortaleza, Brazil. Depressive symptoms were assessed by the Beck Depression Inventory (BDI); quality of sleep was evaluated by the Pittsburgh Sleep Quality Index (PSQI), daytime sleepiness by the Epworth Sleepiness Scale (ESS), and asthma control by the Asthma Control Test (ACT).
Results:
Inadequate asthma control (ACT <20) was found in 94 (76.4 %) subjects, depressive symptoms in 92 (74.8 %), poor quality sleep (PSQI >5) in 99 (80.49 %), and excessive daytime sleepiness (ESS ≥10) in 34 (27.64 %). Depressive symptoms were associated with both poor quality sleep (R = 0.326) and inadequate asthma control (R = -0.299). Regression analysis showed that depressive symptoms and sleep quality were independent predictors of the level of asthma control.
Conclusion:
Asthma control in women is independently associated with depressive symptoms and quality of sleep, suggesting that these patients might benefit from simple measures to promote healthy sleep behavior and sleep hygiene and also that routine screening for depression can be relevant, particularly, in poorly controlled cases.
Background:
Cough is recognised as an important troublesome symptom in the diagnosis and monitoring of asthma. Asthma control is thought to be determined by the degree of airway inflammation and hyper-responsiveness but how these relate to cough frequency is unclear.
Objective:
To investigate the relationships between objective cough frequency, disease control, airflow obstruction and airway inflammation in asthma.
Methods:
Participants with asthma underwent 24 hour ambulatory cough monitoring, exhaled nitric oxide, spirometry, methacholine challenge and sputum induction (cell counts and inflammatory mediator levels). Asthma control was assessed by GINA classification and the Asthma Control Questionnaire (ACQ).
Results:
Eighty-nine subjects with asthma (mean age 57 years (±SD 12); 57% female) were recruited. According to GINA criteria, 18 (20.2%) patients were classified as controlled, 39 (43.8%) partly controlled and 32 (36%) uncontrolled; median (range) ACQ score was 1 (0.0-4.4). ACQ-6 correlated with 24hr cough frequency (r=0.40; p<0.001) and patients with uncontrolled asthma (GINA) had higher median 24hr cough frequency (4.2c/h, range 0.3-27.6) compared with partially controlled and controlled asthma (1.8c/h, range 0.2-25.3 and 1.7c/h range 0.3-6.7, p=0.01 and p=0.002 respectively). Measures of airway inflammation were not significantly different between GINA categories and were not correlated with ACQ. In multivariate analyses, increasing cough frequency and worsening FEV1 independently predicted measures of asthma control.
Conclusion:
Ambulatory cough frequency monitoring provides an objective assessment of asthma symptoms that correlates with standard measures of asthma control, but not airflow obstruction or airway inflammation. Moreover, cough frequency and airflow obstruction represent independent dimensions of asthma control.
Maximum likelihood or restricted maximum likelihood (REML) estimates of the
parameters in linear mixed-effects models can be determined using the lmer
function in the lme4 package for R. As for most model-fitting functions in R,
the model is described in an lmer call by a formula, in this case including
both fixed- and random-effects terms. The formula and data together determine a
numerical representation of the model from which the profiled deviance or the
profiled REML criterion can be evaluated as a function of some of the model
parameters. The appropriate criterion is optimized, using one of the
constrained optimization functions in R, to provide the parameter estimates. We
describe the structure of the model, the steps in evaluating the profiled
deviance or REML criterion, and the structure of classes or types that
represents such a model. Sufficient detail is included to allow specialization
of these structures by users who wish to write functions to fit specialized
linear mixed models, such as models incorporating pedigrees or smoothing
splines, that are not easily expressible in the formula language used by lmer.
Chronic cough and sputum production (chronic mucus hypersecretion) is a poorly described clinical feature of asthma. Our objective was to identify clinical, immunological and computed tomography (CT) measures of airway wall dimensions associated with these symptoms in smokers and never smokers with asthma.
Cross-sectional data was analysed from 120 smokers and never smokers with asthma. Participants with and without a history of chronic mucus hypersecretion were compared for clinical outcomes, sputum differential cell counts and CT measures of airway dimensions (wall thickness, luminal area and percent wall area).
Chronic mucus hypersecretion occurred in a higher proportion of smokers with asthma (56%) than never smokers with asthma (20%), (p < 0.001) and the proportion of patients with these symptoms increased with asthma severity (p = 0.003). Smokers with asthma and chronic mucus hypersecretion had worse current clinical control than smokers without those symptoms [ACQ score 2.3 versus 1.6, p = 0.002]. A greater proportion of never smokers with chronic mucus hypersecretion required short courses of oral corticosteroids in the last year (58% versus 19%, p = 0.011). Sputum neutrophil and eosinophil counts were similar in asthma patients with or without chronic mucus hypersecretion. Of those with severe asthma and chronic mucus hypersecretion, a CT measure of airway lumen area was reduced in smokers compared to never smokers (11.4 mm(2) versus 18.4 mm(2); p = 0.017).
Chronic mucus hypersecretion occurs frequently in adults with stable asthma, particularly in smokers with severe disease and is associated with worse current clinical control in smokers and more exacerbations in never smokers.
