18. Meta-analysis of Primary Data

Keyword(s):  
2019 ◽  
Vol 227 (1) ◽  
pp. 64-82 ◽  
Author(s):  
Martin Voracek ◽  
Michael Kossmeier ◽  
Ulrich S. Tran

Abstract. Which data to analyze, and how, are fundamental questions of all empirical research. As there are always numerous flexibilities in data-analytic decisions (a “garden of forking paths”), this poses perennial problems to all empirical research. Specification-curve analysis and multiverse analysis have recently been proposed as solutions to these issues. Building on the structural analogies between primary data analysis and meta-analysis, we transform and adapt these approaches to the meta-analytic level, in tandem with combinatorial meta-analysis. We explain the rationale of this idea, suggest descriptive and inferential statistical procedures, as well as graphical displays, provide code for meta-analytic practitioners to generate and use these, and present a fully worked real example from digit ratio (2D:4D) research, totaling 1,592 meta-analytic specifications. Specification-curve and multiverse meta-analysis holds promise to resolve conflicting meta-analyses, contested evidence, controversial empirical literatures, and polarized research, and to mitigate the associated detrimental effects of these phenomena on research progress.


BMJ Open ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. e040997
Author(s):  
Varo Kirthi ◽  
Paul Nderitu ◽  
Uazman Alam ◽  
Jennifer Evans ◽  
Sarah Nevitt ◽  
...  

IntroductionThere is growing evidence of a higher than expected prevalence of retinopathy in prediabetes. This paper presents the protocol of a systematic review and meta-analysis of retinopathy in prediabetes. The aim of the review is to estimate the prevalence of retinopathy in prediabetes and to summarise the current data.Methods and analysisThis protocol is developed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols (PRISMA-P) guidelines. A comprehensive electronic bibliographic search will be conducted in MEDLINE, EMBASE, Web of Science, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Google Scholar and the Cochrane Library. Eligible studies will report prevalence data for retinopathy on fundus photography in adults with prediabetes. No time restrictions will be placed on the date of publication. Screening for eligible studies and data extraction will be conducted by two reviewers independently, using predefined inclusion criteria and prepiloted data extraction forms. Disagreements between the reviewers will be resolved by discussion, and if required, a third (senior) reviewer will arbitrate.The primary outcome is the prevalence of any standard features of diabetic retinopathy (DR) on fundus photography, as per International Clinical Diabetic Retinopathy Severity Scale (ICDRSS) classification. Secondary outcomes are the prevalence of (1) any retinal microvascular abnormalities on fundus photography that are not standard features of DR as per ICDRSS classification and (2) any macular microvascular abnormalities on fundus photography, including but not limited to the presence of macular exudates, microaneurysms and haemorrhages. Risk of bias for included studies will be assessed using a validated risk of bias tool for prevalence studies. Pooled estimates for the prespecified outcomes of interest will be calculated using random effects meta-analytic techniques. Heterogeneity will be assessed using the I2 statistic.Ethics and disseminationEthical approval is not required as this is a protocol for a systematic review and no primary data are to be collected. Findings will be disseminated through peer-reviewed publications and presentations at national and international meetings including Diabetes UK, European Association for the Study of Diabetes, American Diabetes Association and International Diabetes Federation conferences.PROSPERO registration numberCRD42020184820.


2021 ◽  
pp. 1-10
Author(s):  
Angelina R. Sutin ◽  
Damaris Aschwanden ◽  
Martina Luchetti ◽  
Yannick Stephan ◽  
Antonio Terracciano

