SELECT trial deep-dive: what semaglutide reduces by 20% in cardiovascular patients

TLDR. The SELECT trial enrolled 17,604 patients with established cardiovascular disease and overweight or obesity, randomized to Wegovy 2.4 mg weekly or placebo. The primary endpoint (a composite of cardiovascular death, non-fatal myocardial infarction, and non-fatal stroke) was reduced by 20 percent on Wegovy. The trial led to the 2024 FDA label addition for cardiovascular risk reduction in patients with established CVD and overweight or obesity. The result reshaped Medicare coverage and shifted the conversation: GLP-1 is now a cardiology drug as much as a weight-loss drug.

SELECT (Semaglutide and Cardiovascular Outcomes in Patients with Overweight or Obesity) was the trial that produced Medicare's 2024 expansion of Wegovy coverage for the cardiovascular indication. The headline finding is a 20% relative-risk reduction in major adverse cardiovascular events. For healthcare-literate readers, here is what the trial actually showed and where the inference is limited.

Trial design

• Population: 17,604 adults with established cardiovascular disease (prior MI, prior stroke or symptomatic peripheral artery disease) AND BMI ≥27. Mean BMI was 33.
• Exclusion: Type 2 diabetes excluded. This is critical, SELECT is the cardiovascular-prevention trial for non-diabetics with established CVD.
• Intervention: Semaglutide 2.4 mg weekly (Wegovy dose) vs. placebo. Both arms received guideline-directed CV medical therapy.
• Primary endpoint: Three-point MACE (cardiovascular death, non-fatal MI, non-fatal stroke).
• Follow-up: Median 39.8 months.

Primary findings

The primary MACE endpoint occurred in 6.5% of the semaglutide arm vs 8.0% of the placebo arm. Hazard ratio 0.80 (95% CI 0.72-0.90), p<0.001. That's the 20% relative-risk reduction in the headline.

The absolute risk reduction is 1.5 percentage points over the median 40-month follow-up. Number-needed-to-treat to prevent one MACE event: approximately 67 patients treated for 40 months.

Secondary endpoints

• Cardiovascular death: HR 0.85 (CI 0.71-1.01), trending positive but did not reach significance.
• Non-fatal MI: HR 0.72 (CI 0.61-0.85), significant.
• Non-fatal stroke: HR 0.93 (CI 0.74-1.15), not significant.
• All-cause mortality: HR 0.81 (CI 0.71-0.93), significant.
• Weight change: 9.4% loss in semaglutide arm vs 0.9% in placebo at 104 weeks.
• Heart failure hospitalisation: HR 0.82 (CI 0.71-0.96), significant.

What the data DOES support

• Wegovy 2.4 mg weekly reduces MACE in adults with established CVD and overweight/obesity but without type 2 diabetes.
• The effect appears driven mostly by MI reduction, not stroke.
• All-cause mortality benefit is real and supports causation rather than chance.
• Weight loss is meaningful but the cardiovascular benefit appeared early (within 6-12 months) before maximum weight loss accrued, suggesting non-weight-mediated mechanisms.

What the data DOES NOT support

• Primary prevention. SELECT patients all had established CVD. Whether semaglutide reduces MACE in patients without established CVD is unstudied.
• Type 2 diabetes patients. T2D was excluded. The cardiovascular benefit of semaglutide in T2D is established from SUSTAIN-6 with similar magnitude, but mechanisms may differ.
• Stroke prevention. The point estimate for stroke trended positive but did not reach significance.
• Other GLP-1 molecules. Tirzepatide does not have a comparable completed CV outcomes trial as of mid-2026. SURPASS-CVOT is ongoing.
• BMI < 27. SELECT enrolled patients with BMI ≥27. Whether the cardiovascular benefit extends to normal-BMI CVD patients is unknown.

The Medicare coverage implications

In March 2024, CMS announced that Medicare Part D plans must cover Wegovy when prescribed for the cardiovascular indication in patients with established cardiovascular disease, even without obesity (BMI ≥27 with concomitant overweight is the formal criterion). This was the first major Medicare expansion of GLP-1 coverage. As of mid-2026, most Part D plans have updated formularies accordingly.

For Medicare patients with established CVD: prescription must be coded for cardiovascular risk reduction (ICD-10 code I25.10 or similar), not for obesity. Patients who present with weight loss as the goal and CVD history as the indication need a prescriber who codes the prescription correctly.

See best for Medicare CV for the programs that handle this coding correctly.

Real-world translation

For a patient with established CVD and BMI 30 considering Wegovy:

• Expected MACE reduction over 3 years: 1.5 percentage points absolute (from ~8% to ~6.5% in the SELECT-eligible population).
• Expected weight loss: 9-15% of body weight (SELECT vs STEP-1; STEP-1 was higher because it enrolled patients with overweight, not pre-selected CVD patients).
• Cost on Medicare with PA approval: $50-$300/month depending on plan tier.
• Number-needed-to-treat to prevent one MACE: ~67 over 40 months.

For comparison, statin NNT for secondary CVD prevention is roughly 50-80 over similar periods. Wegovy in established-CVD patients is in the same magnitude of effect as the baseline of secondary CV prevention.

For the broader GLP-1 trial landscape, see our trial-efficacy overview and the Wegovy drug profile.

Frequently asked questions

What is the SELECT trial?

A 17,604-patient randomized trial that enrolled patients with established cardiovascular disease (prior MI, stroke, or peripheral arterial disease) and overweight or obesity, randomized them to Wegovy 2.4 mg weekly or placebo, and followed them for a median of 39.8 months. The primary endpoint was a composite of cardiovascular death, non-fatal MI, and non-fatal stroke. Published in NEJM 2023.

What were the headline results?

Wegovy reduced the primary MACE endpoint by 20 percent relative to placebo (hazard ratio 0.80, 95% CI 0.72 to 0.90). The benefit emerged early and continued through the follow-up period. Mean weight loss in the Wegovy arm was 9.4 percent, well below the STEP-1 number, partly because the population was different (older, more comorbid).

Does SELECT prove the cardiovascular benefit is independent of weight loss?

The data is consistent with a partly weight-loss-independent benefit. The MACE reduction emerged early in the trial, before maximum weight loss was achieved, and persisted in subgroups with smaller weight losses. The medication appears to affect cardiovascular risk through multiple mechanisms beyond weight: blood pressure, inflammation, lipids, glycemic control.

How did SELECT change Medicare coverage?

The trial led to the 2024 FDA label addition for cardiovascular risk reduction in patients with established CVD and overweight or obesity. That label change opened Medicare Part D coverage for Wegovy in CVD patients despite the statutory obesity exclusion. Practical effect: Medicare beneficiaries with prior MI, stroke, or PAD plus BMI 27 or higher can now get Wegovy covered.

Is the SELECT benefit class-wide or specific to semaglutide?

The CV outcomes data right now is specific to semaglutide at 2.4 mg weekly. The SURPASS-CVOT trial for tirzepatide is in progress, with results expected. Earlier CV outcomes trials for liraglutide (LEADER) showed similar directional benefit. The likely pattern is a GLP-1 class effect on CV outcomes, but the SELECT-quality evidence is currently semaglutide-specific.