MP27-08 STONE PREVENTION WITH MEDICAL MANAGEMENT: FACTORS AFFECTING COMPLIANCE AND ADHERENCE

Abstract

INTRODUCTION AND OBJECTIVES: Osteoporosis, which is characterized by a reduction in bone mineral density (BMD), is frequently detected in postmenopausal women as well as in men. Reduced BMD has been reported in patients with urolithiasis associated with hypercalciuria or normocalciuria. Bisphosphonates potently inhibit bone resorption and are used in the management of osteoporosis. We have reported that bisphosphonate prevents the recurrence of urinary stones in postmenopausal women. In this study, we investigated the ability of bisphosphonate to prevent the recurrence of urolithiasis in men with osteoporosis. METHODS: We studied 25 men aged <70 years (55.4 9.4 years) who were diagnosed with osteoporosis without hypercalciuria. Patients using steroids or anti-osteoporosis drugs were excluded. The patients’ stones were composed of calcium oxalate (CaOx) (n 1⁄4 17) or CaOx + calcium phosphate (CaP; n 1⁄4 8). We analyzed serum and 24hour urine specimens collected before and 1 month, 3 months, and 12 months after initiation of oral administration (5 mg/day or 35 mg/week) of alendronate (ALN), a new-generation bisphosphonate compound. The indices of the ionic activity products of CaOx (AP(CaOx)) and CaP (AP(CaP)) were estimated using the Tiselius method. Eleven of the 12 patients continued treatment for 24 months. We analyzed the ability of ALN to prevent the recurrence of urolithiasis by comparing the results with those of control subjects with osteoporosis (n 1⁄4 18, 56.2 9.7 years) who were treated for urolithiasis without ALN administration. RESULTS: ALN rapidly and significantly reduced the excretion of urinary calcium (162 75 [before] to 116 67 [3 months] and 118 75 [12 months] mg/day; p < 0.05) and the AP(CaOx) index (1.55 0.67 [before] to 0.89 0.79 [3 months] and 0.90 0.77 [12 months]; p < 0.05). The AP(CaP) index tended to decrease (1.27 0.75 [before] to 0.96 1.20 [3 months] and 0.95 1.24 [12 months]) as well. The urinary oxalate and phosphate levels showed no significant change. The incidence of urolithiasis (episodes/year) was significantly lower in patients treated with ALN than in those who were not (0.083 and 0.250, respectively; p < 0.05). CONCLUSIONS: ALN appears not only to improve BMD and alleviate osteoporosis but also to reduce the risk of calcium stone formation in men with osteoporosis. Bisphosphonate is believed to reduce the urinary excretion of calcium by improving bone metabolism and to prevent urolithiasis directly by preventing CaOx crystallization.