Impact of Multiple Cardiovascular Events on Long-Term Outcomes and Bleeding Risk in Patients With Acute Coronary Syndrome: A Nationwide Population-Based Cohort Study.

Background: Patients with acute coronary syndrome (ACS) are at high risk for recurrent cardiovascular events and bleeding complications, particularly in Asian populations. The long-term impact of multiple cardiovascular events and bleeding on outcomes remains unclear.

Methods: Using Taiwan's National Health Insurance Research Database, this retrospective cohort study included 28 086 patients with ACS categorized into single-event and multiple-event groups based on cardiovascular events occurring within 2 years of the index ACS event. After matching for age, sex, and event interval, 8756 patients were assigned to the multiple-event group and 17 446 to the single-event group.

Results: The multiple-event group had higher comorbidity rates, including hypertension, prior coronary disease, heart failure, stroke, and chronic kidney disease. Over 5 years, the multiple-event group had significantly higher all-cause mortality (34.0% versus 24.0%) and cardiovascular mortality (11.2% versus 5.5%) compared with the single-event group (both <0.0001). Major (8.4% versus 1.6%) and minor (35.5% versus 7.4%) bleeding rates were also higher (both <0.0001). Notably, major bleeding persisted beyond 3 months in the multiple-event group, whereas the single-event group showed reduced bleeding after 1 month. In the multiple-event group, each additional major bleeding event was associated with earlier subsequent cardiovascular events (coefficient=-0.2875, =0.0325).

Conclusions: Patients with ACS with multiple cardiovascular events have higher rates of all-cause mortality, cardiovascular mortality, and major bleeding than patients with ACS with a single cardiovascular event. Major bleeding may also be associated with the risk of subsequent cardiovascular events, highlighting the importance of implementing a tailored antiplatelet strategy in Asian populations.