Statin Use and the Risk of Incident Diabetes Mellitus: A Review of the Literature

Statins are one of the most widely prescribed medications in the world. They are beneficial in both the primary and secondary prevention of atherosclerotic cardiovascular disease events. In recent years, however, concern has been raised regarding an increased incidence of new-onset diabetes mellitus observed in clinical trials of statin therapy. While most randomized, placebo controlled, statin trials have not included the incidence of new-onset diabetes as a major primary end point, a very small but consistent adverse effect on glycosylated hemoglobin and blood glucose levels, which is presently of unknown clinical significance, has been observed. Importantly, it should be remembered that some patient subgroups exposed to statin therapy, such as those with the metabolic syndrome, may already be particularly vulnerable to developing diabetes mellitus. Experimentally, although the weight of evidence suggests a protective effect of statins on the development of diabetes mellitus, basic science studies have documented conflicting evidence regarding both the beneficial and adverse effects from statin therapy on insulin secretion and sensitivity. In addition, the possibility that statin-induced muscle inflammation may elevate blood glucose levels cannot be excluded. Thus, although the biological plausibility of statins inducing diabetes certainly may exist, at the present time, sufficient high-quality scientific evidence does not exist to definitively establish the veracity or the strength of any putative cause and effect relationship. And without such evidence, there is no current impetus to alter existing clinical practice recommendations regarding the appropriate use of statin therapy.