Statin heart drugs linked with small diabetes risk in women

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Updated: February 12, 2012 8:09AM

Millions of women taking statin medications to lower their cholesterol appear to be at a slightly higher risk of Type 2 diabetes, a new study suggests.

The researchers advise patients not to stop taking their medications without talking to a doctor because statins’ proven power to prevent heart attacks and strokes outweighs any potential increase in type 2 diabetes risk.

But the results — a nearly 50 percent increase in diabetes among longtime statin users — should throw cold water on the idea of prescribing these drugs to healthy people, which some have recommended as a way to prevent disease, says co-author Dr. JoAnn Manson, a professor of medicine at Harvard Medical School.

About 6.4 percent of the women in the study who didn’t use statins developed diabetes during the eight to nine years of follow-up, Manson says. That rate rose to 9.9 percent among statin users.

“I don’t think there’s any debate remaining, particularly in the higher doses, about whether statins slightly increase the risk of developing diabetes,” says cardiologist Dr. Steve Nissen of the Cleveland Clinic, who wasn’t involved in the new study.

Yet Nissen notes that statins — which sharply reduce the risk of heart attacks and death in people with heart disease — are “among the best drugs we’ve got.”

Patients taking statins should ask their doctors to monitor them for signs of diabetes, though, says Manson, a principal investigator in the long-running Women’s Health Initiative, a study of 161,000 postmenopausal women launched in 1993, on which the new analysis is based.

People taking statins also should be aware of some of the common early warning signs of diabetes, such as increased thirst and urination, as well as fatigue, says Dr. Carolyn Ecelbarger, an associate professor at Georgetown University Medical Center, who wasn’t involved in the new study. About one in four Americans over age 45 takes a statin, according to the National Center for Health Statistics.

“These studies shouldn’t be a cause for alarm,” says Manson, co-author of the study,reported in Tuesday’s Archives of Internal Medicine. “But the findings do raise concerns.”

Although statins have been used since 1987, this kind of side-effect can take time to become apparent, says Robert Eckel, past president of the American Heart Association.

Manson says the link to diabetes might appear more clearly in the Women’s Health Initiative because the study was so large and the women were followed for such a long time. Doctors currently write 255 million prescriptions for cholesterol-lowering drugs each year, according to IMS Health, which monitors the pharmaceutical industry.

An increased risk of diabetes among statin users was first seen in 2008, in a randomized controlled trial of the drug Crestor, says Vivian Fonseca, the American Diabetes’ Association’s president for medicine and science. A 2011 analysis in the Journal of the American Medical Association and a 2010 analysis in The Lancet also found an increased risk of diabetes among statin users.

Fonseca says scientists still don’t understand why statins appear to increase the risk of diabetes. But he says that other important drugs, such as the diuretics used to treat high blood pressure, also are known to increase the risk of diabetes.

“Every medication has risks and benefits,” Fonseca says. “But you don’t want people to have heart attacks because they are so worried about getting diabetes.”

For example, Eckel says a 62-year-old woman who had a heart attack six months ago is still better off on a statin, even if she has diabetes in her family or impaired blood sugar levels.

Manson says it’s important for researchers to figure this out, however, because that might help drug companies develop statins that don’t increase diabetes risk.

Manson speculated that her study could help doctors understand why statins reduce the heart attack risk in people without pre-existing heart disease, but not the overall risk of death. Maybe that’s because a statin’s benefits for preventing heart attacks are canceled out by the increasing diabetes risk, Manson says.

Use of statins among people older than 45 has increased tenfold in the past two decades, from 2 percent in the years 1988 to 1994 to 25(PERCENT) in the years 2005 to 2008, according to the National Center for Health Statistics. Americans spent nearly $19 billion on them, according to IMS Health, which researches the drug market.

Nearly 26 million Americans — or 8.3 percent of the population — have diabetes, according to the American Diabetes Association. Experts say the obesity epidemic is the primary driver of the increase in diabetes.