Statins and glycaemic control in individuals with diabetes: a systematic review and meta-analysis

Current evidence indicates that statins increase the risk of incident diabetes; however, the relationship between statins and glycaemic control in people with established diabetes has not been well characterised. To address this question, we conducted a meta-analysis of randomised controlled trials (RCTs) of statins in patients with diabetes for whom there was available data on glycaemic control.

We identified studies published between January 1970 and November 2013 by searching electronic databases and reference lists. We included RCTs in which the intervention group received statins and the control group received placebo or standard treatment, with >200 participants enrolled, with the intervention lasting >12 weeks and with pre- and post-intervention HbA1c reported. We combined study-specific estimates using random-effects model meta-analysis.

In a pooled analysis of nine trials involving 9,696 participants (4,980 statin, 4,716 control) and an average follow-up of 3.6 years, the mean HbA1c of participants randomised to statins was higher than those randomised to the control group: mean difference (95% CI) was 0.12% (0.04, 0.20) or 1.3 mmol/mol (0.4, 2.2); p = 0.003. There was moderate heterogeneity across the studies (I (2) = 54%, p = 0.014) not explained by available study-level characteristics. This review was limited by the small number of studies, available data on only three statins and sparse reporting on changes in use of glucose-lowering medications.

Statin treatment is associated with a modest increase in HbA1c in patients with diabetes.