Apixaban after hip or knee arthroplasty versus enoxaparin: efficacy and safety in key clinical subgroups


Gary E. Raskob, College of Public Health, University of Oklahoma Health Sciences Center, 801 NE 13th Street, Oklahoma City, OK 73104, USA.
Tel.: +1 405 271 2232; fax: +1 405 271 3039.
E-mail gary-raskob@ouhsc.edu


Background:  New oral anticoagulants for thromboprophylaxis after hip or knee arthroplasty have been given as fixed-dose regimens.

Objective:  To evaluate the consistency of the antithrombotic efficacy and bleeding risk of apixaban 2.5 mg twice daily compared with enoxaparin 40 mg once daily after knee or hip arthroplasty across the clinical characteristics of age, gender, body weight, body mass index (BMI) and creatinine clearance.

Methods:  The pooled results of the ADVANCE-2 (knee arthroplasty) and -3 (hip arthroplasty) randomized trials were used to evaluate if treatment had a statistically significantly different effect (P < 0.10) on major venous thromboembolism (VTE) and bleeding for the characteristics of age, gender, body weight, BMI and creatinine clearance. Both univariate analysis and multivariate logistic regression were used.

Results:  Univariate analyses identified statistically significant interactions for age and major VTE (P = 0.09); for both age (P = 0.07) and body weight (P = 0.07) and the outcome of major bleeding; and for creatinine clearance (P = 0.03) and the composite outcome of major and clinically relevant non-major bleeding. Estimates of these possible differences were not precise, with wide 95% confidence intervals (CIs) that included a zero difference for several subgroups. Multivariate logistic regression analysis did not detect a statistically significant interaction for any outcomes.

Conclusions:  This analysis found no convincing evidence that age, weight, gender, BMI or creatinine clearance influenced the balance of benefit to risk for apixaban compared with enoxaparin. Because only 5% of patients had a creatinine clearance between 30 and 50 mL min−1, further data are needed in such patients.