New England Journal of Medicine AUGUST 25, 2023

Semaglutide in Patients with Heart Failure with Preserved Ejection Fraction and Obesity

Mikhail N. Kosiborod, Steen Z. Abildstrøm, Barry A. Borlaug, et al.

Bottom Line

In patients with HFpEF and obesity without diabetes, once-weekly subcutaneous semaglutide 2.4 mg significantly improved heart failure-related symptoms, physical limitations, and exercise function, and resulted in greater body weight loss compared to placebo over 52 weeks.

Key Findings

1. Semaglutide demonstrated superiority to placebo for the dual primary endpoints: the mean change in the Kansas City Cardiomyopathy Questionnaire-Clinical Summary Score (KCCQ-CSS) was 16.6 points with semaglutide versus 8.7 points with placebo (estimated treatment difference 7.8 points; 95% CI 4.8 to 10.9; P<0.001).
2. The mean percentage change in body weight was -13.3% with semaglutide versus -2.6% with placebo (estimated treatment difference -10.7%; 95% CI -11.9 to -9.4; P<0.001).
3. Confirmatory secondary endpoints showed consistent improvement, including a greater 6-minute walk distance (mean difference 20.3 m; 95% CI 8.6 to 32.1; P<0.001) and a greater reduction in C-reactive protein levels with semaglutide.
4. Serious adverse events were reported less frequently in the semaglutide group (13.3%) compared to the placebo group (26.7%).

Study Design

Design
RCT
Double-Blind
Sample
529
Patients
Duration
52 wk
Median
Setting
Multicenter, international
Population Adults with HFpEF (LVEF ≥45%), BMI ≥30 kg/m2, NYHA class II-IV symptoms, KCCQ-CSS <90 points, and evidence of elevated LV filling pressures or NT-proBNP.
Intervention Subcutaneous semaglutide 2.4 mg once weekly
Comparator Matching placebo once weekly
Outcome Change from baseline to week 52 in KCCQ-CSS and percentage change in body weight.

Study Limitations

The trial was not powered to assess clinical hard endpoints, such as cardiovascular death or heart failure hospitalizations.
The study population was predominantly White, which may limit the generalizability of the findings to more diverse populations.
Patients with diabetes were specifically excluded from this trial, requiring a separate study (STEP-HFpEF DM) to evaluate this phenotype.
The duration of the study was 52 weeks, precluding long-term assessments of clinical outcomes or durability of weight loss.

Clinical Significance

This trial identifies obesity as a primary therapeutic target in the management of HFpEF. Semaglutide 2.4 mg provides a highly effective pharmacological strategy for improving symptoms and functional status in the obesity-related HFpEF phenotype, a group for whom previous conventional heart failure therapies have demonstrated limited symptomatic benefit.

Historical Context

HFpEF has historically been a challenging condition to treat, with few therapies showing benefits beyond symptom management. While SGLT2 inhibitors (e.g., dapagliflozin in PRESERVED-HF) demonstrated modest improvements in quality of life scores, the STEP-HFpEF trial represents the first robust evidence of a drug specifically targeting the obesity-driven pathophysiology of HFpEF, achieving the largest improvement in KCCQ scores reported in this population to date.

Guided Discussion

High-yield insights from every perspective

Med Student
Medical Student

Explain the pathophysiological mechanisms by which obesity contributes to Heart Failure with Preserved Ejection Fraction (HFpEF) and how a GLP-1 receptor agonist like semaglutide addresses these factors.

Key Response

Obesity is not just a comorbid condition but a driver of HFpEF through systemic inflammation, expansion of epicardial adipose tissue (which compresses the heart), and increased plasma volume. Semaglutide acts by reducing visceral and epicardial fat, lowering systemic inflammatory markers like CRP, and inducing weight loss, thereby reducing the preload and afterload while improving diastolic function.

Resident
Resident

In a patient with HFpEF and obesity but without diabetes, how do the outcomes of the STEP-HFpEF trial influence your decision to initiate semaglutide compared to standard diuretic therapy alone?

Key Response

The trial demonstrated that semaglutide 2.4 mg led to a 16.6 point increase in the KCCQ clinical summary score compared to 8.7 in the placebo group, plus a significant improvement in 6-minute walk distance. While diuretics manage congestion, semaglutide treats the underlying metabolic-inflammatory driver, suggesting it should be considered an additive disease-modifying therapy for symptomatic improvement rather than just a weight-loss drug.

