Deterioration of glucose homeostasis in type 2 diabetic patients one year after beginning of statins therapy

OBJECTIVE: We evaluated the long-term effects of rosuvastatin and simvastatin on insulin sensitivity and secretion in patients with well-controlled type 2 diabetes. METHODS: After a 3 weeks run-in, 27 eligible patients were randomly assigned to receive either rosuvastatin 20 mg daily (Group 1) or simvastatin 20 mg daily (Group 2) for 6 months; thereafter they were switched to the other treatment for additional 6 months. Patients were recruited among individuals attending the outpatient service of the Diabetology Unit of the "Policlinico Tor Vergata" University Hospital, Rome, Italy. Serum lipids, glucose and insulin, glycated hemoglobin, C-reactive protein, TNF-α, leptin, adiponectin, insulin sensitivity by euglycemic-hyperinsulinemic clamp, β-cells function by HOMA-β were assessed at months 0, 6 and 12. Additionally, endothelial function was assessed by use of the brachial artery reactivity technique. RESULTS: Besides marked reduction in lipid levels, glycated hemoglobin significantly increased from baseline after 12 months in both Group 1 (+0.8 ± 0.2%, p < 0.001) and Group 2 (+0.9 ± 0.3%; p < 0.001). Similar trends were observed for fasting glucose in both groups. No changes in insulin sensitivity were detected throughout the study, whereas HOMA-β significantly decreased from baseline after 12 months in both Group 1 (-21.9%, p < 0.01) and Group 2 (-38.9%; p < 0.001). In addition, both treatments similarly decreased C-reactive protein and leptin, as well as improved endothelial function. No changes in anthropometric measures were observed. CONCLUSIONS: In well-controlled type 2 diabetic patients both rosuvastatin and simvastatin significantly impaired glycemic control and insulin secretion, without affecting insulin sensitivity.