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Andrew Winnard has been leading systematic review methods for space medicine projects many years to facilitate high quality and transparent synthesis of primary data to enable evidence-based practice. You can find the most up to date methods here: https://sites.google.com/view/sr-methods/home This paper outlines evolution of space medicine synthesis methods and discussion of their initial application. Space medicine systematic review guidance has been developed for protocol planning, quantitative and qualitative synthesis, sourcing grey data, and assessing quality and transferability of space medicine human spaceflight simulation study environments. Decision algorithms for guidance and tool usage were created based on usage. Six reviews used quantitative methods in which no meta analyses were possible due to lack of controlled trials or reporting issues. All reviews scored the quality and transferability of space simulation environments. One review was qualitative. Several research gaps were identified. Successful use of the developed methods demonstrates usability and initial validity. The current space medicine evidence base resulting in no meta analyses to be possible shows the need for standardized guidance on how to synthesize data in this field. It also provides evidence to call for increasing use of controlled trials, standardizing outcome measures and improving minimum reporting standards. Space medicine is a unique field of medical research that requires specific systematic review methods.
To read the full-text of this research, you can request a copy directly from the authors.
... Thematic analysis (Braun and Clarke, 2006;Braun et al., 2019) and thematic synthesis (Thomas and Harden, 2008) following the qualitative systematic review methods guide by Winnard et al. (2021) were used. Thematic analysis is split into 6 stages: The first stage involved reading all the included papers to identify relevant concepts and themes. ...
Background: The recent discovery of a venous thrombosis in the internal jugular vein of an astronaut has highlighted the need to predict the risk of venous thromboembolism in otherwise healthy individuals (VTE) in space. Virchow’s triad defines the three classic risk factors for VTE: blood stasis, hypercoagulability, and endothelial disruption/dysfunction. Among these risk factors, venous endothelial disruption/dysfunction remains incompletely understood, making it difficult to accurately predict risk, set up relevant prophylactic measures and initiate timely treatment of VTE, especially in an extreme environment.
Methods: A qualitative systematic review focused on endothelial disruption/dysfunction was conducted following the guidelines produced by the Space Biomedicine Systematic Review Group, which are based on Cochrane review guidelines. We aimed to assess the venous endothelial biochemical and imaging markers that may predict increased risk of VTE during spaceflight by surveying the existing knowledge base surrounding these markers in analogous populations to astronauts on the ground.
Results: Limited imaging markers related to endothelial dysfunction that were outside the bounds of routine clinical practice were identified. While multiple potential biomarkers were identified that may provide insight into the etiology of endothelial dysfunction and its link to future VTE, insufficient prospective evidence is available to formally recommend screening potential astronauts or healthy patients with any currently available novel biomarker.
Conclusion: Our review highlights a critical knowledge gap regarding the role biomarkers of venous endothelial disruption have in predicting and identifying VTE. Future population-based prospective studies are required to link potential risk factors and biomarkers for venous endothelial dysfunction to occurrence of VTE.
Detrimental health effects from ionizing radiation to living organisms is one of the key concerns identified and addressed by Radiation Protection institutions, nationally and internationally on Earth and for human spaceflight. Thus, new methods for mitigating the adverse effects of ionizing radiation are urgently needed for terrestrial health and deep space exploration. Caloric restriction and (intermittent-) fasting have been reported to elicit a variety of immediate and long-term physiological effects. The rapidly growing body of evidence of research studies investigating the effects of caloric restriction and dietary fasting points towards a multitude of benefits affecting numerous physiological systems. Therefore, a systematic review was performed to evaluate the evidence of caloric restriction and dietary fasting on the physiological response to ionising radiation in humans and animals. All experimental studies of humans, animals and eukaryotic cell lines available in PubMed, Cochrane library and specialised databases were searched comparing irradiation post-caloric restriction or fasting to a non-nutritionally restricted control group on a broad range of outcomes from molecular to clinical responses. The initial search yielded 2653 records. The final analysis included 11 studies. Most studies investigated survival rate or cancer occurrence in animals. Included studies did not reveal any benefit from pre exposure caloric restriction, except when performed with post radiation caloric restriction. However, the effects of pre-exposure fasting suggest increased resilience to ionizing radiation.
