Risk of Clinical Fractures After Gonadotropin-Releasing Hormone Agonist Therapy for Prostate Cancer

Abstract

We assessed the relationship between GnRH agonists and the risk of clinical fractures in men with prostate cancer. Using a database of medical claims from 16 large American companies we identified a study group of 3,779 men with prostate cancer who received treatment with a GnRH agonist and a control group of 8,341 with prostate cancer who were not treated with a GnRH agonist. Men with 1 or more medical claims for bone metastases were excluded. The rates of any clinical fracture, hip fracture and vertebral fracture were compared between the groups. The rate of any fracture was 7.91/100 vs 6.55/100 person-years at risk in men who received vs did not receive a GnRH agonist (relative risk 1.21, 95% CI 1.09 to 1.34). The rates of hip fracture (relative risk 1.76, 95% CI 1.33 to 2.33) and vertebral fracture (relative risk 1.18, 95% CI 0.94 to 1.48) were also higher in men who received a GnRH agonist. GnRH agonist treatment was independently associated with fracture risk on multivariate analyses. GnRH agonists increase the risk of clinical fracture in men with prostate cancer.