What was the primary endpoint of the SELECT trial?

A three-component major adverse cardiovascular event (MACE) composite: non-fatal myocardial infarction, non-fatal stroke, or cardiovascular death. Semaglutide 2.4 mg reduced this endpoint by 20% versus placebo (HR 0.80, 95% CI 0.72–0.90, p<0.001).

Did participants in SELECT have diabetes?

No. SELECT specifically enrolled adults with obesity (BMI ≥27) and established cardiovascular disease who did not have diabetes at baseline — a design that distinguished it from earlier GLP-1 cardiovascular outcome trials such as LEADER and SUSTAIN-6, which enrolled primarily diabetic populations.

How much weight did participants lose in SELECT?

Mean body weight decreased by approximately 9.4% in the semaglutide arm versus 0.9% in the placebo arm at 104 weeks. The cardiovascular benefit appeared to exceed what weight loss alone would predict, suggesting direct cardioprotective mechanisms.

Is semaglutide 2.4 mg (Wegovy) licensed for cardiovascular risk reduction in the UK?

Following the SELECT results, the MHRA approved an extended indication for Wegovy (semaglutide 2.4 mg) in adults with established cardiovascular disease and BMI ≥27. NICE is reviewing the cardiovascular indication separately from the existing obesity guidance.

What were the main safety findings in SELECT?

Gastrointestinal adverse events (nausea, diarrhoea, vomiting) were more frequent with semaglutide, consistent with GLP-1 class effects. Serious GI events, cholelithiasis, and pancreatitis rates were low. No new safety signals were identified beyond the established class profile.

SELECT Trial: Semaglutide CV Outcomes Summary — Method, Results, UK Implications

Q: Did participants in SELECT have diabetes?

No. SELECT specifically enrolled adults with obesity (BMI ≥27) and established cardiovascular disease who did not have diabetes at baseline — a design that distinguished it from earlier GLP-1 cardiovascular outcome trials such as LEADER and SUSTAIN-6, which enrolled primarily diabetic populations.

Q: How much weight did participants lose in SELECT?

Mean body weight decreased by approximately 9.4% in the semaglutide arm versus 0.9% in the placebo arm at 104 weeks. The cardiovascular benefit appeared to exceed what weight loss alone would predict, suggesting direct cardioprotective mechanisms.

Q: Is semaglutide 2.4 mg (Wegovy) licensed for cardiovascular risk reduction in the UK?

Following the SELECT results, the MHRA approved an extended indication for Wegovy (semaglutide 2.4 mg) in adults with established cardiovascular disease and BMI ≥27. NICE is reviewing the cardiovascular indication separately from the existing obesity guidance.

Q: What were the main safety findings in SELECT?

Gastrointestinal adverse events (nausea, diarrhoea, vomiting) were more frequent with semaglutide, consistent with GLP-1 class effects. Serious GI events, cholelithiasis, and pancreatitis rates were low. No new safety signals were identified beyond the established class profile.

Trial in one paragraph

The Semaglutide Effects on Cardiovascular Outcomes in People with Overweight or Obesity (SELECT) trial was a multicentre, double-blind, randomised, placebo-controlled event-driven study published by Lincoff et al. in the New England Journal of Medicine in November 2023 (PMID: 37952131; doi: 10.1056/NEJMoa2307563). It enrolled 17,604 adults aged ≥45 with a BMI of ≥27 kg/m² and established cardiovascular disease — but without diabetes — at 804 sites across 41 countries. Participants received subcutaneous semaglutide 2.4 mg weekly or matched placebo, escalated over 16 weeks to the maintenance dose. Over a median follow-up of 39.8 months, the three-component MACE primary endpoint (cardiovascular death, non-fatal myocardial infarction, or non-fatal stroke) was reduced by 20%: hazard ratio 0.80 (95% CI 0.72–0.90, p<0.001). SELECT was the first large trial to demonstrate a cardiovascular benefit for a weight-management medicine in people who did not have diabetes at enrolment.

