Simvastatin improves flow-mediated dilation but reduces adiponectin levels and insulin sensitivity in hypercholesterolemic patients.

OBJECTIVE We hypothesized that simvastatin may reduce adiponectin levels and insulin sensitivity in hypercholesterolemic patients. RESEARCH DESIGN AND METHODS This was a randomized, double-blind, placebo-controlled, parallel study. Age, sex, and BMI were matched. Thirty-two patients were given placebo, and 30, 32, 31, and 31 patients were given daily 10, 20, 40, and 80 mg simvastatin, respectively, during a 2-month treatment period. RESULTS Simvastatin doses of 10, 20, 40, and 80 mg significantly reduced total cholesterol (mean changes 27, 25, 37, and 38%), LDL cholesterol (39, 38, 52, and 54%), and apolipoprotein B levels (24, 30, 36, and 42%) and improved flow-mediated dilation (FMD) (68, 40, 49, and 63%) after 2 months of therapy compared with baseline (P < 0.001 by paired t test) or compared with placebo (P < 0.001 by ANOVA). Simvastatin doses of 10, 20, 40, and 80 mg significantly decreased plasma adiponectin levels (4, 12, 5, and 10%) and insulin sensitivity (determined by the Quantitative Insulin-Sensitivity Check Index [QUICKI]) (5, 8, 6, and 6%) compared with baseline (P < 0.05 by paired t test) or compared with placebo (P = 0.011 for adiponectin and P = 0.034 for QUICKI by ANOVA). However, the magnitudes of these percent changes (FMD, adiponectin, and QUICKI) were not significantly different among four different doses of simvastatin despite dose-dependent changes in the reduction of apolipoprotein B levels. CONCLUSIONS Simvastatin significantly improved endothelium-dependent dilation, but reduced adiponectin levels and insulin sensitivity in hypercholesterolemic patients independent of dose and the extent of apolipoprotein B reduction.