For more than 15 years, 5-α reductase inhibitors, which block the conversion of testosterone to dihydrotestosterone, have been used in the treatment of benign prostatic hyperplasia (BPH). Short-term studies show no effects of these agents on bone metabolism, but long-term data are not available. This study [1] aimed to assess the association between use of 5-α reductase inhibitors (eg, finasteride) for BPH and occurrence of hip fracture. It is a population-based case-control study using data from Kaiser Permanente Southern California, a managed care organization with more than 3 million members. Case patients included 7076 men 45 years and older with incident hip fracture from 1997-2006. Control patients were 7076 men without incident hip fracture, optimally matched at a 1:1 ratio to case patients on age and medical center. Electronic information on pharmaceutical use was used to identify use of finasteride from 1991 forward.

Overall, 2547 (36%) and 2488 (35%) case and control patients, respectively, had a diagnosis of BPH (P=.30), and 109 (1.5%) and 141 (2.0%) of case and control patients, respectively, had been exposed to finasteride prior to the index date (matched odds ratio, 0.77; P=.04). There was no suggestion of a dose-response relationship between exposure to 5-α reductase inhibitors when the exposure was stratified into tertiles of total exposure (P=.12). By contrast, there was a slightly higher prevalence of α-blocker use in case vs control patients (32% vs 30%, respectively; P=.04).

In conclusion, exposure to 5-α reductase inhibitors was not associated with increased risk of hip fracture. The reduction in risk observed with exposure to 5-α reductase inhibitors and the modest increase in risk associated with exposure to α-blockers require replication and warrant further investigation.

1. Jacobsen SJ et al. JAMA. 2008;300:1660-1664.