# SUMMIT Trial Composite Endpoint: Tirzepatide in HFpEF, Broken Down | This GLP The SUMMIT trial of tirzepatide in HFpEF with obesity: how a 38% cut in a composite endpoint splits between worsening heart failure and cardiovascular death. Publisher: This GLP Editorial Team Canonical: https://thisglp.com/research/tirzepatide-heart-failure-composite Updated: 2026-09-18 Published: 2026-09-16 [← Research](https://thisglp.com/research) Evidence # SUMMIT Trial Composite Endpoint: Tirzepatide in HFpEF, Broken Down Tirzepatide cut a composite of cardiovascular death or worsening heart failure by 38%. Almost all of that was the heart-failure half; the death half went the other way, on thirteen events. [This GLP Editorial Team](https://thisglp.com/about)September 20266 min readUpdated September 2026 Event rates: tirzepatide (solid) against placebo (pale) · the composite · 9.9% · 15.3% · worsening heart failure · 8% · 14.2% · cardiovascular death · 2.2% · 1.4% · The third row runs the other way. It is 13 events in total. **Research, not medical advice.** This GLP is independent and educational. Nothing here is a substitute for individualized care from a licensed clinician, and reading it creates no doctor–patient relationship. Talk to your own provider before starting, stopping, or changing any medication, peptide, or therapy. See our [methodology](https://thisglp.com/methodology) and [terms](https://thisglp.com/terms). ## Key takeaways - In 731 patients with heart failure with preserved ejection fraction and obesity, the composite of cardiovascular death or worsening heart failure occurred in 9.9% on tirzepatide against 15.3% on placebo (HR 0.62). - Worsening heart failure alone drove it: 8.0% against 14.2%, a hazard ratio of 0.54. - ⛔ Cardiovascular death alone went the other way — 8 patients against 5, a hazard ratio of 1.58 with an interval from 0.52 to 4.83. - Thirteen deaths cannot establish anything, and that is the point: a composite reports a result its components cannot individually support. - Adverse events led 6.3% of the tirzepatide arm to discontinue, against 1.4% on placebo. Composite endpoints exist because rare events are hard to study, and they are honest arithmetic. They also produce a sentence — “reduced death from cardiovascular causes or worsening heart failure” — that a reader hears as two claims when the trial supports one. This is a clean example, and worth reading before the next time that sentence appears on a product page — a habit this site has already had to apply to a hazard ratio in [semaglutide and kidney disease](https://thisglp.com/research/semaglutide-and-kidney-disease). ## What the trial did Seven hundred and thirty-one patients with heart failure with preserved ejection fraction and obesity were randomized to tirzepatide or placebo and followed for a median of 104 weeks[\[1\]](https://thisglp.com/research/tirzepatide-heart-failure-composite#ref-1). ## What it found The composite of adjudicated cardiovascular death or a worsening heart-failure event occurred in 36 patients on tirzepatide (9.9%) against 56 on placebo (15.3%) — a hazard ratio of 0.62 (95% CI 0.41 to 0.95, p=0.026). Health status improved too: the mean change on the symptom score at 52 weeks was 19.5 against 12.7, a between-group difference of 6.9 (95% CI 3.3 to 10.6). Worsening heart-failure events alone accounted for nearly all of the composite: 29 patients (8.0%) against 52 (14.2%), a hazard ratio of 0.54 (95% CI 0.34 to 0.85). That is a substantial result on an outcome patients experience directly. The component that runs the other way Adjudicated cardiovascular death occurred in 8 patients on tirzepatide (2.2%) and 5 on placebo (1.4%) — a hazard ratio of 1.58, with a confidence interval from 0.52 to 4.83. ⛔ That interval contains 1 comfortably, and thirteen deaths across 731 patients cannot establish anything in either direction. This is not evidence of harm and the page is not claiming it is. It is printed because a reader who hears the composite as covering death is hearing a claim the trial did not make, and because leaving a component inside a composite is the commonest way a true sentence misleads. ## What the trial does establish That in this population, tirzepatide reduced how often people had a worsening heart-failure event and made them feel meaningfully better. Both are real, both are useful, and neither is a claim about mortality. It cost something: adverse events, mainly gastrointestinal, led 6.3% of the tirzepatide arm to stop the drug against 1.4% of placebo — a fourfold difference in a trial with study staff and no bill to pay, which is the context for the discontinuation figures in [stopping and weight regain](https://thisglp.com/research/stopping-glp1-and-weight-regain). ## How to read the next composite Ask which component moved. A composite is a legitimate way to study rare events and a convenient way to describe a narrow result broadly, and the difference is visible only in the component table. The same discipline applies to every large claim in this field, which is the subject of [what the semaglutide trials are worth](https://thisglp.com/research/semaglutide-cochrane-review) and of [semaglutide and heart failure](https://thisglp.com/research/do-glp1-drugs-help-heart-failure). And notice which population was studied. Everyone here had heart failure with preserved ejection fraction and obesity, which is not the person buying a compounded vial to lose weight — the transferability problem this site keeps running into, counted in [what sellers will not tell you](https://thisglp.com/research/what-glp1-sellers-do-not-publish). ## Frequently asked What did the trial find? The composite of cardiovascular death or worsening heart failure fell from 15.3% to 9.9%, and symptom scores improved by 6.9 points more than placebo. Did it reduce deaths? No. Cardiovascular deaths were 8 on tirzepatide against 5 on placebo, a hazard ratio of 1.58 with an interval from 0.52 to 4.83. Thirteen events cannot establish anything in either direction. So is the composite misleading? Not dishonest, but easy to over-hear. Almost all the benefit came from the worsening-heart-failure component, and a reader who takes the phrase as covering mortality is taking a claim the trial did not make. Who was studied? Patients with heart failure with preserved ejection fraction and obesity, followed for a median of 104 weeks — not people buying a compounded vial for weight loss. ## Sources 1. \[1\] Packer M, et al. (2025). Tirzepatide for Heart Failure with Preserved Ejection Fraction and Obesity New England Journal of Medicine. [PMID 39555826](https://pubmed.ncbi.nlm.nih.gov/39555826/) ## Where to get it ### Best GLP-1 injections Every injectable seller we can verify, with the price each one publishes and an honest read of what the trials measured. [Compare providers →](https://thisglp.com/best/compounded-semaglutide) ## More in Evidence - [ 150 minutes · Weekly activity goal · 2 days · Muscle strengthening · Adapt · Symptoms and ability ### Exercise on Ozempic: Building Strength Without Ignoring Symptoms ](https://thisglp.com/research/exercise-on-ozempic) - [ STEP 1, semaglutide 2.4 mg vs placebo, % change at 68 weeks · LDL cholesterol · −2.5% vs +1.3% · Total cholesterol · −3.3% vs +0.1% · HDL cholesterol · +5.2% vs +1.4% · Triglycerides · −21.9% vs −7.3% · Wegovy label, Table 13. Adults without diabetes. Ozempic doses are lower. ### Does Ozempic Lower Cholesterol? What the Lipid Results in the Trials Show ](https://thisglp.com/research/does-ozempic-lower-cholesterol) - [ Where the insulin reduction came from, units per day · week 4 · 13.4 total · week 26 · 21.9 · the drug itself · the weight loss · The drug’s own contribution barely moved: 11.1 then 11.4. · Everything added between weeks 4 and 26 came from weight. ### Does Semaglutide Help Type 1 Diabetes? What Two Small Trials Found ](https://thisglp.com/research/semaglutide-in-type-1-diabetes)