TUESDAY, Aug. 24 (HealthDay News) -- A new study finds that the risk of heart attacks or death after taking the glucose-lowering diabetes drugs Avandia and Actos are about the same.
This is a direct contradiction to numerous other studies that found that the risk was elevated for Avandia (rosiglitazone) but not for Actos (pioglitazone). The findings are, however, in line with some other previous studies, further muddying the picture for patients and doctors trying to select the best drug with the least side effects.
"The rosiglitazone story gets more and more interesting and confusing. It seems every time we have a study that indicates a problem with the drug, another one finds no trouble with it," said Dr. Kirk Garratt, clinical director of interventional cardiovascular research at Lenox Hill Hospital in New York City.
In July, members of a U.S. Food and Drug Administration advisory panel recommended adding a second black-box warning to Avandia's label warning of the cardiac dangers, while essentially clearing Actos, at least for the time being.
But one expert feels that both drugs, which belong to a class of medications known as thiazolidinediones, should be avoided.
"Purely from a heart standpoint, none of these medicines have been shown to help and probably do increase the risk [of heart problems]," said Dr. Bryan Henry, a cardiologist and assistant professor of medicine at the University of Rochester Medical Center in New York. "I think glucophage or Metformin should always be the first-line drug to start treatment."
While not preventing heart attacks or strokes, Avandia and Actos have been shown to prevent some of the microvascular complications of diabetes, such as kidney trouble and neuropathy.
The new study, published Aug. 24 in the journal Circulation: Cardiovascular Quality and Outcomes, differed from many previous trials in several respects, which may account for the differences in findings.
"The patients in this study seem to have been younger [average age 54] and healthier than we've seen in other studies: only about 2 percent had significant pre-existing cardiac conditions," Garratt said. "Most importantly, [cardiovascular] event rates were remarkably low. In fact, event rates were so low it wasn't possible to analyze subgroups, to see if things like kidney function or prior heart attack influenced the response to rosiglitazone."
The study authors analyzed prescribing data for about 30,000 patients with type 2 diabetes, all of whom were members of a private insurance group.
The risk of a heart attack, heart failure or dying hovered at 4 percent over close to three years no matter which medication the patient was taking.
"Our study looked at a population of commercially insured patients so these potentially could represent healthier and younger patients," said study lead author Debra Wertz, outcomes research manager for HealthCore, Inc., the research subsidiary of the insurance company WellPoint, which funded the study.
The time frame of this study -- early 2001 through late 2005 -- may also have affected the findings. "Over the course of time, treatment patterns may change and could impact differences. Avandia use, for instance, has changed quite a bit," she said, with fewer prescriptions written.
"As a general statement, this is not going to change prescribing per se, but it does offer another tool for patients and providers for evaluating the use of rosiglitazone and pioglitazone," Wertz added. "I think it's helpful for doctors and patients to be aware of all the available data and then use that information when making decisions."
The U.S. National Library of Medicine has more on thiazolidinediones.
SOURCES: Debra Wertz, Pharm.D., outcomes research manager, HealthCore, Inc., Wilmington, Del.; Bryan Henry, M.D., assistant professor of medicine, University of Rochester Medical Center, New York; Kirk Garratt, M.D., clinical director of interventional cardiovascular research, Lenox Hill Hospital, New York City; Aug. 24, 2010, Circulation: Cardiovascular Quality and Outcomes
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