P1379Atrial fibrillation, bone marrow density and the risk of fracture in patients with osteoporosis

Abstract

Background: Atrial fibrillation (AF) is common in older adults and is associated with an increased risk of stroke, heart failure, dementia, and death. AF is associated with dizziness, weakness, and decreased cardiac and cerebral perfusion, and these in turn may increase the likelihood of falls. Oral anticoagulants, used to prevent stroke in AF, have also been linked to reduced bone mineral density (BMD). However, the influence of comorbid AF on the incidence and outcome of fracture, and BMD are not well understood in patients with osteoporosis. Purpose: The purpose of this study was to investigate whether comorbid AF was associated with facture occurrence, mortality after fracture and the change of BMD in general population with osteoporosis. Methods: This nationwide, population-based, propensity score-matched cohort study used data from Korean National Health Insurance Service-National Sample Cohort. We included 36,179 patients with osteoporosis who aged 50 years and older and received national health check-up between 2009 and 2013. Patients with malignant neoplasm history were excluded. Propensity scores for comorbid AF were estimated for each of study patients and used to assemble a cohort for patients with AF (n = 1,479) and matched patients without AF (n = 4,437), who were balanced on 14 baseline characteristics. We also assess the potential relationship between AF and the changes of bone marrow density (BMD), and the correlation of antithrombotics with BMD in 2,604 osteoporosis patients in one Hospital, Korea. Results: AF was observed in 4.1% (1,484 of 36,179) of osteoporotic patients. Compared with the matched non-AF patients, AF patients had higher fracture rate (38.8 vs. 32.0 per 1,000 person-year, p = 0.015). In a multivariate Cox regression analysis, AF was associated with incidence of fracture independently of other risk factors among propensity-matched patients with osteoporosis (HR: 1.24, 95% CI: 1.05- 1.46, p = 0.010). In subgroup analysis, this association was especially pronounced in patients without heart failure (HR: 1.34, 95% CI: 1.09-1.64, p = 0.006) and patients with hypertension (HR: 1.28, 95% CI: 1.08-1.53, p = 0.005). The mortality after fracture event was significantly higher in AF than non-AF patients (28.1% vs. 8.4%, p<0.001). AF patients with warfarin had significantly lower BMD than AF patients without warfarin (0.73 ± 0.10 g/cm2 vs. 0.79 ± 0.02 g/cm2, p=0.031) and propensitymatched non-AF patients (0.79 ± 0.01 g/cm2, p=0.030) Conclusions: Comorbid AF in patients with osteoporosis is an independent risk factor for facture occurrence and increases mortality after fracture event.