Gage and colleagues found that in elderly patients, warfarin use to treat atrial fibrillation for more than 1 year was independently associated with osteoporotic fracture.1 Adjusting for multiple cofounders of fractures and plausible mechanism-linked reasons for warfarin use and osteoporotic fracture made their finding more real than by chance. However, their study did not show the size of the effect of warfarin use on osteoporotic fracture.1 The size of the effect in an observational study is important.2 Many risk factors of osteoporotic fractures such as age and fall risk in elderly patients have been adjusted,1 but it is still unclear how many osteoporotic fractures were due to long-term use of warfarin. Elderly patients with high risk for falls were excluded from clinical trials of atrial fibrillation.3 It will be helpful to examine the effect of long-term use of warfarin on the incidence of osteoporotic fractures in future trials.
Cheng HY. The Association of Warfarin Use With Osteoporotic Fracture in Elderly Patients With Atrial Fibrillation. Arch Intern Med. 2006;166(14):1525. doi:10.1001/archinte.166.14.1525-a