GLP-1s and Heart Health: What the SELECT Trial Changed

SELECT (Semaglutide Effects on Cardiovascular Outcomes in People with Overweight or Obesity) was a randomized, double-blind, placebo-controlled trial of 17,604 adults age 45+ with a BMI ≥27 and established cardiovascular disease but no diabetes. Participants received either weekly semaglutide 2.4 mg (Wegovy) or placebo and were followed for an average of about 3.3 years. The primary endpoint — a composite of cardiovascular death, nonfatal heart attack, or nonfatal stroke — occurred in 6.5% of the semaglutide group vs 8.0% of the placebo group, a 20% relative risk reduction. The benefit was statistically significant and consistent across subgroups.

Before SELECT, GLP-1 cardiovascular benefits had been demonstrated mainly in people with type 2 diabetes (LEADER, SUSTAIN-6, REWIND). SELECT extended that benefit to a much larger population: roughly 150 million American adults have a BMI ≥27 with cardiovascular disease but no diabetes. The trial established that obesity itself, treated effectively, lowers heart-attack and stroke risk. The FDA expanded Wegovy's label in March 2024 to include cardiovascular risk reduction, the first such approval for a weight-loss medication. That label change has expanded insurance coverage — including portions of Medicare under Part D — for patients who previously could not afford treatment.

The Kaplan-Meier curves in SELECT separated within the first months of treatment, before participants had lost meaningful weight. This suggests that semaglutide's cardiovascular benefits are not entirely dependent on weight loss. A 2024 secondary analysis found that participants who lost less than 5% of body weight still had reduced cardiovascular events, pointing to direct vascular effects of the medication: improved endothelial function, reduced inflammation (lower C-reactive protein), modest blood-pressure lowering (3–5 mmHg), and changes in lipid profiles. Heart-failure outcomes were also improved in companion trials like STEP-HFpEF for preserved-ejection-fraction heart failure.

Probably yes, but the definitive trial isn't out yet. SURMOUNT-MMO is the ongoing cardiovascular outcomes trial for tirzepatide in adults with obesity, with completion expected in 2027. Earlier trials in adults with diabetes (SURPASS-CVOT) and heart-failure trials (SUMMIT) have shown improvements in cardiovascular risk factors and heart-failure symptoms. SUMMIT, published in 2024, demonstrated that tirzepatide improved exercise capacity and quality of life in people with HFpEF and obesity. While tirzepatide is widely expected to show CV benefits similar to semaglutide, doctors generally consider semaglutide the more evidence-backed choice for patients with established heart disease — until SURMOUNT-MMO reports.

Most cardiovascular concerns from early in GLP-1 history have not held up. Heart rate increases of 1–4 bpm are seen on average, which is generally considered clinically minor in patients without arrhythmias. There is no signal for increased heart attack, stroke, or cardiovascular death — the trials in fact show the opposite. Rare GLP-1 risks like pancreatitis and gallstones are not directly cardiovascular. Patients with active arrhythmia, severe heart failure, or recent myocardial infarction should discuss timing carefully with their cardiologist. Many cardiology programs now actively prescribe semaglutide as part of secondary prevention rather than waiting for primary-care referral.

If you have established cardiovascular disease and a BMI ≥27, semaglutide is FDA-approved for cardiovascular risk reduction and is increasingly considered alongside statins, antihypertensives, and antiplatelets as standard secondary prevention. If you have only cardiovascular risk factors (high LDL, hypertension, family history) without established disease, the evidence is less direct — though many cardiologists are extrapolating SELECT findings. Decisions should be individualized with your provider based on your full risk profile, kidney function, prior medication tolerance, and access. A GLP-1 is not a replacement for statins, blood-pressure control, smoking cessation, or exercise — but it is a meaningful addition to the toolkit.