DENVER—Niacin treatment is known to lower phosphorus levels in patients with stage 5 CKD and hyperphosphatemia, but new findings show that this effect extends across a broad spectrum of renal function in patients with type 2 diabetes without stage 4 or 5 CKD, researchers reported.
The findings come from a 36-week placebo-controlled study of 785 patients with type 2 diabetes led by Andrew G. Bostom, MD, of Rhode Island Hospital in Providence. He and his colleagues analyzed serial phosphorus level data collected from 446 patients randomly assigned to receive extended-release niacin plus laropiprant (ERN-L) and 339 to receive placebo. Laropripant is a specific inhibitor of prostaglandin-mediated, niacin-induced flushing.
The estimated glomerular filtration rate (eGFR) in the study population ranged from 36-184 mL/min/1.73 m2, with 111 patients (14.1%) having an eGFR below 60. The treatment and placebo groups had mean baseline serum phosphorus values of 3.57 and 3.56 mg/dL, respectively. The researchers measured serum phosphorus concentrations at weeks 0, 4, 8, 12, 18, 24, 30, and 36.
Subjects received one tablet daily of ERN-L (ERN 1g/L 20 mg) for the first four-weeks, and two tablets once daily thereafter, or matched placebo. Compared with the placebo group, the ERN-L group experienced an average 0.36 mg/dL decrease in serum phosphorus levels from week 12-36. Among the 391 subjects with baseline serum phosphorus levels above 3.5 mg/dL, the 224 ERN-L recipients experienced a significant mean decrease of 0.39 mg/dL compared with the 169 placebo patients.
The phosphorus-lowering effect of ERN-L was not modified by eGFR (less than 60 vs. 60 or greater), phosphorus level (3.5 mg/dL or less vs. more than 3.5 mg/dL), or prior statin use.