Abstract 16330: Aspirin Dosing by Body Mass Index: A Patient-Centric Trial Assessing Benefits and Long-Term Effectiveness

Abstract

Introduction: Elevated body mass index (BMI) is a risk factor for cardiovascular (CV) events. It remains unclear if the effectiveness and safety of aspirin dose (81mg vs 325mg) is modified by baseline BMI. Research Question: To determine differences in CV event rates and major bleeding between aspirin dose and BMI in patients with coronary artery disease (CAD). Methods: Participants from the ADAPTABLE trial were stratified by BMI categories defined as normal weight (BMI <25 kg/m 2 ), overweight (BMI ≥25 to <30 kg/m 2 ), and obese (≥30 kg/m 2 ). The primary outcome was a composite of all cause death, hospitalization for myocardial infarction (MI), or hospitalization for stroke, assessed in a time-to-event analysis. The event rate represented events per 100 patient years of follow up. The primary safety outcome was hospitalization for major bleeding with blood product transfusion. Cox proportional hazards models were used to evaluate the primary outcome by aspirin dose and BMI category. Results: A total of 12,715 participants (n=1,822 normal weight, n=4,485 overweight, and n=6,408 obese) had data available for BMI and analysis. The event rate for the primary outcome in those at normal weight was similar across aspirin dose (5.38 for 81mg vs 5.43 for 325 mg, adjusted HR 1.06 [95% CI 0.81-1.39]). This relationship was also seen in both overweight (3.53 for 81mg vs. 3.27 for 325mg, 1.10 [0.88-1.36]), and obese (3.50 for 81mg vs 3.45 for 325 mg, 1.04 [0.87-1.25]) BMI (figure). There was no difference in the primary safety outcome by aspirin dose [normal weight 0.92 (0.41-2.08), overweight 1.65 (0.77-3.55), obese 1.17 (0.62-2.20)]. The overall event rate for the primary outcome was lower in overweight (0.68 [0.57-0.81]) and obese (0.65 [0.55-0.78]) groups compared to normal weight. Conclusion: In ADAPTABLE, no difference was seen in CV event rates and major bleeding across BMI by aspirin dose. However, the overall event rates were lower in elevated BMI groups suggesting an obesity paradox.