To the Editor:
Chronic cough is a difficult clinical problem, partly because there is an absence of well-validated means to assess cough [1, 2]. We have previously reported that the semi-automated computerised Leicester Cough Monitor detects cough accurately over 6 h and that cough frequency is increased in patients with chronic cough compared to controls [3, 4]. There remains uncertainty on the performance of the system over 24 h and across the range of expected cough frequency in larger populations. We set out to address these questions in healthy adult volunteers and adult volunteers with respiratory disease.
44 healthy volunteers were recruited from those responding to a poster advertisement. All reported no current respiratory symptoms, were nonsmokers with a <5 pack-yr past smoking history and had normal spirometric values, methacholine airway responsiveness and induced sputum inflammatory cell counts. 78 patients with respiratory disease were recruited from respiratory clinics. The diagnostic criteria for the conditions have been described previously [5]. Six current smokers and four males taking angiotensin converting enzyme inhibitors (ACEi) were also recruited. The study was approved by the Leicestershire, Northampton and Rutland Research Ethics Committee.
All volunteers underwent spirometry and those with normal spirometry had a methacholine inhalation test using the tidal breathing method. The Leicester Cough Monitor (iRiver iFP-799 mp3 device; iRiver Europe GmbH, Eschborn, Germany and Sennheiser MKE 2–5 field microphone; Sennheiser electronic GmbH & Co. KG, Wedemark, Germany) was attached and recordings obtained and analysed as …
Purpose
The effect of sleep quality on asthma control independent from common comorbidities like gastroesophageal reflux disease (GERD) and obstructive sleep apnea (OSA) is unknown. This study examined the association between sleep quality and asthma control and quality of life after accounting for OSA and GERD in non-severe (NSA) and severe (SA) asthma.
Methods
Cross-sectional data from 60 normal controls, 143 with NSA, and 79 with SA participating in the Severe Asthma Research Program was examined. Those who reported using positive airway pressure therapy or were at high risk for OSA were excluded.
Results
Both SA and NSA had poorer sleep quality than controls, with SA reporting the worst sleep quality. All asthmatics with GERD and 92% of those without GERD had poor sleep quality (p = 0.02). The majority (88–100%) of NSA and SA participants who did not report nighttime asthma disturbances still reported having poor sleep quality. In both NSA and SA, poor sleep quality was associated with worse asthma control and quality of life after controlling for GERD and other covariates.
Conclusions
These results suggest that poor sleep quality is associated with poor asthma control and quality of life among asthmatics and cannot be explained by comorbid GERD and nighttime asthma disturbances.
Dyspnea is the impairing, cardinal symptom patients with asthma repeatedly experience over the course of the disease. However, its accurate perception is also crucial for timely initiation of treatment. Reduced perception of dyspnea is associated with negative treatment outcome, but the underlying brain mechanisms of perceived dyspnea in patients with asthma remain poorly understood. We examined whether increasing disease duration in fourteen patients with mild-to-moderate asthma is related to structural brain changes in the insular cortex and brainstem periaqueductal grey (PAG). In addition, the association between structural brain changes and perceived dyspnea were studied. By using magnetic resonance imaging in combination with voxel-based morphometry, gray matter volumes of the insular cortex and the PAG were analysed and correlated with asthma duration and perceived affective unpleasantness of resistive load induced dyspnea. Whereas no associations were observed for the insular cortex, longer duration of asthma was associated with increased gray matter volume in the PAG. Moreover, increased PAG gray matter volume was related to reduced ratings of dyspnea unpleasantness. Our results demonstrate that increasing disease duration is associated with increased gray matter volume in the brainstem PAG in patients with mild-to-moderate asthma. This structural brain change might contribute to the reduced perception of dyspnea in some patients with asthma and negatively impact the treatment outcome.
Defining Biomarker Performance and Clinical Validity
In the evaluation of biomarkers three questions can be answered: what is the analytical validity of the marker, what is its clinical validity, and does the marker have clinical utility? In most cases, clinical validity will be expressed in terms of the marker's accuracy: the degree to which it can be used to correctly identify diseased patients or, more generally, patients with the target condition. Diagnostic accuracy is evaluated in studies in which the biomarker values are compared to the outcome of the clinical reference standard in the same patients. There are several ways in which the results of diagnostic accuracy studies can be summarized, reported, and interpreted. In this paper we summarize and present the available measures. We classify these as error-based measures, information-based measures, and measures of the strength of the association. Clinical validity is linked to clinical utility. If the target condition is well defined and associated with unequivocal downstream management decisions, clinical validity, when defined in comparative terms, may sometimes act as a surrogate outcome measure for clinical utility.
The aims of this study were to quantify and describe the variations in respiratory symptoms and diagnosis prevalence across regions of the world according to national income. In 2002 and 2003, the World Health Organization implemented the World Health Survey (WHS), which used a standardised survey instrument to compile comprehensive baseline information on health and healthcare expenditure. We analysed the WHS data to assess the global patterns of self-reported wheeze and doctor-diagnosed asthma, two commonly reported measures of respiratory health. In total there were 308,218 participants with complete records, from 64 countries. The weighted mean age of the survey population was 43 yrs. Global prevalence of current wheezing symptoms ranged from 2.4% in Vietnam to 24% in Brazil; the prevalence of diagnosed asthma ranged from 1.8% in Vietnam to 32.8% in Australia. Overall, the prevalence of symptoms and diagnosis showed a U-shaped pattern with the largest prevalence reported in low- and high-income countries. The smallest prevalence was consistently found in middle-income countries. These WHS analyses have provided global prevalence estimates of wheeze and doctor-diagnosed asthma using data gathered simultaneously and consistently across six continents. These findings support the need for continued global respiratory illness surveillance for disease prevention, health policy and management.