Fellow
Fellow

The STEP-HFpEF trial showed significant reductions in C-reactive protein (CRP) levels in the semaglutide group. How does this inform the 'metabolic-inflammatory' phenotype of HFpEF, and how should we integrate this with SGLT2 inhibitor therapy?

Key Response

HFpEF is increasingly recognized as a heterogeneous syndrome; the obese-HFpEF phenotype is specifically characterized by high inflammatory stress. SGLT2 inhibitors (like empagliflozin/dapagliflozin) primarily improve hemodynamics and reduce HF hospitalizations, whereas semaglutide shows a profound impact on the metabolic-inflammatory axis. Using them together could theoretically provide synergistic benefits by addressing both hemodynamic and metabolic drivers.

Attending
Attending

The primary endpoints of STEP-HFpEF focused on quality of life and functional capacity rather than 'hard' clinical events. How does this shift the value proposition of GLP-1 RAs in heart failure management for your clinical practice?

Key Response

For many HFpEF patients, functional status and symptom burden are as important as longevity. This study validates that targeting weight is a primary therapeutic goal in HFpEF. It changes the teaching point from 'weight loss is recommended' to 'pharmacological weight loss is a validated intervention for improving heart failure symptoms,' bridging the gap between metabolic health and cardiology.

Scholarly Review

Critical appraisal through the lens of expert reviewers and guideline development

PhD
PhD

Evaluate the use of the KCCQ-CSS as a primary endpoint in STEP-HFpEF. What are the statistical implications of using a patient-reported outcome (PRO) in a trial where the intervention produces a visible physical change (weight loss) that could potentially unblind participants?

Key Response

The visible nature of weight loss (13.3% vs 2.6%) creates a risk of 'expectancy bias' where patients on the active drug report better quality of life because they know they are losing weight. This challenges the internal validity of subjective endpoints. To build on this, researchers should focus on objective physiological markers (e.g., invasive hemodynamics via CardioMEMS or peak VO2) to confirm that functional improvements are independent of the psychological benefit of weight loss.

Journal Editor
Journal Editor

What are the primary threats to the external validity of the STEP-HFpEF trial, and why might a reviewer be concerned about the exclusion of patients with diabetes in this specific cohort?

Key Response

The trial excluded patients with diabetes to isolate the effects of semaglutide on HFpEF without the confounding influence of glycemic control. However, in clinical practice, obesity, diabetes, and HFpEF are frequently concurrent. A reviewer would flag that the results may not be perfectly generalizable to the diabetic HFpEF population, who often have more advanced microvascular disease and might show a different magnitude of benefit (an issue being addressed in the companion STEP-HFpEF DM trial).

Guideline Committee
Guideline Committee

Should current HFpEF guidelines be updated to include GLP-1 receptor agonists as a Class I or IIa recommendation based on STEP-HFpEF, and how does this compare to the existing evidence for SGLT2 inhibitors?

Key Response

Current ACC/AHA and ESC guidelines give SGLT2 inhibitors a Class I (Level A) recommendation based on mortality and hospitalization data (EMPEROR-Preserved/DELIVER). While STEP-HFpEF provides Level B-R evidence for symptom and functional improvement, it lacks data on hard outcomes (CV death/HF hospitalizations). Therefore, a Class IIa recommendation for symptom management in obese HFpEF is likely more appropriate until long-term outcome data (like the FLOW trial or meta-analyses) are available.

Clinical Landscape

Noteworthy Related Trials

2019

PARAGON-HF Trial

n = 4,822 · NEJM

Tested

Sacubitril/valsartan

Population

Patients with HFpEF

Comparator

Valsartan

Endpoint

Total hospitalizations for heart failure and cardiovascular death

Key result: The trial did not reach statistical significance for the primary composite outcome, though it showed potential benefits in certain subgroups.
2021

EMPEROR-Preserved Trial

n = 5,988 · NEJM

Tested

Empagliflozin 10mg daily

Population

Patients with heart failure and LVEF > 40%

Comparator

Placebo

Endpoint

Cardiovascular death or hospitalization for heart failure

Key result: Empagliflozin significantly reduced the primary composite outcome in patients with heart failure across a broad spectrum of ejection fraction.
2022

DELIVER Trial

n = 6,263 · NEJM

Tested

Dapagliflozin 10mg daily

Population

Patients with heart failure and LVEF > 40%

Comparator

Placebo

Endpoint

Cardiovascular death or worsening heart failure events

Key result: Dapagliflozin significantly reduced the risk of cardiovascular death or worsening heart failure events in patients with mildly reduced or preserved ejection fraction.

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