Warfarin users may have higher risk for fracture
Patients with atrial fibrillation who used warfarin had a higher fracture risk than those who used direct oral anticoagulants, according to a study published in JAMA Internal Medicine.
“This study adds to the growing body of evidence suggesting that warfarin has an adverse effect on bone health,” Pamela L. Lutsey, PhD, an associate professor in the division of epidemiology and community health at the University of Minnesota, told Healio Primary Care. “Caution should be used when prescribing warfarin to [atrial fibrillation] patients at elevated fracture risk.”
Using the MarketScan database, Lutsey and colleagues identified patients with atrial fibrillation who received warfarin or direct oral anticoagulants (DOACs) between January 2010 and September 2015. DOAC users were matched with up to three warfarin users by age, sex, time of database enrollment and treatment initiation date. Researchers compared incidence of hip fracture, fractures that required hospitalization and clinical fractures between the two groups.
A total of 167,275 patients with atrial fibrillation who had a mean age of 68.9 years were included in the study. Within the cohort 7,294 fractures occurred during a mean follow-up period of 16.9 months, including 817 hip fractures and 2,013 hospitalized fractures.
Lutsey and colleagues found that new users of DOACs tended to have a lower risk for fractures that required hospitalization (HR = 0.87; 95% CI, 0.79-0.96) and all fractures (HR = 0.93; 95% CI, 0.88-0.98) compared with those who took warfarin.
There was not a statistically significant difference in risk for hip fracture between warfarin and DOAC users (HR = 0.91; 95% CI, 0.78-1.07).
When comparing results between warfarin and specific DOACs, researchers found that apixaban (Eliquis, Bristol-Myers Squibb) was associated with the lowest risk for hip fracture (HR = 0.67; 95% CI, 0.45-0.98), fractures requiring hospitalization (HR = 0.6; 95% CI, 0.47-0.78) and all fractures (HR = 0.86; 95% CI, 0.75-0.98) compared with warfarin.
In a subgroup analysis, researchers found that use of DOACs was more beneficial among patients with osteoporosis compared with those without.
“There are many considerations when deciding between oral anticoagulants, such as cost, convenience, reversibility, food and drug interactions, and the need for monitoring,” Lutsey said. “For patients at high fracture risk, the potential adverse effect of warfarin on bone health may be an important consideration when deciding which oral anticoagulant to start, or whether to switch from warfarin to a direct oral anticoagulant.” – by Erin Michael
Disclosures: Lutsey reports no relevant financial disclosures. Please see study for all other authors’ relevant financial disclosures.