Subjective and objective sleep disturbance was studied in children with nocturnal asthma. Relations between such disturbance and daytime psychological function were also explored, including possible changes in learning and behaviour associated with improvements in nocturnal asthma and sleep. Assessments included home polysomnography, parental questionnaires concerning sleep disturbance, behaviour, and mood and cognitive testing. Compared with matched controls, children with asthma had significantly more disturbed sleep, tended to have more psychological problems, and they performed less well on some tests of memory and concentration. In general, improvement of nocturnal asthma symptoms by changes in treatment was followed by improvement in sleep and psychological function in subsequent weeks. The effects of asthma on sleep and the possible psychological consequences are important aspects of overall care.
Background:
Cough is a frequent symptom of asthma. Cough frequency (CoFr) monitoring devices are now available to objectively measure cough counts and offer a novel endpoint to assess asthma. However, little is known about CoFr in asthma.
Objective:
The aims were firstly, to determine whether unique features of CoFr exist in asthmatic and non-asthmatic patients, and secondly, to evaluate relationships between CoFr and pathophysiological parameters of asthma.
Methods:
In the current study, 73 asthmatic and 63 non-asthmatic patients suffering from persistent cough were enrolled. At study entry, the Leicester Cough Questionnaire (LCQ health status), cough visual analogue scale (VAS), Leicester Cough Monitor (LCM), fractional exhaled nitric oxide (FeNO) measurements, and spirometry were performed. In asthmatic patients, bronchial hyperresponsiveness (BHR) test was conducted if applicable. In 28 asthmatic and 17 non-asthmatic patients, LCQ, VAS and LCM were examined before and after treatment.
Results:
CoFr during night-time (asleep) was significantly higher in asthmatic patients than in non-asthmatic patients. 24-hour CoFr significantly decreased after appropriate treatment and was correlated with changes in VAS and LCQ in all patients. The improvement in cough in asthmatic patients was greater during night-time than during daytime (awake). CoFr in asthmatic patients was significantly correlated with BHR, but not with FeNO.
Conclusions:
In asthmatic patients, nocturnal CoFr can be associated with BHR, was significantly higher before treatment, but improved more after treatment compared to non-asthmatic patients. Monitoring nocturnal CoFr may provide unique and valuable information on making an early prediction of therapeutic effects in asthma.
Objectives:
To compare estimates of sleep duration defined by polysomnography (PSG), actigraphy, daily diary, and retrospective questionnaire and to identify characteristics associated with differences between measures.
Design:
Cross-sectional.
Setting:
Community sample.
Participants:
The sample consisted of 223 Black, White, and Asian middle- to older-aged men and women residing in the Pittsburgh, PA area.
Interventions:
Not applicable.
Measurements:
Two nights of in-home PSG; 9 nights of wrist actigraphy and sleep diaries; retrospective sleep questionnaires; and measures of sociodemographic, psychosocial, and adiposity characteristics.
Results:
All measures of sleep duration differed significantly, with modest associations between PSG-assessed and retrospective questionnaire-assessed sleep duration. Individuals estimated their habitual sleep duration about 20-30 minutes longer by questionnaire and their prospective sleep diaries compared with both PSG- and actigraphy-assessed sleep duration. Persons reporting higher hostility had smaller associations between PSG-assessed sleep duration and other methods compared with those with lower hostility; those reporting more depressive symptoms and poorer overall health had smaller associations between actigraphy-assessed sleep duration and questionnaire and diary measures. Apnea-hypopnea index was not related to differences among estimates of sleep duration.
Conclusions:
PSG, actigraphy, diary, and retrospective questionnaire assessments yield different estimates of sleep duration. Hostility, depressive symptoms, and perceptions of poor health were associated with the magnitude of differences among some estimates. These findings may be useful in understanding the health consequences of short or long self-reported sleep duration and for guiding investigator decisions about choices of measures in specific populations.
Introduction:
Night-time respiratory symptoms have a considerable impact on sleep and life quality in patients with chronic obstructive pulmonary disease (COPD). Lack of awareness of night-time symptoms can lead to worsened COPD control. Automated long-term monitoring of respiratory symptoms with LEOSound enables assessment of nocturnal wheezing and cough.
Methods:
In this observational study we investigated the prevalence and severity of cough and wheezing in patients with stable COPD [Global Initiative for Chronic Obstructive Lung Disease (GOLD) II-IV] disease for two consecutive nights with the LEOSound system. 48 patients (30 males, 63%) were eligible for inclusion, median age was 67 years, and body mass index (BMI) was 25.3 kg/m(2).
Results:
In 15 out of 48 patients (31%), we found wheezing periods for at least 10-minute duration. Wheezing periods >30 minutes were monitored in seven patients and wheezing periods >60 minutes were monitored in three patients. The maximum duration of wheezing was 470 minutes in one patient with COPD II. The median wheezing rate differed between the COPD stages and between active and non-active smokers. Cough was found in 42 patients (87.5%) with a range of 1-326 events. The cough-period-index in night one was 0.83 n/hour (P25:0.33||P75: 2.04) and night two 0.97 n/hour (P25:0.25||P75: 1.9). Most of the cough events were non-productive with a median of 0.86.