This document is intended to guide potential reviewers through the process of conducting a qualitative systematic review. You are advised to use this as a basic overview of the key steps and to supplement (not replace) gold standard qualitative systematic review methods provided by PRISMA and Cochrane. It should be noted that there are times at present when gold standard methods have been adapted for space medicine reviews and these are highlighted in this guide. Overall, this guide will help you navigate a space medicine qualitative review, while conforming as best as possible to gold standards, but without methods becoming prohibitive or unrealistic to apply to the space medicine area.
The aim is to help you understand the systematic review process, know tools that can make the process easier, understand the various types of analysis and guide when to use Cochrane or adapted methods.
Please cite this tool as: Laws, J.M., Bruce-Martin, C., Winnard, A. (2020) Qualitative Methods Guide for Space Medicine Focussed Systematic Reviews.
Background: Space Agencies are planning human missions beyond Low Earth Orbit. Consideration of how physiological system adaptation with microgravity (μG) will be managed during these mission scenarios is required. Exercise countermeasures (CM) could be used more sparingly to decrease limited resource costs, including periods of no exercise. This study provides a complete overview of the current evidence, making recommendations on the length of time humans exposed to simulated μG might safely perform no exercise considering muscles only. Methods: Electronic databases were searched for astronaut or space simulation bed rest studies, as the most valid terrestrial simulation, from start of records to July 2017. Studies were assessed with the Quality in Prognostic Studies and bed rest analog studies assessed for transferability to astronauts using the Aerospace Medicine Systematic Review Group Tool for Assessing Bed Rest Methods. Effect sizes, based on no CM groups, were used to assess muscle outcomes over time. Outcomes included were contractile work capacity, muscle cross sectional area, muscle activity, muscle thickness, muscle volume, maximal voluntary contraction force during one repetition maximum, peak power, performance based outcomes, power, and torque/strength. Results: Seventy-five bed rest μG simulation studies were included, many with high risk of confounding factors and participation bias. Most muscle outcomes deteriorated over time with no countermeasures. Moderate effects were apparent by 7–15 days and large by 28–56 days. Moderate effects (>0.6) became apparent in the following order, power and MVC during one repetition maximum (7 days), followed by volume, cross sectional area, torques and strengths, contractile work capacity, thickness and endurance (14 days), then muscle activity (15 days). Large effects (>1.2) became apparent in the following order, volume, cross sectional area (28 days) torques and strengths, thickness (35 days) and peak power (56 days). Conclusions: Moderate effects on a range of muscle parameters may occur within 7–14 days of unloading, with large effects within 35 days. Combined with muscle performance requirements for mission tasks, these data, may support the design of CM programmes to maximize efficiency without compromising crew safety and mission success when incorporated with data from additional physiological systems that also need consideration.
Musculoskeletal loss in actual or simulated microgravity occurs at a high rate. Bed rest studies are a reliable ground-based spaceflight analogue that allow for direct comparison of intervention and control participants. The aim of this review was to investigate the impact of exercise compared to no intervention on bone mineral density (BMD) and muscle cross-sectional area (muscle CSA) in bed rest studies relative to other terrestrial models. Eligible bed rest studies with healthy participants had an intervention arm with an exercise countermeasure and a control arm. A search strategy was implemented for MEDLINE. After screening, eight studies were identified for inclusion. Interventions included resistive exercise (RE), resistive vibration exercise (RVE), flywheel resistive exercise, treadmill exercise with lower body negative pressure (LBNP) and a zero-gravity locomotion simulator (ZLS). Lower limb skeletal sites had the most significant BMD losses, particularly at the hip which reduced in density by 4.59% (p < 0.05) and the tibial epiphysis by 6% (p < 0.05). Exercise attenuated bone loss at the hip and distal tibia compared to controls (p < 0.05). Muscle CSA changes indicated that the calf and quadriceps were most affected by bed rest. Exercise interventions significantly attenuated loss of muscle mass. ZLS, LBNP treadmill and RE significantly attenuated bone and muscle loss at the hip compared to baseline and controls. Despite exercise intervention, high rates of bone loss were still observed. Future studies should consider adding bisphosphonates and pharmacological/nutrition-based interventions for consideration of longer-duration missions. These findings correlate to terrestrial bed rest settings, for example, stroke or spinal-injury patients.
