Prostate-selective α antagonists increase fracture risk in prostate cancer patients with and without a history of androgen deprivation therapy: A nationwide population-based study

Introductions: Prostate-selective α antagonists are recommended for relief of lower urinary tract symptoms in prostate cancer patients despite uncertainty of fracture risk as an addition to androgen deprivation therapy (ADT). The purpose of this study is to estimate fracture risk associated with these medications in prostate cancer patients who did and did not receive ADT. Methods: The Taiwan National Health Insurance database was used to identify prostate cancer patients. We identified all 90-day person-quarters exposed to and not exposed to prostate-selective α antagonists. A generalized estimating equation model was used to estimated adjusted odd ratios (ORs) and 95% confidence intervals (CIs) for fracture associated with prostate-selective α antagonists with consideration for confounding by indication bias using propensity score. Results: During 1997-2008, 16,601 persons received a diagnosis of prostate cancer, among whom 13,694 received ADT. Among prostate cancer patients receiving ADT, fracture was significantly more common in person-quarters with prostateselective α antagonist use than in quarters without such treatment (OR, 1.08; 95% CI, 1.00-1.18). Prostate-selective α antagonist use was most strongly associated with femur fracture (OR, 1.22; 95% CI, 1.09-1.38), followed by skull fracture (OR, 1.29; 95% CIs: 0.93-1.80). Among patients who did not receive ADT, fracture was more common in person-quarters with prostate-selective α antagonist use than in those without medication use (OR, 1.19; 95% CI, 0.91-1.55).