Background: A sense of purpose in life has been associated with healthier cognitive outcomes across adulthood, including risk of dementia. The robustness and replicability of this association, however, has yet to be evaluated systematically. Objective: To test whether a greater sense of purpose in life is associated with lower risk of dementia in four population-based cohorts and combined with the published literature. Methods: Random-effect meta-analysis of prospective studies (individual participant data and from the published literature identified through a systematic review) that examined sense of purpose and risk of incident dementia. Results: In six samples followed up to 17 years (four primary data and two published; total N = 53,499; n = 5,862 incident dementia), greater sense of purpose in life was associated with lower dementia risk (HR = 0.77, 95%CI = 0.73–0.81, p <  0.001). The association was generally consistent across cohorts (I2 = 47%), remained significant controlling for clinical (e.g., depression) and behavioral (e.g., physical inactivity) risk factors, and was not moderated by age, gender, or education. Conclusion: Sense of purpose is a replicable and robust predictor of lower risk of incident dementia and is a promising target of intervention for cognitive health outcomes.


BMJ Open ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. e024405 ◽  
Author(s):  
Vignan Yogendrakumar ◽  
Ronda Lun ◽  
Brian Hutton ◽  
Dean A Fergusson ◽  
Dar Dowlatshahi

IntroductionPatients with an intracerebral haemorrhage are at increased risk of venous thromboembolism. Pharmacotherapy and pneumatic compression devices are capable of preventing venous thromboembolism, however both interventions have limitations. There are no head-to-head comparisons between these two interventions. To address this knowledge gap, we plan to perform a systematic review and network meta-analysis to examine the comparative effectiveness of pharmacological prophylaxis and mechanical compression devices in the context of intracerebral haemorrhage.Methods and analysisMEDLINE, PUBMED, EMBASE, CENTRAL, ClinicalTrials.gov and the Internet Stroke Trials Registry will be searched with assistance from an experienced information specialist. Eligible studies will include those that have enrolled adults presenting with spontaneous intracerebral haemorrhage and compared one or more of the respective interventions against each other and/or a control. Primary outcomes to be assessed are occurrence of new venous thromboembolism (deep vein thrombosis and/or pulmonary embolism) and haematoma expansion, defined as a significant enlargement of baseline haemorrhage or new haemorrhage occurrence. Both randomised and non-randomised comparative studies will be included. Data on participant characteristics, study design, intervention details and outcomes will be extracted. Study quality will be assessed using the Cochrane Risk of Bias Tool and the Robins-I tool. Bayesian network meta-analyses will be performed to compare interventions based on all available direct and indirect evidence. If the transitivity assumption for network meta-analysis cannot be met, we will perform a qualitative assessment.Ethics and disseminationFormal ethics is not required as primary data will not be collected. The findings of this study will be disseminated through conference presentations, and peer-reviewed publications. In an area of clinical practice where equipoise exists, the findings of this study may assist in determining which treatment intervention is most effective in venous thromboembolism prevention.PROSPERO registration numberCRD42018090960.


2022 ◽  
Author(s):  
Shehong Zhang ◽  
Hongyu Xie ◽  
Chuanjie Wang ◽  
Fengfeng Wu ◽  
Xin Wang

Abstract Introduction: Motor function is essential in our daily lives, one of the most common impairments caused by stroke is loss of functional movement. Over 70% of stroke survivors have motor or other neurological functional disabilities. However, rehabilitation of motor function suffered from a stroke can be rather difficult due to the complexity of organs and systems related to motor function, as well as the neural system that supported motor function. In particularly, previous evidence for the effectiveness of physiotherapy, a commonly prescribed intervention method for people with stroke, that recover motor function in people following a stroke is varied and limited in the chronic rehabilitation phase and therefore has never been reviewed systematically. With the progress of study in neurology and the development of novel tools for rehabilitation, results from more and more clinical trials are now available, thus here justifying conducting a systematic review. Methods and analysis: This systematic review protocol is developed in accordance with the methodology recommended by the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols, as well as the Cochrane handbook for systematic reviews of interventions. Relevant studies will be identified by searching the databases. We will perform searches for relevant studies in databases, including PubMed, Embase, CINAHL, and Web of Science, Physiotherapy Evidence Database and Cochrane Library databases. The reference lists of included articles and reviews will be searched manually. The date range parameters used in searching all databases will be restricted between January 2001 and January 2021. Randomized controlled trials (RCTs) published will be included. The language used in the articles included was restricted to English. The GRADE (Grading of Recommendations, Assessment, Development and Evaluation system from the Cochrane Handbook for Systematic Reviews of Interventions) approach will be used to systematically appraise the quality of methodology. We will assess the risk of bias of the RCTs included using the Cochrane Collaboration’s tool and provide a qualitative synthesis. After that, we will consider conducting a meta-analysis if the final data across outcomes shows sufficient homogeneity. Ethics and dissemination: No ethical approval is needed as the proposed study does not involve the collection of primary data, and the results of this review will be disseminated via peer-reviewed publications and conference presentations. Trial registration number: CRD42021267069.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Daryl Mahon

