Weight-loss drugs show a remarkable and unexpected side effect in new study

A large and surprising real-world study was detailed last month at the European Society of Cardiology meeting. It linked diabetes weight-loss medication GLP-1 medicines, such as Ozempic, with improving the mortality rate of people with heart issues by 50 percent.

More than 60 million people suffer from heart disease worldwide, placing a massive burden on families and health systems.

Nils Krüger, MD, of Brigham and Women’s Hospital, Mass General Brigham (MGB), led the analysis using nationwide insurance claims. His team followed patients for up to 52 weeks and tracked hospitalizations and deaths.

HFpEF is a form of heart failure where the heart’s squeeze is preserved but the muscle is stiff, which makes filling difficult. It accounts for about half of cases and is common in people with obesity and type 2 diabetes.

Options for this subtype have been limited, which frustrates both patients and clinicians. A therapy that safely cuts hospital visits and early deaths would matter in day to day care.

What GLP-1 drugs do

GLP-1 agonists mimic a gut hormone that helps control appetite and blood sugar. These medicines slow stomach emptying, reduce hunger signals, and improve glucose control, as outlined in a review.

Two drugs in this class, semaglutide and tirzepatide, are now widely used for diabetes and weight management. Doctors typically give them as weekly injections and adjust doses based on goals and tolerance.

They are not a quick fix, and they are not for everyone. Side effects, drug interactions, and cost need careful attention in routine practice.

Work on GLP-1 medicines began in the 1990s with early diabetes trials that focused on improving insulin release and lowering blood sugar.

The appetite suppressing effect was noticed along the way and eventually shaped a wave of obesity treatments.

Over time, trial data revealed potential benefits outside of glucose control, including reduced blood pressure, lower inflammation, and improved heart health markers.

These observations set the stage for large scale studies in people with HFpEF, obesity, and diabetes.

Studying heart health and GLP-1

The researchers evaluated more than 90,000 adults with obesity, type 2 diabetes, and HFpEF treated in U.S. clinical practice between 2018 and 2024. Everyone had the most common form of heart failure and shared the same high risk profile.

They compared new users of semaglutide or tirzepatide with patients starting sitagliptin, a diabetes drug chosen as a neutral proxy. The primary outcome combined heart failure hospitalization or death from any cause during the first year.

Results were reported as a hazard ratio, which describes relative risk over time. Lower than 1.0 means fewer events in the treatment group compared with the comparison group.

What the numbers say

Starting semaglutide was linked to a hazard ratio of 0.58 for the combined outcome. That corresponds to a 42 percent lower risk compared with sitagliptin over one year.

Starting tirzepatide was linked to a hazard ratio of 0.42. That corresponds to a 58 percent lower risk compared with sitagliptin during the same follow up period.

“Our findings show that in the future, GLP-1 targeting medications could provide a much-needed treatment option for patients with heart failure,” said Krüger, MD.

The study also reported no substantial increase in select safety outcomes over the one year window.

How this fits with other evidence

The cardiovascular signal is consistent with the SELECT trial. Adults with overweight or obesity but no diabetes had a 20 percent lower risk of cardiovascular death, heart attack, or stroke on semaglutide than on placebo.

The convergence matters because it suggests benefits beyond symptom scores or weight alone. It also points to metabolic and inflammatory pathways that intersect with heart failure biology.

GLP-1 and future heart health

These new data come from clinical practice rather than a randomized trial, so confounding can still influence results. Professional societies will weigh this evidence before changing guidance for HFpEF.

People with obesity, type 2 diabetes, and HFpEF who already meet criteria for GLP-1 treatment may see additional potential upside. The next step is a conversation with a clinician who knows their medications, risks, and goals.

Choices depend on many factors, including glucose control, kidney and liver function, past side effects, and out of pocket costs. Access and supply also vary by region and insurer.

No one should start or stop a prescription without medical input. Close follow up helps manage benefits, side effects, and expectations.

The study is published in JAMA.

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