Extended-release niacin/laropiprant lowers serum phosphorus concentrations in patients with type 2 diabetes

BackgroundNiacin compounds lower serum phosphorus concentrations in patients with end-stage renal disease.MethodologyWe evaluated the impact of extended release niacin, given in fixed-dose combination with laropiprant, a specific inhibitor of prostaglandin-mediated, niacin-induced flushing, versus placebo, on serum phosphorus concentrations measured serially (at weeks 0, 4, 8, 12, 18, 24, 30, and 36) during a 36-week randomized, controlled trial. All subjects had a confirmed diagnosis of type 2 diabetes (n = 446 niacin/laropiprant; n = 339 placebo). Estimated glomerular filtration rate ranged from 36 to 184 mL/min/1.73 m2, with n = 111 (14.1%) having a value <60 mL/min/1.73 m2. Subjects received one tablet daily of extended-release niacin/laropiprant (1g niacin/ 20 mg laropiprant) for the first 4 weeks, and 2 tablets once daily, thereafter, or matched placebo. Niacin lowered serum phosphorus concentrations by 0.36 mg/dL (95% CI: −0.40, −0.31; P < .001), relative to placebo, from baseline values of 3.57 and 3.56 mg/dL in the niacin and placebo groups, respectively. Subgroup analyses revealed no evidence for phosphorus-lowering effect modification by these baseline variables: glomerular filtration rate <60 (n = 111;14.1%) vs ≥60 mL/min/m2 (n = 674; 85.9%); phosphorus ≤3.5 mg/dL (n = 392; 49.9%) vs >3.5 mg/dL (n = 393; 50.1%); or prior statin use (n = 618; 78.7%) vs nonuse (n = 167; 21.3%).Conclusions and ImplicationsThese data confirm that niacin’s phosphorus-lowering effects—which may have therapeutic implications for the management of hyperphosphatemia and possible prevention of cardiorenal outcomes in renal disease—extend across a broad spectrum of renal function in type 2 diabetics without stage 4 or 5 chronic kidney disease (a glomerular filtration rate ≥30 mL/min/1.73 m2).