Purpose This paper aims to set out a model of servant leadership that can be infused within a supervisory setting to mitigate employee burnout and negative stressful experiences in the health and social care sector. Design/methodology/approach A brief targeted review of the literature was undertaken to assess the prevalence of burnout in the health and social care sectors. The supervision literature was also explored. The outcomes associated with servant leadership were also distilled, focusing on employee well-being. Findings Research suggests that burnout and related concepts such as secondary trauma and compassion fatigue impact these professions disproportionately. At the same time, servant leadership is suggested to mitigate some of these factors. The author presents a conceptual model of servant leadership supervision consisting of an ideographic model of servant leadership, Servant Leadership Scale-28 (SLS-28), using the most recent meta-analysis defining this construct, and previously validated measures in the extant literature to inform its design. A Servant Leadership Supervision Scale (SLSS) is also presented aligning its use to several of the core characteristics of servant leadership practice. Research limitations/implications In doing so, the author proposes that this approach will help reduce burnout of health and social care sector employees. Limitations are considered in light of the conceptual paper and no primary data. Practical implications A model of servant leadership supervision that can be infused into health and social care supervision. Originality/value This is the first model of servant leadership supervision articulated for the health and social care sector.


Author(s):  
Tim Colbourn

This chapter provides an overview of research methods used to build the evidence base for global maternal and child health. It covers primary data collection, secondary data analysis, systematic reviews, and meta-analysis, and provides tips on how to interpret the scientific literature. This chapter should be read in conjunction with Chapters 1–3, Chapter 5 on economic evaluation, and Chapter 4 on converting research into policy to put the use of research evidence into context. The three key points from this chapter are: (1) you need to clearly define a research question before deciding what study type is best suited to answer it; (2) designing a research study involves detailed attention to practical details, including how groups are going to be defined; and (3) scientific studies are sometimes published with incorrect conclusions. Critically appraise each study, and define appropriate conclusions that are based on the data and methodology.


BMJ Open ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. e034903
Author(s):  
Fiona Stanaway ◽  
Naomi Noguchi ◽  
Erin Mathieu ◽  
Saman Khalatbari-Soltani ◽  
Raj Bhopal

IntroductionGrowing ethnic diversity in the UK has made it increasingly important to determine the presence of ethnic health inequalities. There has been no systematic review that has drawn together research on ethnic differences in mortality in the UK.MethodsAll types of observational studies that compare all-cause mortality between major ethnic groups and the white majority population in the UK will be included. We will search Medline (OvidSP), Embase (OvidSP), Scopus and Web of Science and search the grey literature through conference proceedings and online thesis registries. Searches will be carried out from inception to 2 August 2019 with no language or other restrictions. Database searches will be repeated prior to publication to identify new articles published since the initial search. We will conduct forward and backward citation tracking of identified references and consult with experts in the field to identify further publications and ongoing or unpublished studies. Two reviewers will independently screen studies and extract data. Two reviewers will independently assess the quality of included studies using the Newcastle-Ottawa Scale. If at least two studies are located for each ethnic group and studies are sufficiently homogeneous, we will conduct a meta-analysis. If insufficient studies are located or if there is high heterogeneity we will produce a narrative summary of results.Ethics and disseminationAs no primary data will be collected, formal ethical approval is not required. The findings of this review will be disseminated through publication in peer reviewed journals and conference presentations.PROSPERO registration numberCRD42019146143.


