Labels on statin medications in the United States now include information concerning glycaemic effects, including diabetes and increases in haemoglobin A1c or fasting plasma glucose. The US Food and Drug Administration approved these labelling changes in February 2012, based mainly on evidence drawn from two meta-analyses of randomised controlled trials.1 The first meta-analysis of statins compared with placebo, conducted by Rajpathak and colleagues,2 included 57 593 patients from six trials and showed a small increase in risk for type 2 diabetes (relative risk 1.13, 95% confidence interval 1.03 to 1.23). The second meta-analysis, reported the following year by Sattar and colleagues, examined the effect of statins on the risk of diabetes in 91 140 patients from 13 trials.3 That meta-analysis showed that statins were associated with a 9% increased risk of diabetes (odds ratio 1.09, 1.02 to 1.17). Preiss and colleagues also compared the risk of diabetes associated with higher potency and lower potency statins in a meta-analysis of 32 752 patients in five trials,4 and found that higher potency statins were associated with a 12% increased risk of diabetes relative to lower potency statins (odds ratio 1.12, 1.04 to 1.22).