Risk of osteoporosis in patients with atrial fibrillation with and without oral anticoagulant therapy.

Background: We aimed to compare the risk of developing osteoporosis in patients prescribed warfarin or direct-acting oral anticoagulants (DOACs) with those with no therapy.
Research Design and Methods: We included 37,632 patients aged between 18 and 111 years with a recorded diagnosis of AF between 1 January 2013 and 31 December 2017. Patients were followed until the diagnosis of osteoporosis, switch or discontinuation of the OAC, last clinical visit, or end of the study period, whichever occurred first. The incidences of new-onset osteoporosis were calculated using the Cox proportional hazards model.
Results: Of total, 16,995 (45.2%) had no recorded OAC prescription, and 20,637 had a recorded prescription of warfarin (6,609) or DOAC (14,028). Compared with those not prescribed an OAC, the risk of being diagnosed with new-onset osteoporosis increased in patients prescribed warfarin (HR 2.22, 95% CI 2.00-2.47, p < 0.001) and DOACs (HR 1.42, 95% CI 1.29-1.58, p < 0.001). However, the effect of DOACs was not statistically significant (HR 1.07, 95% CI 0.86-1.33, p < 0.535) after excluding patients with at least one recorded prescription of systemic corticosteroids, antiepileptics, or proton pump inhibitors.
Conclusions: Use of warfarin or DOACs was associated with a significantly increased risk of developing osteoporosis compared with no OAC treatment.