The risk was most significant in patients taking atorvastatin (Lipitor), rosuvastatin (Crestor) and simvastatin (Zocor), according to the study, published in BMJ.
Statins are the most widely prescribed medications for the prevention of cardiovascular events. Generally, these medications are well received, however, a new link to diabetes has been suggested.
Previous studies have indicated a 27% elevated risk of diabetes with rosuvastatin. One found that taking pravastatin actually lowered the risk by 30%.
Research on this topic is scarce, which led investigators from Canada to conduct a population-based study on 1.5 million residents in Ontario, Canada, to analyze the link between individual statin use and new-onset diabetes.
The participants were all the age of 66 or older and began statin therapy between 1997 and 2010. The median age was 73 years. Follow-up occurred at the end of 2010 or a maximum of five years after the start of the statins - whichever came first. The primary outcome was incident diabetes.
Data was analyzed from the Ontario Drug Benefit database, the Canadian Institute for Health Information Discharge Abstract Database and the Ontario Diabetes Database.
Statins examined in the study included:
The researchers analyzed data on 471,250 participants who had no history of diabetes and who were newly using statins - 54% were women.
The total risk of developing diabetes was low, but this risk rose among some subjects taking statins. Between 162 and 407 patients would have to be treated with different statins for one extra patient to develop diabetes.
Subjects treated with atorvastatin were found to have a 22% elevated risk of new-onset diabetes, rosuvastatin an 18% elevated risk, and simvastatin a 10% increased risk, relative to pravastatin.
In contrast, participants treated with fluvastatin were at a 5% lower risk and lovastatin a 1% lower risk.
The rate of events was highest for atorvastatin (30 outcomes per 1000 person-years) and rosuvastatin (34 per 1000 person-years). Simvastatin made up for 26 outcomes per 1000 person-years with both fluvastatin and lovastatin at 21 outcomes per 100 person-years.
Do Statins Benefits Outweigh the Negatives?Investigators discovered consistent outcomes in analyses looking at the use of statins for primary prevention (when those without diagnosed disease are treated) and secondary prevention (when those with diagnosed disease are treated).
Their results also suggest that older participants are at an elevated risk regardless of dose for atorvastatin and simvastatin or whether therapy is used for primary or secondary prevention.
Many factors could explain why the risk among people taking certain statins is increased for new-onset diabetes.
The researchers concluded that clinicians need to be aware of questioning statin therapy. They say, "preferential use of pravastatin, and potentially fluvastatin may be warranted," and that pravastatin could be advantageous to patients at high risk for diabetes.
In an editorial, doctors from the University of Turku in Finland say that "the overall benefit of statins still clearly outweighs the potential risk of incident diabetes." They also point out that because statins have been shown to decrease cardiovascular events in patients, they are an important factor in treatment.
An unrelated study conducted by Harvard argued that the cardiac benefits of taking statins outweigh the risk of developing diabetes in some patients.
A separate study suggests that older women who are taking statins, those who are in menopause, have a higher risk of developing diabetes.
Written by Kelly Fitzgerald