Design and population

SELECT was designed as a superiority trial with event-driven follow-up, powered to detect a 17% reduction in MACE. Randomisation was 1:1 (semaglutide 2.4 mg weekly vs. placebo), stratified by geographic region and the presence or absence of heart failure. The dose-escalation schedule started at 0.24 mg weekly for four weeks, then 0.5 mg, 1.0 mg, 1.7 mg, and finally 2.4 mg — identical to the Wegovy obesity dosing schedule.

Key inclusion criteria: age ≥45 years; BMI ≥27 kg/m²; established cardiovascular disease defined as prior myocardial infarction, prior stroke, or symptomatic peripheral arterial disease. Crucially, participants with type 2 diabetes or a haemoglobin A1c ≥6.5% at screening were excluded. Mean BMI at baseline was 33.4 kg/m²; mean age was 61.6 years; 72% were male; and approximately 23% had a history of heart failure. Median follow-up was 39.8 months (roughly 3.3 years), with a maximum of 57 months.

Primary endpoint result

MACE occurred in 569 of 8,803 participants (6.5%) in the semaglutide group and in 701 of 8,801 participants (8.0%) in the placebo group. The hazard ratio was 0.80 (95% CI 0.72–0.90, p<0.001), meeting the pre-specified superiority threshold. In absolute terms, semaglutide prevented approximately 15 MACE events per 1,000 patients treated over the median follow-up period — a clinically meaningful number-needed-to-treat that compares favourably with other secondary prevention interventions. The benefit appeared consistent across pre-specified subgroups including sex, baseline BMI category, age, and history of heart failure, although the trial was not powered for individual subgroup inference.

Secondary endpoints

Several hierarchically tested secondary endpoints also favoured semaglutide:

Cardiovascular death or heart-failure exacerbation: HR 0.82 (95% CI 0.71–0.96) — a 18% relative risk reduction.
All-cause mortality: HR 0.81 (95% CI 0.71–0.93), a 19% relative reduction.
Non-fatal myocardial infarction: HR 0.72 (95% CI 0.61–0.85), a 28% relative reduction and numerically the largest contributor to the primary endpoint benefit.
Non-fatal stroke: HR 0.93 (95% CI 0.76–1.13) — directionally favourable but the confidence interval crossed 1.0 and statistical significance was not demonstrated for stroke alone.
Body weight: Mean reduction of 9.4% with semaglutide vs. 0.9% with placebo at 104 weeks — a 8.5 percentage-point treatment difference.
C-reactive protein: Significant reductions in inflammatory markers with semaglutide, consistent with anti-inflammatory mechanisms independent of weight loss.

Safety signals

The safety profile of semaglutide 2.4 mg in SELECT mirrored the established GLP-1 receptor agonist class profile. Gastrointestinal adverse events — nausea (predominantly mild to moderate), diarrhoea, vomiting, and constipation — were more frequent in the semaglutide arm and were the primary driver of treatment discontinuation during dose escalation. Overall discontinuation due to adverse events was 16.6% with semaglutide vs. 8.2% with placebo.

Cholelithiasis was more common with semaglutide (2.8% vs. 2.3%), consistent with GLP-1-class and rapid-weight-loss effects on bile composition. Acute pancreatitis was rare and not significantly different between groups (0.3% vs. 0.2%). Serious GI events overall were similar between arms. No new safety signals emerged beyond the known GLP-1 class profile, and notably there was no excess of cancer, diabetic retinopathy (in the non-diabetic population), or psychiatric events.

