The Effect of Extended Release Niacin on Markers of Mineral Metabolism in CKD.

BACKGROUND AND OBJECTIVES: Niacin downregulates intestinal sodium-dependent phosphate transporter 2b expression and reduces intestinal phosphate transport. Short-term studies have suggested that niacin lowers serum phosphate concentrations in patients with CKD and ESRD. However, the long-term effects of niacin on serum phosphate and other mineral markers are unknown.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: The Atherothrombosis Intervention in Metabolic Syndrome with Low HDL/High Triglycerides: Impact on Global Health Trial was a randomized, double-blind, placebo-controlled trial testing extended release niacin in persons with prevalent cardiovascular disease. We examined the effect of randomized treatment with niacin (1500 or 2000 mg) or placebo on temporal changes in markers of mineral metabolism in 352 participants with eGFR<60 ml/min per 1.73 m2 over 3 years. Changes in each marker were compared over time between the niacin and placebo arms using linear mixed effects models.

RESULTS: Randomization to niacin led to 0.08 mg/dl lower plasma phosphate concentrations per year of treatment compared with placebo ( P <0.01) and 0.25 mg/dl lower mean phosphate 3 years after baseline (3.32 versus 3.57 mg/dl; P =0.03). In contrast, randomization to niacin was not associated with statistically significant changes in plasma intact fibroblast growth factor 23, parathyroid hormone, calcium, or vitamin D metabolites over 3 years.

CONCLUSIONS: The use of niacin over 3 years lowered serum phosphorous concentrations but did not affect other markers of mineral metabolism in participants with CKD.