Conclusions:
Night-time symptoms are common in COPD patients. LEOSound offers an opportunity to evaluate objectively night-time symptoms like wheezing and cough in patients with COPD which remain otherwise unnoticed. We found a high incidence of night-time wheezing in these patients, which was related to persistant smoking.
A generalized form of the cross‐validation criterion is applied to the choice and assessment of prediction using the data‐analytic concept of a prescription. The examples used to illustrate the application are drawn from the problem areas of univariate estimation, linear regression and analysis of variance.
Background:
Although a number of patients with asthma report experiencing persistent cough during sleep, it has not yet been objectively investigated.
Objective:
To classify cough severity and evaluate a characteristic pattern of cough frequency in children with asthma using an objective cough monitoring system.
Methods:
An objective cough monitoring system that specialized in children was used to measure cough frequency and nocturnal cough patterns. Coughs were recorded with microphone and accelerometer and analyzed using a customized software program. The number of nocturnal coughs and the pattern of cough frequency in 30-minute intervals were measured along with the severity of each asthma exacerbation, and the results were compared with children without asthma.
Results:
The total overnight cough count of 34 children with asthma was higher than that of 15 children without asthma (P < .001). The total overnight cough count in children with severe asthma exacerbation was higher than that in children with moderate asthma exacerbation (P < .05). The cough counts were significantly increased at the time of falling asleep and waking. This pattern was not observed in children without asthma. The total cough counts and cough patterns in children with asthma were not affected by sex, age, cause of asthma exacerbation, or therapy.
Conclusion:
Our data indicate huge cough counts and characteristic nocturnal cough patterns in children with asthma. Objective and precise cough monitoring is useful for the management of childhood asthma.
Aims:
A longitudinal birth cohort provides an opportunity to study the impact of childhood conditions persisting into adulthood. This study examines the cross-sectional association of asthma with sleep quality and snoring in the adolescent and young adult population and the extent to which asthma, sleep quality and snoring at 14 years independently predict themselves or each other at 21 years.
Methods:
Data from a 21-year follow-up of mothers and their children recruited into the Mater-University of Queensland Study of Pregnancy (n = 7223). Complete asthma and sleep information (questionnaire data) was available for 5015 participants at 14 years and 3527 at 21 years, with 3237 participants at both 14 and 21 years.
Results:
Poor sleep quality and snoring were independently associated with asthma at 14 years and 21 years, with stronger associations evident in women. At 21 years, associations were mediated by asthma symptom severity. Asthma, sleep quality and snoring at 14 years each strongly and independently predicted themselves at 21 years. Asthma at 14 years predicted snoring at 21 years, while poor sleep quality and snoring in women predicted asthma at 21 years, the latter partially mediated by body mass index.
Conclusions:
The relationship between asthma, sleep quality and snoring varied by gender. Sleep quality and snoring should be considered in the assessment and holistic management of asthma. The predictive relationship seen between 14 and 21 years provides an opportunity to address these issues at a younger age.
Introduction Development of novel treatments for cough and its management are hampered by the lack of well validated objective cough frequency methodologies. Previous validations have been performed over limited time periods or in laboratory conditions not always representative of typical usage. We describe the rigorous validation of a semi-automated 24 hour ambulatory cough monitoring system (Vitalojak; Vitalograph; Buckinghamshire, England) operating in a manner which completely replicates routine practise.
Methods In total 10 (4 female) patients (mean age 60.4 years [SD ±14.1] including 6 chronic cough, 2 asthma, 1 COPD and 1 healthy control underwent full 24 Hour ambulatory monitoring (VitaloJAK™). These recordings were manually counted by trained cough counters who also recorded the time at which each cough occurred. These 24 hour recordings were then compressed using custom designed compression software and the sensitivity to cough and the reduced file times were determined. Importantly in each case we confirmed that cough sounds identified in the compressed files were the same sounds identified by the trained manual cough counters in the full 24 hour recording. We tested the software algorithm using three distinct compression levels (1, 2 and 3).
Results All results are presented as median (IQR).
Sensitivities to cough (%) for compression levels 1, 2 and 3 are 100(100, 100), 100(99.53, 100) and 99.92(99.33, 100) and for reduced file times (minutes) 65.89 (62.40, 83.07), 43.21 (35.94, 57.23) and 26.30 (25.07,46.81) respectively (Table 1).
Conclusions The vitaloJAK™ is a reliable, robust and efficient tool for the objective measurement of cough frequency. Importantly it reduces 24 hour recordings by up to 98% whilst preserving close to 100% of recorded cough sounds. This development facilitates efficient and speedy manual cough counting and the level of compression achieved represents significant progress towards fully automated cough monitoring.