This tool is concerned with quantifying the methodological quality of different partial gravity simulation models. The underlying assumption of this tool is how well the simulation study reflects the reality. This can provide an indicative rating of how well the simulation study results are transferable to real human partial gravity missions. The methods were rated as per how accurate they might mimic the effects of partial gravity for relevant physiological and biomechanical categories. The ratings are based on the advantages and limitations of partial gravity simulation models and were performed in agreement with physiological and biomechanical experts from ESA’s Space Medicine Office and from the German Sport University.
Systematic reviews should build on a protocol that describes the rationale, hypothesis, and planned methods of the review; few reviews report whether a protocol exists. Detailed, well-described protocols can facilitate the understanding and appraisal of the review methods, as well as the detection of modifications to methods and selective reporting in completed reviews. We describe the development of a reporting guideline, the Preferred Reporting Items for Systematic reviews and Meta-Analyses for Protocols 2015 (PRISMA-P 2015). PRISMA-P consists of a 17-item checklist intended to facilitate the preparation and reporting of a robust protocol for the systematic review. Funders and those commissioning reviews might consider mandating the use of the checklist to facilitate the submission of relevant protocol information in funding applications. Similarly, peer reviewers and editors can use the guidance to gauge the completeness and transparency of a systematic review protocol submitted for publication in a journal or other medium.
Effect sizes are the most important outcome of empirical studies. Most articles on effect sizes highlight their importance to communicate the practical significance of results. For scientists themselves, effect sizes are most useful because they facilitate cumulative science. Effect sizes can be used to determine the sample size for follow-up studies, or examining effects across studies. This article aims to provide a practical primer on how to calculate and report effect sizes for t-tests and ANOVA's such that effect sizes can be used in a-priori power analyses and meta-analyses. Whereas many articles about effect sizes focus on between-subjects designs and address within-subjects designs only briefly, I provide a detailed overview of the similarities and differences between within- and between-subjects designs. I suggest that some research questions in experimental psychology examine inherently intra-individual effects, which makes effect sizes that incorporate the correlation between measures the best summary of the results. Finally, a supplementary spreadsheet is provided to make it as easy as possible for researchers to incorporate effect size calculations into their workflow.
Previous work has identified 6 important areas to consider when evaluating validity and bias in studies of prognostic factors: participation, attrition, prognostic factor measurement, confounding measurement and account, outcome measurement, and analysis and reporting. This article describes the Quality In Prognosis Studies tool, which includes questions related to these areas that can inform judgments of risk of bias in prognostic research.A working group comprising epidemiologists, statisticians, and clinicians developed the tool as they considered prognosis studies of low back pain. Forty-three groups reviewing studies addressing prognosis in other topic areas used the tool and provided feedback. Most reviewers (74%) reported that reaching consensus on judgments was easy. Median completion time per study was 20 minutes; interrater agreement (κ statistic) reported by 9 review teams varied from 0.56 to 0.82 (median, 0.75). Some reviewers reported challenges making judgments across prompting items, which were addressed by providing comprehensive guidance and examples. The refined Quality In Prognosis Studies tool may be useful to assess the risk of bias in studies of prognostic factors.
There is no specific guidance for the reporting of Cochrane systematic reviews that do not have studies eligible for inclusion. As a result, the reporting of these so-called "empty reviews" may vary across reviews. This research explores the incidence of empty systematic reviews in The Cochrane Database of Systematic Reviews (The CDSR) and describes their current characteristics.
Empty reviews within The CDSR as of 15 August 2010 were identified, extracted, and coded for analysis. Review group, original publication year, and time since last update, as well as number of studies listed as excluded, awaiting assessment, or on-going within empty reviews were examined. 376 (8.7%) active reviews in The CDSR reported no included studies. At the time of data collection, 45 (84.9%) of the Cochrane Collaboration's 53 Review Groups sustained at least one empty review, with the number of empty reviews for each of these 45 groups ranging from 1 to 35 (2.2-26.9%). Time since original publication of empty reviews ranged from 0 to 15 years with a mean of 4.2 years (SD = 3.4). Time since last assessed as up-to-date ranged from 0 to 12 years with a mean of 2.8 years (SD = 2.2). The number of excluded studies reported in these reviews ranged from 0 to 124, with an average of 9.6 per review (SD = 14.5). Eighty-eight (23.4%) empty reviews reported no excluded studies, studies awaiting assessment, or on-going studies.
