Stopping GLP-1 drugs could increase heart attack risk for some, study says

Stopping treatment of type 2 diabetes with GLP-1 weight loss medications may lead to a doubled risk of heart attack, stroke or death, a new study shows.

The study, published Monday in the Lancet Regional Health Europe, looked at more than 80,000 Italians with type 2 diabetes and no established heart disease. Data was collected between 2004 and 2024.

Researchers found four in every 100 of those people a year who stopped taking GLP-1 treatments had a non-fatal heart attack or stroke, or died, compared to about two in 100 of the people who stayed on the medication.

Those with a body mass index of 30 or more, people considered medically obese, also showed a higher risk among those who stopped treatment than those under that BMI range.

Of the more than 80,000 people who started GLP-1s, those who stayed on treatment did so for about three years. The group that did not stay on treatment, about 60 per cent, is reported to have stopped use after about one year.

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But while the study raises questions about what factors could be behind that increase for some, researchers caution that as an observational study there are certain factors they couldn’t determine.

An analysis by the British Medical Journal notes the study could not determine if discontinuing GLP-1 drugs directly caused the increased risk, or if people who experienced a higher risk of health events were already in poorer health.

The BMJ also cautioned the study did not analyze why people stopped taking the drugs, such as potential gastrointestinal side effects, the high cost some drugs have, or potential illnesses. Some patients may have stopped because they were already in poor health, the journal added.

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Dr. Christopher Labos, cardiologist and epidemiologist at McGill University, stressed the Lancet study compared two groups of diabetic patients.

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“In one sense, what you’re saying is that these medications actually have a very clear cardiovascular benefit, which is known, and if you stop them, you don’t get that cardiovascular benefit,” Labos said.

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Some previous studies have shown weight-loss drugs could lead to regaining weight when people stop using the medication.

A study published in the BMJ in January 2026 showed weight-loss drug users on average regain weight at a rate of 0.4 kilograms or 0.88 pounds per month after they stop. That study reviewed 63 trials covering more than 9,000 individuals up to February 2025.

Patients who went on the drugs then stopped them regained their entire baseline weight on average about 20 months after they stopped taking the medications.

Labos noted the Lancet study further underscores these are chronic medications for chronic conditions and should only be stopped due to issues such as side effects or ineffectiveness.

“If you’re stopping them just because you think they’ve worked and now you want to stop, number one, you are probably going to see a regain of the weight,” he said. “Number two, you’re putting yourself to an increased risk because you no longer are having the metabolic benefits that are coming from the weight loss and the cardiovascular protection that goes with it.”

The Lancet study says it only included a small group of semaglutide users, with most patients using liraglutide or dulaglutide: all of which are types of GLP-1 medications.

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Tirzepatide, also known as Mounjaro for type 2 diabetes users and Zepbound for weight loss, was released after the period of the study and was not included.

Type 2 diabetes patients who stopped GLP-1 treatment found their weight, blood sugar concentrations and blood pressure changed “only modestly,” the study says. Similar amounts were seen in patients whether they went on to have a heart attack, stroke, or died.

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Researchers also cautioned the heightened risk of heart attack, stroke or death if you stop taking GLP-1s may not affect people without type 2 diabetes who take the drugs for weight loss or other conditions.

Further research is needed into whether stopping GLP-1 medications can directly cause increased cardiovascular risk or if it instead represents “a marker of higher underlying risk rather than a direct cause of adverse outcomes,” the study says.

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The study should not be taken to imply the drugs are dangerous, instead Labos said people should understand it outlines how the GLP-1 medications should be taken.

“If the interpretation that you draw from this is that, oh, these medications are potentially dangerous I think that’s the wrong interpretation,” he said. “If the interpretation you draw from this is that you shouldn’t just be starting and stopping these medications on a whim, I think that’s the correct interpretation.”