A study published yesterday shows a 46% increase in risk of developing type 2 diabetes associated with taking statins.

Within people not on statins, the risk of developing diabetes over the 5.9 year monitoring period was 5.8%, whereas the risk for those taking statins was 11.2%. After adjusting for confounding factors, the risk of developing diabetes was calculated to be 46% higher in people taking statins. The findings also showed that the higher the dose of statins used, the higher the risk of diabetes.

The large increase in risk of diabetes is noteworthy as previous studies have reported diabetes risks as being up to 20%.

How reliable are the findings?

Questions have been asked as to how the study findings should be interpreted. The study was not a randomised controlled trial and there is a notable point to be made that, as high cholesterol is one of the primary risk factors for type 2 diabetes, it should come as no surprise that the people being treated for high cholesterol would likely have an increased risk of developing type 2 diabetes anyway.

To convincingly tease out the true risk of developing diabetes associated with statin use would require a trial in which patients with similarly high cholesterol levels before treatment, and a similar diabetes risk, were given either a statin drug or a placebo and be monitored for diabetes on a regular basis over a number of years.

Until such a trial is carried out, there will always be questions over the real risk of diabetes that statins pose.

Statins and insulin resistance

The study also noted that insulin sensitivity was reduced by 24% in those taking statins and that insulin secretion was 12% lower. Again, it’s hard to know how much the effect on insulin resistance and secretion was directly related to statins treatment but it does represent an avenue which can be explored with further research specifically into this area.

Another factor to consider when prescribing statins

Whilst there are certainly doubts about the true size of the increase in risk of diabetes, the fact that the increase in risk is large in this study will give doctors another factor to consider when prescribing statins.

The results could mean that doctors choose to push the importance of lifestyle changes harder in people with a family history of diabetes or those that have prediabetes before considering whether to prescribe statins.