The objective of a recently published meta-analysis by Seshasai and colleagues  was to assess the impact (and safety) of aspirin on vascular and non-vascular outcomes in primary prevention. Nine randomized, placebo-controlled trials with at least 1000 participants each, reporting on cardiovascular disease (CVD), non-vascular outcomes, or death were included. During a mean (standard deviation) follow-up of 6.0 (2.1) years involving over 100,000 participants, aspirin treatment reduced total CVD events by 10% (odds ratio (OR) 0.90; 95% confidence interval (CI) 0.85–0.96; number needed to treat = 120), driven primarily by reduction in non-fatal myocardial infarction (OR 0.80; 95% CI 0.67–0.96; number needed to treat = 162). There was no significant reduction in CVD death (OR 0.99; 95% CI 0.85–1.15) or cancer mortality (OR 0.93; 95% CI 0.84–1.03), and there was increased risk of non-trivial bleeding events (OR1.31; 95% CI 1.14–1.50; number needed to harm = 73). Significant heterogeneity was observed for coronary heart disease and bleeding outcomes, which could not be accounted for by major demographic or participant characteristics. Despite important reductions in non-fatal myocardial infarction, aspirin prophylaxis in people without prior CVD does not lead to reductions in either cardiovascular death or cancer mortality. Because the benefits are further offset by clinically important bleeding events, routine use of aspirin for primary prevention is not warranted and treatment decisions need to be considered on a case-by-case basis.
Department of Medicine T, Ichilov Hospital, Tel-Aviv, Israel
Seshasai SR, Wijesuriya S, Sivakumaran R, et al. Effect of aspirin on vascular and nonvascular outcomes: meta-analysis of randomized controlled trials. Arch Intern Med 2012 Jan 9. Epub ahead of print
Berger JS, Roncaglioni MC, Avanzini F, et al. Aspirin for the primary prevention of cardiovascular events in women and men: a sex-specific meta-analysis of randomized controlled trials. JAMA 2006;295:306-13