Link between statins and diabetes explored in 2 studies

Two new studies looked at how and why statin treatment increases the risk of type 2 diabetes.

First, a Finnish study followed more than 8,000 men age 45 to 73 years without diabetes at baseline for up to 5.9 years. Diabetes was diagnosed in 625 men, and the researchers found that patients on statin treatment (n=2,142) had a 46% increased risk of developing diabetes compared to those not on statins (adjusted hazard ratio, 1.46 [95% CI, 1.22 to 1.74]), which is higher than most previous research has shown. The risk was dose dependent for simvastatin and atorvastatin. Pravastatin, fluvastatin, and lovastatin were found to be less diabetogenic, but only a small number of patients were on those drugs, so findings were inconclusive.

The study, which was published by Diabetologia on March 4, also found that statin users had decreased insulin sensitivity (by 24%) and insulin secretion (by 12%) compared to nonusers (P<0.01). The findings suggest that these decreases in sensitivity and secretion are possible mechanisms for the association between statins and diabetes, the authors said.

The other study analyzed more than 1,500 Dutch patients with familial hypercholesterolemia and their relatives without the disease to explore a possible association with diabetes. The study found that people with familial hypercholesterolemia had a significantly lower risk of diabetes than their unaffected relatives (1.75% vs. 2.93%; P<0.001). Once the researchers adjusted for other factors, the hypercholesterolemia patients' risk for diabetes declined even further, to 1.44%. Diabetes risk was particularly low in patients with severe familial hypercholesterolemia (as defined by the specific gene mutation).

The study's findings support the hypothesis that the common pathway in familial hypercholesterolemia and statin therapy—cellular cholesterol uptake—plays a role in the development of type 2 diabetes. The authors speculated that the mechanism is that increased intracellular cholesterol levels have a detrimental effect on pancreatic beta cell function. The results could encourage development of new treatments for type 2 diabetes focused on improving function and survival of the beta cells, they added. The results can also reassure physicians prescribing statins to patients with familial hypercholesterolemia that these patients are less likely to develop diabetes, and the findings should be considered in future research on cholesterol drugs, said an accompanying editorial. The study and editorial were published in the March 10 Journal of the American Medical Association.