Forearm fractures as predictors of subsequent osteoporotic fractures

Abstract

To assess the ability of distal forearm fractures to predict future fractures, we conducted a population-based retrospective cohort study among the 1288 residents (243 men, 1045 women) of Rochester, Minnesota age 35 years or older who experienced their first distal forearm fracture in 1975-94. During 9664 person-years of follow-up, 548 patients experienced 1109 subsequent fractures, excluding 195 that occurred on the same day as the index forearm fracture. The cumulative incidence of any subsequent fracture was 55% by 10 years and 80% by 20 years following the initial distal forearm fracture. Compared to expected fracture rates in the community, the risk of a hip fracture following the index forearm fracture was increased 1.4-fold in women (95% CI, 1.1-1.8) and 2.7-fold in men (95% CI, 0.98-5.8). In women, the risk of hip fracture differed by age, as we had found in a previous study. Women over age 70 had a 1.6-fold increase (95% CI, 1.2-2.0) in subsequent hip fracture risk whereas women who sustained their first forearm fracture before age 70 years did not have significantly increase risk. By contrast, vertebral fractures were significantly increased at all ages, with a 5.2-fold increase (95% CI, 4.5-5.9) in risk among women and a 10.7-fold increase (95% CI, 6.7-16.3) among men following a first distal forearm fracture. The increased risk in men suggests that a sentinel forearm fracture should not be ignored. Among the women, we also found a missed opportunity for intervention as hormone replacement therapy was underutilized.