Semaglutide and Cardiovascular Risk: What SELECT Actually Showed

GLP-1 receptor agonists started as diabetes drugs. Then they became weight-loss drugs. The SELECT trial is the moment they started to look like cardiovascular drugs — and unlike most headlines, this shift is now written into the drug’s FDA label.

What the trial measured

SELECT (published in the New England Journal of Medicine in 2023) enrolled 17,604 adults aged 45 or older with established cardiovascular disease — prior heart attack, stroke, peripheral artery disease, or revascularization — and a BMI of 27 or higher, but without diabetes. Participants received either once-weekly subcutaneous semaglutide titrated to 2.4 mg (8,803 people) or placebo (8,801), with mean exposure to the target dose of about 33 months.

The primary endpoint was a composite of cardiovascular death, non-fatal heart attack, or non-fatal stroke.

Major adverse cardiovascular events occurred in 6.5% of the semaglutide group versus 8.0% on placebo — a 20% relative reduction (hazard ratio 0.80; 95% CI 0.72–0.90; p < 0.001).

This is a secondary-prevention result: every participant already had cardiovascular disease.

Why “independent of weight loss” gets cited

The intuitive story is that people lost weight, so their hearts did better. The data complicate that. A prespecified SELECT analysis found the cardiovascular benefit was largely independent of baseline adiposity and of how much weight a person lost — the reduction held across weight-change categories, including people who lost relatively little. Statistical mediation analysis attributed only roughly a third of the MACE benefit to waist-circumference reduction.

That points to mechanisms beyond appetite and weight — possibly direct effects on inflammation, blood pressure, or vascular function. The full mechanistic picture isn’t settled, and honest interpretation means saying so.

What this does not mean

• It does not mean semaglutide is a primary-prevention drug for otherwise healthy people. SELECT studied people with existing cardiovascular disease.
• It does not mean the weight loss is irrelevant — only that it doesn’t appear to explain the whole effect.
• It does not replace foundational work: training, sleep, and nutrition still do the heavy lifting.

The takeaway

The evidence was strong enough that on March 8, 2024, the FDA approved semaglutide 2.4 mg (Wegovy) to reduce the risk of cardiovascular death, heart attack, and stroke in adults with established cardiovascular disease and obesity or overweight — the first weight-management drug to carry such an indication. For that specific population, SELECT moved GLP-1 therapy from a metabolic tool to a cardiovascular one. For everyone else, it remains a signal worth watching, not a prescription.

Sources

• Semaglutide and Cardiovascular Outcomes in Obesity without Diabetes (SELECT) — ACC clinical trial summary
• SELECT semaglutide to improve outcomes in patients with obesity and cardiovascular disease — PMC
• FDA Approves Semaglutide to Prevent Heart Events in Patients With CVD and Excess Weight — AJMC
• Semaglutide and cardiovascular outcomes by baseline and changes in adiposity measurements: a prespecified analysis of SELECT — The Lancet