DOCSLIB.ORG

Umbrella Reviews: What They Are and Why We Need Them

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Umbrella Reviews: What They Are and Why We Need Them European Journal of Epidemiology (2019) 34:543–546 https://doi.org/10.1007/s10654-019-00505-6 COMMENTARY Umbrella reviews: what they are and why we need them Stefania Papatheodorou1,2 Received: 15 February 2019 / Accepted: 22 February 2019 / Published online: 9 March 2019 © Springer Nature B.V. 2019 Introduction Knowledge gap Evidence in clinical research and public health is hierar- The information that systematic reviews and meta-analy- chical. From animal studies to observational epidemiol- ses are conveying is directly associated with the quantity, ogy, randomized control trials and their synthesis, there quality and comparability of the available evidence from is a pipeline of diferent study designs providing diferent the primary studies. In observational and experimental nature and quality of information. Systematic reviews and research, diferences in interventions, metrics, outcomes, meta-analyses stand on top of this hierarchy most of the designs, participants and settings-collectively character- times and are key components of evidence-based medicine ized as sources of heterogeneity—as well as confounding, [1]. Their production and publication has increased expo- known and unknown biases, are often infated in a meta- nentially in the last decade across almost all disciplines with analysis [6]. Because of the increase in the sample size and approximately 20,000 records labeled as meta-analysis in statistical power, the pooled estimates can have spuriously 2018 compared to 3300 in 2008. One would expect that this tight confdence intervals. Sometimes it is doubtful whether growth would refect the increase in the number of primary statistical signifcance is real or a function of the additive or observational and experimental studies but this is not true cumulative impact of biases. In addition, meta-analyses or because all Pubmed-indexed items increased by 153% from randomized trials, usually to ensure comparability, examine 1991 to 2014 [2]. the association between one treatment option and one out- This abundance of published evidence synthesis cannot come. However, usually there are multiple treatments for the be considered only positive. It is not uncommon for meta- same condition and multiple clinically relevant outcomes analyses on the same research question to reach diferent and the meaningful question is what intervention is the best conclusions even when published within the same year. This for every outcome. Single risk factors are not specifc as well unavoidably leads to confusion and debate in clinicians and since many risk factors apply to several outcomes. Therefore public health policy makers on where to base their deci- a more comprehensive approach is needed. sions on. There are several preventive measures proposed An umbrella review systematically collects and evalu- in order to minimize bias in meta-analyses. A priori pub- ates information from multiple systematic reviews and meta- lication of protocols is highly encouraged and each ana- analyses on all clinical outcomes for which these have been lytical step and every subjective judgment call should be performed [7]. The number of papers tagged as “umbrella reported [3]. Finally there are tools to appraise the reporting review” in Pubmed from 2007 until today has increased [4] and quality [5] of the published systematic reviews and (Fig. 1). There is a very wide range of topics covered includ- meta-analyses. ing nutrition [8], psychiatry [9] and neurology [10], internal medicine [11] and Obstetrics and Gynecology [12]. There is also a variety of studies that can be included in the umbrella review depending on the research question: meta-analyses of observational studies examining risk factors for disease [13], interventions [14] or incorporating evidence from Mendelian * Stefania Papatheodorou Randomization studies [15]. [email protected] Not all published umbrella reviews follow a standard- 1 Department of Epidemiology, Harvard T.H. Chan School ized methodology despite the clear description of this of Public Health, Boston, MA, USA study design several years ago [7]. Such a broad synthesis 2 Cyprus University of Technology, Limassol, Cyprus and analysis of data from many systematic reviews and Vol.:(0123456789)1 3 544 S. Papatheodorou Number of papers tagged as "Umbrella Review" in Pubmed need to be evaluated in terms of their quality by using vali- 60 dated tools [5]. Measures of association and exposure‑outcome categories 40 Systematic reviews and meta-analyses use diferent meas- ures of association depending on the nature of the research 20 question, the design and the analytical approach. In large- Number of papers scale assessments, we can have