Effect of low-dose aspirin on health outcomes: An umbrella review of systematic reviews and meta-analyses

Abstract

Aims: This study aimed to use an umbrella review methodology to capture the range of outcomes that were associated with low-dose aspirin and to systematically assess the credibility of this evidence. Methods: Aspirin is associated with several health outcomes, but the overall benefit/risk balance related to aspirin use is unclear. We searched three major databases up to 15 August 2019 for meta-analyses of observational studies and randomized controlled trials (RCTs) including low-dose aspirin compared to placebo or other treatments. Based on random-effects summary effect sizes, 95% prediction intervals, heterogeneity, small-study effects and excess significance, significant meta-analyses of observational studies were classified from convincing (class I) to weak (class IV). For meta-analyses of RCTs, outcomes with random effects P-value