Prediction of the change in bone mineral density induced by gonadotropin-releasing hormone agonist treatment for endometriosis

OBJECTIVE: To observe the long-term changes in bone metabolism induced by GnRH agonist (GnRHa) treatment and to determine the factor that affected the change in bone mineral density (BMD). DESIGN: Prospective observational study. SETTING: Department of obstetrics and gynecology in university and general hospitals. PATIENT(S): Fifty women with endometriosis treated with GnRHa between 1994 and 1996. INTERVENTION(S): Leuprolide acetate administered for 24 weeks. Bone mineral density measurement by dual energy x-ray absorptiometry and collection of blood and urine samples were conducted until 12 months of posttreatment. MAIN OUTCOME MEASURE(S): Spinal BMD and bone turnover markers. RESULT(S): Mean BMD percent changes from pretreatment were -4.9% and -3.4% at 6 months of treatment and at 12 months of posttreatment, respectively. When the patients were divided by the median pretreatment deoxypyridinoline (DP) level, recovery of BMD after GnRHa discontinuation was slower in the Low-DP group than in the High-DP group. A significant positive correlation was found between the pretreatment DP level and the percent change in BMD at 12 months of posttreatment. No significant relation between BMD and the other bone turnover markers was noted. CONCLUSION(S): Bone mineral density changes were diverse among patients who were administered GnRHa. The pretreatment DP level may be the predictive factor for GnRHa-induced BMD change.