relative and absolute meas- ures describing the same exposure-outcome association. The use of diferent measures of association should not 0 2007 2008 2009 2010 20112012201320142015201620172018 prohibit the researchers from synthesizing them in an umbrella review as long as they use the established meth- Fig. 1 Number of papers tagged as “umbrella reviews” in Pubmed ods for transformations [16]. That will allow a straight- forward presentation and interpretation of the evidence. In most cases, the defnition of the risk factors of any multiple meta-analyses is not simple and it requires both nature (clinical, environmental, biomarkers and others) subject-matter experts and experienced methodologists. is very heterogeneous. One possible option is to use the The basic steps on performing an umbrella review are pre- defnitions as presented in the primary studies without fur- sented below. ther categorization. This approach may reduce the risk of introducing newly defned factors not originally described in the literature. However, in some cases, it makes more sense to refer to categories of exposure for example in biomarkers. So instead of evaluating biomarkers one by Methods one, we can evaluate large categories of biomarkers such as hormones, diet, infammatory markers, IGF/insulin sys- The need for a new umbrella review has to be identifed a tem [17]. The advantage of this method is that we may be priori based on several factors: usually it is performed in able to collectively evaluate the state of the evidence in topics that are highly controversial or when the biases that broad categories of research, which may make more sense afect a certain research feld have not been systematically in clinical practice than evaluating biomarkers one by one. evaluated. Fields with many meta-analyses having incon- This is not always possible and it requires very thoughtful clusive evidence are clearly suitable for an umbrella review and justifed decisions from the analysts’ side. The same assessment, as it may shed light on the robustness of epide- reasoning applies in the defnition and categorization of miologic evidence by using a ranking approach. the outcomes. Systematic reviews can be summarized by using a descriptive approach [18]. The conclusions can be cat- egorized in the following categories: defnite association, Inclusion and exclusion criteria suggestive (possible) association, no association or incon- clusive association (insufcient evidence). As in all synthesis methods, the protocol must be registered in an open-access database such as PROSPERO (https :// www.crd.york.ac.uk/PROSP ERO/). The authors should Heterogeneity and other biases describe clearly the type of systematic reviews and meta- analyses included in their assessment (observational studies, Heterogeneity should be recorded and evaluated. In the randomized trials, mendelian randomization studies or all of presence of large between study heterogeneity, the results them). Certain criteria regarding the defnition of the expo- of the meta-analysis might not be applicable to any of the sure/intervention and the outcome need to be determined synthesized studies or in future studies. Publication bias just like in standard systematic reviews. The search strategy and small study efects are incorporated in the grading cri- and the databases searched for records must be fully reported teria used for ranking the epidemiologic evidence. Finally, for all databases for replication purposes. In addition, the the excess‐of‐statistical‐signifcance test is performed to included studies need to provide the data in enough detail evaluate whether there was a relative excess of formally so as to perform the statistical analysis. The included studies 1 3 545 Umbrella reviews: what they are and why we need them signifcant fndings in the published literature for any rea- Conclusions son as per Ioannidis and Trikalinos [19]. Umbrella reviews have the potential to provide the highest quality of evidence, if performed and interpreted properly. Grading criteria With almost 200 articles characterized as umbrella reviews in Pubmed and several others registered at PROSPERO data- Finally, the credibility of each proposed association is base, this is a fascinating feld with a great potential for large graded based on the following categories: contributions in the hierarchy of evidence. • Convincing evidence (Class I): Associations with a sta- tistical signifcance of P < 10 − 6, more than 1000 cases included (or more than 20,000 participants for continu- References ous outcomes), the largest component study reporting a signifcant result P < 0.05, a 95% prediction interval 1. Sackett DL, Rosenberg WM, Gray JA, Haynes RB, Richardson that excluded the null, absence of large heterogeneity WS. Evidence based medicine: what it is and what it isn’t. BMJ. P 1996;312(7023):71–2.
