People taking statins face an increased risk of developing diabetes,researchers have warned.
Treatment with high potency statins,especially atorvastatin and simvastatin,may increase the risk of developing diabetes,according to the study published in British Medical Journal (BMJ).
Statins are among the most widely prescribed medications for the prevention of cardiovascular events. Although tolerated well,an association with new-onset diabetes has recently been suggested.
One trial suggested a 27 per cent increased risk of diabetes with rosuvastatin whereas another suggested patients taking pravastatin benefitted from a 30 per cent lower risk.
Researchers from Canada carried out a population-based study on 1.5 million residents in Ontario,Canada to examine the association between individual statin use and new-onset diabetes.
All patients were aged 66 and over and started statin therapy between 1997 and 2010. The median age was 73 years. Follow up ended either at the end of 2010 or a maximum of five years following the initiation of statins,whichever came first. The primary outcome was incident diabetes.
Statins included in the study were: fluvastatin,lovastatin,pravastatin,simvastatin,atorvastatin and rosuvastatin.
All studies used pravastatin-treated patients as the comparison group as this has been shown to have favourable effects on newly diagnosed diabetes in animal models and clinical trials.
As many as 471,250 patients were identified with no history of diabetes and who were newly treated with a statin. 54 per cent were women. Atorvastatin accounted for more than half of all new statin prescriptions followed by rosuvastatin,simvastatin,pravastatin,lovastatin and fluvastatin.
The overall risk of developing diabetes was low but this risk was increased among some patients taking statins. Between 162 and 407 patients would have to be treated with the various statins for one extra patient to develop diabetes.
Patients treated with atorvastatin were found to have a 22 per cent increased risk of new-onset diabetes,rosuvastatin an 18 per cent increased risk and simvastatin a 10 per cent increased risk,relative to pravastatin. In contrast,patients treated with fluvastatin were at a 5 per cent decreased risk and lovastatin a 1 per cent decreased risk.
The event rate was highest for atorvastatin (30 outcomes per 1000 person-years) and rosuvastatin (34 per 1000 person-years). Simvastatin accounted for 26 outcomes per 1000 person-years with both fluvastatin and lovastatin at 21 outcomes per 1000 person-years.
The findings also suggest that older patients are at an increased risk regardless of dose for atorvastatin and simvastatin or whether therapy is used for primary or secondary prevention.