Statin therapy on glycaemic control in type 2 diabetes: a meta-analysis

Objective: Randomised controlled trials (RCTs) indicate that statin therapy has cardiovascular benefit among patients with type 2 diabetes. Recently, statins were reported to increase risk of diabetes by 9%. The aim was to investigate by a meta-analysis whether statins deteriorate glycaemic control in type 2 diabetes.

Methods: Medline, EMBASE and Cochrane Central Register of Controlled Trials from 1966 to 2012 were searched for RCTs of statins. Included were only trials with type 2 diabetes.

Main outcome measures: The I² statistic was used to measure heterogeneity between trials and calculated mean differences for glycaemic parameters with random-effect meta-analysis.

Results: 26 eligible studies were identified with 3232 participants. Statin therapy had no remarkable influence on HbA1c (WMD 0.04%, 95% CI -0.08 to 0.16, I² = 45.7%, n = 3070), FPG (2.25 mg/dl, 95% CI -3.50 to 7.99, I² = 46%, n = 1176), BMI, fasting insulin or HOMA-IR. However, subgroup analysis showed significant, detrimental effect of atorvastatin on HbA1c, whereas simvastatin presented an ameliorative effect. Meta-regression presented that neither baseline age nor relative reduction in LDL-cholesterol concentrations accounted for residual heterogeneity.

Conclusion: Statin therapy showed non-significant effect on glycaemic control in type 2 diabetes. Statin therapy need not change among them with moderate or high cardiovascular risk or existing cardiovascular disease.