Background: Sevelamer, a nonabsorbed hydrogel that binds phosphate, is reported to reduce the serum urate concentration in maintenance hemodialysis patients, however the urate-lowering mechanism remains obscure. In this study we verify the urate-lowering effect of sevelamer in Japan in which the hemodialysis environment is different from that of western countries, and we also clarify the urate-lowering mechanism of sevelamer.
Methods: A total of 127 Japanese patients undergoing maintenance hemodialysis were investigated. These patients consisted of 93 males and 34 females, and their mean age was 58.4+/-12.4 years (range, 25-88 years). The mean duration of hemodialysis was 8.7+/-6.1 years (range, 0.5-27.5 years). Sevelamer was added to each patient's former prescription for the treatment of hyperphosphatemia, and the changes in laboratory data before and after administration of sevelamer were compared. In order to clarify the mechanism of urate-lowering effect by sevelamer, a urate adsorption experiment was carried out in vitro.
Results: Sevelamer significantly decreased serum phosphate value three and six months after administration. Sevelamer showed a significant reduction in serum urate values in maintenance hemodialysis patients with hyperuricemia, but not in patients with normouricemia. The change rate of serum urate correlated with the change rate of serum phosphate and the change rate of serum calcium x phosphate product, but did not correlate with that of serum calcium. Sevelamer hydrochloride adsorbed urate in vitro.
Conclusion: Sevelamer decreases serum urate possibly by adsorbing urate in hemodialysis patients.