Effects of micronized fenofibrate on insulin resistance in patients with metabolic syndrome

BACKGROUND AND OBJECTIVE: Metabolic syndrome is characterized by insulin resistance (IR) as well as dyslipidemia, ventral overweight, hypertension and elevated fasting plasma glucose. Since diabetic and prediabetic states are commonly associated with hypertriglyceridemia, fenofibrates have been used in such patients. The aim of this pilot open trial was to study the influence of micronized fenofibrate on insulin resistance and plasma insulin levels in prediabetic and diabetic patients. SUBJECTS: From 114 dyslipidemic patients, 31 with dyslipidemia and insulin resistance were selected to take part in the study. Of the 31 patients, 20 were nondiabetic and only 11 had noninsulin-dependent diabetes mellitus. Eighteen dyslipidemic patients acted as controls. METHODS: Insulin resistance was assessed in a short-term insulin tolerance test. Plasma insulin, antiinsulin antibodies, lipid parameters and the insulin sensitivity index (ISI) were measured at entry and after a 3-month therapy with 200 mg micronized fenofibrate daily. RESULTS: Three-month therapy with micronized fenofibrate resulted in significant ISI increase and was accompanied by a decrease in plasma insulin levels in dyslipidemic patients with metabolic syndrome. ISI also improved in patients with type 2 diabetes mellitus and there was an unexpected increase in plasma insulin levels. Antiinsulin antibodies were unchanged throughout the trial. Reductions in plasma triglycerides and total cholesterol exceeding 50% and 20%, respectively, were observed in patients with metabolic syndrome. These changes were accompanied by an increase in mean levels of plasma high-density lipoprotein (HDL) cholesterol (above 35%). CONCLUSIONS: Micronized fenofibrate is an effective drug in normalizing lipid-lipoprotein levels in patients with metabolic syndrome. After a 3-month fenofibrate therapy, insulin resistance was reduced in a group of patients with dyslipidemia and metabolic syndrome.