Load more

Recommended publications
  • Health Economics & Decision Science
    School of Health And Related Research Health Economics & Decision Science (HEDS) Discussion Paper Series Factors influencing the use of research for policy-making: an umbrella review protocol Authors: Erika E. Atienzo, Eva Kaltenthaler, Susan K. Baxter Corresponding author: Erika E. Atienzo ScHARR, University of Sheffield, Regent Court, 30 Regent Street, Sheffield, S1 4DA Fax: (+44) (0)114 222 0749 Email: [email protected] No. 16.07 Disclaimer: This series is intended to promote discussion and to provide information about work in progress. The views expressed in this series are those of the authors. Comments are welcome, and should be sent to the corresponding author. This paper is also hosted on the White Rose Repository: http://eprints.whiterose.ac.uk/ FACTORS INFLUENCING THE USE OF RESEARCH FOR POLICY-MAKING: AN UMBRELLA REVIEW PROTOCOL Erika E. Atienzoa*, Eva Kaltenthalera, Susan K. Baxterb a Health Economics and Decision Science, School of Health and Related Research, University of Sheffield b Public Health, School of Health and Related Research, University of Sheffield *Corresponding author: Erika E. Atienzo ScHARR, University of Sheffield Regent Court, 30 Regent Street Sheffield, S1 4DA (UK) [email protected] March 2016 ABSTRACT Over the last two decades, there has been an emphasis on the concept of evidence-based policy. However, evidence-based policy remains a major challenge and a gap exists in the systematic translation of scientific knowledge into policies. The awareness of this evidence- policy gap has led to a proliferation of research. As the demand for evidence-informed policy-making escalates, so does the need to unveil the mechanisms by which we can influence the process of research uptake.
    [Show full text]
  • A Meta-Review of Transparency and Reproducibility-Related Reporting Practices in Published Meta- Analyses on Clinical Psychological Interventions (2000-2020)
    A meta-review of transparency and reproducibility-related reporting practices in published meta- analyses on clinical psychological interventions (2000-2020). Rubén López-Nicolás1, José Antonio López-López1, María Rubio-Aparicio2 & Julio Sánchez- Meca1 1 Universidad de Murcia (Spain) 2 Universidad de Alicante (Spain) Author note: This paper has been published at Behavior Research Methods. The published version is available at: https://doi.org/10.3758/s13428-021-01644-z. All materials, data, and analysis script coded have been made publicly available on the Open Science Framework: https://osf.io/xg97b/. Correspondence should be addressed to Rubén López-Nicolás, Facultad de Psicología, Campus de Espinardo, Universidad de Murcia, edificio nº 31, 30100 Murcia, España. E-mail: [email protected] 1 Abstract Meta-analysis is a powerful and important tool to synthesize the literature about a research topic. Like other kinds of research, meta-analyses must be reproducible to be compliant with the principles of the scientific method. Furthermore, reproducible meta-analyses can be easily updated with new data and reanalysed applying new and more refined analysis techniques. We attempted to empirically assess the prevalence of transparency and reproducibility-related reporting practices in published meta-analyses from clinical psychology by examining a random sample of 100 meta-analyses. Our purpose was to identify the key points that could be improved with the aim to provide some recommendations to carry out reproducible meta-analyses. We conducted a meta-review of meta-analyses of psychological interventions published between 2000 and 2020. We searched PubMed, PsycInfo and Web of Science databases. A structured coding form to assess transparency indicators was created based on previous studies and existing meta-analysis guidelines.
    [Show full text]
  • Therapeutic Benefits of Glutamine: an Umbrella Review of Meta-Analyses
    576 BIOMEDICAL REPORTS 6: 576-584, 2017 Therapeutic benefits of glutamine: An umbrella review of meta-analyses MARC P. McRAE Department of Basic Science, National University of Health Sciences, Lombard, IL 60148, USA Received February 8, 2017; Accepted March 9, 2017 DOI: 10.3892/br.2017.885 Abstract. Glutamine may be an essential amino acid in and shortening of the length of stay in hospital. Furthermore, patients with catabolic disease, as it has been demonstrated glutamine supplementation appeared to reduce the rate of that circulating glutamine levels drop during critical illness in-patient mortality, but the majority of meta-analyses did and following major surgery; this may result in an increase in not reach statistical significance. However, researchers must secondary infection risk, recovery time and mortality rates. appreciate the positive results with caution in light of the However, there is much discrepancy in the literature with fact that there exists statistically significant heterogeneity for regards to randomized controlled studies, and therefore, the the majority of meta-analyses, and statistically significant present study is an umbrella review of published meta-analyses, publication bias in almost half. conducted to examine the effectiveness of glutamine's role as a therapeutic agent. A search using PubMed, Cochrane Library Introduction and CINAHL from January 1st, 1980 to December 31st, 2016 was conducted using the following strategy: ‘Glutamine AND Glutamine may be a conditionally essential amino acid in (meta-analysis OR systematic review)’ and publications were patients with catabolic disease as it has been demonstrated retrieved, which provided quantitative statistical analysis of that circulating plasma glutamine concentrations drop during pooled treatment effects on the relative risks of infectious critical illness and following major surgery (1).
