‘Reassuring’ findings on microvascular risk in diabetic statin users

Sep 17 2014

By Eleanor McDermid, Senior medwireNews Reporter

Statin treatment prior to diabetes onset does not appear to increase the risk of microvascular disease and may even be protective against some forms, findings from a registry study suggest.

Statins have previously been linked to an increased diabetes risk via an effect on blood glucose levels, so the study addressed the possibility that this could lead to increased diabetic complications. In a press statement, study author Børge Nordestgaard (Copenhagen University Hospital, Denmark) said: “Surprisingly, the results showed that statins decreased rather than increased risk of these complications.”

After accounting for confounders, patients who had been taking a statin at the time of diabetes diagnosis had a 40% reduction in the risk of developing diabetic retinopathy, a 34% reduction in the risk of diabetic neuropathy and a 12% reduction in the risk of gangrene of the foot. Statin treatment had a neutral effect on the risk of diabetic nephropathy.

The study included 62,716 diabetic patients randomly selected from more than 200,000 in a national registry. These patients included 15,679 who had been using statins at the time of diagnosis and 47,037 who had not. Over a median follow-up of 2.7 years, 2866 patients developed diabetic retinopathy, 1406 developed diabetic neuropathy and there were 1248 new cases of diabetic nephropathy and 2392 of gangrene of the foot.

The same neutral or protective effects of statins were found in an analysis adjusted for the propensity to receive statins, involving 9791 statin users and 29,373 nonusers. Adding 19,246 patients who began taking statins within a year after diabetes diagnosis weakened the findings, indicating some confounding by indication, but it did not abolish the associations.

Writing in The Lancet Diabetes & Endocrinology, the team says that, given the reported association between statin treatment and increased blood glucose, the absence of an increased risk of microvascular complications in diabetic patients taking the drugs “is important and clinically reassuring on its own.”

Study co-author Sune Nielsen (Copenhagen University Hospital, Denmark) said that the possible protective effects of statins “will need to be addressed in studies similar to ours, or in mendelian randomisation studies, but preferably in randomised controlled trials.”

However, in a commentary accompanying the study, David Preiss (University of Glasgow, UK) observes that it will be very difficult to conclusively demonstrate an effect of statins on microvascular complications, with, for example, ethical issues precluding randomised, controlled trials in this population.

“For now, any benefit of statins on microvascular complications remains unproven”, he says.

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