Comparison of the effects of simvastatin versus atorvastatin on oxidative stress in patients with type 2 diabetes mellitus.

The aim of this study was to determine the effects of simvastatin and atorvastatin on the markers of oxidative stress in patients with type 2 diabetes mellitus (T2DM). The study population consisted of 151 patients with T2DM and 147 control individuals. The patients with T2DM were treated with 40 mg of simvastatin per day or 10 mg of simvastatin per day. Waist circumference, body mass index, blood pressure, and glucose and insulin values were obtained; and fasting serum lipids, malondialdehyde, nitric oxide, glutathione peroxidase and superoxide dismutase activity were determined before and after 12 weeks of treatment. Statin treatment significantly decreased plasma lipids in all patients with diabetes (P < 0.05). No significant differences were detected between the two treatment groups with respect to plasma lipid profile (P < 0.05). In addition, the effects of atorvastatin to increase nitric oxide concentration (33.28 +/- 3.37 micromol/L versus 27.32 +/- 4.15 micromol/L, P < 0.05) and glutathione peroxidase (17.67 +/- 1.41 micromol/L versus 14.28 +/- 1.65 micromol/L, P < 0.05), superoxide dismutase activity (34.28 +/- 4.71 micromol/L versus 27.91 +/- 3.38 micromol/L, P < 0.05 ) and decreased malondialdehyde level (49.52 +/- 5.67 micromol/L versus 42.08 +/- 5.16 micromol/L, P < 0.05) were significantly greater in patients with T2DM compared with simvastatin. The changes in the markers of oxidative stress did not correlate with the changes in plasma lipid profile (P > 0.05). This study suggested that atorvastatin reduced oxidative stress more effectively than simvastatin in patients with T2DM and the clinical benefits of statins may be independent of their cholesterol-lowering effects.