    [Show full text]
  • Ozone Exposure and Health Effects: a Protocol for an Umbrella Review and Effect-­Specific Systematic Maps
    Open access Protocol BMJ Open: first published as 10.1136/bmjopen-2019-034854 on 13 August 2020. Downloaded from Ozone exposure and health effects: a protocol for an umbrella review and effect-­specific­systematic­maps Tianyu Zhao ,1,2,3,4 Iana Markevych,1,2,3,5 Christian Janßen,4 Dennis Nowak,1,2 Nadine Steckling- Muschack,1,6 Joachim Heinrich1,2,3,7 To cite: Zhao T, Markevych I, ABSTRACT Strengths and limitations of this study Janßen C, et al. Ozone Introduction Ambient ozone exposure may be adverse exposure and health effects: to health. Since the reported associations between ozone ► To the best of our knowledge, this protocol is the a protocol for an umbrella and health effects are heterogeneous and the underlying review and effect- specific first one for an umbrella review or a systematic map pathways are indistinct, the overall relationship remains systematic maps. BMJ Open focusing on ozone exposure and health outcomes. unclear. Only a few overall syntheses of the evidence 2020;10:e034854. doi:10.1136/ ► The umbrella review will provide a comprehensive regarding ozone and health effects are available to date. bmjopen-2019-034854 outline of the currently available systematic reviews Methods and analysis We plan to summarise the current on ambient ozone exposure and health outcomes, ► Prepublication history and evidence on ozone- related health effects systematically. and an epidemiological evidence reservoir accessi- additional material for this First, to identify the possible associations between paper are available online. To ble to the public. ambient ozone exposure and health outcomes, we will view these files, please visit ► The systematic map of a specific ozone-rela ted conduct an umbrella review.
    [Show full text]
  • Identifying Approaches for Assessing Methodological and Reporting
    Pussegoda et al. Systematic Reviews (2017) 6:117 DOI 10.1186/s13643-017-0507-6 RESEARCH Open Access Identifying approaches for assessing methodological and reporting quality of systematic reviews: a descriptive study Kusala Pussegoda1, Lucy Turner1, Chantelle Garritty1,2, Alain Mayhew1, Becky Skidmore1, Adrienne Stevens1,2, Isabelle Boutron3, Rafael Sarkis-Onofre4, Lise M. Bjerre5,6,7, Asbjørn Hróbjartsson8, Douglas G. Altman9 and David Moher10* Abstract Background: The methodological quality and completeness of reporting of the systematic reviews (SRs) is fundamental to optimal implementation of evidence-based health care and the reduction of research waste. Methods exist to appraise SRs yet little is known about how they are used in SRs or where there are potential gaps in research best-practice guidance materials. The aims of this study are to identify reports assessing the methodological quality (MQ) and/or reporting quality (RQ) of a cohort of SRs and to assess their number, general characteristics, and approaches to ‘quality’ assessment over time. Methods: The Cochrane Library, MEDLINE®, and EMBASE® were searched from January 1990 to October 16, 2014, for reports assessing MQ and/or RQ of SRs. Title, abstract, and full-text screening of all reports were conducted independently by two reviewers. Reports assessing the MQ and/or RQ of a cohort of ten or more SRs of interventions were included. All results are reported as frequencies and percentages of reports. Results: Of 20,765 unique records retrieved, 1189 of them were reviewed for full-text review, of which 76 reports were included. Eight previously published approaches to assessing MQ or reporting guidelines used as proxy to assess RQ were used in 80% (61/76) of identified reports.
