The impact of body mass index on antiplatelet monotherapy strategy for secondary prevention after percutaneous coronary intervention: A substudy of the HOST-EXAM trial.

Background: Body mass index (BMI) may influence both clinical risk and pharmacologic response after percutaneous coronary intervention (PCI). We aimed to evaluate the association between BMI and long-term outcomes in a stabilized post-PCI population and to determine whether the effects of clopidogrel versus aspirin as single antiplatelet therapy (SAPT) differ across BMI strata.

Methods: This secondary analysis of the HOST-EXAM Extended study (median follow-up 5.8 years) included 4,549 per-protocol patients randomized to aspirin or clopidogrel after uneventful dual antiplatelet therapy. The primary endpoint was a composite of all-cause death, myocardial infarction, stroke, acute coronary syndrome readmission, or major bleeding (BARC ≥3). BMI was analyzed both categorically and continuously using multivariable Cox regression and restricted cubic spline models.

Results: There was a decreasing trend in adverse outcomes across increasing BMI categories (p for trend < .001), although most differences were attenuated after adjustment. Clopidogrel was associated with a significantly lower risk of the primary endpoint compared to aspirin in overweight and obese patients (adjusted HRs: 0.51 for overweight, 0.69 for obese), with similar reductions for thrombotic events (HRs: 0.43 and 0.59, respectively). These findings were consistent in both categorical and spline-based analyses. No significant differences were observed between treatment groups for bleeding outcomes.

Conclusions: In stabilized post-PCI patients, clopidogrel was associated with improved long-term outcomes compared to aspirin in overweight and obese patients. Further studies are warranted to explore BMI-guided antiplatelet strategies.

Trial Registration: This trial was registered at ClinicalTrials.gov (Registration number: NCT02044250). URL: https://clinicaltrials.gov/study/NCT02044250.