Two drugs with FDA warnings may benefit some heart failure patients

Two drugs that the U.S. Food and Drug Administration warns against using in many heart failure patients may benefit some people with diabetes who have heart failure, according to an observational study in today’s Circulation: Journal of the American Heart Association. “Our study found that patients with heart failure and diabetes who were prescribed one or both of two types of diabetes drugs –metformin and thiazolidinediones — had lower death rates than those who did not receive these drugs,” said lead author Frederick A. Masoudi, M.D., M.S.P.H., assistant professor of medicine at Denver Health Medical Center and the University of Colorado Health Sciences Center. “For both drug classes, current labeling advises against use in high-risk patients like those in this study, who had congestive heart failure.”

Currently the FDA cautions against using thiazolidinediones in patients with advanced heart failure symptoms and requires a “black box” warning against prescribing metformin to patients with heart failure that requires drug treatment.

“Despite the warnings, doctors are prescribing these drugs to this group of high-risk patients, perhaps because they think the drugs will reduce cardiovascular risk factors or because they consider the evidence behind the warnings to be inadequate,” Masoudi said.

The observational study followed 16,417 diabetic Medicare patients discharged from hospitals after treatment for heart failure. The researchers divided the patients into groups based on their diabetes treatment, then looked for associations between that treatment and outcomes such as death or re-hospitalization due to all causes or congestive heart failure.

Crude one-year death rates were lower among the 2,226 patients treated with a thiazolidinedione or metformin, compared to the 12,069 treated with neither insulin-sensitizing drug. The 261 patients discharged on both drugs also had a lower risk of death.

After controlling for differences in patient populations, treatment with thiazolidinediones was associated with a 13 percent lower risk of death, metformin a 14 percent lower risk, and both drugs a 24 percent lower risk. Researchers found no link between treatment with other drugs, such as insulin, and death.

Hospital admissions for all causes did not differ with either medication class; however there was a six percent higher risk of readmission for heart failure with thiazolidinedione treatment and an eight percent lower risk with metformin treatment.

“These findings do not support the existing recommendations against the use of insulin sensitizers in many, if not all, patients with heart failure but emphasize the importance of close monitoring of patients treated with thiazolidinediones,” the researchers wrote.

The authors conclude that randomized trials are warranted to corroborate their findings to be sure that their results don’t reflect differences in patient treatments that were due to differences in the severity of a patient’s diabetes or other factors.

Co-authors are Silio E. Inzucchi, M.D.; Yongfei Want, M.S.; Edward P. Havranek, M.D., JoAnne M. Foody, M.D.; and Harlan M. Krumholz, M.D.

Statements and conclusions of study authors that are published in the American Heart Association scientific journals are solely those of the study authors and do not necessarily reflect association policy or position. The American Heart Association makes no representation or warranty as to their accuracy or reliability.

From American Heart Association

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