Finasteride not associated with increased risk of hip fracture in men

Key Points

A study published in the Journal of the American Medical Association reported that use of finasteride, a 5-alpha reductase inhibitor commonly used to treat benign prostatic hyperplasia (BPH), does not appear to be associated with an increased incidence of hip fractures in men; in fact, the agent appears to decrease the risk of hip fracture.

This population-based, case-control study of hip fracture used data from Kaiser Permanente Southern California (KPSC) to compare 7,076 men aged ≥45 years who had a new diagnosis of hip fracture between 1997 and 2006 (case patients) with 7,076 men without hip fracture (control patients). Patients were matched 1:1 based on age, race/ethnicity, membership in the health plan on the fracture date, and medical center. Use of 5-alpha reductase inhibitors was identified from electronic pharmacy files from 1991 onward. Prescriptions for alpha-blockers (terazosin, tamsulosin, doxazosin, alfuzosin, phentolamine, phenoxybenzamine, and prazosin) were also identified. The primary analysis was a comparison of the frequencies of exposure to 5-alpha inhibitors in case and control patients. Investigators also included the use of alpha-blockers, a diagnosis of BPH, and surgical treatment of BPH in secondary analyses.

The median age of patients at time of fracture was 77 years. Patients with hip fracture were more likely than those without hip fracture to have multiple comorbid conditions (P<.001). Among enrolled patients, 2,547 case patients (36%) and 2,488 control patients (35%) had a diagnosis of BPH (P=.30). A total of 109 case patients (1.5%) and 141 control patients (2.0%) were exposed to finasteride (no dutasteride prescriptions were recorded); finasteride use was associated with a lower risk of hip fracture than nonuse (OR=0.77; 95% CI, 0.59–1.00; P=.04). Investigators did not observe a dose-response relationship between use of finasteride and hip fracture (P=.12).

The authors pointed out that although this decreased risk of hip fracture associated with finasteride does not appear to be the result of underlying BPH or confounding by comorbidity, it is possible that an unmeasured confounder may have skewed the results; they suggested that further study is needed to examine this theory, adding, "While presumably this lower risk is related to hormonal mechanisms, further understanding of the biological mechanisms underlying this phenomenon may lead to new insights that can be exploited for preventive measures."

SOURCE

Jacobsen SJ, Cheetham TC, Haque R, Shi JM, Loo RK. Association between 5-alpha reductase inhibition and risk of hip fracture. JAMA. 2008;300:1660–1664.