There is a substantial number of empty reviews in The CDSR, and there is some variation in the reporting and updating of empty reviews across Cochrane Review Groups. This variation warrants further analysis, and may indicate a need to develop guidance for the reporting of empty systematic reviews in The CDSR.
There is a growing recognition of the value of synthesising qualitative research in the evidence base in order to facilitate effective and appropriate health care. In response to this, methods for undertaking these syntheses are currently being developed. Thematic analysis is a method that is often used to analyse data in primary qualitative research. This paper reports on the use of this type of analysis in systematic reviews to bring together and integrate the findings of multiple qualitative studies.
We describe thematic synthesis, outline several steps for its conduct and illustrate the process and outcome of this approach using a completed review of health promotion research. Thematic synthesis has three stages: the coding of text 'line-by-line'; the development of 'descriptive themes'; and the generation of 'analytical themes'. While the development of descriptive themes remains 'close' to the primary studies, the analytical themes represent a stage of interpretation whereby the reviewers 'go beyond' the primary studies and generate new interpretive constructs, explanations or hypotheses. The use of computer software can facilitate this method of synthesis; detailed guidance is given on how this can be achieved.
We used thematic synthesis to combine the studies of children's views and identified key themes to explore in the intervention studies. Most interventions were based in school and often combined learning about health benefits with 'hands-on' experience. The studies of children's views suggested that fruit and vegetables should be treated in different ways, and that messages should not focus on health warnings. Interventions that were in line with these suggestions tended to be more effective. Thematic synthesis enabled us to stay 'close' to the results of the primary studies, synthesising them in a transparent way, and facilitating the explicit production of new concepts and hypotheses.
We compare thematic synthesis to other methods for the synthesis of qualitative research, discussing issues of context and rigour. Thematic synthesis is presented as a tried and tested method that preserves an explicit and transparent link between conclusions and the text of primary studies; as such it preserves principles that have traditionally been important to systematic reviewing.
A range of statistical synthesis methods are available, and these may be divided into three categories based on their preferability. Preferable methods are the meta-analysis methods. This chapter focuses on methods that might be considered when a meta-analysis of effect estimates is not possible due to incompletely reported data in the primary studies. These methods divide into those that are ‘acceptable’ and ‘unacceptable’. The ‘acceptable’ methods differ in the data they require, the hypotheses they address, limitations around their use, and the conclusions and recommendations that can be drawn. The ‘unacceptable’ methods in common use are described, along with the reasons for why they are problematic. Visual display and presentation of data is especially important for transparent reporting in reviews without meta-analysis, and should be considered irrespective of whether synthesis is undertaken. Tables and plots structure information to show patterns in the data and convey detailed information more efficiently than text.
This tool provides a list of potentially relevant sources to find trials, qualitative data and grey literature relevant to aerospace medicine systematic reviews. It is not an exhaustive list and review authors should beware that data may well exist with agency databases or be classified. It is advised to search all data sources you think may be relevant. Pre-scoping searches should be used to refine the final choice of data sources and your key terms. It is not expected that all sources will be relevant to all reviews and additional sources likely exist beyond this list. Note that some of the scientific journal article databases may require a paid subscription, but most universities will have an institutional subscription that you might be able to use to gain access.
Find the most up to date methods here: https://sites.google.com/view/sr-methods/home
This chapter provides authors (who already have experience of undertaking qualitative research and qualitative evidence synthesis) with additional guidance on undertaking a qualitative evidence synthesis that is subsequently integrated with an intervention review. There are two main designs for synthesizing qualitative evidence with evidence of the effects of interventions: sequential reviews; and convergent mixed-methods review. The Cochrane Qualitative and Implementation Methods Group website provides links to practical guidance and key steps for authors who are considering a qualitative evidence synthesis. The RETREAT framework outlines seven key considerations that review authors should systematically work through when planning a review. The review question is critical to development of the qualitative evidence synthesis. Question development affords a key point for integration with the intervention review. Review authors can integrate a qualitative evidence synthesis with an existing intervention review published on a similar topic, or conduct a new intervention review and qualitative evidence syntheses in parallel before integration.
