Some statin drugs do seem to raise users' risk of diabetes: study
The drug Lipitor is displayed at Medco Health Solutions Inc., in Willingboro, N.J., Tuesday, June 14, 2011. (AP / Matt Rourke)
TORONTO -- Some cholesterol-lowering drugs called statins appear to put users at an elevated risk of developing diabetes, a new study reports.
The work, by Toronto scientists, suggests that higher potency statins increase the diabetes risk, while for lower dose statin brands the elevated risk is not seen.
At the end of the day, the cholesterol-lowering benefits of the drugs may outweigh the diabetes risks in many cases, said senior author Dr. Muhammad Mamdani. But he suggested it makes sense to try to use a lower dose statin when possible.
"If a patient has a really high LDL" -- the dangerous form of cholesterol -- "then maybe you do need the high powered stuff like Lipitor and rosuvastatin or Crestor and you can actually go a bit higher on the dose," said Mamdani, director of the applied health research centre at the St. Michael's Hospital's Li Ka Shing Knowledge Institute.
"But for most of the patients you could probably get away with using something like pravastatin or even lovastatin.... I'd say for the vast majority of patients, those would be just fine."
Pravastatin, which is sold as Pravachol or Selektine, has actually been shown to be protective against diabetes in some studies. Lovastatin is sold under the brand name Mevacor.
Mamdani estimated the risk as follows: "For every 1,000 patients who takes one of the higher potency statins, you're going to see six to 10 additional patients being diagnosed with diabetes. ... Had you used pravastatin, you would have seen between six to 10 fewer patients with diabetes."
"So the risks aren't huge," he continued. "But there are a lot of people taking these high potency statins. In fact, atorvastatin is by far -- by far -- the most popular statin."
The possible link between taking some statins and diabetes has been seen in the past. In fact, Health Canada warned in January that statin users may have a small increased risk of developing the condition and changed the labelling on the drugs to reflect that fact.
But previous studies have found conflicting results, so Mamdani and some colleagues conducted another. They looked at the records of more than 470,000 people 66 and older in Ontario who did not have diabetes when they started taking a statin, and found three brands of the drugs seemed to increase their diabetes risk.
The three drugs were atorvastatin, rosuvastatin and simvastatin, which are sold as Lipitor, Crestor and Zocor respectively.
The researchers said no increased risk was seen with fluvastatin (which is sold under the brand names Lescol, Canef and Vastin) or lovastatin.
Mamdani said there isn't an across-the-board answer here. "I don't think it should be . . . 'Everybody ditch the statin that you're on and take pravastatin.' It really should be left to the physician and the patient to see where the patient is at."
"(But) if you're one of the I think majority of patients who probably could do well on pravastatin, that's a conversation the patient may want to have with their physician."
The study was published in BMJ, a journal of the British Medication Association. The work was done by researchers at Toronto General Hospital, the Institute of Clinical Evaluative Studies, Sunnybrook Research Institute and the Li Ka Shing Knowledge Institute.