Definition of a systematic review used in overviews of systematic reviews, meta-epidemiological studies and textbooks

BackgroundA standard or consensus definition of a systematic review does not exist. Therefore, if there is no definition about a systematic review in secondary studies that analyse them or the definition is too broad, inappropriate studies might be included in such evidence synthesis. The aim of this study was to analyse the definition of a systematic review (SR) in health care literature, elements of the definitions that are used and to propose a starting point for an explicit and non-ambiguous SR definition.MethodsWe included overviews of systematic reviews (OSRs), meta-epidemiological studies and epidemiology textbooks. We extracted the definitions of SRs, as well as the inclusion and exclusion criteria that could indicate which definition of a SR the authors used. We extracted individual elements of SR definitions, categorised and quantified them.ResultsAmong the 535 analysed sources of information, 188 (35%) provided a definition of a SR. The most commonly used reference points for the definitions of SRs were Cochrane and the PRISMA statement. We found 188 different elements of SR definitions and divided them into 14 categories. The highest number of SR definition elements was found in categories related to searching (N = 51), analysis/synthesis (N = 23), overall methods (N = 22), quality/bias/appraisal/validity (N = 22) and aim/question (N = 13). The same five categories were also the most commonly used combination of categories in the SR definitions.ConclusionCurrently used definitions of SRs are vague and ambiguous, often using terms such as clear, explicit and systematic, without further elaboration. In this manuscript we propose a more specific definition of a systematic review, with the ultimate aim of motivating the research community to establish a clear and unambiguous definition of this type of research.

[1]  U. Nassar,et al.  Methodological quality and descriptive characteristics of prosthodontic-related systematic reviews. , 2013, Journal of oral rehabilitation.

[2]  R. Fernandes,et al.  Epidemiology and reporting characteristics of overviews of reviews of healthcare interventions published 2012–2016: protocol for a systematic review , 2017, Systematic Reviews.

[3]  D. Pieper,et al.  How is AMSTAR applied by authors – a call for better reporting , 2018, BMC Medical Research Methodology.

[4]  F. Mosteller,et al.  A comparison of results of meta-analyses of randomized control trials and recommendations of clinical experts. Treatments for myocardial infarction. , 1992, JAMA.

[5]  L. Puljak If there is only one author or only one database was searched, a study should not be called a systematic review. , 2017, Journal of clinical epidemiology.

[6]  G. Guyatt,et al.  The Science of Reviewing Research a , 1993, Annals of the New York Academy of Sciences.

[7]  D. Sackett,et al.  Evidence based medicine: what it is and what it isn't , 1996, BMJ.

[8]  P. Shekelle,et al.  Preferred reporting items for systematic review and meta-analysis protocols (PRISMA-P) 2015 statement , 2015, Systematic Reviews.

[9]  A. Detsky,et al.  Evidence-based medicine. A new approach to teaching the practice of medicine. , 1992, JAMA.

[10]  David Moher,et al.  What is a predatory journal? A scoping review , 2018, F1000Research.

[11]  S. Schwartz,et al.  Toward a Clarification of the Taxonomy of “Bias” in Epidemiology Textbooks , 2015, Epidemiology.

[12]  D. Moher,et al.  Preferred reporting items for systematic reviews and meta-analyses: the PRISMA Statement , 2009, BMJ : British Medical Journal.

[13]  D. Moher,et al.  Preferred Reporting Items for Systematic Reviews and Meta-Analyses: The PRISMA Statement , 2009, BMJ : British Medical Journal.

[14]  John P A Ioannidis,et al.  The Mass Production of Redundant, Misleading, and Conflicted Systematic Reviews and Meta-analyses. , 2016, The Milbank quarterly.

[15]  D. Moher,et al.  What is a predatory journal? A scoping review. , 2018, F1000Research.

[16]  David Moher,et al.  Epidemiology and Reporting Characteristics of Systematic Reviews of Biomedical Research: A Cross-Sectional Study , 2016, PLoS medicine.

[17]  T. Greenhalgh,et al.  Evidence based medicine: a movement in crisis? , 2014, BMJ : British Medical Journal.

[18]  Steve McDonald,et al.  Retrieval of overviews of systematic reviews in MEDLINE was improved by the development of an objectively derived and validated search strategy. , 2016, Journal of clinical epidemiology.

[19]  I Chalmers,et al.  Discussion sections in reports of controlled trials published in general medical journals: islands in search of continents? , 1998, JAMA.

[20]  W. Ageno,et al.  Multiple overlapping systematic reviews facilitate the origin of disputes: the case of thrombolytic therapy for pulmonary embolism. , 2017, Journal of clinical epidemiology.

[21]  Roger L. Sur,et al.  History of evidence-based medicine , 2011, Indian journal of urology : IJU : journal of the Urological Society of India.