A Multicenter Propensity Score-Matched Cohort Study of Preoperative Antiplatelet Therapy and Postoperative Outcomes in Elderly Surgical Patients

<i>Background and Objectives</i>: Elderly patients frequently receive antiplatelet therapy, creating a clinical dilemma between bleeding risk and cardiovascular protection during surgery. We evaluated the association between preoperative antiplatelet therapy and postoperative bleeding and cardiovascular events using multicenter observational data. <i>Materials and Methods</i>: We conducted a retrospective cohort study using standardized OMOP-CDM databases from 10 tertiary hospitals. Patients aged ≥65 years undergoing surgery were classified by preoperative aspirin or clopidogrel exposure. Propensity score matching was performed within each site. Hazard ratios (HRs) were estimated using Cox regression and pooled using meta-analytic techniques. <i>Results</i>: A total of 1464 exposed patients and 7038 matched comparators were analyzed. Across sites, hazard ratios varied without a statistically significant pooled association. The pooled HR for postoperative events was 1.01 (95% CI 0.57-1.78, <i>p</i> = 0.967). Covariate balance improved substantially after matching. <i>Conclusions</i>: Preoperative antiplatelet therapy was not associated with a consistent increase in postoperative bleeding or cardiovascular events in elderly surgical patients. These findings support individualized perioperative management rather than routine discontinuation.