Background—Quality of life measures are increasingly important in evaluating outcomes in asthma. If some asthma symptoms are more troublesome to patients than others, this may aVect their contribution to outcome measures. This study was designed to assess the relative importance of common symptoms in adults with asthma. Methods—A postal survey using conjoint analysis was performed in 272 adults attending hospital outpatient clinics with moderately severe asthma. Patients were asked to chose between “symptom scenarios” oVering diVerent combinations of levels of five common asthma symptoms over one week. Two versions of the questionnaire were used with identical scenarios presenting symptoms in diVerent orders. DiVerent patients answered the two versions. Regression analysis was used to calculate symptom weights for daytime cough, breathlessness, wheeze and chest tightness, and sleep disturbance. Results—Symptom order, percentage predicted peak expiratory flow (PEF), and symptoms in the week before the survey did not influence the choice of scenario. In both questionnaires patients were more likely to choose scenarios with low levels of cough and breathlessness than low sleep disturbance, wheeze or chest tightness. Regression weights for cough (‐0.52) and breathlessness (‐0.49) were twice those of wheeze (‐0.25), chest tightness (‐0.27), and sleep disturbance (‐0.25). For 12% of patients cough dominated patient preferences, regardless of all other symptoms. Age was inversely related to weight given by patients to breathlessness. Conclusions—The prominence of cough among other asthma symptoms was unexpected.Daytime cough and breathlessness had greater impact for patients than wheeze or sleep disturbance. Age influenced symptom burden, with younger patients giving greater weight to breathlessness than older patients. Conjoint analysis appears to be a useful method for establishing the relative importance of common symptoms. (Thorax 2001;56:138‐142)
Considerable progress has been achieved in the development of tools that assess cough. The visual analogue scale (VAS) for cough severity is widely used in clinical practice because it's simple and practical. The Leicester cough questionnaire (LCQ) and the cough-specific quality of life questionnaire (CQLQ) are the most widely used health status questionnaires for adults with chronic cough. They are well validated for assessing the impact of cough. Cough can be assessed objectively with challenge tests that measure the sensitivity of the cough reflex. Cough challenge tests are better used to determine the mechanism of action of therapy, rather than efficacy. Cough frequency monitoring, the preferred tool to objectively assess cough, is increasingly being used as primary end-points in clinical trials. The most widely used cough monitors are the Leicester cough monitor (LCM) and VitaloJak. They are ambulatory devices that consist of a microphone and recording device. Cough frequency monitors do not reflect the intensity or the impact of cough; hence their relationship with subjective measures of cough is weak. Cough should therefore be assessed with a combination of subjective and objective tools. There is a paucity of studies that have investigated the minimal important difference of cough frequency monitors, rendering further investigations needed.
Our aim was to validate optimal action points in written action plans for early detection of asthma exacerbations.We analysed daily symptoms and morning peak-flows (PEF) from two previous studies. Potential action points were based on analysis of symptom scores (SDs) percentage of personal best PEF, or PEF variability in relation to a run-in period, or combinations of these measures. Sensitivity and specificity for predicting exacerbations were obtained for each action point. The numbers needed to treat to prevent one exacerbation and the time interval between reaching action point criteria and the start of the exacerbation were calculated. Based on these parameters, the optimal action points for symptoms, PEF, and PEF plus symptoms were determined, and their performance compared to published guidelines action points.The optimal action points were: for symptoms, statistical variability (SDs); for PEF, <70% of personal best. The combination of PEF plus symptoms performed best, with improved specificity and earlier detection. The main benefits associated with using these action points was to reduce false positive rates for detecting exacerbations.Early detection of asthma exacerbations can be improved using a composite action point comprising symptoms and PEF measurements over one week.
Estimation of mortality risk in patients hospitalized with acute decompensated heart failure (ADHF) may help clinicians guide care.
To develop a practical user-friendly bedside tool for risk stratification for patients hospitalized with ADHF.
The Acute Decompensated Heart Failure National Registry (ADHERE) of patients hospitalized with a primary diagnosis of ADHF in 263 hospitals in the United States was queried with analysis of patient data to develop a risk stratification model. The first 33,046 hospitalizations (derivation cohort; October 2001-February 2003) were analyzed to develop the model and then the validity of the model was prospectively tested using data from 32,229 subsequent hospitalizations (validation cohort; March-July 2003). Patients had a mean age of 72.5 years and 52% were female.
Variables predicting mortality in ADHF.
When the derivation and validation cohorts are combined, 37,772 (58%) of 65,275 patient-records had coronary artery disease. Of a combined cohort consisting of 52,164 patient-records, 23,910 (46%) had preserved left ventricular systolic function. In-hospital mortality was similar in the derivation (4.2%) and validation (4.0%) cohorts. Recursive partitioning of the derivation cohort for 39 variables indicated that the best single predictor for mortality was high admission levels of blood urea nitrogen (> or =43 mg/dL [15.35 mmol/L]) followed by low admission systolic blood pressure (<115 mm Hg) and then by high levels of serum creatinine (> or =2.75 mg/dL [243.1 micromol/L]). A simple risk tree identified patient groups with mortality ranging from 2.1% to 21.9%. The odds ratio for mortality between patients identified as high and low risk was 12.9 (95% confidence interval, 10.4-15.9) and similar results were seen when this risk stratification was applied prospectively to the validation cohort.
These results suggest that ADHF patients at low, intermediate, and high risk for in-hospital mortality can be easily identified using vital sign and laboratory data obtained on hospital admission. The ADHERE risk tree provides clinicians with a validated, practical bedside tool for mortality risk stratification.
