Direct oral anticoagulants are administered in fixed doses irrespective of body weight, but guidelines recommend against their use in patients with extremes of body weight.
This study determined the effects of dual-pathway inhibition antithrombotic regimen (rivaroxaban 2.5 mg twice daily plus aspirin 100 mg/day) compared with aspirin Halone across a range of patient body mass indexes (BMIs) and body weights.
This was a secondary analysis of the COMPASS (Cardiovascular OutcoMes for People using Anticoagulation StrategieS) trial, which included patients with chronic coronary artery disease or peripheral artery disease. Efficacy and safety outcomes were studied in relation to BMI: (normal 18.5 ≤BMI <25 kg/m2, overweight 25 ≤BMI <30 kg/m2, obese ≥30 kg/m2) and body weight (≤70 kg, 70 < weight ≤90 kg, and >90 kg; as well as ≤120 kg vs. >120 kg).
Among 27,395 randomized patients, 6,459 (24%) had normal BMI, 12,047 (44%) were overweight, and 8,701 (32%) were obese. The combination of rivaroxaban and aspirin compared with aspirin produced a consistent reduction in the primary outcome of cardiovascular death, stroke, or myocardial infarction, irrespective of BMI or body weight. For 18.5 ≤BMI <25 kg/m2: 3.5% vs. 5.0%; hazard ratio (HR): 0.73 (95% credible interval [CrI]: 0.58 to 0.90); 25 ≤ BMI <30 kg/m2: 4.3% vs. 5.1%; HR: 0.80 (95% CrI: 0.66 to 0.96); BMI ≥30 kg/m2: 4.2% vs. 6.1%; HR: 0.71 (95% CrI: 0.57 to 0.86). For body weight ≤70 kg: 4.1% vs. 5.3%; HR: 0.75 (95% CrI: 0.62 to 0.91); 70 < weight ≤90 kg: 4.1% vs. 5.3%; HR: 0.76 (95% CrI: 0.65 to 0.89); >90 kg: 4.2% vs. 5.7%; HR: 0.74 (95% CrI: 0.61 to 0.90). Effects on bleeding, mortality, and net clinical benefit were consistent irrespective of BMI or bodyweight.
The effects of dual-pathway antithrombotic therapy are consistent irrespective of BMI or body weight, suggesting no need for dose adjustments in the ranges of weights and BMI of patients enrolled in the COMPASS trial. Further studies need to address this problem in relation to greater extremes of body weight. (Rivaroxaban for the Prevention of Major Cardiovascular Events in Coronary or Peripheral Artery Disease [COMPASS]; NCT01776424).