Rapid reviews may produce different results to systematic reviews: a meta-epidemiological study

• Published in: Journal of clinical epidemiology Vol. 109; pp. 30 - 41
• Main Authors: Marshall, Iain J., Marshall, Rachel, Wallace, Byron C., Brassey, Jon, Thomas, James
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.05.2019; Elsevier Limited; Elsevier
• Subjects: Bias; Bibliographic data bases; Clinical trials; Epidemiologic Methods; Epidemiologic Studies; Epidemiology; Humans; Literature reviews; Meta-analysis; Meta-epidemiological studies; Methods; PubMed; Rapid reviews; Research synthesis; Review Literature as Topic; Reviews; Searching; Simulation; Statistical significance; Statistics; Studies; Systematic review; Systematic reviews; Systematic Reviews as Topic; Systematic reviews; Research synthesis; Rapid reviews; Meta-epidemiological studies
• ISSN: 0895-4356; 1878-5921
• DOI: 10.1016/j.jclinepi.2018.12.015

To simulate possible changes in systematic review results if rapid review methods were used. We recalculated meta-analyses for binary primary outcomes in Cochrane systematic reviews, simulating rapid review methods. We simulated searching only PubMed, excluding older articles (5, 7, 10, 15, and 20 years before the search date), excluding smaller trials (<50, <100, and <200 participants), and using the largest trial only. We examined percentage changes in pooled odds ratios (ORs) (classed as no important change [<5%], small [<20%], moderate [<30%], or large [≥30%]), statistical significance, and biases observed using rapid methods. Two thousand five hundred and twelve systematic reviews (16,088 studies) were included. Rapid methods resulted in the loss of all data in 3.7–44.7% of meta-analyses. Searching only PubMed had the smallest risk of changed ORs (19% [477/2,512] were small changes or greater; 10% [260/2,512] were moderate or greater). Changes in ORs varied substantially with each rapid review method; 8.4–21.3% were small, 1.9–8.8% were moderate, and 4.7–34.1% were large. Changes in statistical significance occurred in 6.5–38.6% of meta-analyses. Changes from significant to nonsignificant were most common (2.1–13.7% meta-analyses). We found no evidence of bias with any rapid review method. Searching PubMed only might be considered where a ∼10% risk of the primary outcome OR changing by >20% could be tolerated. This could be the case in scoping reviews, resource limitation, or where syntheses are needed urgently. Other situations, such as clinical guidelines and regulatory decisions, favor more comprehensive systematic review methods.