Past asthma surveys have shown suboptimal management and control of asthma in the United States. No major survey of asthma management has been conducted since the Third Expert Panel Report for the National Asthma Education and Prevention Program (NAEPP) guidelines on diagnosis and treatment
of asthma (August 2007). This study was designed to report asthma management and control results from the Asthma Insight and Management survey of U.S. patients and physicians. A telephone-based survey was conducted during 2009 in 2500 patients with asthma, aged ≥12 years, and 309 physicians
(104 allergists, 54 pulmonologists, 101 family practitioners, and 50 internists). Patients' asthma control perceptions (71% “completely controlled” or “well controlled”) were inconsistent with their NAEPP control level as determined by self-reported symptoms (29% well
controlled). Patients and physicians had low expectations for effective asthma management; patients considered asthma well managed if rescue medication was used three times per week (46%), urgent care visits occurred twice per year (67%), or emergency department visits occurred once per year
(60%). Asthma-related syncope, seizure, intensive care unit admission, and intubation were associated with uncontrolled asthma based on NAEPP guidelines. Respiratory specialists (allergists/pulmonologists) implemented asthma management recommendations more than other physicians surveyed. However,
only 22% of patients visited a specialist for usual asthma care and 48% had never visited a specialist. Despite detailed NAEPP guidance, asthma management and control in U.S. patients is unsatisfactory. Improved asthma control assessment (impairment and risk) and implementation of NAEPP management
recommendations are needed to improve asthma control and outcomes.
The Asthma Control Test (ACT) has been well validated, but a minimally important difference (MID) has not been established.
We sought to identify an MID for the ACT.
Data come from 4 independent samples of adult asthmatic patients. Distributional methods for determining the MID included 0.5 SD, 1 SEM, and 2 SEM. Anchor-based methods assessed the relationship of differences in ACT scores to (1) self-reported asthma severity, (2) asthma episode frequency in the past 4 weeks, (3) physician ratings of asthma control, (4) physician recommendation of a change in therapy, (5) FEV(1), (6) the risk over the next 12 months of excess short-acting beta-agonist use and exacerbations, and (7) patient-defined changes in asthma course over 3 months.
Four thousand one hundred eighteen patients completed the ACT. The 0.5 SD criterion for MID ranged from 2.03 to 2.45 points (mean, 2.2 points). The 1 SEM criterion ranged from 1.77 to 2.05 points (mean, 1.88 points), and the 2 SEM criterion ranged from 3.55 to 4.10 points (mean, 3.75 points). Differences in mean ACT scores across patient groups differing on criterion measures ranged from 1.06 to 5.28 points (mean, 3.1 points). Predictive analyses showed that a difference of 3 points on the ACT was associated with a subsequent 76% increased risk (95% CI, 73% to 79%) of excess short-acting beta-agonist use and a 33% increased risk (95% CI, 31% to 35%) of exacerbations.
The data support an MID for the ACT of 3 points.
Cough is widely recognized as a key symptom in the diagnosis and the monitoring of asthma, but little is known about how best to assess cough in asthma.
To determine how objective cough rates correlate with subjective measures of cough in asthma.
We studied 56 subjects, median age 42.0 years (range, 28.5-71), 34 (60.7%) female, with asthma. Subjects performed cough reflex sensitivity testing (concentration of citric acid causing 2 and 5 coughs [C2 and C5]), 24-hour fully ambulatory cough recordings, subjectively scored the severity of their cough (visual analog scales and 0-5 score) and completed a cough-related quality of life questionnaire (Leicester Cough Questionnaire). Ambulatory cough recordings were manually counted and reported in cough seconds per hour (cs/h).
The median time spent coughing was 2.6 cs/h (range, 0.0-14.2), with subjects spending more time coughing by day (median, 3.9 cs/h [0.0-18.5]) than by night (median, 0.3 cs/h [0.0-8.7]; P < .001). A weak inverse relationship was seen between day cough rates and log(10)C2 (r = -0.39; P = .03) but not log(10)C5 (r = -0.08; P = .65). Objective time spent coughing was also weak-moderately associated with subjective cough scores and visual analog scales, and most strongly correlated with cough-related quality of life (r = -0.54; P < .001).
Subjective measures of cough and cough reflex sensitivity are poor surrogates for objective cough frequency in asthma. When designing studies to assess interventions for cough in asthma, we advocate a combination of both objective measures of cough and cough-related quality of life.
Statisticians most often use the linear mixed model to analyze Gaussian longitudinal data. The value and familiarity of the R(2) statistic in the linear univariate model naturally creates great interest in extending it to the linear mixed model. We define and describe how to compute a model R(2) statistic for the linear mixed model by using only a single model. The proposed R(2) statistic measures multivariate association between the repeated outcomes and the fixed effects in the linear mixed model. The R(2) statistic arises as a 1-1 function of an appropriate F statistic for testing all fixed effects (except typically the intercept) in a full model. The statistic compares the full model with a null model with all fixed effects deleted (except typically the intercept) while retaining exactly the same covariance structure. Furthermore, the R(2) statistic leads immediately to a natural definition of a partial R(2) statistic. A mixed model in which ethnicity gives a very small p-value as a longitudinal predictor of blood pressure (BP) compellingly illustrates the value of the statistic. In sharp contrast to the extreme p-value, a very small R(2) , a measure of statistical and scientific importance, indicates that ethnicity has an almost negligible association with the repeated BP outcomes for the study.
