RESEARCH DESIGN AND METHODS: A systematic literature search through March 20, 2009 was conducted to identify randomized, placebo-controlled trials of statins that report data on the incidence of new-onset diabetes mellitus. Incidence of new-onset DM was treated as a dichotomous variable. Weighted averages were reported as relative risks (RR) with associated 95% confidence intervals (CI). A random-effects model was used.

RESULTS: Six prospective, randomized, placebocontrolled trials (n=57,593) were identified. Upon metaanalysis, the use of statins did not significantly increase the risk nor prevent the development of new-onset DM (relative risk 1.06; 95% confidence interval 0.93-1.22). Moderate statistical heterogeneity was observed in this analysis (I2=58%, Q statistic p=0.04) arising from pravastatinÊs tendency towards a reduction in risk of developing diabetes and the other statins showing an increase in risk. There was also no significant impact on the incidence of new-onset DM with either high- or low-dose statin use (RR 1.13, 95% CI 0.95 to 1.35 for low-dose statin; RR 1.02, 95% CI 0.84 to 1.25 for high-dose statin).

CONCLUSIONS: Statins as a class did not demonstrate a statistically significant positive or negative impact on a patientÊs risk of developing new-onset DM. Randomized controlled trials of statin therapy with incidence of newonset DM as a primary outcome are required to definitely determine its impact on the development of DM. The mechanisms by which these statins affect glucose metabolism also need to be studied further. However, the beneficial effects of statins in decreasing major vascular events and vascular mortality far outweigh the risks of any adverse effects of statin therapy on glucose metabolism.