Higher Risk for Major Bleeding with Dabigatran vs. Warfarin in Certain Atrial Fibrillation Patients

The original trials that led to approval of dabigatran (Pradaxa) for preventing strokes in patients with nonvalvular atrial fibrillation (AF) showed that risk for major bleeding was similar with dabigatran and warfarin (NEJM JW Cardiol Sep 1 2009). However, some (but not all) postmarketing case reports and analyses suggested that risk was greater with dabigatran in high-risk patients and in patients with reduced renal function (JAMA Intern Med 2014; 174:150).

In a retrospective cohort study of 9404 Medicare patients with newly diagnosed AF (mean age, 75; mostly white), 1302 patients received dabigatran, and 8102 received warfarin. Follow-up was about 6 months. Adjusted analyses showed that patients who received dabigatran had significantly h…