Oral anticoagulants and the risk of osteoporotic fractures among elderly.

PURPOSE: Coumadin-based oral anticoagulants are associated with a decrease in bone mass density, but their role in fracture risk is equivocal. Because the use of oral anticoagulants is prevalent among the elderly, as is the risk and morbidity of osteoporotic fractures, the association between osteoporotic fractures and oral anticoagulants needs to be clarified.
METHOD: We conducted a case-control study on a 10% random sample of subjects aged 70 years and older enrolled in the Quebec universal health insurance plan between 1992 and 1994. Incident cases of a first osteoporotic fracture were identified by International Classification of Diseases, Ninth Revision codes. Exposure was defined as one or more prescriptions of oral anticoagulants dispensed before the osteoporotic fracture. Ten controls for each case, matched by age and date of osteoporotic fracture, were identified.
RESULTS: Among 1523 cases, 48 (3.2%) were ever exposed to oral anticoagulants; among 15,205 controls, 461 (3.0%) were ever exposed (crude odds ratio: 1.0: 95% confidence interval: 0.7-1.5). These negative results persisted after adjusting for potential confounding variables and stratifying exposure into cumulative dose and treatment duration.
CONCLUSIONS: Coumadin-based oral anticoagulants are not significantly associated with osteoporotic fractures among the elderly, providing reassurance for elderly patients on long-term oral anticoagulants. Copyright 2003 John Wiley & Sons, Ltd.