In recent years, the medical community has become increasingly aware that taking statins can result in slightly higher glucose levels, and this can lead to a diagnosis of diabetes in a small but statistically significant number of people. But it has been unclear whether the diagnosis of diabetes in people taking statins also places them at increased risk for the microvascular complications linked to diabetes. Now, an observational study published in the Lancet Diabetes & Endocrinology finds that among people newly diagnosed with diabetes, statin users are less likely than nonusers to develop most of these complications. (The beneficial effects of statins in reducing macrovascular complications — cardiovascular disease — in diabetics and others is well established in people at high risk for these events.)
Danish researchers examined the rate of microvascular outcomes in more than 15,000 statin users who developed diabetes and 47,000 nonusers of statins who developed diabetes. Over a median follow-up of 2.7 years, statin users had a 40% reduction in the risk for developing retinopathy (hazard ratio 0.60, CI 0.54–0.66, p<0.0001), a 34% reduction in the risk for diabetic neuropathy (HR 0.66, 0.57–0.75, p<0.0001), and a 12% reduction in gangrene of the foot (HR 0.88, 0.80–0.97, p=0.010). There was no significant difference in the rate of diabetic nephropathy (HR 0.97, 0.85–1.10, p=0•62). The overall results were similar after adjusting for differences between the groups. In rough accord with previous research, the Danish researchers observed that statin users had a 17% increase in the risk for developing diabetes.
The authors conclude: “Whether or not statins are protective against some forms of microvascular disease, a possibility raised by these data, and by which mechanism, will need to be addressed in studies similar to ours, or in mendelian randomization studies…. Ideally, however, this question should be addressed in the setting of a randomized controlled trial.”
Commenting on the study, Darrel Francis offered an overview of the risks and benefits of statins: “For every 1000 primary prevention patients randomized to statin, 5 patients gain a diagnosis of diabetes, while 5 patients are saved from death, 10 from nonfatal myocardial infarction, and 6 from stroke. Some people find this a good deal, but others a are cautious because of the justified fear of diabetes.”