Effects of raloxifene on bone metabolism in postmenopausal women on chronic hemodialysis.

BACKGROUND: Postmenopausal women with end-stage renal failure are at an increased risk of fracture because of the effects of secondary hyperparathyroidism and postmenopausal osteoporosis. In the present study, we investigated the feasibility of using raloxifene to prevent fractures in postmenopausal women with end-stage renal failure on hemodialysis. METHODS: This study was conducted using a multicenter, single-arm, prospective design. Raloxifene was administered to postmenopausal women aged ≥50 years who were on maintenance hemodialysis and met any of the following criteria after a 24-week run-in period: an alkaline phosphatase level (bone formation marker) of ≥6.18 µkat/L (≥370 U/L), a bone-specific alkaline phosphatase (BAP; bone formation marker) level of ≥0.59 µkat/L (≥35.4 U/L), or a bone-derived tartrate-resistant acid phosphatase (TRACP-5b; bone resorption marker) level of ≥4.2 U/L. RESULTS: A total of 48 individuals were eligible for study inclusion. Of them, 30 individuals participated in this study. The BAP levels were significantly decreased at week 4, but returned to the baseline levels at week 24. Similarly, the TRACP-5b levels were significantly decreased at week 4, but returned to the baseline levels at week 24. The serum calcium value decreased consistently after the start of raloxifene therapy. The intact parathyroid hormone (iPTH) levels were likely increased at week 4. The ratio of BAP to iPTH levels and the ratio of TRACP-5b to iPTH levels both showed significant decreases over time. During the raloxifene therapy, no thrombosis or other drug-related adverse events developed. CONCLUSION: The study results indicated that raloxifene can transiently reduce the levels of bone metabolism markers and might be useful for preventing fractures in postmenopausal women with end-stage renal failure, although raloxifene use over the long term may not have adequate efficacy in the absence of appropriate concomitant active vitamin D therapy.

Influence of sevelamer on mineral metabolism and hyperparathyroidism in Japanese hemodialysis patients.

In June 2003, sevelamer hydrochloride became widely available in Japan and was expected to control hyperphosphatemia in hemodialysis patients without inducing hypercalcemia. To evaluate the impact of sevelamer therapy on mineral metabolism, we recruited 954 hemodialysis patients from 21 renal units just before the general release of sevelamer in Japan. The serum calcium, phosphate, and parathyroid hormone levels determined on enrollment were compared with those later measured in June 2004. Sevelamer was prescribed for 169 of the 859 patients for whom data were available in 2004. The mean calcium level, phosphate level, and calcium x phosphate product were all significantly reduced during the 12-month study period, but the intact parathyroid hormone (iPTH) level did not change. As a result, the percentage of patients who achieved a calcium x phosphate product of <55 mg(2)/dL(2) was significantly increased, but there were no changes in that of patients who achieved the target ranges for phosphate (3.5-5.5 mg/dL) or iPTH (150-300 pg/mL). Among sevelamer-treated patients, iPTH significantly increased, and this change was more marked in the patients with an initial iPTH level <150 pg/mL. Sevelamer was useful for reducing the serum calcium level and calcium x phosphate product, but hyperphosphatemia and hyperparathyroidism were not improved in our study population at 12 months after the release of sevelamer. A decrease in the calcium load might result in the exacerbation of hyperparathyroidism. However, among patients with relative hypoparathyroidism, sevelamer therapy may be beneficial for the prevention of adynamic bone disease.