Effect of atrial fibrillation on the incidence and outcome of osteoporotic fracture ― A nationwide population-based study ―

Background: Both atrial fibrillation (AF) and osteoporosis are common in older adults. The purpose of this study was to investigate whether comorbid AF in patients with osteoporosis is associated with fracture incidence, or death after fracture. Methods and Results: From the National Health Insurance Service database of Korea, we selected 31,778 patients with osteoporosis. During a median follow-up of 48 months, the incidence of bone fractures was higher in AF patients than in non-AF patients (3.20 vs. 2.18 per 100 person-years), respectively. In the multivariate Cox regression analysis, AF was associated with fracture independently of other risk factors with an adjusted hazard ratio (HR) of 1.21 (95% confidence interval [CI], 1.02–1.41; P=0.031). The mortality rate after fracture was significantly higher in AF patients than it was in non-AF patients (adjusted HR, 1.92; 95% CI, 1.35–3.27; P=0.016). After propensity score-matching, AF was consistently associated with a higher risk of osteoporotic fracture and subsequent death after fracture. In AF patients, older age, female sex, being underweight (body mass index <18.5 kg/m²), decreased physical activity (exercise <3 times/week), history of stroke or transient ischemic attack, thiazide use, sedative use, and higher CHADS₂ (≥2 points) or CHA₂DS₂-VASc (≥2 points) scores were associated with the incidence of fractures. Conclusions: Comorbid AF in patients with osteoporosis was associated with an increased risk of bone fracture and death after fracture.