Two popular drugs used to treat late-onset diabetes may double the risk of heart failure, according to a new study. Researchers who analysed data on 78,000 patients who took Avandia or Actos to treat type II diabetes found that it increased the risk of heart failure by up to 100 percent, said the study released Thursday.
The researchers estimate that for every 50 patients taking the medications over a period of 26 months, one person will develop heart failure. The manufacturers cautioned from the beginning that the drugs were not suitable for patients at risk for - or with a history of - heart failure, and that patients who combined the drugs with insulin treatments were at increased risk for this complication. But this analysis found that this adverse effect occurred in patients with no risk for heart failure, even in the absence of insulin. The study also showed that it occurred in young people and at high and low doses.
On average, patients who developed this complication did so 24 weeks after starting on the drug, the investigators report in the journal Diabetes Care. "Our analysis quantifies the risk for the first time and it shows that nobody is immune," said Sonal Singh, lead author of the study and an assistant professor in internal medicine at Wake Forest University Baptist Medical Center in Winston Salem, North Carolina. Singh said the findings raise the question of whether doctors should revert to using older drugs such as Glucophage and or insulin injections. The researchers did not evaluate whether the adverse effects were fatal, nor did they study what went wrong.
They suggest that the drugs cause some people to retain fluid, which can trigger heart failure, symptoms of which include shortness of breath and an inability to exercise. GlaxoSmithKline, which has been marketing Avandia in the United States since 1999 and in Europe since 2000, downplayed the findings. Actos is made by Takeda Pharmaceutical.
"The risk of heart failure in diabetes patients and with use of these medicines is well recognised and is clearly identified in prescribing information to doctors," the company said in a statement.
"GSK is confident in the overall safety profile of rosiglitazone when used appropriately." Rosiglitazone is the trade name for Avandia. GSH's blockbuster drug has also been linked with other problems. In May, a study in a US medical journal said people taking the drug had a 43 percent higher risk of heart attack. The US Food and Drug Administration will consult with medical experts on Monday to see whether the data merits adding so-called "black box warnings" to the drug packaging that would alert consumers to the potential risk.