Tirzepatide vs GLP-1 agonists: MACE in T2D

A retrospective cohort study published in the Journal of the American Heart Association on 17 July 2026 compared tirzepatide against established GLP-1 receptor agonists in 16,402 propensity score-matched patients with type-2 diabetes and atherosclerotic cardiovascular disease (ASCVD)^[1]. Over a one-year follow-up, tirzepatide was associated with a 25% lower risk of major adverse cardiovascular events (MACE) (hazard ratio 0.75; 95% CI 0.63 to 0.91) compared with GLP-1 receptor agonists taken as a class. The finding adds real-world weight to a question the incretin field has been circling for several years: does tirzepatide's dual GIP and GLP-1 mechanism produce cardiovascular outcomes that single-pathway GLP-1 agonists cannot match?

What the study measured and found

The researchers used the TriNetX network, a federated database of US electronic health records, and identified adults with type-2 diabetes and ASCVD who started either tirzepatide or a GLP-1 receptor agonist between January 2022 and March 2025. After 1:1 propensity score matching on demographic and clinical covariates, each arm contained 8,201 patients. The primary outcome was one-year MACE. Tirzepatide was associated with lower rates across every pre-specified endpoint^[1]:

Major adverse cardiovascular events: HR 0.75 (95% CI 0.63 to 0.91). All-cause mortality: HR 0.69 (95% CI 0.53 to 0.90). Acute myocardial infarction: HR 0.70 (95% CI 0.53 to 0.93). Major adverse limb events: HR 0.59 (95% CI 0.39 to 0.88). The results held across subgroup and sensitivity analyses.

How this fits the randomized trial evidence

The picture from randomized trials is more nuanced. SURPASS-CVOT, published in the New England Journal of Medicine in December 2025, compared tirzepatide (up to 15 mg weekly) directly against dulaglutide (1.5 mg weekly) in 13,165 patients with type-2 diabetes and ASCVD over a median four-year follow-up^[2]. Tirzepatide produced substantially larger reductions in body weight (11.6% versus 4.5%) and HbA1c (1.66 versus 0.88 percentage points), yet the primary MACE composite (cardiovascular death, myocardial infarction, or stroke) occurred in 12.2% of the tirzepatide group and 13.1% of the dulaglutide group. The hazard ratio was 0.92 (95.3% CI 0.83 to 1.01). Noninferiority was confirmed; superiority was not.

A separate target-trial emulation published in Diabetes Care in May 2026, using commercially insured US patients, found that tirzepatide reduced MACE risk versus dulaglutide (HR 0.80; 95% CI 0.65 to 0.99) and all-cause mortality (HR 0.60; 95% CI 0.43 to 0.83) in a matched cohort of 9,233 pairs, but showed results comparable to semaglutide (HR 1.03; 95% CI 0.90 to 1.17) in a cohort of 25,266 pairs^[3]. Taken together, the pattern suggests tirzepatide may hold a cardiovascular advantage over older GLP-1 agents such as dulaglutide while sitting in a similar range to semaglutide.

What a retrospective design can and cannot show

The JAHA study has real strengths: a large matched sample, multiple outcomes tracked simultaneously, and analyses in a patient population that resembles clinical practice more closely than trial enrolment criteria do. But retrospective cohort studies carry inherent limitations that randomized trials are designed to avoid. Unmeasured confounding is the main one: patients who receive tirzepatide in routine care may differ from those receiving older GLP-1 agonists in ways that propensity matching cannot fully account for, including access to specialist care, adherence patterns, and reasons for drug selection. The one-year follow-up is also shorter than the four-year SURPASS-CVOT window, which limits what can be said about cardiovascular event trajectories over time. The authors call for prospective validation, and they are right to do so.

What is not yet known

The mechanism behind any cardiovascular advantage remains contested. Whether GIP receptor activation contributes something distinct to cardiac protection beyond what GLP-1 signalling alone provides has not been established in humans. The large review of tirzepatide's cardiovascular effects published in the Journal of Endocrinology in January 2025 concluded that "whether cardiovascular benefits will be found with dual GLP-1/GIP receptor agonists remains uncertain"^[4]. The JAHA study does not resolve this. It shows an association in a real-world cohort; it does not identify the pathway driving it.

The secondary endpoint comparisons in SURPASS-CVOT were not adjusted for multiplicity, which means they generate hypotheses rather than confirmations. And the safety picture is not one-sided: in the randomized trial, gastrointestinal adverse events and discontinuation rates were higher in the tirzepatide arm (13.2% versus 10.1% for dulaglutide). Real-world prescribing data reflect that too.

Where this lands

The JAHA paper is a useful addition to the cardiovascular evidence base for tirzepatide in type-2 diabetes with ASCVD, particularly because it tracks outcomes beyond the MACE composite to include limb events and all-cause mortality. Its results are broadly consistent with the direction of the real-world and trial literature, though they are stronger in magnitude than the randomized evidence, which warrants careful interpretation. For regulatory status by country, see the tirzepatide regulation pages. Patients with cardiovascular disease who are considering or currently using incretin-class therapy should discuss the full risk-benefit picture with their prescribing clinician.