Tirzepatide cut the risk of cardiovascular death or worsening heart failure by 38% in obese patients with a specific type of heart failure, while significantly improving quality of life and exercise capacity.
38%Reduction in risk of cardiovascular death or worsening heart failure events with tirzepatide vs placebo (HR 0.62, p=0.026)
What the researchers found
Tirzepatide reduced the composite of cardiovascular death or worsening heart failure events by 38% (HR 0.62, p=0.026), and produced a 15% body weight reduction along with clinically meaningful improvements in quality-of-life scores and 6-minute walk distance.
Why it matters
HFpEF is the most common form of heart failure and has almost no proven disease-modifying treatments. Tirzepatide is already approved for diabetes and obesity; this trial opens a new therapeutic indication with significant public health impact, given that obesity is the dominant driver of HFpEF.
The numbers in context
- 731 patients randomized (364 tirzepatide, 367 placebo)
- Median follow-up: 104 weeks
- CV death or worsening HF: 9.9% vs 15.3% (HR 0.62, p=0.026)
- Worsening HF alone: 8.0% vs 14.2% (HR 0.54)
- CV death: 2.2% vs 1.4% (HR 1.58, not significant, very few events)
- KCCQ-CSS improvement: 19.5 vs 12.7 points (difference 6.9, p<0.001)
- GI-related discontinuation: 6.3% vs 1.4%
How the study worked
International, double-blind, placebo-controlled randomized trial (SUMMIT) enrolling 731 patients; 1:1 randomization to tirzepatide (up to 15 mg/week subcutaneously) or placebo; median 104 weeks follow-up; two co-primary endpoints.
Who was studied
N=731 patients with HFpEF (EF 50%+) and BMI 30+, randomized 1:1 to tirzepatide or placebo. International, double-blind trial. Median follow-up 104 weeks.
What this study cannot tell us
Enrolled patients were enriched for obesity-related HFpEF; results may not apply to HFpEF with other causes. Event rates were lower than expected, meaning the trial may have been underpowered for cardiovascular mortality alone. Longer-term durability unknown.
How to read the evidence
Rated strong: large international double-blind RCT with propensity-matched comparison, dual primary endpoints, and median 2-year follow-up published in NEJM.
When this study was published
Published in 2025 in the New England Journal of Medicine; SUMMIT trial ran across multiple countries.
The bigger picture
Following trials of GLP-1 drugs in heart failure with reduced ejection fraction (STEP-HFpEF), SUMMIT establishes tirzepatide as the most powerful pharmacological treatment yet for obesity-driven HFpEF, and suggests the GIP component may add incremental cardiovascular benefit beyond GLP-1 alone.
Questions still open
- How does tirzepatide compare head-to-head to semaglutide in HFpEF patients?
- Do patients need to continue tirzepatide indefinitely to preserve cardiovascular benefits?
- Is the benefit driven primarily by weight loss or by direct cardiac effects of the drug?
Common questions
What is heart failure with preserved ejection fraction (HFpEF)?
Is tirzepatide approved for heart failure?
Read the original research
Tirzepatide for Heart Failure with Preserved Ejection Fraction and Obesity.
The New England journal of medicine, 392(5), 427-437
Citation
Packer, Milton; Zile, Michael R; Kramer, Christopher M; Baum, Seth J; Litwin, Sheldon E; Menon, Venu; Ge, Junbo; Weerakkody, Govinda J; Ou, Yang; Bunck, Mathijs C; Hurt, Karla C; Murakami, Masahiro; Borlaug, Barry A. (2025). Tirzepatide for Heart Failure with Preserved Ejection Fraction and Obesity.. The New England journal of medicine, 392(5), 427-437. https://doi.org/10.1056/NEJMoa2410027