A Bias in the Evaluation of Bias Comparing Randomized Trials with Nonexperimental Studies.

ABSTRACT: In a recent BMJ article, the authors conducted a meta-analysis to compare estimated treatment effects from randomized trials with those derived from observational studies based on routinely collected data (RCD). They calculated a pooled relative odds ratio (ROR) of 1.31 (95% confidence interval [CI]: 1.03-1.65) and concluded that RCD studies systematically over-estimated protective effects. However, their meta-analysis inverted results for some clinical questions to force all estimates from RCD to be below 1. We evaluated the statistical properties of this pooled ROR, and found that the selective inversion rule employed in the original meta-analysis can positively bias the estimate of the ROR. We then repeated the random effects meta-analysis using a different inversion rule and found an e

SUBMITTER: Franklin JM 

PROVIDER: S-EPMC5710821 | biostudies-literature | 2017 Apr

REPOSITORIES: biostudies-literature