    [Show full text]
  • Summarizing Systematic Reviews: Methodological Development
    METHODOLOGY PAPER Summarizing systematic reviews: methodological development, conduct and reporting of an umbrella review approach Edoardo Aromataris,1 Ritin Fernandez,2 Christina M. Godfrey,3 Cheryl Holly,4 Hanan Khalil5 and Patraporn Tungpunkom6 1The Joanna Briggs Institute, University of Adelaide, Adelaide, South Australia, 2School of Nursing, University of Wollongong; Centre for Research in 05/21/2018 on BhDMf5ePHKav1zEoum1tQfN4a+kJLhEZgbsIHo4XMi0hCywCX1AWnYQp/IlQrHD3gy8G8VagVy1noQVV3wH2du7UHDCprP5m8mBdFQ69S0Y= by https://journals.lww.com/ijebh from Downloaded 3 Downloaded Nursing and Health, St George Hospital, Sydney, Australia, Queen’s Joanna Briggs Collaboration, Queen’s University School of Nursing, Kingston, Ontario, Canada, 4Northeast Institute for Evidence Synthesis and Translation Rutgers, University School of Nursing Newark, New Jersey, USA, 5 6 from Monash University, School of Rural Health, Victoria, Australia, and Thailand Centre for Evidence Based Nursing, Midwifery, and Health Science: https://journals.lww.com/ijebh a Collaborating Centre of JBI, Faculty of Nursing, Chiang Mai University, Chiang Mai, Thailand ABSTRACT by BhDMf5ePHKav1zEoum1tQfN4a+kJLhEZgbsIHo4XMi0hCywCX1AWnYQp/IlQrHD3gy8G8VagVy1noQVV3wH2du7UHDCprP5m8mBdFQ69S0Y= Aims: With the increase in the number of systematic reviews available, a logical next step to provide decision makers in healthcare with the evidence they require has been the conduct of reviews of existing systematic reviews. Syntheses of existing systematic reviews are referred to by many different
    [Show full text]
  • An Umbrella Review and Narrative Synthesis of the Effectiveness Of
    International Journal of Environmental Research and Public Health Review An Umbrella Review and Narrative Synthesis of the Effectiveness of Interventions Aimed at Decreasing Food Prices to Increase Food Quality Chiara Milani 1, Chiara Lorini 2,* , Alberto Baldasseroni 3, Claudia Dellisanti 3 and Guglielmo Bonaccorsi 2 1 School of Specialization in Hygiene and Preventive Medicine, University of Florence, 50134 Florence, Italy 2 Department of Health Sciences, University of Florence, 50134 Florence, Italy 3 Department of Prevention, Local Health Unit Toscana Centro, 50135 Florence, Italy * Correspondence: chiara.lorini@unifi.it; Tel.: +39-0552751065 Received: 12 June 2019; Accepted: 1 July 2019; Published: 2 July 2019 Abstract: Background: sustainability of population diet is a public health concern: the high price of healthy food is one of the main causes of diet-related health problems. The aim of this study is to synthesize the evidence produced by systematic reviews that evaluated the effectiveness of decreasing healthy food prices to improve accessibility in order to positively modify the dietary pattern. Methods: We carried out a review of systematic reviews that examined the effects of the interventions, by exploring the online databases PubMed, Embase, Web of Science, Cochrane Library and hand-searching the reference lists. Results: after screening by titles and abstracts, we selected 11 systematic reviews that met the inclusion criteria, plus one that was hand-searched. The review generally presented a good quality. Studies concluded that measures aimed at modifying the prices of targeted healthy food were effective in improving population diet by modifying what people buy. Conclusions: the complexity of the outcome—population diet—as well as the poor transferability of data across populations and geographical areas makes it obligatory to provide clear and universal conclusions.
    [Show full text]
  • Analysis CMAJ
    Analysis CMAJ Integration of evidence from multiple meta-analyses: a primer on umbrella reviews, treatment networks and multiple treatments meta-analyses John P.A. Ioannidis MD Previously published at www.cmaj.ca eta-analysis is an important research design for appraising evidence and guiding medical practice Key points and health policy.1 Meta-analyses draw strength from • A single meta-analysis of a treatment comparison for a M single outcome offers a limited view if there are many combining data from many studies. However, even if perfectly treatments or many important outcomes to consider. done with perfect data, a single meta-analysis that addresses • Umbrella reviews assemble together several systematic 1 treatment comparison for 1 outcome may offer a short- reviews on the same condition. sighted view of the evidence. This may suffice for decision- • Treatment networks quantitatively analyze data for all making if there is only 1 treatment choice for this condition, treatment comparisons on the same disease. only 1 outcome of interest and research results are perfect. • Multiple treatments meta-analysis can rank the However, usually there are many treatments to choose from, effectiveness of many treatments in a network. many outcomes to consider and research is imperfect. For • Integration of evidence from multiple meta-analyses may example, there are 68 antidepressant drugs to choose from,2 be extended across many diseases. dozens of scales to measure depression outcomes, and biases abound in research about antidepressants.3,4 Given this complexity, one has to consider what alternative ples behind these types of analysis. I also briefly discuss treatments are available and what their effects are on various methods that analyze together data about several diseases and beneficial and harmful outcomes.
