PROTRACTED USE, UP TO 6 YEARS, OF AN ORALAMINOBISPHOSPHONATE IN PATIENTS WITH ESTABLISHED OSTEOPOROSIS

In osteoporotic women (n:163), 63.8 (+/-8.1) years old and 15.2 (+/-8. 3) years since menopause, oral (200mg/day) pamidronate was administere d during protracted periods, up to 6 years. During the first 4 years o f therapy significant increases from basal in both, lumbar spine and f emoral neck were reported (p<0.01). Patients who underwent to 5-6 year s of treatment also showed positive results in both skeletal sites. Wh ole body mineral content estimated a 23,8g/year mean gain during a 4-y ear period. Biochemical bone markers of resorption and formation refle cted a variable degree of bone turnover decrease. Such changes were mo re pronounced at the beginning, and remained steady after the first ye ar of continuous therapy. Calcemia remained between normal range witho ut any hypocalcemic episode being reported. Phosphatemia, within norma l range, showed a smooth trend to increase. PTH remained within normal range and vitamin D tended to slightly increase. The total number of new bone fractures and total number of patients with new fractures wer e less frequent during the pamidronate treatment period than before (p <0.01). Indeed, the relative risk (RR) of fracture was estimated compa ring the treatment lapse, 495 patient/year, vs a pretreatment period o f 1,814 patient/year. Overall RR resulted less than 1 (RR = 0.83; CI 9 5% = 0.53-1.26). In total, hip, forearm and ''other'' fractures, RR wa s also less than 1 and remained over 1 in vertebral fractures. The lat ter can be explained because our sample started its treatment probably in a period of increased spine crushing. Overall fracture results, in a sample of patients as own controls and in spite of differences in a ges, suggested that during treatment, patients improved their skeletal biomechanical competence, mainly in sites where cortical bone plays a meaningful role, as in femoral neck. It is concluded that pamidronate is an effective tool to ameliorate the skeletal conditions of postmen opausal osteoporotic women.