Abstract 4145: Effects of Statin and Niacin Therapy on Flow Mediated Dilation and High Sensitivity C-reactive Protein in Patients with the Metabolic Syndrome
Background: Elevated triglycerides and a low serum high density lipoprotein (HDL) are characteristics of the metabolic syndrome. Impaired endothelial function in a pro-inflammatory vascular environment appears to be a hallmark in the initiation and progression of the metabolic syndrome. We tested the hypothesis that statins and/or niacin would improve endothelial function and have a beneficial effect on inflammatory markers in the metabolic syndrome.
Methods: 18 patients that met the ATP III criteria for the metabolic syndrome were placed on simvastatin (S: 40 mg/day), extended release niacin (N: 1000 mg/day), or both (S+N) in a crossover fashion for 4 weeks in each study group. Fasting lipid levels were measured in all patients pre- and post-therapy. Flow mediated dilation (FMD) and serum levels of high sensitivity C-reactive protein (hsCRP) were obtained at the same time points.
Results: Both N and S+N but not S increased HDL-C significantly (S-pre: 39±6, post: 42±5 mg/dl, NS) (N-pre:37±5, post: 47±6 mg/dl, p<0.005 pre vs post) (N=S-pre: 38±5, post: 52±8 mg/dl, p<0.005 pre vs post). Similarly, N and S+N but not S decreased TG significantly (S-pre: 194±15, post: 189±23 mg/dl, NS) (N-pre: 203±27, post: 123±24 mg/dl, p<0.005 pre vs post) (S+N-pre: 212±29, post: 100±13 mg/dl, p<0.005 pre vs post). In all three treatment groups, there was a reduction in hsCRP; moreover, the greatest reduction was observed in the S+N group (S-pre: 2.14±0.19, post: 1.51±0.22 mg/L, p<0.005 pre vs post) (N-pre: 2.04±0.22, post: 1.58±0.21 mg/L, p<0.005 pre vs post) (S+N-pre:2.08±0.21, post: 1.12±0.21 mg/L, p<0.005 pre vs post). There was an increase in FMD in all three groups; the largest increase was in the S+N group (S-pre: 4.5±0.5, post: 5.4±0.8 percent, p<0.005 pre vs post) (N-pre: 4.3±0.6, post: 5.1±0.4 percent, p<0.005 pre vs post) (S+N-pre:4.4±0.2, post: 6.4±0.4 percent, p<0.005 pre vs post) Therapy was equally tolerated in all three treatment groups.
Conclusions: Lipid lowering therapy in the form of statins and niacin are powerful agents in improving dyslipidemia, endothelial function, and markers of inflammation in the metabolic syndrome. Moreover, the combination of the two classes of drugs has a strong additive effect on these parameters.