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Most patients on dialysis have persistent hyperphosphatemia, despite dietary phosphate restriction and treatment with phosphate binders. Previous small randomized controlled trials have suggested that nicotinamide effectively reduces serum phosphate concentrations in dialysis patients. However, the treatment remains controversial.
We systematically searched PubMed, Embase, and Cochrane databases for parallel arm randomized controlled trials that compared nicotinamide with placebo in patients on dialysis therapy regarding the following outcomes: change in serum phosphorus, calcium, PTH, HDL, and platelet count. Statistical analysis was performed using Review Manager 5.1.7, and heterogeneity was assessed by I2 statistics. P values less than 0.05 were considered statistically significant.
Six randomized controlled trials were included, comprising 1002 patients, of whom 575 (57,3%) have received nicotinamide. The serum phosphorus levels were significantly lower in those treated with nicotinamide (MD -0.91; 95% CI -1.60 to -0.23; p=0.009; I²=94%; Figure 1A), but there was no difference in serum calcium (MD -0.37; 95% CI -1.07-0.33; p=0.30; I²=95%; Figure 1B), and PTH levels (MD -36.51; 95% CI -99.58-26.57; p=0.26; I²=95%; Figure 1C). There was no significant difference in the HDL levels (MD 6.20; 95% CI 0.10-12.30; p=0.05; I²=73%; Figure 2A). Regarding platelets count, the nicotinamide group had a significantly higher risk of thrombocytopenia (MD -10.18; 95% CI -20.13 to -0.24; p=0.04; I²=0%; Figure 2B) than did the control group.
This meta-analysis suggests that in patients with hyperphosphatemia on dialysis, nicotinamide was associated with a significant reduction in phosphorus levels than placebo. However, nicotinamide probably causes thrombocytopenia.