Safety risks higher with Avandia than Actos -study
By Julie Steenhuysen
CHICAGO, Nov 24 (Reuters) - Older diabetics who took GlaxoSmithKline's (GSK.L) Avandia to control their blood sugar had a higher risk of death and heart failure while on the drug than those who took Takeda Pharmaceutical's (4502.T) Actos, a drug in the same class, U.S. researchers said on Monday.
They said the head-to-head comparison confirms prior analyses finding Avandia carries greater risks than Actos, particularly in older diabetics.
Surprisingly, the study found no difference in heart attack and stroke risks. But since 75 percent of diabetics die from heart-related causes, the researchers think heart attacks and strokes likely contributed to the overall increased deaths in the Avandia group.
"We hypothesize that many of the deaths were due to myocardial infarction (heart attack) and stroke," Dr. Wolfgang Winkelmayer of Brigham and Women's Hospital in Boston and colleagues wrote in the Archives of Internal Medicine.
Recent analyses of clinical studies found Avandia raised the risk of heart attacks, which has sent sales of the drug plummeting. An analysis of studies on Actos, meanwhile, suggested it reduced the risk of heart attacks and strokes.
Both Avandia, known generically as rosiglitazone, and Actos, known generically as pioglitazone, raise the risks of heart failure and carry strong warnings on their labels.
"Altogether, the picture people got was it looks like rosiglitazone might be associated with badness and pioglitazone is neutral and even beneficial," Winkelmayer said in a telephone interview.
"For me, that left an important question open. What if you happen to directly compare those two treatments together," Winkelmayer said in a telephone interview.
He and colleagues studied Medicare claims data from 28,361 U.S. patients older than 65 years who began taking either rosiglitazone or pioglitazone between 2000 and 2005.
ANOTHER PIECE OF THE PUZZLE
They checked for overall risk of death while taking the drug, as well as heart attacks and heart failure and other side effects in this population of older diabetics.
Of those studied, 14,260 began treatment with pioglitazone and 14,101 with rosiglitazone.
"Those who started with rosiglitazone had a 15 percent increased risk of dying from any cause compared with pioglitazone," Winkelmayer said. They also found patients on rosiglitazone had a 13 percent great risk of heart failure compared with those on pioglitazone.
"The interesting part is that we didn't find any difference for the risk of stroke or heart attack," he said.
Winkelmayer thinks this may be because older diabetics are less likely to survive a heart attack or stroke. "This hypothesis we cannot test because we don't have any cause of death data for these patients. It remains speculation," Winkelmayer said.
Winkelmayer said the study was not a randomized clinical trial, which is the most reliable type of study, but he said the characteristics in both study populations were surprisingly similar, making the comparison quite strong.
"I think it's one more piece of the puzzle," he said.
"It will contribute to a more compelling picture that will inform policymakers with regard to how to move forward."
Last month, two major medical groups dropped Avandia from the list of recommended treatments for people with type 2 diabetes, the most common form of the disease.
Some 23.6 million U.S. children and adults have diabetes, according to the American Diabetes Association. Type 2 diabetes is closely linked to obesity and has become increasingly common as more people become obese.
(Editing by Will Dunham and Cynthia Osterman)