    [Show full text]
  • Improving Peer Review of Systematic Reviews by Involving Librarians and Information 2 Specialists: Protocol for a Randomized Controlled Trial
    1 Improving peer review of systematic reviews by involving librarians and information 2 specialists: protocol for a randomized controlled trial 3 Melissa L. Rethlefsen1, Sara Schroter2, Lex M. Bouter3, David Moher4, Ana Patricia Ayala5, 4 Jamie J. Kirkham6, Maurice P. Zeegers7 5 1. Health Sciences Library & Informatics Center, University of New Mexico, MSC 09 5100, 1 University of New Mexico, Albuquerque, 6 NM 87131-0001, [email protected], https://orcid.org/0000-0001-5322-9368 7 2. BMJ Publishing Group, London, United Kingdom, https://orcid.org/0000-0002-8791-8564 8 3. Department of Philosophy, Faculty of Humanities, Vrije Universiteit Amsterdam, De Boelelaan 1105, 1081 HV, Amsterdam, The 9 Netherlands; Department of Epidemiology and Data Science, Amsterdam UMC, Vrije Universiteit Amsterdam, De Boelelaan 1089a, 10 1081 HV, Amsterdam, The Netherlands, https://orcid.org/0000-0002-2659-5482 11 4. Centre for Journalology, Clinical Epidemiology Program, Ottawa Hospital Research Institute, The Ottawa Hospital, General Campus, 12 Centre for Practice Changing Research Building, 501 Smyth Road, PO BOX 201B, Ottawa, Ontario, K1H 8L6, Canada, https://orcid.org/ 13 0000-0003-2434-4206 14 5. Gerstein Science Information Centre, University of Toronto, Toronto, Canada, https://orcid.org/0000-0002-3613-2270 15 6. Centre for Biostatistics, University of Manchester, Manchester, UK, https://orcid.org/0000-0003-2579-9325 16 7. Care and Public Health Research Institute (CAPHRI), Maastricht University Medical Center+, Universiteitssingel 40, 6229, ER, 17 Maastricht, the Netherlands, https://orcid.org/0000-0002-2387-083X 18Abstract 19Background: Problems continue to exist with the reporting of and risk of bias in search methods and 20strategies in systematic reviews and related review types.
    [Show full text]
  • Ambient Air Pollution, Extreme Temperatures and Birth Outcomes: a Protocol for an Umbrella Review, Systematic Review and Meta-Analysis
    International Journal of Environmental Research and Public Health Study Protocol Ambient Air Pollution, Extreme Temperatures and Birth Outcomes: A Protocol for an Umbrella Review, Systematic Review and Meta-Analysis Sylvester Dodzi Nyadanu 1,2,*, Gizachew Assefa Tessema 2,3 , Ben Mullins 2, Bernard Kumi-Boateng 4 , Michelle Lee Bell 5 and Gavin Pereira 2,6,7 1 Education, Culture and Health Opportunities (ECHO) Ghana, ECHO Research Group International, P. O. Box 424, Aflao, Ghana 2 School of Public Health, Curtin University, Perth, Kent Street, Bentley, Western Australia 6102, Australia; [email protected] (G.A.T.); [email protected] (B.M.); [email protected] (G.P.) 3 School of Public Health, University of Adelaide, Adelaide, South Australia 5000, Australia 4 Department of Geomatic Engineering, University of Mines and Technology, P. O. Box 237, Tarkwa, Ghana; [email protected] 5 School of the Environment, Yale University, New Haven, CT 06511, USA; [email protected] 6 Telethon Kids Institute, Northern Entrance, Perth Children’s Hospital, Nedlands, Western Australia 6009, Australia 7 Centre for Fertility and Health (CeFH), Norwegian Institute of Public Health, 0473 Oslo, Norway * Correspondence: [email protected] Received: 1 October 2020; Accepted: 18 November 2020; Published: 21 November 2020 Abstract: Prenatal exposure to ambient air pollution and extreme temperatures are among the major risk factors of adverse birth outcomes and with potential long-term effects during the life course. Although low- and middle-income countries (LMICs) are most vulnerable, there is limited synthesis of evidence in such settings. This document describes a protocol for both an umbrella review (Systematic Review 1) and a focused systematic review and meta-analysis of studies from LMICs (Systematic Review 2).
