BACKGROUND This study evaluated the association of body mass index (BMI) with adverse clinical outcomes during chronic maintenance antiplatelet monotherapy after percutaneous coronary intervention (PCI) with drug-eluting stents (DES).

METHODS AND RESULTS Overall, 5,112 patients were stratified (in kg/m²) into underweight (BMI ≤18.4), normal weight (18.5-22.9), overweight (23.0-24.9), obesity (25.0-29.9) and severe obesity (≥30.0) categories with randomized antiplatelet monotherapy of aspirin 100 mg or clopidogrel 75 mg once daily for 24 months. The primary endpoint was the composite of all-cause death, non-fatal myocardial infarction, stroke, readmission due to acute coronary syndrome and major bleeding of Bleeding Academic Research Consortium type ≥3. Compared with normal weight, the risk of primary composite outcomes was higher in the underweight (hazard ratio [HR] 2.183 [1.199-3.974]), but lower in the obesity (HR 0.730 [0.558-0.954]) and severe obesity (HR 0.518 [0.278-0.966]) categories, which is partly driven by the difference in all-cause death. The risk of major bleeding was significantly higher in the underweight (HR 4.140 [1.704-10.059]) than in the normal weight category. A decrease in categorical BMI was independently associated with the increased risk of primary composite outcomes.

CONCLUSIONS Lower BMI is associated with a higher risk of primary composite outcomes, which is primarily related to the events of all-cause death or major bleeding during chronic maintenance antiplatelet monotherapy after PCI with DES.