Abstract
BACKGROUND: Hyperphosphatemia is a common complication of late-stage chronic kidney disease (CKD). Nicotinamide (NAM) has been reported as an adjunctive therapy for hyperphosphatasemia, but the effect of NAM on fibroblast growth factor 23 (FGF23) and Klotho has rarely been reported. METHODS: We randomly assigned 98 patients who underwent regular hemodialysis to received NAM (0.5-1.5 g per day, or 1-3 tablets per day) or placebo (1-3 tablets per day) as an add-on therapy of calcium-based phosphorus binders in a 1:1 ratio. All enrollments were followed-up for 52 weeks. We investigated the serum phosphorus as the primary outcome and serum FGF23 and Klotho as the secondary outcomes. Abdominal aortic calcification (AAC), which had a good correlation with coronary calcification was also compared between the two groups. RESULTS: In total, 37 patients in the placebo group and 35 patients in the NAM group completed the 52-week follow-up. Compared with the placebo group, the NAM group showed a significant decrease of serum phosphorus at the 8(th), 12(th), 20(th), 44(th), and 52(nd) week. There was a declining trend of FGF23 and Klotho in both the placebo and NAM groups. Linear mixed models (LMMs) for overall comparisons by repeated measures of analysis of variance (ANOVA) revealed a significant decrease of FGF23 and slower declining rate of Klotho in the NAM group. No significant difference of AAC was detected between the two groups (P=0.805). CONCLUSIONS: NAM can not only further decrease the phosphorus level but also reduce the FGF23 level and slow down the descending rate of Klotho in chronic hemodialysis patients.