SURPASS-CVOT: Tirzepatide's Diabetic Heart Disease Data

SURPASS-CVOT tested tirzepatide against dulaglutide for cardiovascular outcomes in diabetes. Here's what the trial found and how it compares to SELECT.

SURPASS-CVOT is the cardiovascular outcomes trial for tirzepatide, comparing the drug against dulaglutide (another GLP-1 receptor agonist) in patients with type 2 diabetes and established cardiovascular disease or high cardiovascular risk. The trial's topline results were released by Eli Lilly in late 2024, and the full publication has informed tirzepatide's emerging cardiovascular evidence base.

The headline finding: tirzepatide demonstrated non-inferiority and, on specific analyses, superiority to dulaglutide for major adverse cardiovascular events. This is a different evidentiary standard than SELECT's placebo comparison — it establishes tirzepatide's cardiovascular benefit relative to another active GLP-1 agent, which is meaningful for a class that already has established cardiovascular protection.

Trial Design

SURPASS-CVOT enrolled approximately 13,000 adults with type 2 diabetes and established atherosclerotic cardiovascular disease. Participants were randomized 1:1 to weekly subcutaneous tirzepatide (titrated to 15 mg) or weekly dulaglutide (1.5 mg). The primary endpoint was a composite of cardiovascular death, nonfatal myocardial infarction, or nonfatal stroke (MACE). The trial was powered to demonstrate non-inferiority first, with pre-specified testing for superiority if non-inferiority was established.

Primary Results

Tirzepatide met the primary endpoint of non-inferiority to dulaglutide for MACE. Additional analyses supported tirzepatide on secondary cardiovascular endpoints, and on body weight, glycemic control, and cardiometabolic parameters the advantage over dulaglutide was clear. Safety findings were consistent with the established tirzepatide profile, with gastrointestinal adverse events the most common class effect.

What the Non-Inferiority Finding Means

Non-inferiority in an active-controlled trial means that the test drug is not meaningfully worse than the comparator. For SURPASS-CVOT, that establishes tirzepatide provides cardiovascular protection at least equivalent to dulaglutide — a drug with its own established cardiovascular benefit from the REWIND trial. The practical clinical implication is that tirzepatide can be used for its weight and glycemic advantages without cardiovascular compromise.

The question of whether tirzepatide is meaningfully superior to dulaglutide on cardiovascular endpoints — rather than equivalent — depends on which specific analyses are emphasized and how the composite endpoints are parsed. The core regulatory finding is non-inferiority with numerical superiority trends on several key measures.

How SURPASS-CVOT Compares to SELECT

SELECT (semaglutide) and SURPASS-CVOT (tirzepatide) ask different questions. SELECT asked whether semaglutide is better than placebo for cardiovascular events in patients without diabetes but with obesity and cardiovascular disease. SURPASS-CVOT asked whether tirzepatide is at least as good as another established GLP-1 for cardiovascular events in patients with diabetes. The answers are complementary: both semaglutide and tirzepatide provide cardiovascular benefit, and neither has a distinct disadvantage relative to its comparator.

What SURPASS-CVOT does not establish — and was not designed to establish — is whether tirzepatide's cardiovascular benefit in non-diabetic patients with obesity parallels semaglutide's benefit in the same population. That is the question an equivalent-to-SELECT tirzepatide trial would address, and no such completed trial exists yet.

Safety and Tolerability Observations

Gastrointestinal adverse events were more common with tirzepatide than dulaglutide, consistent with the general class pattern at higher doses. Discontinuation rates were modestly higher with tirzepatide due to GI tolerability. No new safety signals emerged. Cardiovascular death and all-cause mortality favored tirzepatide numerically, though the primary power was on non-inferiority for the composite MACE endpoint.

Clinical Implications

SURPASS-CVOT supports tirzepatide as a reasonable choice for patients with type 2 diabetes, established cardiovascular disease, and weight-management priorities. Combined with SURMOUNT-5 (weight loss superiority over semaglutide) and the broader SURPASS and SURMOUNT programs, tirzepatide's evidence base is now robust across diabetes, weight management, and cardiovascular contexts. The remaining open question — cardiovascular benefit in non-diabetic obese populations at the placebo-vs-drug level — is an area of continued investigation.

See our related reviews: SELECT trial and SURMOUNT-OSA.

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