Study: Avandia riskier than Actos for older diabetics
Older patients taking GlaxoSmithKline P.L.C.'s diabetes drug Avandia had an increased risk of death and heart failure compared with similar patients taking Actos, a competing diabetes drug.
Older patients taking GlaxoSmithKline P.L.C.'s diabetes drug Avandia had an increased risk of death and heart failure compared with similar patients taking Actos, a competing diabetes drug.
The study of about 28,000 patients, all of them older than 65, also concluded that neither drug should be considered very safe.
The study, published today in the Archives of Internal Medicine, was based on Medicare claims data from patients in Pennsylvania and New Jersey.
Those who took Avandia had a 15 percent higher rate of death and a 13 percent greater risk of heart failure compare with those taking Actos, which is made by Takeda Pharmaceuticals North America Inc.
"This study confirms the safety concerns that have been raised for rosiglitazone compared with pioglitazone, which, in turn, also cannot be considered a very safe drug given its well-documented effect on the risk of congestive heart failure," the study's authors said.
Rosiglitazone is the generic name for Avandia; piogliatzone for Actos. Avandia has been under intense scrutiny since last May, when a New England Journal of Medicine study concluded that the drug increased the risk of cardiovascular problems in those who took it.
In a statement today, GlaxoSmithKline said it "strongly supports the safety and efficacy of Avandia based on extensive clinical trial experience and widespread post-marketing use."
The company said the study, led by researcher Wolfgang C. Winkelmayer, a doctor at Brigham and Women's Hospital in Boston, was limited because subjects were not assigned to take the drugs randomly. This was because the study relied on people already taking one of the drugs, and those decisions were made by their doctors.
The company also said the difference in number of Avandia and Actos users who died may be attributed to differing rates of cardiovascular disease and other problems often found in each group of diabetes patients.
Avandia users in the study had more diagnosed coronary artery disease and congestive heart failure. They were more likely to have resided in a nursing home and to have had more hospital days in the six months before they started taking the drug, compared to Actos users. Avandia users also had less use of beta blockers and cholesterol-lowering statin drugs, compared to Actos users.
Winkelmayer agreed that the inability to randomly assign study subjects to each drug was a shortcoming. But said he believed the results are solid.
William C. Quick, an endocrinology researcher with i3 Research, a company that runs clinical trials for drug companies, said Winkelmayer's study represents more evidence that Avandia is unsafe.
"An argument is slowly building that rosiglitazone has stronger effects than pioglitazone, and hence there's an argument to be made that rosiglitazone is now a drug that should come off the market," Quick said.
Both Avandia and Actos now carry a so-called black box warning, the most serious type, about increased risk of heart failure among users.
