On Thursday, September 27, 2007, U.S. researchers released a report revealing that the popular diabetes drugs Avandia and Actos increase heart failure risk but do not increase the risk for cardiovascular death in patients with type 2 diabetes.

The already controversial Avandia and Actos medications, which belong to a class of sugar-lowering drugs called thiazoilidinediones (TZDs), prompted the United States Food and Drug Administration (FDA) to require makers to place a “black box” warning on the labels after the risk of heart failure was linked to the medications.

The FDA decided not to remove the drugs from the market in July 2007, reasoning that evidence linking Avandia to heart failure was inconclusive.

Dr. Robert Nesto is the chair of the department of cardiovascular medicine at the Lahey Clinic Medical Center, in Burlington, Massachusetts, and the lead researcher of the September 27th study of Avandia and Actos. This study examined the results of seven clinical trials involving 20,000 patients administered Avandia or Actos.

Nesto’s team discovered a 72 percent increase of congestive heart failure among diabetes patients with different medical backgrounds and congestive heart failure histories. The risk of cardiovascular death was not increased in the patients, however, according to the study.

GlaxoSmithKline, maker of Avandia, suggests that congestive heart failure and fluid retention are linked, and “it is well known that TZDs can cause some fluid retention, which can lead to, or worsen, congestive heart failure. If congestive heart failure signs and symptoms develop, and heart failure is confirmed, heart failure can be appropriately managed by a physician.”

Dr. Nesto however, believes that doctors should avoid prescribing Avandia and Actos to patients with heart failure.

Dr. Steven Nissen, chairman of the department of cardiovascular medicine at the Cleveland Clinic, was the original researcher who linked Avandia to heart attack risk. He lightly criticizes Nesto’s study for not dealing with specific risks of using the drugs.

“The new analysis does not answer the question whether the observed increase in heart failure leads to other serious complications, including death,” according to Nissen. “The authors did not examining the risk of cardiac death in patients who developed congestive heart failure while taking a TZD drug. Instead they looked at overall cardiovascular mortality. This finding neither confirms, no refutes, the hypothesis that TZDs lead to major complications of heart failure.”

Source: “Diabetes Drugs Boost Heart Failure But Not Death,” Forbes.Com, September 28, 2007.