Evaluation of Fracture Risk Among Patients With Type 2 Diabetes and Nonvalvular Atrial Fibrillation Receiving Different Oral Anticoagulants

Abstract

OBJECTIVE Patients with type 2 diabetes are at higher risk for fracture risk because of attenuated bone turnover and impaired bone microarchitecture. The comparative effect of warfarin over non–vitamin K antagonist oral anticoagulants (NOACs) on incident fractures among patients with type 2 diabetes comorbid with atrial fibrillation (AF) remains to be elucidated. RESEARCH DESIGN AND METHODS This was a retrospective, propensity score–weighted, population-based cohort study of adults with type 2 diabetes and AF who were started on warfarin or NOAC between 2005 and 2019 identified from an electronic database of the Hong Kong Hospital Authority. The primary outcome was a composite of major osteoporotic fractures (hip, clinical vertebral, proximal humerus, and wrist). Hazard ratios (HRs) were calculated using Cox proportional hazards regression models. RESULTS A total of 15,770 patients with type 2 diabetes comorbid with AF were included (9,288 on NOAC, 6,482 on warfarin). During a median follow-up of 20 months, 551 patients (3.5%) sustained major osteoporotic fractures (201 [2.2%] in the NOAC group, 350 [5.4%] in the warfarin group). The adjusted cumulative incidence was lower among NOAC users than warfarin users (HR 0.80; 95% CI 0.64, 0.99; P = 0.044). Subgroup analyses showed consistent protective effects against major osteoporotic fractures among NOAC users across sex, age, HbA1c, duration of diabetes, and history of severe hypoglycemia compared with warfarin users. CONCLUSIONS NOAC use was associated with a lower risk of major osteoporotic fractures than warfarin use among patients with type 2 diabetes comorbid with AF. NOAC may be the preferred anticoagulant from the perspective of bone health.