Aspirin for primary prevention reduces ischaemic events but increases bleeding
Use of aspirin for primary prevention of cardiovascular (CV) events leads to lower nonfatal ischaemic events but significantly greater nonfatal bleeding events, a recent study has shown.
This analysis sought to examine the clinical outcomes with aspirin for primary prevention of CV disease after the recent publication of large trials adding >45,000 individuals to the published data. Included were randomized controlled trials (RCTs) comparing clinical outcomes with aspirin vs control with follow-up duration of at least 1 year.
Efficacy outcomes were as follows: all-cause death, CV death, myocardial infarction (MI), stroke, transient ischaemic attack (TIA) and major adverse CV events. Safety outcomes were major bleeding, intracranial bleeding, fatal bleeding and major gastrointestinal (GI) bleeding. The investigators calculated random effects DerSimonian-Laird risk ratios (RRs) for outcomes.
Fifteen RCTs involving a total of 165,502 participants (aspirin, n=83,529; control, n=81,973) were included in the analysis.
Aspirin, compared with control, correlated with similar all-cause death (RR, 0.97, 95 percent CI, 0.93–1.01), CV death (RR, 0.93, 0.86–1.00) and non-CV death (RR, 0.98, 0.92–1.05) but reduced risks of nonfatal MI (RR, 0.82, 0.72–0.94), TIA (RR, 0.79, 0.71–0.89) and ischaemic stroke (RR, 0.87, 0.79–0.95).
Aspirin users also had a higher risk of major bleeding (RR, 1.5, 1.33–1.69), intracranial bleeding (RR, 1.32, 1.12–1.55) and major GI bleeding (RR, 1.52, 1.34–1.73), with similar rates of fatal bleeding (RR, 1.09, 0.78–1.55) compared with controls. Within the follow-up period of the study, both groups had comparable total cancer and cancer-related deaths.