Sevelamer HCL improves parathyroid hormone (PTH) and bone function in peritoneal dialysis (PD) patients with probable low turnover bone disease

SEVELAMER HCL IMPROVES PARATHYROID HORMONE (PTH) AND BONE FUNCTION 1N PERITONEAL DIALYSIS (PD) PATIENTS WITH PROBABLE LOW TURNOVER BONE DISEASE Sharon Mae*, Jan Paterson, Cindy Murphy, Erika Johnson, Mark Deeg. Indiana Univ and Roudebush VAMC, Indpls, IN Patients on PD are more likely to have adynamic or low-turnover bone disease and hypereholesternlemia than are HD patients. Calcium containing phosphate binders may contribute to the high incidence of adynamic bone disease due to the positive calcium balance they induce. We hypothesized that sevelamer HCL (Renagel®, Geltex/Genzyme, 1⁄2c = SEV) may normalize the excessively low PTH levels observed in PD patients because of the decreased calcium load compared to calcium acetate. To test this, we compared these phosphate binders in PD patients who had a persistent PTH < 200 pg/ml, and BAP < 20 IU, on no Vitamin D in a randomized, cross-over design with 12 wk treatment arms. In each man, PTH, BAP, total calcium corrected for albumin (tCa) and ionized calcium (iCa) were measured after a 2 wk washout (=baseline) and every 4 wks for each 12 wk treatment ann. In addition, the subjects had pre and post lipid studies. Five patients completed the study, with one shortened sevelamer (SEV) arm due to diarrhea. Three other patients dropped out due to transpiantatinn and pancreatitis. The PTH decreased from baseline to 12 weeks by 21 ~16 % in the CaA, vs an increase of 47 :k 12 % in the SEV arm (Mean ± SEM, p = 0.05). This occurred despite equivalent tCa (+0.02 ± 0.11 CaA vs +0.15 ± 0.06 mg/dl in SEV), iCa (-0.31 ± 0.19 CaA vs -0.95 :k 0.17 mg/di in SEV), and phosphorus (-0.31 ± 0.19 CaA vs -0.95 ± 0. I7 rag/all in SEV; all p = NS). The BAP decreased in the CaA arm by 1.52 ± 1.06 IV, compared to an increase of 2.20 ± 0.72 IU in the SEV arm (p < 0.007), supporting improved osteuhlast function. The to~al cholesterol was unchanged in the CaA group (9.5 :~ 13.5%) but decreased by 26.9 ~= 22.9% in the SEV arm, p = 0.08, due primarily to changes in LDL. Dietary recall revealed similar calcium, phosphorus, and cholesterol intake in each arm for each patient. In summary, SEV appears to be a safe and effective phosphate binder in PD patients. The rise in PTH and BAP, and decrease in cholesterol indicates sevelamer may offer a distinct advantage over CaA. Larger, long-term studies are required to confirm these f'mdings. 59