title: Systematic reviews and meta-analyses in coloproctology: interpretation and potential pitfalls.
abstract: A systematic review (SR) is the unbiased appraisal of systematically identified relevant studies. Implicit in its definition is a robust and scientifically valid process, and when performed as such, SR is an important clinical research tool and influence in health policy decision-making. This educational paper outlines that, from the original prototype based on randomized trials, there are now many other types of SRs including those based on: nonrandomized comparative studies, observational studies, prognostic studies, and studies of diagnostic and screening tools. While each of these has a similar 'anatomy' or format, at an individual class level, there are principles specific to each SR type. Several examples from the coloproctology literature are used as case-studies to illustrate potential pitfalls, and upon re-analysis, often reverse or attenuate the conclusions stated in the original publication. These examples serve to emphasize the need for health professionals to understand the process of SR and meta-analysis so that we all arrive at appropriate interpretations to the benefit of our patients.
authors.affiliation: Department of Surgery K, Bispebjerg Hospital, University of Copenhagen, Copenhagen, Denmark. pwj01@bbh.regionh.dk
authors.forename: P
authors.initials: P
authors.lastname: Wille-Jørgensen
authors.forename: A G
authors.initials: AG
authors.lastname: Renehan
mesh_terms: D003082:Colectomy / Q000592:standards / Q000639:trends; D015179:Colorectal Neoplasms / Q000401:mortality* / Q000473:pathology / Q000601:surgery*; D003107:Colorectal Surgery / Q000592:standards / Q000639:trends; D018849:Controlled Clinical Trials as Topic; D016021:Epidemiologic Studies; D005260:Female; D006801:Humans; D008297:Male; D015201:Meta-Analysis as Topic; D016737:Proctocolectomy, Restorative / Q000592:standards* / Q000639:trends; D016032:Randomized Controlled Trials as Topic; D012196:Review Literature as Topic; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D016019:Survival Analysis; D016896:Treatment Outcome; D006113:United Kingdom