TUESDAY, June 21, 2011 (HealthDay News) -- High doses of the widely popular cholesterol-lowering drugs known as statins may have a downside.
A new meta-analysis finds that intensive doses of statins, such as Lipitor and Zocor, upped the risk of being diagnosed with type 2 diabetes compared with moderate doses of the drugs.
But the review still revealed a lower incidence of heart attacks, stroke and death, meaning the balance remains tipped in favor of taking statins to protect your heart.
"The benefit with respect to heart protection still favors high-dose statins because those taking high doses of statins often have heart disease so are at very high risk of further events," said Dr. Kausik K. Ray, senior author of a paper published in the June 22/29 issue of the Journal of the American Medical Association.
"Patients should get annual checks of blood sugars and, if elevated, be treated appropriately," added Ray, a professor of cardiovascular disease prevention at St. George's University of London. "Of the agents tested, the net benefit was better with high-dose atorvastatin [Lipitor] as compared with high-dose simvastatin [Zocor]."
Statins have been very successful in lowering cholesterol levels and are used in people with and without diabetes, which is a major risk factor for cardiovascular disease.
According to Ray, only about 20 percent of patients taking statins are on high doses. About 80 percent take low to moderate doses.
Ray, along with colleagues from the University of Glasgow, pooled data from five randomized studies comparing intensive statin treatment with more moderate doses.
Essentially, all of the studies involved Lipitor and Zocor, either comparing them against each other, or comparing different doses of the same medication.
All together, they involved almost 33,000 participants and an average follow-up of almost five years.
People taking high doses (80 milligrams) of one of these drugs had a 12 percent higher risk for new-onset diabetes but a 16 percent reduced risk of cardiovascular events, compared with moderate doses.
That translates to one new case of diabetes for every 500 patients treated for one year with a high-dose statin compared with one fewer patient having a stroke or heart attack for every 155 patients treated for one year.
But the study had a number of limitations, other experts stated.
For one thing, it was a meta-analysis which, says Dr. Jacob Warman, chief of endocrinology at the Brooklyn Hospital Center in New York City, "doesn't prove anything." These types of analyses tend to be more "hypothesis-generating." (When researchers conduct a meta-analysis, they synthesize previous studies to look for patterns that would not show up in an individual study).
"It's suggestive but I don't know that it's conclusive," added Dr. Steven D. Wittlin, clinical director of the diabetes service at the University of Rochester Medical Center in Rochester, N.Y.
While there was a benefit seen in macrovascular complications, such as heart attacks, it's unclear if the same would be true with microvascular complications or those that involve small blood vessels and contribute to conditions such as neuropathy, Wittlin said.
That could change the risk-benefit ratio, he noted.
Also, as the authors themselves pointed out, the biological mechanisms behind the effect are still not clearly understood.
The U.S. Food and Drug Administration has more on statins.