Outcomes table

Endpoint	Semaglutide (%)	Placebo (%)	HR (95% CI)	p-value
3-component MACE (primary)	6.5%	8.0%	0.80 (0.72–0.90)	<0.001
CV death	2.5%	3.0%	0.85 (0.71–1.01)	0.07
Non-fatal MI	3.8%	5.2%	0.72 (0.61–0.85)	<0.001
Non-fatal stroke	2.1%	2.3%	0.93 (0.76–1.13)	0.46
All-cause mortality	3.3%	4.1%	0.81 (0.71–0.93)	0.002
CV death or HF exacerbation	3.9%	4.8%	0.82 (0.71–0.96)	0.013
Mean weight change at 104 wks	−9.4%	−0.9%	—	<0.001

Methodological strengths and caveats

SELECT has several important methodological strengths. It was a large, international, event-driven superiority trial with blinded adjudication of cardiovascular endpoints. The 17,604-participant sample provided robust statistical power, and the 39.8-month median follow-up is longer than many industry-sponsored cardiovascular outcome trials. The exclusion of participants with diabetes at baseline was deliberate and adds a novel layer of evidence — demonstrating that the cardiovascular benefit is not mediated solely by glycaemic improvement.

Important caveats: the trial used the full Wegovy 2.4 mg dose rather than the lower obesity doses used in some markets; results may not extrapolate to populations with different baseline cardiovascular risk profiles. The non-diabetic enrolment criterion means the findings cannot be directly generalised to patients with co-existing T2DM (for whom LEADER and SUSTAIN-6 data remain primary). The mechanism of cardiovascular benefit beyond weight loss — proposed to include direct myocardial effects, anti-inflammatory pathways, blood-pressure reduction, and lipid improvement — has not been fully disaggregated from the weight-loss contribution by the trial design alone.

UK implications

The SELECT results were submitted to the MHRA to support an extended indication for semaglutide 2.4 mg (Wegovy) covering reduction of cardiovascular events in adults with established CVD and obesity or overweight (BMI ≥27). The MHRA granted this indication in 2024, making Wegovy the first obesity medicine in the UK with an approved cardiovascular risk-reduction label — a significant shift in how the drug may be positioned in NHS prescribing frameworks.

NICE has historically appraised Wegovy under technology appraisal TA875 (obesity) with a two-year prescribing cap tied to specialist services. The cardiovascular indication opens a separate pathway — potentially via TA-level appraisal or direct commissioning through cardiovascular secondary prevention budgets — which could materially expand access. NHS England and integrated care boards are expected to evaluate whether SELECT-eligible patients (secondary prevention population, BMI ≥27, non-diabetic) should be treated through cardiology rather than weight-management pathways. Clinicians reviewing patients on existing antiplatelet or statin regimens following myocardial infarction or stroke may now consider semaglutide 2.4 mg as an adjunct secondary prevention therapy, independent of obesity management targets.

Frequently asked questions

What was the primary endpoint of the SELECT trial?: A three-component major adverse cardiovascular event (MACE) composite: non-fatal myocardial infarction, non-fatal stroke, or cardiovascular death. Semaglutide 2.4 mg reduced this endpoint by 20% versus placebo (HR 0.80, 95% CI 0.72–0.90, p<0.001).
Did participants in SELECT have diabetes?: No. SELECT specifically enrolled adults with obesity (BMI ≥27) and established cardiovascular disease who did not have diabetes at baseline — a design that distinguished it from earlier GLP-1 cardiovascular outcome trials such as LEADER and SUSTAIN-6, which enrolled primarily diabetic populations.
How much weight did participants lose in SELECT?: Mean body weight decreased by approximately 9.4% in the semaglutide arm versus 0.9% in the placebo arm at 104 weeks. The cardiovascular benefit appeared to exceed what weight loss alone would predict, suggesting direct cardioprotective mechanisms.
Is semaglutide 2.4 mg (Wegovy) licensed for cardiovascular risk reduction in the UK?: Following the SELECT results, the MHRA approved an extended indication for Wegovy (semaglutide 2.4 mg) in adults with established cardiovascular disease and BMI ≥27. NICE is reviewing the cardiovascular indication separately from the existing obesity guidance.
What were the main safety findings in SELECT?: Gastrointestinal adverse events (nausea, diarrhoea, vomiting) were more frequent with semaglutide, consistent with GLP-1 class effects. Serious GI events, cholelithiasis, and pancreatitis rates were low. No new safety signals were identified beyond the established class profile.