The prevalence of sleep complaints and sleep disturbances was studied prospectively in 98 consecutive adult asthmatic patients (mean age 45 years, 46% men) attending an out-patient clinic by means of questionnaires and sleep diaries. The results were compared with those from an age- and sex-matched group of 226 healthy individuals. The most common sleep disturbances among the asthmatic patients were early morning awakening (51%), difficulty in maintaining sleep (DMS; 44%) and daytime sleepiness (44%). With decreasing asthma control (i.e. increased number of acute asthmatic attacks) there was an increase of DMS, nocturnal wakefulness, nocturnal breathing problems and bronchodilator inhalations at night. A decrease in estimated sleep time (P less than 0.05) and increase in nocturnal wakefulness (P less than 0.05) was seen with decreasing daytime FEV1--measured as percentage of the predicted value (%FEV1). There was also significant correlation between increasing age and decreasing %FEV1 (P less than 0.01). Among the 26 patients who were only taking one oral bronchodilator, no definite difference regarding sleep quality was found between those treated with theophylline and those taking an oral beta 2-agonist. The prevalence rates of DIS, DMS and daytime sleepiness were about twice as high among the asthmatic patients than in the healthy population. It is concluded that impaired quality of sleep, with disturbed sleep during the night, early morning awakenings and daytime sleepiness, is common among patients with bronchial asthma.
Despite the prevalence of sleep complaints among psychiatric patients, few questionnaires have been specifically designed to measure sleep quality in clinical populations. The Pittsburgh Sleep Quality Index (PSQI) is a self-rated questionnaire which assesses sleep quality and disturbances over a 1-month time interval. Nineteen individual items generate seven "component" scores: subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbances, use of sleeping medication, and daytime dysfunction. The sum of scores for these seven components yields one global score. Clinical and clinimetric properties of the PSQI were assessed over an 18-month period with "good" sleepers (healthy subjects, n = 52) and "poor" sleepers (depressed patients, n = 54; sleep-disorder patients, n = 62). Acceptable measures of internal homogeneity, consistency (test-retest reliability), and validity were obtained. A global PSQI score greater than 5 yielded a diagnostic sensitivity of 89.6% and specificity of 86.5% (kappa = 0.75, p less than 0.001) in distinguishing good and poor sleepers. The clinimetric and clinical properties of the PSQI suggest its utility both in psychiatric clinical practice and research activities.
Diagnostic systems of several kinds are used to distinguish between two classes of events, essentially "signals" and "noise".
For them, analysis in terms of the "relative operating characteristic" of signal detection theory provides a precise and valid
measure of diagnostic accuracy. It is the only measure available that is uninfluenced by decision biases and prior probabilities,
and it places the performances of diverse systems on a common, easily interpreted scale. Representative values of this measure
are reported here for systems in medical imaging, materials testing, weather forecasting, information retrieval, polygraph
lie detection, and aptitude testing. Though the measure itself is sound, the values obtained from tests of diagnostic systems
often require qualification because the test data on which they are based are of unsure quality. A common set of problems
in testing is faced in all fields. How well these problems are handled, or can be handled in a given field, determines the
degree of confidence that can be placed in a measured value of accuracy. Some fields fare much better than others.
A questionnaire was sent to a random sample of adults in eight locations throughout Britain, to investigate the prevalence of snoring, asthma and sleep complaints in community-based British adult. Of the 1,478 respondents (831 females, 647 males; mean +/- SD age 45 +/- 18 yrs), 37% reported snoring at least occasionally, and 11% reported snoring on at least four nights per week (frequent snorers). Frequent snorers reported spending less time asleep at night, falling asleep accidentally during the day more often, taking planned daytime naps, and falling asleep whilst driving or operating machinery more often than the other respondent. Using ordinal logistic regression analysis to allow for the age and sex of the respondents, both accidental daytime sleep and planned daytime naps were commoner in frequent snorers than other respondents. Six percent of all respondents and 6% of those aged under 40 yrs reported that they had asthma (asthmatics). Seven percent of respondents aged less than 40 yrs reported wheezing on three or more occasions per year, and had been prescribed oral or inhaled bronchodilators (young wheezers). More than 80% of the asthmatic respondents of all ages, and young wheezers, reported waking at night with wheeze at least occasionally, and more than 30% of each group reported this symptom frequently. A larger proportion of asthmatics and young wheezers reported that their night-time sleep was unrefreshing, and that they had too little sleep at night than the other respondents.(ABSTRACT TRUNCATED AT 250 WORDS)
The identification, prevention, and prompt treatment of exacerbations are major objectives of asthma management. We looked at change in PEF, symptoms, and use of rescue beta-agonists during the 425 severe exacerbations that occurred during a 12-mo parallel group study (FACET) in which low and high doses of budesonide with and without formoterol were compared in patients with asthma. Oral corticosteroids were prescribed for severe exacerbations, the main study end point, defined as the need for a course of oral corticosteroids (n = 311) or a reduction in morning PEF of > 30% on two consecutive days. PEF, symptoms, and bronchodilator use over the 14 d before and after the exacerbation were obtained from diary cards. Exacerbations were characterized by a gradual fall in PEF over several days, followed by more rapid changes over 2 to 3 d; an increase in symptoms and rescue beta-agonist use occurred in parallel, and both the severity and time course of the changes were similar in all treatment groups. Exacerbations identified by the need for oral corticosteroids were associated with more symptoms and smaller changes in PEF than those identified on the basis of PEF criteria. Female sex was the main patient characteristic associated with an increased risk of having a severe exacerbation. Exacerbations may be characterized predominantly by change in symptoms or change in PEF, but the pattern was not affected by the dose of inhaled corticosteroid or by whether the patient was taking formoterol.
