Wegovy reduced the risk of non-fatal heart attack by 28% in the five-year trial. It produced a smaller 7% reduction in the occurrence of non-fatal stroke, though few strokes were seen in the trial overall.

What’s more, Wegovy started to show a reduction in overall cardiovascular events within months of participants starting the drug, with the difference between the drug and placebo widening as the study continued. Researchers observed that effect even before people lost significant weight, a “fascinating” finding that suggests both weight loss and the drug itself could be playing a role in heart health, said Dr. Ania Jastreboff, director of the Yale Obesity Research Center.

“I think it’s all additive, and I don’t think we can parse out one from the other,” Jastreboff, who was not involved in the study, said at a press briefing.

About two-thirds of participants had blood sugar levels that put them in the range of prediabetes. Wegovy decreased progression to diabetes by 73%, suggesting the drug could be used as an early treatment. Novo’s Ozempic, which uses the same active ingredient as Wegovy, is approved for diabetes. 

The study enrolled both patients whose body-mass index met the threshold for overweight or obesity, though most of the patients were considered obese.

Almost 17% of people receiving Wegovy in the trial stopped taking the drug, mainly because of gastrointestinal issues like vomiting and diarrhea, double the rate of people who discontinued the placebo. But more people in the control group experienced serious adverse events such as cardiac disorders and medical procedures. 

The discontinuations may reflect less familiarity with Wegovy among doctors involved in the study, said Kushner, who specializes in caring for patients who are overweight or have obesity. Adjusting the dosage or tweaking diet can help people navigate unpleasant side effects.

Participants also lost less weight in this study than previous ones examining Wegovy, though this study didn’t incorporate lifestyle changes and it enrolled people with different characteristics. 

One limitation of the study was its lack of diversity. Nearly three-quarters of the participants were male, and even more were white. Just about 4% of participants were Black.

Regardless, doctors expect the results to increase the number of people who take Wegovy. 

Seeing a diabetes drug producing positive cardiovascular and metabolic effects “opens a new door to treat obese patients with cardiovascular disease,” said Dr. George Dangas, director of cardiovascular innovation for Mount Sinai Hospital. But it could take time and energy to incorporate it into clinical practice.

“Those are good problems to have,” Dangas said. “We have something good for the patient, that’s great.” 

— CNBC’s Patrick Manning contributed to this report.

CORRECTION: This article has been updated to correct the title of Dr. George Dangas, director of cardiovascular innovation for Mount Sinai Hospital.