80 OSTEOPOROSIS MANAGEMENT PROGRAM DECREASES THE INCIDENCE OF HIP FRACTURES IN PATIENTS WITH PROSTATE CANCER ON ANDROGEN SUPPRESSION

Abstract

INTRODUCTION AND OBJECTIVES: Androgen suppression as a treatment for prostate cancer can cause osteoporosis, which can result in hip fractures. Kaiser Permanente Southern California (KPSC) has pioneered an osteoporosis disease management program, Healthy Bones Program (HBP), which has shown to reduce hip fracture rates in the osteoporotic population. However, it is currently unknown if patients who are on androgen suppression due to prostate cancer would also experience a lower rate of hip fracture if enrolled in HBP. METHODS: Since 2002, the Healthy Bones Program has been implemented at all KPSC hospitals for any patient who has the risk of developing osteoporosis. HBP patients undergo a dual x-ray absorptiometry scan (DEXA), and are started on oral Vitamin D/calcium and/or bisphosphonate therapy based on their initial T score. Using the KPSC Cancer Registry, we performed a retrospective review of 2,182 patients who were diagnosed with prostate cancer between January 2003 and December 2007 and are on leuprolide androgen suppression up to September 2008. Patients who were in the HBP were identified by the presence of DEXA scans, whereas patients who were not followed by the protocol did not have DEXA scans. Exclusion criteria included: patients who had less than 6 months of health plan membership, were younger than 50 years of age, had a DEXA scan performed greater than 3 months prior to the first leuprolide dose, had less than 6 months of follow up, had a previous hip fracture, and patients who had only one dose of leuprolide. The number of hip fractures was recorded. RESULTS: A final group of 1,482 patients was identified. There were 1,025 patients in the HBP cohort, and 457 patients in the nonHBP group. The mean age was older in the HBP group, 74 vs. 71 years, respectively (p 0.01). The mean total number of leuprolide dosages given was also higher for the HBP group, 6.3 vs. 4.8, respectively (p 0.01). The racial breakdown was similar between the two groups (p 0.5). The incidence rate of hip fractures per 1,000 person years was lower for the HBP group, 4.44 vs. 11.96, respectively. For patients who sustained hip fractures, median time from first leuprolide dose to hip fracture was longer for the HBP group, 834 days to 390 days, respectively. CONCLUSIONS: Hip fracture incidence rates are reduced by nearly one third when castrated prostate cancer patients are enrolled in the HBP. Due to the high healthcare costs, morbidity and mortality of hip fractures, this finding may have a significant implication in the management of this population of patients on androgen suppression for prostate cancer.