Asthma guidelines indicate that the goal of treatment should be optimum asthma control. In a busy clinic practice with limited time and resources, there is need for a simple method for assessing asthma control with or without lung function testing.
The objective of this article was to describe the development of the Asthma Control Test (ACT), a patient-based tool for identifying patients with poorly controlled asthma.
A 22-item survey was administered to 471 patients with asthma in the offices of asthma specialists. The specialist's rating of asthma control after spirometry was also collected. Stepwise regression methods were used to select a subset of items that showed the greatest discriminant validity in relation to the specialist's rating of asthma control. Internal consistency reliability was computed, and discriminant validity tests were conducted for ACT scale scores. The performance of ACT was investigated by using logistic regression methods and receiver operating characteristic analyses.
Five items were selected from regression analyses. The internal consistency reliability of the 5-item ACT scale was 0.84. ACT scale scores discriminated between groups of patients differing in the specialist's rating of asthma control (F = 34.5, P <.00001), the need for change in patient's therapy (F = 40.3, P <.00001), and percent predicted FEV(1) (F = 4.3, P =.0052). As a screening tool, the overall agreement between ACT and the specialist's rating ranged from 71% to 78% depending on the cut points used, and the area under the receiver operating characteristic curve was 0.77.
Results reinforce the usefulness of a brief, easy to administer, patient-based index of asthma control.
The development of the Asthma Control Test (ACT), a short, simple, patient-based tool for identifying patients with poorly controlled asthma, was recently described in patients under the routine care of an asthma specialist.
We sought to evaluate the reliability and validity of the ACT in a longitudinal study of asthmatic patients new to the care of an asthma specialist.
Patients (n=313) completed the ACT and the Asthma Control Questionnaire (ACQ) at 2 physician visits (4-12 weeks apart). Pulmonary function was measured, and asthma specialists rated asthma control.
Internal consistency reliability of the ACT was 0.85 (baseline) and 0.79 (follow-up). Test-retest reliability was 0.77. Criterion validity was demonstrated by significant correlations between baseline ACT scores and baseline specialists' ratings of asthma control (r=0.52, P<.001) and ACQ scores (r=-0.89, P<.001). Discriminant validity was demonstrated, with significant (P<.001) differences in mean ACT scores across patients differing in asthma control, pulmonary function, and treatment recommendation. Responsiveness of the ACT to changes in asthma control and lung function was demonstrated with significant correlations between changes in ACT scores and changes in specialists' ratings (r=0.44, P<.001), ACQ scores (r=-0.69, P<.001), and percent predicted FEV1 values (r=0.29, P<.001). An ACT score of 19 or less provided optimum balance of sensitivity (71%) and specificity (71%) for detecting uncontrolled asthma.
The ACT is reliable, valid, and responsive to changes in asthma control over time in patients new to the care of asthma specialists. A cutoff score of 19 or less identifies patients with poorly controlled asthma.
In a clinical setting the ACT should be a useful tool to help physicians identify patients with uncontrolled asthma and facilitate their ability to follow patients' progress with treatment.
The natural history of asthma severity is poorly known.
To investigate prognostic factors of asthma severity.
All current patients with asthma identified in 1991 to 1993 in the European Community Respiratory Health Survey were followed up, and their severity was assessed in 2002 by using the Global Initiative for Asthma categorization (n = 856). Asthma severity (remittent, intermittent, mild, moderate, severe) was related to potential determinants evaluated at baseline and during the follow-up by a multinomial logistic model, using the intermittent group as the reference category for relative risk ratios (RRRs).
Asthma severity measured at baseline was a determinant of a patient's severity at the end of the follow-up. At baseline, severe persistent had a poorer FEV1% predicted, a poorer symptom control, higher IgE levels (RRR, 2.06; 95% CI, 1.38-3.06), and a higher prevalence of chronic cough/mucus hypersecretion (RRR, 4.90; 95% CI, 2.18-11.02) than patients with intermittent asthma. Moderate persistent showed the same prognostic factors as severe persistent, even if the associations were weaker. Mild persistent had a distribution of prognostic factors that was similar to patients with intermittent asthma, although the former showed a poorer symptom control than the latter. Remission mainly occurred in patients with less severe asthma and was negatively associated with a change in body mass index (RRR, 0.86; 95% CI, 0.75-0.97). Allergic rhinitis, smoking, and respiratory infections in childhood were not associated with asthma severity.
Patients with moderate and severe persistent asthma are characterized by early deterioration of lung function. High IgE levels and persistent cough/mucus hypersecretion are strong markers of moderate/severe asthma, which seems to be a different phenotype from mild persistent or intermittent asthma.
Our results suggest that the evolution of asthma severity is to a large extent predictable.