Extended-release niacin treatment of the atherogenic lipid profile and lipoprotein(a) in diabetes

Abstract

We tested the hypotheses that extended-release niacin is effective for the separate treatments of abnormalities in low-density liprotein (LDL) size, high-density lipoprotein (HDL)-2, and lipoprotein(a) [Lp(a)] without potential negative effects on glycated hemoglobin levels. The lipids that constitute the atherogenic lipid profile (ALP), such as triglycerides, small, dense LDL-cholesterol particle concentration, LDL particle size, total HDL-cholesterol (HDLc), HDL-2, and HDL-2 cholesterol concentration, as well as total LDL-cholesterol (LDLc) and Lp(a), were measured in 36 diabetic patients with primary abnormalities of LDL particle size (n = 25), HDL-2 (n = 23), and/or Lp(a) (n = 12) before and after extended-release niacin treatment. LDL particle size and HDL-2 were measured using polyacrylamide gradient gel electrophoreses and Lp(a) was measured by enzyme-linked immunosorbent assay (ELISA). After extended-release niacin, LDL peak particle diameter increased from 25.2 +/- 0.6 nm to 26.1 +/- 0.7 nm (P <.0001); small, dense LDLc concentration decreased from 30 +/- 17 mg/dL to 17 +/- 10 mg/dL (P <.0001); total HDLc increased from 42 +/- 9 mg/dL to 57 +/- 16 mg/dL (P <.0001); HDL-2 as the percent of total HDLc mass increased from 34% +/- 10% to 51% +/- 17% (P <.0001); and Lp(a) decreased from 37 +/- 10 mg/dL to 23 +/- 10 mg/dL (P <.001). Mean hemoglobin A(1c) level was improved during treatment from 7.5% +/- 1.6% to 6.5% +/- 0.9% (P <.0001). A subset of patients who had no change in hemoglobin A(1c) levels before and after treatment (6.8% +/- 1% v 6.7% +/- 1%; not significant) showed identical lipid changes. Twenty-two percent of patients were unable to tolerate extended-release niacin due to reversible side effects. These data indicate that in diabetic patients, extended-release niacin (1) is effective for separately treating diabetic dyslipidemias associated with abnormal LDL size, HDL-2, and Lp(a) independently of glycated hemoglobin levels; (2) must be used with modern and aggressive oral hypoglycemic agents or insulin treatment; and (3) is a major drug for the treatment of diabetic dyslipidemias because of its broad spectrum of effectiveness for the ALP and Lp(a).