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.
