title: Pooling systematic reviews of systematic reviews: a Bayesian panoramic meta-analysis.
abstract: Systematic reviews and meta-analyses usually synthesise evidence from studies reporting outcomes from particular interventions in specific diseases. For example, a meta-analysis of prophylactic antibiotics (intervention) in elective arterial reconstruction (disease) for rates of wound infection (outcome). However, because systematic reviews and meta-analyses are so widespread, a body of evidence often exists around specific intervention effects on particular outcomes over a range of diseases. So for example, a multitude of independent meta-analyses have evaluated rates of wound infection with and without the use of prophylactic antibiotics over multiple surgery types. A systematic review of systematic reviews is a means of synthesising evidence for the same intervention over multiple disease types. We propose a panoramic meta-analysis as a means of pooling effect estimates over systematic reviews of systematic reviews. We explore several methods ranging from a simple two-step approach, to a meta-regression or mixed effects approach, where variation between diseases are modelled as fixed covariate effects and between-study variation by random effects, and to a three-level hierarchical model in which exchangeability is assumed, which allows both a between-disease component of variance and a between-study (within disease) component of variance. In the surgery example, we pool 18 meta-analyses (each including between 4 and 26 studies) of prophylactic antibiotics reporting rates of wound infection from 18 different surgery sites to obtain a single pooled estimate of effect and estimates of between-disease, within-disease and within-study variability.
authors.affiliation: Unit of Public Health, Epidemiology and Biostatistics, University of Birmingham, Birmingham, UK. K.Hemming@bham.ac.uk
authors.forename: Karla
authors.initials: K
authors.lastname: Hemming
authors.forename: Russell James
authors.initials: RJ
authors.lastname: Bowater
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Lilford
mesh_terms: D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D019072:Antibiotic Prophylaxis; D001158:Arteries / Q000601:surgery; D001499:Bayes Theorem; D019317:Evidence-Based Medicine / Q000706:statistics & numerical data; D006801:Humans; D015201:Meta-Analysis as Topic; D008954:Models, Biological; D015233:Models, Statistical; D012044:Regression Analysis; D014946:Wound Infection / Q000188:drug therapy
chemical_list: D000900:Anti-Bacterial Agents