AIMS/HYPOTHESES: 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.
METHODS: 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.
RESULTS: 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.
CONCLUSIONS/INTERPRETATION: Statin treatment is associated with a modest 
increase in HbA1c in patients with diabetes.