Extended-Release Niacin/Laropiprant Effects on Lipoprotein Subfractions in Patients with Type 2 Diabetes Mellitus

Background: A potentially atherogenic lipid profile often found in patients with type 2 diabetes mellitus (T2DM) includes increased concentrations of small, low-density lipoprotein (LDL) and intermediate-density lipoprotein (IDL) and decreased concentration of medium/large high-density lipoprotein (HDL) particles. Extended-release niacin/laropiprant (ERN/LRPT) lowers LDL-cholesterol (LDL-C) and triglycerides (TG), and raises HDL cholesterol (HDL-C) levels with attenuation of niacin-induced flushing. Methods: Plasma HDL, LDL, IDL, very-low-density lipoprotein (VLDL), and chylomicron particle concentration and size at were evaluated at baseline and week 12 using nuclear magnetic resonance (NMR). The data were acquired from a randomized, multicenter, double-blind, placebo-controlled study including 796 patients with T2DM treated with either 1 tablet of ERN 1 gram/LRPT 20mg or matching placebo daily, increased after 4 weeks to 2 tablets daily. Results: ERN/LRPT significantly (P <= 0.001 for all) reduced LDL-C 17.9% and TG 23.1%, and increased HDL-C levels 23.2%. Compared to placebo, ERN/LRPT decreased LDL, IDL, VLDL, and chylomicron particle concentrations [ median concentration of smallest LDL particles decreased 16.6%, 95% confidence interval (CI) -22.3, -10.9, whereas the largest LDL particles decreased 11.0%, 95% CI -18.7, -3.2, and total VLDL/chylomicron mean plasma particle concentration decreased 34.7%, 95% CI -41.3, -28.1]. Compared to placebo, ERN/LRPT shifted the distribution of HDL particle diameter from smaller to larger (median concentration of the largest HDL particles increased 32.7% (95% CI 25.30, 40.58), whereas concentration of the smallest HDL particles decreased 8.2% (95% CI -11.29, -5.06). Conclusions: Compared with placebo in patients with T2DM, ERN/LRPT shifted the lipoprotein profile toward a potentially less atherogenic pattern with reduced atherogenic LDL and IDL particle concentrations, and increased large HDL plasma particle concentrations. (ClinicalTrials.gov: NCT00485758)