GLP-1 Drugs Protect Heart Health Independently of Weight Loss

Clinical evidence indicates that glucagon-like peptide-1 (GLP-1) receptor agonists provide cardiovascular protection that extends beyond the effects of weight loss. Research shows these medications can reduce the risk of major heart-related events through direct cardioprotective mechanisms, altering the medical calculus for patients and providers who may have previously viewed this therapy as optional rather than medically indicated.

The United States Food and Drug Administration granted semaglutide a cardiovascular risk reduction indication in 2024. This decision was based on data from the SELECT (Semaglutide Effects on Cardiovascular Outcomes in People with Overweight or Obesity) trial, which focused on adults with established cardiovascular disease and overweight or obesity, defined as a BMI of 27 or higher, who did not have type 2 diabetes.

The SELECT Trial Outcomes

The SELECT trial enrolled 17,604 adults who were randomized to receive either a placebo or 2.4 mg of semaglutide once weekly, with the dose escalated over 16 weeks. Participants were followed for a median of approximately 33 months, with a maximum follow-up of 58 months.

The primary endpoint of the study was the time to the first major adverse cardiovascular event (MACE), a three-point composite consisting of cardiovascular death, nonfatal myocardial infarction (heart attack), or nonfatal stroke. The results demonstrated a 20% reduction in MACE for those taking semaglutide compared to the placebo group.

Specific findings from the SELECT trial include:

• A 19% reduction in cardiovascular death.
• A 28% reduction in nonfatal myocardial infarction.
• A 7% reduction in nonfatal stroke, though this specific endpoint was not statistically significant.
• A 73% reduction in the development of new-onset type 2 diabetes.

Cardiovascular Benefits Independent of Weight Loss

While weight loss is a known contributor to improved heart health by lowering blood pressure and reducing strain on the heart, researchers have found that GLP-1 medications offer benefits that weight loss alone cannot explain. Data from the STEP-HFpEF (Semaglutide Treatment Effect in People with Obesity and Heart Failure with Preserved Ejection Fraction) and STEP-HFpEF DM trials suggest that semaglutide improves cardiovascular health independently of weight loss in patients with obesity-related heart failure with preserved ejection fraction (HFpEF).

HFpEF is characterized by increased ventricular stiffness and the impaired relaxation of the left ventricle during diastole, which prevents the ventricle from filling adequately with blood and decreases cardiac output.

Several factors suggest that the biology of GLP-1 drugs goes beyond weight reduction:

• Meaningful reductions in cardiovascular events have been observed even when the average weight loss was modest.
• The timeline for cardiovascular risk reduction often begins earlier than would be expected if weight loss were the sole driver of the improvement.
• The drugs appear to exert direct effects on the vascular system and metabolism.

These medications are believed to protect the heart by reducing inflammation and improving the function of blood vessels, blood pressure, and overall metabolism.

Broadening the Therapeutic Scope

The evidence for cardiovascular benefits in GLP-1 therapy is not limited to semaglutide. The LEADER trial previously demonstrated that liraglutide reduced major adverse cardiovascular events in people with type 2 diabetes who already had cardiovascular disease or were at high risk.

Because of these findings, GLP-1 receptor agonists may be considered for high-risk individuals even in cases where weight loss is not the primary therapeutic objective.

However, the duration of these benefits is tied to the continuation of the medication. Reports indicate that the heart benefits associated with GLP-1 medications fade shortly after the therapy is stopped.