Low-dose aspirin in the primary prevention of cardiovascular diseases: A retrospective, propensity score matched study.

BACKGROUND AND AIMS:Although the guidelines have been revised recently, the effect of aspirin for the primary prevention of cardiovascular disease (CVD) is still controversial. Thus, we aimed to evaluate the effect of aspirin on primary prevention in the real world. METHODS:Among the 4,266,268 participants without a history of CVD or previous prescription of aspirin and other antiplatelet agents who were screened between 2002 and 2008, 268,963 persons who were prescribed low-dose aspirin (≤100 mg/day) over 90 days in 2002-2008 and 1,075,852 persons who did not receive aspirin were selected after propensity score matching. A Cox proportional-hazards model was used to evaluate the effect of low-dose aspirin on the development of CVD and bleeding episodes. RESULTS:Aspirin showed a protective effect on total CVD events (hazard ratio (HR); 0.737, 95% confidence interval; 0.729-0.745). The protective effect of aspirin on total CVD events was significant in men, women and even in young participants (<65 years). Aspirin had a protective effect in participants with diabetes or hypertension against all subcategories of CVD. The HR of bleeding risk was 1.4-1.5 in aspirin group. CONCLUSIONS:Low-dose aspirin generally showed a protective effect against CVD regardless of age, sex, and underlying comorbidities in the real world. Though, the effect of aspirin was evident at a young age, the risk of bleeding was also high (1.4-1.5 times), and thus, careful prescription is required.