Potential side effects of Lipitor may increase the risk of developing diabetes by more than one-third, according to the findings of a new study.
Researchers from the United States, the Netherlands, Australia and from Pfizer, Inc. reviewed data from three large clinical trials in a study published in the Journal of the American College of Cardiology, finding evidence that strengthens the link between diabetes and Lipitor.
When compared to subjects given a placebo, users of Lipitor had about a 33% higher risk of developing type 2 diabetes over five years. However, researchers also determined that the most important contributors were still the classic diabetes risk factors, such as excess weight, high blood sugar and blood pressure and elevated triglycerides.
Lipitor (atorvastatin) is a Pfizer drug approved in 1996 by the FDA to help lower high levels of cholesterol. In 2008, Pfizer reported that the drug had brought in $12.4 billion in sales and was the top selling brand-name drug in the world.
In one of the clinical trials examined by the researchers, involving 3,800 people over a five year period, they found that slightly less than 9% of those taking Lipitor developed diabetes; compared to 6% of those given a placebo after researchers accounted for other factors like age, smoking and weight. However, the increased risk was even greater for Lipitor users than for those given a placebo when traditional diabetes warning signs were factored into the study. Nearly half of the Lipitor users with the four risk factors developed diabetes, compared to only 20% of placebo users with the four classic diabetes risk factors.
In the other two clinical trials, links between Lipitor and diabetes was less clear. One trial compared Lipitor to Zocor and found a slightly increased diabetes risk; 6.4% compared to 5.6%. In another, researchers compared high doses of Lipitor to low doses and found that 9% of the patients given Lipitor developed diabetes, compared to 8% given a much lower dose.
The findings come a little more than a year after a study on all statins was conducted by University of Glasgow scientists. In that study, published in The Lancet, researchers determined that users of statin-based cholesterol drugs faced an overall 9% increased risk of being diagnosed with type 2 diabetes.