June 5, 2013
Which Statins Most Increase Risk of New-Onset
Diabetes in Users?

Toronto—Although some statins may reduce the risk developing diabetes, others—such as high-potency atorvastatin and simvastatin—appear to increase the risk, according to a Canadian study.

Background in the study, published online by the British Medical Journal, noted that one trial suggested a 27% increased risk of diabetes with rosuvastatin, while another proposed that patients taking pravastatin benefitted from a 30% lower risk.

To develop more information, researchers carried out a population-based study on 1.5 million residents in Ontario to examine the association between individual statin use and new-onset diabetes. Using data from the Ontario Drug Benefit database, the Canadian Institute for Health Information Discharge Abstract Database and the Ontario Diabetes Database, study authors looked at fluvastatin, lovastatin, pravastatin, simvastatin, atorvastatin and rosuvastatin, with incident diabetes the primary outcome.

Patients under review were 66-years-old and older—median age 73—and began statin therapy between 1997 and 2010. Study follow-up ended either at the end of 2010 or after a maximum of 5 years following the initiation of statins, whichever came first.

Pravastatin-treated patients were used as the comparison group because the drug has been demonstrated to have a favorable effect on newly diagnosed diabetes in animal models and in clinical trials, according to the authors.

Researchers identified 471,250 patients, 54% female, as having no history of diabetes and who were newly treated with a statin. More than half of those initiating statins received a prescription for atorvastatin, followed in popularity by rosuvastatin, simvastatin, pravastatin, lovastatin, and fluvastatin.

While the overall risk of developing diabetes was found to be low, researchers noted that the risk was increased among some patients taking statins. They estimated that between 162 and 407 patients would have to be treated with the various statins for one extra patient to develop diabetes.

The greatest increased risk of new-onset diabetes, 22%, was found among patients treated with atorvastatin, followed by rosuvastatin (18%) and simvastatin (10%). On the other hand, patients treated with fluvastatin had a 5% decreased risk, and those on lovastatin had a 1% decreased risk, according to the authors.

In terms of event rate, rosuvastatin and atorvastatin were highest, 34 outcomes per 1,000 person-years and 30 outcomes per 1,000 person-years, respectively. Next were simvastatin at 26 outcomes per 1,000 person-years, and both fluvastatin and lovastatin at 21.

Researchers noted that the reason for the prescriptions, whether for primary prevention or to treat established disease, didn’t appear to matter with risk for developing diabetes. Older patients, however, were at increased risk, regardless of dose for atorvastatin and simvastatin or whether therapy was used for primary or secondary prevention.

The authors suggested that certain statins could play a role in impaired insulin secretion and inhibited insulin release.

Clinicians should consider risk when contemplating statin therapy, they recommended, adding that “preferential use of pravastatin, and potentially fluvastatin […] may be warranted” and that pravastatin may even offer some benefits to patients at high risk of diabetes.

An accompanying editorial from the University of Turku in Finland suggests that “the overall benefit of statins still clearly outweighs the potential risk of incident diabetes.”

U.S. Pharmacist Social Connect