Impact of Chronic Antiplatelet Therapy on Clinical Outcomes of First-Time ST-Elevation Myocardial Infarction.

ST-elevation myocardial infarction (STEMI) is a leading cause of morbidity and mortality in the United States. A retrospective cross-sectional study was conducted using the National Inpatient Sample database (2015-2022). We included patients ≥18 years-old hospitalized with STEMI and without history of myocardial infarction. Outcomes included inpatient mortality, routine discharge, complications, comorbidities, and treatment modalities in patients on chronic antiplatelet therapy (cAPT). Propensity score-based inverse probability of treatment weighting adjusted for confounding factors. Multivariable logistic regression estimated adjusted odds ratios and 95% confidence intervals. Among 1,070,085 first-time STEMI hospitalizations, 236,085 (22.1%) involved patients receiving cAPT. The median age of these patients was 66 years (interquartile range: 57-75) and 74,120 (31.4%) were women. Patients on cAPT had significantly higher odds of treatment with coronary artery bypass graft (adjusted odds ratios: 1.86, 95% confidence intervals [1.77-1.97], P < 0.001) and percutaneous coronary intervention (1.04 [1.01-1.07], P = 0.010). cAPT was also significantly associated with reduced bleeding (0.831 [0.789-0.876], P < 0.001), mural thrombus (0.703 [0.587-0.841], P < 0.001), and acute heart failure (0.889 [0.859-0.921], P < 0.001), without increased risk of any complication. Following inverse probability of treatment weighting, cAPT was associated with significantly lower inpatient mortality (0.562 [0.534-0.591], P < 0.001) and higher routine discharge (1.38 [1.34-1.43], P < 0.001). cAPT was associated with significantly improved inpatient outcomes among STEMI hospitalizations.