BMJ Open ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. e041776
Author(s):  
Ryan Daniel Gotesman ◽  
Naomi Niznick ◽  
Brian Dewar ◽  
Dean A Fergusson ◽  
Risa Shorr ◽  
...  

IntroductionReversible cerebral vasoconstriction syndrome (RCVS) is characterised by severe, recurrent thunderclap headaches (TCHs) and vasoconstriction of cerebral arteries that resolve within 3 months. Abnormalities on non-contrast CT (NCCT) such as ischaemic strokes, intracerebral haemorrhage and subarachnoid haemorrhages are frequently observed on brain imaging of patients with RCVS though their prevalence varies considerably between studies. The aim of this systematic review and meta-analysis is to estimate the prevalence of NCCT abnormalities seen on neuroimaging of adult patients with RCVS.Methods and analysisWe will search the Medline, Embase and the Cochrane Library databases for studies on the prevalence of NCCT abnormalities on neuroimaging of patients with RCVS. Search results will be screened for eligibility by title and abstract. Suitable studies will be fully reviewed and relevant data extracted using a data abstraction form. The studies will be assessed for methodological quality, risk of bias and heterogeneity. Prevalence estimates across studies will be pooled using a random-effects model and subgroup analysis will be performed to assess the impact of age, sex, publication year and study design on prevalence of vascular lesions. Sensitivity analysis will be used to investigate the robustness of the findings. This protocol has been devised using the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols 2015 checklist.Ethics and disseminationFormal ethics is not required as primary data will not be collected. The findings of this study will be disseminated through a peer-reviewed publication and conference presentations.Trial registration numberCRD42020190637.


BMJ Open ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. e030147 ◽  
Author(s):  
Paul Doody ◽  
Justin Aunger ◽  
Evans Asamane ◽  
Carolyn A Greig ◽  
Janet Lord ◽  
...  

IntroductionFrailty is a common and clinically significant condition in geriatric populations, associated with adverse health outcomes such as hospitalisation, disability and mortality. Although there are systematic reviews/meta-analyses assessing the prevalence of frailty in community-dwelling older adults, nursing home residents, and cancer and general surgery patients, there are none assessing the overall prevalence of frailty in geriatric hospital inpatients.Methods and analysisThis review will systematically search and analyse the prevalence of frailty within geriatric hospital inpatients within the literature. A search will be employed on the platforms of Ovid, Web of Science and databases of Cumulative Index to Nursing and Allied Health Literature (CINAHL) Plus, SCOPUS and the Cochrane Library. Any observational or experimental study design which utilises a validated operational definition of frailty, reports the prevalence of frailty, has a minimum age ≥65 years, attempts to assess the whole ward/clinical population and occurs in hospital inpatients, will be included. Title and abstract and full-text screenings will be conducted by three reviewers. Methodological quality of eligible studies will be assessed using the Joanna Briggs Institute critical appraisal tool. Data extraction will be performed by two reviewers. If sufficient data are available, a meta-analysis synthesising pooled estimates of the prevalence of frailty and pre-frailty, as well as the prevalence of frailty stratified by age, sex, operational frailty definition, prevalent morbidities, ward type and location, among older hospitalised inpatients will be conducted. Clinical heterogeneity will be assessed by two reviewers. Statistical heterogeneity will be assessed through a Cochran Q test, and an I2test performed to assess its magnitude.Ethics and disseminationEthical approval was not required as primary data will not be collected. Findings will be disseminated through publication in peer reviewed open access scientific journals, public engagement events, conference presentations and social media.PROSPERO registration number79202.


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