A drug used to help patients lose weight and manage diabetes may also help those with heart failure, an international clinical trial shows.

The test of tirzepatide, brand named Zepbound, included 731 patients with diastolic heart failure and obesity who were followed for two years.

"This class of drugs continue to show benefits far beyond weight loss," said researcher Dr. Christopher Kramer, chief of cardiovascular medicine at UVA Health. "This drug will become an important part of the armamentarium for patients with obesity-related heart failure and preserved heart function."

In nearly half of heart failure cases, the left ventricle of the heart becomes stiff and can no longer pump blood properly. Doctors call this diastolic heart failure or heart failure with preserved ejection fraction.

Obesity is a major cause of heart failure, so Kramer's team wondered if the weight-loss drug tirzepatide could help.

The new trial — published in four journals and reported Saturday at an American Heart Association meeting in Chicago — showed that tirzepatide offered big benefits for managing heart failure. 

Patients saw improvements in how far they could walk in six minutes and big decreases in a biological marker used to measure inflammation and predict risk of serious heart events, the study found.

During the two-year follow-up, 56 participants who received a placebo died or saw their heart failure get worse, compared to 36 who took tirzepatide.

Those who took tirzepatide also slimmed down, losing 11.6% of their body weight, on average.

Side effects were mostly mild — nausea and diarrhea, researchers said.

Kramer also led a companion study that examined how the drug affected the structure and function of participants' hearts. MRIs showed beneficial reductions in the heart's weight and surrounding fat. 

"This drug is reversing the abnormal properties of the heart brought on by obesity," Kramer said in a UVA news release. "There is much more to those drugs than weight loss alone."

The findings appear in four journals: The New England Journal of Medicine, Nature Medicine, Circulation and the Journal of the American College of Cardiology.

Eli Lilly, maker of Zepbound, sponsored the trial.