Effects of atorvastatin 10 mg/d on insulin resistance: A 12-week, open-label study in hyperlipidemic patients

In addition to their cholesterol-lowering effects, hydroxymethylglutaryl coenzyme A reductase inhibitors ("statins") might have pleiotropic, nonlipid effects. Insulin resistance syndrome is known to increase the risk for cardiovascular disease. However, the effects of statins on insulin resistance are a subject of controversy.

We aimed to investigate the effects of atorvastatin on insulin resistance in hyperlipidemic patients.

This 12-week, prospective, nonrandomized, open-label study was conducted at the outpatient cardiology clinic, Ege University Medical School, Bornova-Izmir, Turkey. Hyperlipidemic patients aged ≥18 years with insulin resistance and no other components of the metabolic syndrome were included in the study. Atorvastatin 10 mg QD (after the evening meal) was administered by mouth (tablet) over a 12-week period. At baseline and after 12 weeks of treatment, insulin sensitivity was assessed using homeostasis model assessment (HOMA) index methodology. Serum lipid parameters and fasting levels of plasma glucose and insulin (FPG and FPI, respectively) were measured at the same 2 time points. The tolerability of atorvastatin was assessed using laboratory analysis and physical examination, including vital sign measurements.

Fifteen white patients (9 women, 6 men; mean [SD] age, 52 [8] years) participated in the study. No significant changes in HOMA index were found (mean [SD], 3.1 [1.5] vs 3.2 [1.9]). The lipid profile was improved significantly at 12 weeks compared with baseline (mean [SD] low-density lipoprotein cholesterol, 173.2 [21.3] vs 110.8 [43.6] mg/dL; total cholesterol, 270.9 [21.5] vs 201.2 [46.7] mg/dL; and triglycerides, 269.5 [46.3] vs 205.5 [49.3] mg/dL; all, P < 0.001). No significant change in mean (SD) plasma high-density lipoprotein cholesterol level (45.5 [6.6] vs 43.7 [8.1] mg/dL) was found. In addition, no significant changes in FPG (85.3 [12.71 vs 84.8 [10.4] mg/dL), or FPI (13.5 [9.7] vs 13.9 [10.1] μU/mL) were found. None of the patients required withdrawal of medication due to an adverse event.

In this pilot study in hyperlipidemic patients with insulin resistance, 12 weeks of treatment with atorvastatin 10 mg QD was effective in controlling hyperlipidemia but did not reduce the severity of insulin resistance.