Aspirin for primary prevention in patients with high cardiovascular risk: insights from CORE-Thailand registry

Aspirin may be considered for primary prevention in non-elderly patients with high cardiovascular risk. However, contemporary management aimed at aggressive cardiovascular risk factor control may alter benefit-risk ratio of aspirin. Therefore, we aimed to examine the effect of aspirin for primary prevention on the long-term MACEs in a large cohort registry. Cohort Of patients with high Risk for cardiovascular Events (CORE-Thailand) registry is a prospective, multicenter, observational, longitudinal study of Thai patients with high atherosclerotic risk. Patients with established atherosclerotic cardiovascular diseases were excluded. Among 4259 patients with multiple cardiovascular risk factors, 1945 (45.7%) patients used aspirin. After propensity score matching, there were 3228 patients remained in post-matching analysis. During the median follow-up period of 58.2 months, we demonstrated that aspirin use increased risk of long-term MACEs in pre-matching cohort (unadjusted HR 1.76, 95% CI 1.43-2.17, P < 0.001) and post-matching cohort (HR 1.66 (1.31-2.10), P < 0.001). In addition, patients taking aspirin had a higher risk of bleeding than non-aspirin users in pre-matching cohort (unadjusted HR 2.28, 95% CI 1.09-4.75, P = 0.028). We demonstrated that aspirin was associated with increased risk of long-term MACEs in patients with multiple cardiovascular risk factors. Due to the non-randomized design, our results should be interpreted with caution.