Statins and Risk of Incident Diabetes

The use of statins to prevent primary and secondary cardiovascular morbidity and mortality is widespread in the United States, particularly among the population of older Americans. However, increased use of statins has highlighted risks associated with the medications, including the growing risk of incident diabetes mellitus (DM). Evidence has emerged showing that incident DM associated with statin use may be more common in the elderly, in women, and in Asians. It has not been clearly demonstrated whether the risk varies with individual statins or if it is a dose-driven class effect. Although a large part of the aging population, postmenopausal women have not been well represented in previous clinical trials. Researchers recently utilized data from the Women’s Health Initiative (WHI) to examine whether the incidence of new-onset DM is associated with statin use among postmenopausal women. The WHI included 161,808 postmenopausal women 50 to 79 years of age at 40 clinical centers in the United States from 1993 to 1998. Follow-up is ongoing. The current analysis utilized data through 2005. Results of the analysis were reported online in Archives of Internal Medicine [doi:10.1001/archinternmed.2011.625]. The mean age at baseline of the current study cohort (n=153,840) was 63.2 years, approximately 16.30% were other than white, with the largest representation African American (8.32%); 2.56% were Asian. At baseline, 7.04% took a statin; 30.29% took simvastatin, 27.29%, lovastatin; 22.52%, pravastatin; 12.15%, fluvastatin; and 7.74%, atorvastatin. There were significant differences in baseline characteristics between statin users and nonusers. Over 1,004,466 person-years of follow-up, there were 10,242 incident cases of self-reported DM. Unadjusted analyses found a significant association between statin use at baseline and the risk of incident DM (hazard ratio [HR], 1.71; 95% confidence interval [CI], 1.61-1.83). Following adjustment for potential confounders, the association was lessened but remained significant (HR, 1.48; 95% CI, 1.38-1.59). The association was observed for all types of statin medications. The researchers performed subset analyses on 125,575 women to evaluate the association of self-reported DM with longitudinal measures of statin use; these analyses confirmed the findings from the larger cohort. In summary the researchers noted, “statin medication use in postmenopausal women is associated with an increased risk for DM. This may be a medication class effect. Further study by statin type and dose may reveal varying risk levels for new-onset DM in this population.”