However, researchers say that the absolute increase in diabetes risk is small and is outweighed by the reduction in cardiovascular events achieved by using statins.
Naveed Sattar (University of Glasgow, UK) and colleagues selected 13 trials for analysis with a total of 91,140 participants, of whom 4278 developed Type 2 diabetes over a mean period of 4 years.
To be included, studies had to have more than 1000 participants, have identical follow-up in both statin and non-statin treated groups, and have a duration lasting longer than 1 year.
Writing in The Lancet, the team reports that more of the patients who developed diabetes over the follow-up period were taking statins than control treatments, at 2226 versus 2052.
This difference translated to a significant 9% increase in risk for incident Type 2 diabetes in patients taking statins versus controls, with little between-trial heterogeneity.
Use of meta-regression analysis suggested that the risk for developing diabetes associated with statins was increased in older participants, but baseline body mass index and changes in low-density lipoprotein (LDL) cholesterol between groups did not seem to significantly influence the association with diabetes.
The researchers explain that in absolute terms, the increased risk for diabetes could be stated as treatment of 255 patients with statins for 4 years resulting in one additional case of Type 2 diabetes.
But for every 1 mmol/l (38.67 mg/dl) decrease in LDL cholesterol achieved by taking statins, the same 255 patients could expect to have five fewer major coronary events (fatal/nonfatal coronary heart disease or myocardial infarction).
In an accompanying commentary, Christopher Cannon (Harvard Medical School, Boston, USA) said that “the benefit [of taking statins] in preventing total vascular events to the risk of diabetes is a ratio of about 9:1 in favor of the cardiovascular benefit. Thus the benefit seems to greatly outweigh the risk.”
He added: “Nonetheless, this newly identified risk does warrant monitoring, and as such, in addition to periodic monitoring of liver-function tests and creatine kinase, it seems reasonable to add glucose to the list of tests to monitor in older patients on statins. Thus, whilst a new risk of statins has been identified, the risk seems small and far outweighed by the benefits of this life-saving class of drugs.”