What is the effect of adding aspirin and/or clopidogrel to VKA on the risk of bleeding?
The risk of bleeding increased by more than 50% when aspirin (HR, 1.50; 95% CI, 1.23-1.82) or clopidogrel (HR, 1.84; 95% CI, 1.11-3.06) was added to VKA. In the RCTs of NOACs compared with warfarin, aspirin at < 100 mg daily was allowed. Ancillary analyses show no added benefit of adding aspirin on stroke or mortality rates; however, absolute bleeding rates were higher with combination therapy, but the relative efficacy and safety with NOAC vs warfarin use were maintained irrespective of aspirin use.