5 YEARS OF CLINICAL-EXPERIENCE WITH INTERMITTENT CYCLICAL ETIDRONATE FOR POSTMENOPAUSAL OSTEOPOROSIS

Objective. To evaluate the effects of 120 weeks of intermittent cyclic al etidronate on the progression of bone loss and fracture incidence a nd rare in postmenopausal osteoporotic women after 150 weeks of either etidronate or placebo treatment, Methods. This was an open label foll ow up study of 37 postmenopausal osteoporotic women enrolled from the earlier 150 week study, 17 from the etidronate group and 20 from the p lacebo group. Treatment cycles were of oral doses of etidronate 400 mg /day for 2 weeks, followed by a 13 week drug-free period fur a total o f 120 weeks, All patients received a daily supplement of 0,5 g calcium and 400 U vitamin D. Results, During the earlier 150 week study, mean vertebral bone mineral content increased significantly in the etidron ate group by 5.5% (p = 0.013) and decreased by 2.7% (not significant) in the placebo group. After 120 weeks of etidronate treatment in this followup study, patients who had formerly received etidronate experien ced an additional 1.4% increase; after 5 years, bone mineral content w as 6.9% above the original baseline (p = 0.037). Bone mineral content also increased in the former placebo group during the latter study, up to 5.3% above the original study baseline (not significant). The vert ebral fracture rate in the former placebo group decreased significantl y, from 103 to 27 per 100 patient-years (p < 0.01), while the fracture rate in the former etidronate group was unchanged (38 and 33 per 100 patient-years). Conclusion. Five years of etidronate therapy for postm enopausal osteoporosis results in significant increases in vertebral b one mineral content, and the previously observed reduction in vertebra l fracture rate in the etidronate group is maintained during at least 5 years of therapy.