    [Show full text]
  • Violence Prevention Interventions: an Umbrella Review Protocol
    Violence prevention interventions: An Umbrella Review protocol Achim Wolf, John P. A. Ioannidis, Seena Fazel Protocol v 1.0 – June 29, 2015 University of Oxford, Department of Psychiatry, Warneford Hospital, Warneford Lane, Headington, Oxford, United Kingdom Funding: Wellcome Trust (095806) Background Violence is among the largest causes of disability-adjusted life years worldwide according to the World Health Organization.[1] In the US alone, the yearly impact of violence on health services is in excess of $5 billion.[2] A wide range of studies on violence prevention interventions have been reported, and a synthesis of this evidence would be important for public policy and planning and the development of preventive efforts.[3, 4] Therefore, we propose to conduct an umbrella review on the effectiveness of violence prevention interventions worldwide, and use this review as a basis for recommendations for future prevention programs and research. Review objectives “What are effective interventions for the prevention of violence?” Methods Inclusion criteria For inclusion, reviews have to evaluate the effectiveness of primary prevention (aimed at groups regardless of risk), secondary prevention interventions (aimed at high risk groups), or tertiary prevention (aimed at previously violent groups). Types of participants Participants include general population groups, those considered at high-risk, and previous offenders or previously violent people. Interventions All types of interventions will be included if they examine effects on violence, defined below. Outcomes The outcome to be examined in this umbrella review is violence. The definition of the World Health Organization will be used: “The intentional use of physical force or power, threatened or actual, against oneself, another person, or against a group or community, that either results in or has a high likelihood of resulting in injury, death, psychological harm, maldevelopment or deprivation.”[5] Reviews focusing on self-directed violence (i.e.
    [Show full text]
  • Validity of Observational Evidence on Putative Risk and Protective Factors
    Janiaud et al. BMC Medicine (2021) 19:157 https://doi.org/10.1186/s12916-021-02020-6 RESEARCH ARTICLE Open Access Validity of observational evidence on putative risk and protective factors: appraisal of 3744 meta-analyses on 57 topics Perrine Janiaud1,2, Arnav Agarwal3, Ioanna Tzoulaki4,5, Evropi Theodoratou6,7, Konstantinos K. Tsilidis4,5, Evangelos Evangelou4,5 and John P. A. Ioannidis1,8,9,10,11* Abstract Background: The validity of observational studies and their meta-analyses is contested. Here, we aimed to appraise thousands of meta-analyses of observational studies using a pre-specified set of quantitative criteria that assess the significance, amount, consistency, and bias of the evidence. We also aimed to compare results from meta-analyses of observational studies against meta-analyses of randomized controlled trials (RCTs) and Mendelian randomization (MR) studies. Methods: We retrieved from PubMed (last update, November 19, 2020) umbrella reviews including meta-analyses of observational studies assessing putative risk or protective factors, regardless of the nature of the exposure and health outcome. We extracted information on 7 quantitative criteria that reflect the level of statistical support, the amount of data, the consistency across different studies, and hints pointing to potential bias. These criteria were level of statistical significance (pre-categorized according to 10−6, 0.001, and 0.05 p-value thresholds), sample size, statistical significance for the largest study, 95% prediction intervals, between-study heterogeneity, and the results of tests for small study effects and for excess significance. * Correspondence: [email protected] 1Meta-Research Innovation Center at Stanford (METRICS), Stanford, CA 94305, USA 8Department of Epidemiology and Population Health, Stanford University School of Medicine, Stanford, CA 94305, USA Full list of author information is available at the end of the article © The Author(s).
    [Show full text]