Clinical Expectation of Online Hemodiafiltration: A Japanese Perspective.

Many pieces of evidence of online hemodiafiltration (HDF) have been reported, and the clinical advantage of postdilution online HDF with sufficient substitution is now established. After the approval of online HDF in 2012, the number of online HDF patients has been dramatically increasing in Japan and reached 10% of the total dialysis population at the end of 2013. One of the marked characteristics of Japanese online HDF is a widespread use of predilution treatment and, in 2013, 90.8% of online HDFs were carried out with the predilution mode. The main reason for the wide use of predilution online HDF results from the low blood flow rate in Japan, by which it is difficult to substitute a sufficient volume during the limited treatment time. Other reasons to choose the predilution mode include the reduction of albumin loss and the suppression of membrane fouling during treatment. Contrary to postdilution treatment, adequate clinical evidence has not been reported for predilution online HDF to provide a better outcome of the patients. A further clinical trial is expected to elucidate the clinical advantages over conventional hemodialysis for predilution online HDF.

Combination therapy with sevelamer hydrochloride and calcium carbonate in Japanese patients with long-term hemodialysis: alternative approach for optimal mineral management.

Calcium (Ca) overload by Ca-containing phosphorus (P) binder has been suggested to be implicated in the pathogenesis of soft tissue and vascular calcification, which contribute to increased morbidity and mortality of cardiovascular disease in patients undergoing dialysis. Recently, a noncalcium P binder, sevelamer hydrochloride (sevelamer), has become available in Japan. However, Japanese patients undergoing dialysis might be less tolerant of sevelamer treatment, and it is likely to cause hypocalcemia because their dietary Ca intake is less than that in European and American patients. We evaluated the effects of combination therapy with sevelamer and calcium carbonate (CC) on mineral metabolism in Japanese hemodialysis patients, as an alternative form of P management. A total of 210 hemodialysis patients were enrolled, and were given a small dose of sevelamer (0.75-1.5 g/day) on CC treatment. Sevelamer dose was gradually increased, while CC decreased during 24 weeks. Five patients discontinued sevelamer treatment because of severe constipation, anorexia, and parathyroidectomy for severe secondary hyperparathyroidism. After 24 weeks, the dose of sevelamer was significantly increased to 3.29 g/day (initial dose: 1.47 g/day), while CC was decreased by 54%. Adjusted serum Ca significantly decreased (9.63 +/- 0.57-9.45 +/- 0.67 mg/dL; P = 0.0012), although serum P increased (5.89 +/- 1.32-6.25 +/- 1.32 mg/dL; P = 0.017). Serum intact PTH (iPTH) significantly increased in patients with a low or normal iPTH level (< or =300 pg/mL), while it did not change in patients with secondary hyperparathyroidism (>300 pg/mL). The results suggest that the therapeutic regimen is more tolerant and reduces Ca load in Japanese hemodialysis patients while avoiding hypocalcemia. In addition, the mitigated Ca overload could improve PTH hyposecretion in patients with adynamic bone disease, which is associated with soft tissue calcification and higher mortality in uremia.