Abstract
Background/Introduction
Osteoporotic fractures are associated with high mortality and reduced life quality in an elderly population. Several studies report an increased risk of fractures among patients treated with oral anticoagulants (OAC), however, only sparse research has been made to clarify the difference between treatment with vitamin K antagonists (VKA) and non-VKA oral anticoagulants (NOACs) regarding the risk of osteoporotic fractures.
Purpose
The purpose of this study was to evaluate the risk of osteoporotic fractures among patients with atrial fibrillation (AF) in long-term VKA or NOAC treatment.
Methods
Patients with AF were identified using Danish national registries and were included when they had undergone 180 days OAC treatment, and only if they had no prior use of osteoporosis medication. The study period was from 1 January 2013 until 30 June 2017, and patients were followed for 2 years, or until death, outcome or emigration. Outcomes were hip fracture, major osteoporotic fracture, any fracture, initiation of osteoporosis medication, and a combined endpoint. G-formula was used to determine standardized absolute risk, and multiple covariate adjusted Cox regressions were used to calculate hazard ratios (HR).
Results
Overall, 37,350 patients with AF were included; 32.6% received VKA treatment (median age 72 years, 61.8% men) and 67.4% received NOAC treatment (median age 73 years, 55.9% men). The standardized absolute 2-year risk of any fracture was low among NOAC treated patients (3.1%; 95% CI: 2.9% to 3.3%), and among VKA treated patients (3.8%; 95% CI: 3.4% to 4.2%).
NOAC was associated with a significantly lower relative risk of any fracture (HR: 0.85; 95% CI: 0.74 to 0.97), of major osteoporotic fractures (HR: 0.85; 95% CI: 0.72 to 0.99), and of initiating osteoporotic medication (HR: 0.82; 95% CI: 0.71 to 0.95). A combined endpoint showed that patients treated with NOAC had a significantly lower risk of suffering from any fracture or initiating osteoporosis medication (HR: 0.84; 95% CI: 0.76 to 0.93).
Adjusted relative two-year risks
Conclusion
In a nationwide population, the absolute risk of osteoporotic fractures was low among AF patients on OAC, but NOAC was associated with a significantly lower risk of osteoporotic fractures compared to VKA.
Acknowledgement/Funding
Scholarship from The Copenhagen University Hospital Herlev and Gentofte