For people at risk for cardiovascular disease, the prophylactic use of low-dose aspirin reduces the risk for nonfatal myocardial infarction (MI) and transient ischemic attack (TIA), but increases the risk for nonfatal bleeding events, according to a study published in the Journal of the American College of Cardiology.
Researchers conducted a literature review of 15 randomized, controlled clinical trials that assessed the efficacy and safety of aspirin in people at risk for cardiovascular disease. They included trials that compared an aspirin cohort with a control cohort and followed participants for at least 1 year. The main cardiovascular outcomes of interest were all-cause death, cardiovascular death, MI, stroke, TIA, and major adverse cardiovascular events. The main safety outcomes were major bleeding, intracranial bleeding, fatal bleeding, and major gastrointestinal bleeding.
The 15 clinical trials included an aggregate of 165,502 patients. Of these, 83,529 were in aspirin cohorts and 81,973 were controls. The cohorts were comparable for age and cardiovascular risk factors. Both groups also had similar risk factors for all-cause death (risk ratio [RR] 0.97; 95% CI, 0.93-1.01; P =.13); non-cardiovascular death (RR 0.98; 95% CI, 0.92-1.05; P =.53); fatal MI (RR 0.93; 95% CI, 0.79-1.11; P =.43); angina pectoris (RR 0.92; 95% CI, 0.79-1.08; P =.30); coronary revascularization (RR 0.96; 95% CI, 0.87-1.05; P =.36); symptomatic peripheral arterial disease (RR 0.88; 95% CI, 0.7-1.09; P =.24); fatal strokes (RR 1.03; 95% CI, 0.84-1.26; P =.81); and nonfatal stroke (RR 0.94; 95% CI, 0.85-1.02; P =.15).
Compared with controls, the aspirin cohorts had a lower risk for nonfatal MI (RR 0.82; 95% CI, 0.72-0.94; P =.005); TIA (RR 0.79; 95% CI, 0.71-0.89; P <.001); and ischemic stroke (RR 0.87; 95% CI, 0.79-0.95; P =.002). However, they were also at increased risk for major bleeding (RR 1.5; 95% CI, 1.33-1.69; P <.001); intracranial bleeding (RR 1.32; 95% CI, 1.12-1.55; P =.001); major gastrointestinal bleeding (RR 1.52; 95% CI, 1.34-1.73; P <.001); and gastrointestinal ulcers (RR 1.37; 95% CI, 1.07-1.76; P =.013).
The researchers found that low-dose aspirin (≤100 mg/day) did reduce the risk for all-cause death for ≥5 years (RR 0.95; 95% CI, 0.9-0.99; P =.032); total stroke (RR, 0.92; 95% CI, 0.85-0.99; P =.04); and nonfatal stroke (RR 0.88; 95% CI, 0.8-0.96; P =.007).
Participants in the aspirin cohorts who were at high risk for 10-year atherosclerotic cardiovascular disease also had reduced cardiovascular death risk compared with controls (RR 0.92; 95% CI, 0.84-1.0; P =.06).
Limitations of this study include the heterogeneity of the trial outcomes, the use of summary estimates to determine risk ratios, and the inability to incorporate patient-level data.
The researchers concluded that “[t]hese findings suggest that the decision to use aspirin for primary prevention should be tailored to the individual patient based on estimated [atherosclerotic cardiovascular disease] risk and perceived bleeding risk, as well as patient preferences regarding types of events prevented versus potential bleeding caused.”
Several authors reported an association with organizations and pharmaceutical companies. Please see the original reference for a full list of authors’ disclosures.
Abdelaziz HK, Saad M, Pothineni NVK, et al. Aspirin for primary prevention of cardiovascular events. J Am Coll Cardiol. 2019;73(23):2915-2929.