Writing / Reading the evidence
SURPASS-CVOT: what it shows, and what it does not
Tirzepatide now has a cardiovascular indication. Read the trial design before you extend it to every patient.
In August 2026 the US FDA approved tirzepatide to lower the risk of major adverse cardiovascular events in adults with type 2 diabetes at high cardiovascular risk. The approval rests on SURPASS-CVOT, which enrolled people with established atherosclerotic disease. It is a real advance, and it is also easy to over-read.
What the trial did
- It enrolled adults with type 2 diabetes and established atherosclerotic cardiovascular disease.
- It compared tirzepatide with dulaglutide, an active comparator that already has its own cardiovascular benefit. There was no placebo arm.
- The primary end point was three-point MACE: cardiovascular death, myocardial infarction or stroke.
What it showed
In 13,299 patients, tirzepatide was non-inferior to dulaglutide 1.5 mg for MACE, with a hazard ratio of 0.92 (95.3% CI 0.83 to 1.01). Superiority over dulaglutide was not established.
Read correctly, that is a strong result. My own reading is that matching an active comparator with proven benefit implies a cardiovascular benefit of its own in this population, though without a placebo arm that benefit can only be estimated from other trials. What it does not do is show that tirzepatide is better for the heart than an older GLP-1 receptor agonist.
What it does not show
| Question | SURPASS-CVOT | Semaglutide evidence |
|---|---|---|
| Cardiovascular benefit in type 2 diabetes | Yes, non-inferior to an active comparator | Yes (SUSTAIN-6, placebo-controlled) |
| MACE in obesity with atherosclerotic disease, no diabetes | Not studied | Yes (SELECT, placebo-controlled, HR 0.80) |
| Obesity with HFpEF | Yes (SUMMIT, placebo-controlled, HR 0.62 for CV death or worsening heart failure) | Yes (STEP-HFpEF, symptoms and function) |
| Kidney outcomes | Not a primary end point | Yes, in type 2 diabetes with CKD (FLOW) |
The gap that matters most for an obesity clinic is the second row. The patient with obesity, established atherosclerotic disease and no diabetes was not in SURPASS-CVOT. For that patient, placebo-controlled MACE evidence still belongs to semaglutide (SELECT). Heart failure with preserved ejection fraction is different: tirzepatide has its own placebo-controlled outcome data there (SUMMIT), with or without diabetes.
How I have changed my own rule
Before this trial, I treated established cardiovascular disease as a reason to prefer semaglutide in every obesity patient. I now split the rule on diabetes:
- Obesity with type 2 diabetes and cardiovascular disease: tirzepatide is no longer ruled out on cardiovascular grounds, and its greater weight and glucose effect can tip the choice.
- Obesity with atherosclerotic cardiovascular disease but no diabetes: semaglutide remains the evidence-based choice, because SURPASS-CVOT does not transfer to this group. Obesity with HFpEF is a separate decision, where both molecules have data.
We applied the same split to the free treatment planner for patients at caspianhealthcare.in/obesity/treatment-options. Cost still comes first in that planner, for the reasons set out in affordability is a gate.