Clinical effects of the new phosphorus binder, bixalomer in hemodialysis patients switched from sevelamer hydrochloride.

It has been reported that sevelamer hydrochloride, which is often used as a polymer phosphorus (P) binder for managing serum P concentration in dialysis patients, causes gastrointestinal adverse effects such as constipation, etc. The reason for this is thought to be that sevelamer hydrochloride has high water absorption, causing it to absorb water and swell in the gastrointestinal tract. In June 2012, the new polymer P binder bixalomer was launched in Japan. Since bixalomer has low swelling due to water absorption, it can be expected to alleviate adverse effects in the gastrointestinal system. In our study, for 21 cases of maintenance hemodialysis patients undergoing treatment with sevelamer hydrochloride at our hospital, the P binder was switched from sevelamer hydrochloride to the same dosage of bixalomer, and the concentrations of serum P, corrected calcium (Ca) and whole parathyroid hormone (PTH) before and one month after the switch were compared. In addition, gastrointestinal symptoms (acid reflux, abdominal pain, indigestion, diarrhea and constipation) were evaluated before and after the switch using a questionnaire based on the Japanese version of the Gastrointestinal Symptom Rating Scale (GSRS). By switching to bixalomer, serum P concentration was significantly reduced (P=0.024), but there were no significant changes observed for serum corrected Ca and whole PTH. Furthermore, there were no significant changes observed for all five of the evaluation items of the GSRS, before and after the switch. These results suggest that although bixalomer can more potently reduce the serum P concentration than sevelamer hydrochloride, there were no significant differences in the effects of both P binders on the gastrointestinal symptoms.

Close association of vascular and valvular calcification and prognosis of patients on continuous ambulatory peritoneal dialysis.

In the present study, we examined the association between vascular and valvular calcification and the prognosis of patients on continuous ambulatory peritoneal dialysis (CAPD). Data were collected from the records of patients introduced onto CAPD therapy during 1999 - 2006 at the Department of Nephrology, Saitama Medical University. At the start of CAPD, cardiac and vascular echography were used to examine 162 patients (average age: 56 +/- 5 years; 58 men, 104 women; 43 with and 119 without diabetes) for evaluation of vascular and valvular calcification. Both vascular and valvular calcification were found in 32 patients. Vascular calcification was found in 16, and valvular calcification in 11. Over 5 years, 11 patients suffered from cardiovascular disease (7 with stroke, 4 with myocardial infarction). All of these patients had vascular or valvular calcification at the start of CAPD therapy. We also used Cox hazard analysis to examine values for Ca, P, Ca x P, intact parathyroid hormone (iPTH), and lipids. None of these values were independent contributory factors for incidence of cardiovascular disease in patients on CAPD. These data suggest the importance of vascular and valvular echography to evaluate patients on CAPD, especially at the start of CAPD therapy. Vascular and valvular calcification are important factors for determining the prognosis of patients on CAPD.