Trial review
SUMMIT Trial: Tirzepatide and HFpEF
Tirzepatide in heart failure with preserved ejection fraction and obesity
SUMMIT was a phase 3, randomised, double-blind, parallel-group, placebo-controlled, multicentre funded by Eli Lilly and Company. A 38% reduction in the combined endpoint of cardiovascular death and worsening heart-failure events, with improvement in symptoms, physical limitations and exercise capacity. That figure belongs to the population, dose, comparator and 52 weeks to the symptom endpoint, with event follow-up shown below, and describes a group average under trial conditions rather than a prediction for any individual.
| Design | Phase 3, randomised, double-blind, parallel-group, placebo-controlled, multicentre |
|---|---|
| Population | Adults with heart failure with preserved ejection fraction and obesity (BMI 30 or above), with or without type 2 diabetes |
| Sample size | 731 randomised 1:1 |
| Intervention | Tirzepatide once weekly at maximum tolerated dose |
| Comparator | Placebo |
| Duration | 52 weeks to the symptom endpoint, with event follow-up |
| Primary endpoint | Co-primary: time to first occurrence of a heart-failure outcome, and change in heart-failure symptoms and physical limitations at 52 weeks |
| Main result | A 38% reduction in the combined endpoint of cardiovascular death and worsening heart-failure events, with improvement in symptoms, physical limitations and exercise capacity |
Show this figure as a table
| Step | Stage | What happens |
|---|---|---|
| 1 | Who was eligible | Adults with heart failure with preserved ejection fraction and obesity (BMI 30 or above), with or without type 2 diabetes |
| 2 | What they received | Tirzepatide once weekly at maximum tolerated dose |
| 3 | What it was compared against | Placebo |
| 4 | For how long | 52 weeks to the symptom endpoint, with event follow-up |
| 5 | What was measured first | Co-primary: time to first occurrence of a heart-failure outcome, and change in heart-failure symptoms and physical limitations at 52 weeks |
| 6 | What the group average was | A 38% reduction in the combined endpoint of cardiovascular death and worsening heart-failure events, with improvement in symptoms, physical limitations and exercise capacity |
| 7 | What it does not tell you | A group average is not a prediction for any individual reader. |
Show this figure as a table
| Item | Weight change | Evidence |
|---|---|---|
| Intervention group | not captured | |
| Comparator group | not captured |
| Question | Position |
|---|---|
| Average effect in the studied population | Reported once captured |
| Your individual outcome | Not predicted by any trial |
| Effect of a compounded preparation | Not studied here |
| Effect at doses outside the protocol | Not studied here |
| Effect after stopping | Only if the trial included a withdrawal phase |
| Long-term safety beyond the trial | Outside the observation window |
Who was studied
- Inclusion and exclusion criteria in plain language. Say who was not studied — that is usually the more useful half.
What was given, and what it was compared against
- Dose, titration schedule, comparator, and whether the comparator was placebo or an active drug.
Results
- Primary endpoint first, with absolute numbers alongside percentages. Secondary endpoints labelled as secondary.
Adverse events and discontinuations
- Never omitted for length. Report discontinuation rates alongside efficacy.
Limitations
- Funding, blinding, dropout handling, generalisability, duration.
How this should and should not be read
- Explicitly address the misreadings this trial commonly attracts.
How it compares with other trials
- Only where designs are comparable. Say so when they are not.
- Retrieve the registry record and the peer-reviewed publication. Record NCT, DOI and PMID.
- Do not summarise from a manufacturer press release, a conference abstract described as a result, or a news article.
- Where only topline or preprint data exists, label it as such everywhere it appears, including the direct answer.
- Medical review is mandatory on this page before publication.
Questions readers actually ask
Does this mean I would lose that much weight?
No. Trials report group averages under controlled conditions with specific eligibility criteria. Individual results vary widely, and the trial population may not resemble you.
Do these results apply to compounded tirzepatide?
Not automatically. Trials studied the approved product at studied doses. A compounded preparation at a different concentration, formulation or route has not been through those trials.
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GLP-1 Tirzepatide Review. “SUMMIT Trial: Tirzepatide and HFpEF.” S.J Partners LLC, 2026-07-24. https://glp1tirzepatidereview.com/research/summit-hfpef/
When quoting a figure, include the capture date shown beside it rather than the date you read this page. A price without its capture date is not a usable citation.