The revised edition of the Handbook offers the only guide on how to conduct, report and maintain a Cochrane Review ? The second edition of The Cochrane Handbook for Systematic Reviews of Interventions contains essential guidance for preparing and maintaining Cochrane Reviews of the effects of health interventions. Designed to be an accessible resource, the Handbook will also be of interest to anyone undertaking systematic reviews of interventions outside Cochrane, and many of the principles and methods presented are appropriate for systematic reviews addressing research questions other than effects of interventions. This fully updated edition contains extensive new material on systematic review methods addressing a wide-range of topics including network meta-analysis, equity, complex interventions, narrative synthesis, and automation. Also new to this edition, integrated throughout the Handbook, is the set of standards Cochrane expects its reviews to meet. Written for review authors, editors, trainers and others with an interest in Cochrane Reviews, the second edition of The Cochrane Handbook for Systematic Reviews of Interventions continues to offer an invaluable resource for understanding the role of systematic reviews, critically appraising health research studies and conducting reviews.
The past decade has been rich with methodological advancements in systematic reviews, several of which were inspired by the literature on mixed methods research. Systematic mixed studies reviews—that is, reviews combining qualitative and quantitative evidence—are increasingly popular as they can provide a better understanding of complex phenomena and interventions. However, they raise new challenges, especially regarding how to perform critical appraisal of the included studies that vary regarding the methodologies used. To address this challenge, conceptually clarifying critical appraisal is necessary. To this end, this article provides a framework for critical appraisal in systematic mixed studies reviews. This framework is an essential first step toward providing clear guidance on how to perform critical appraisal.
We are seeing the use of qualitative research methods more regularly in health professions education as well as pharmacy education. Often, the term “thematic analysis” is used in research studies and subsequently labeled as qualitative research, but saying that one did this type of analysis does not necessarily equate with a rigorous qualitative study. This methodology review will outline how to perform rigorous thematic analyses on qualitative data to draw interpretations from the data.
Methodological Literature Review
Despite not having an analysis guidebook that fits every research situation, there are general steps that you can take to make sure that your thematic analysis is systematic and thorough. A model of qualitative data analysis can be outlined in five steps: compiling, disassembling, reassembling, interpreting, and concluding.
My Recommendations and Their Applications
Nine practical recommendations are provided to help researchers implement rigorous thematic analyses.
As researchers become comfortable in properly using qualitative research methods, the standards for publication will be elevated. By using these rigorous standards for thematic analysis and making them explicitly known in your data process, your findings will be more valuable.
No studies have been published on an astronaut population to assess the effectiveness of countermeasures for limiting physiological changes in the lumbopelvic region caused by microgravity exposure during spaceflight. However, several studies in this area have been done using spaceflight simulation via bed-rest. The purpose of this systematic review was to evaluate the effectiveness of countermeasures designed to limit physiological changes to the lumbopelvic region caused by spaceflight simulation by means of bed-rest.
Electronic databases were searched from the start of their records to November 2014. Studies were assessed with PEDro, Cochrane Risk of Bias and a bed-rest study quality tool. Magnitude based inferences were used to assess countermeasure effectiveness.
Seven studies were included. There was a lack of consistency across studies in reporting of outcome measures. Some countermeasures were found to be successful in preventing some lumbopelvic musculoskeletal changes, but not others. For example, resistive vibration exercise prevented muscle changes, but showed the potential to worsen loss of lumbar lordosis and intervertebral disc height.
Future studies investigating countermeasures should report consistent outcomes, and also use an actual microgravity environment. Additional research with patient reported quality of life and functional outcome measures is advocated.
This article makes an argument for a ‘qualitatively driven’ approach to mixing methods. It focuses on the value of mixed-methods approaches for researching questions about social experience and lived realities. It suggests that ‘qualitative thinking’ is a useful starting point for mixing methods, but that it is ultimately more helpful to think in terms of multi-dimensional research strategies that transcend or even subvert the so-called qualitative-quantitative divide. Mixing methods helps us to think creatively and ‘outside the box’, to theorize beyond the micro-macro divide, and to enhance and extend the logic of qualitative explanation. Mixed-methods approaches raise challenges in reconciling different epistemologies and ontologies, and in integrating different forms of data and knowledge. The article argues that we should think more in terms of ‘meshing’ or ‘linking’ than ‘integrating’ data and method. It goes on to argue for the development of ‘multi-nodal’ dialogic explanations that allow the distinctiveness of different methods and approaches to be held in creative tension. The article concludes with a discussion of qualitatively derived principles for mixing methods.
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