Atrial Fibrillation and Semaglutide Effects in Obesity-Related Heart Failure With Preserved Ejection Fraction: STEP-HFpEF Program.

Background: Obesity is a key factor in the development and progression of both heart failure with preserved ejection fraction (HFpEF) and atrial fibrillation (AF). In the STEP-HFpEF Program (comprising the STEP-HFpEF [Research Study to Investigate How Well Semaglutide Works in People Living With Heart Failure and Obesity] and STEP-HFpEF DM [Research Study to Look at How Well Semaglutide Works in People Living With Heart Failure, Obesity and Type 2 Diabetes] trials), once-weekly semaglutide 2.4 mg improved HF-related symptoms, physical limitations, and exercise function and reduced body weight in patients with obesity-related HFpEF. Whether the effects of semaglutide in this patient group differ in participants with and without AF (and across various AF types) has not been fully examined.

Objectives: The goals of this study were: 1) to evaluate baseline characteristics and clinical features of patients with obesity-related HFpEF with and without a history of AF; and 2) to determine if the efficacy of semaglutide across all key trial outcomes are influenced by baseline history of AF (and AF types) in the STEP-HFpEF Program.

Methods: This was a secondary analysis of pooled data from the STEP-HFpEF and STEP-HFpEF DM trials. Patients with heart failure, left ventricular ejection fraction ≥45%, body mass index ≥30 kg/m², and Kansas City Cardiomyopathy Questionnaire-Clinical Summary Score (KCCQ-CSS) <90 points were randomized 1:1 to receive once-weekly semaglutide 2.4 mg or matching placebo for 52 weeks. Dual primary endpoints (change in KCCQ-CSS and percent change in body weight), confirmatory secondary endpoints (change in 6-minute walk distance; hierarchical composite endpoint comprising all-cause death, HF events, thresholds of change in KCCQ-CSS, and 6-minute walk distance; and C-reactive protein [CRP]), and exploratory endpoint (change in N-terminal pro-B-type natriuretic peptide [NT-proBNP]) were examined according to investigator-reported history of AF (yes/no). Responder analyses examined the proportions of patients who experienced a ≥5-, ≥10, ≥15, and ≥20-point improvement in KCCQ-CSS per history of AF.

Results: Of the 1,145 participants, 518 (45%) had a history of AF (40% paroxysmal, 24% persistent AF, and 35% permanent AF) and 627 (55%) did not. Participants with (vs without) AF were older, more often male, had higher NT-proBNP levels, included a higher proportion of those with NYHA functional class III symptoms, and used more antithrombotic therapies, beta-blockers, and diuretics. Semaglutide led to larger improvements in KCCQ-CSS (11.5 points [95% CI: 8.3-14.8] vs 4.3 points [95% CI: 1.3-7.2]; P interaction = 0.001) and the hierarchal composite endpoint (win ratio of 2.25 [95% CI: 1.79-2.83] vs 1.30 [95% CI: 1.06-1.59]; P interaction < 0.001) in participants with AF vs without AF, respectively. The proportions of patients receiving semaglutide vs those receiving placebo experiencing ≥5-, ≥10-, ≥15-, and ≥20-point improvement in KCCQ-CSS were also higher in those with (vs without) AF (all P interaction values <0.05). Semaglutide consistently reduced CRP, NT-proBNP, and body weight regardless of AF status (all P interaction values not significant). There were fewer serious adverse events and serious cardiac disorders in participants treated with semaglutide vs placebo irrespective of AF history.

Conclusions: In the STEP-HFpEF Program, AF was observed in nearly one-half of patients with obesity-related HFpEF and was associated with several features of more advanced HF. Treatment with semaglutide led to significant improvements in HF-related symptoms, physical limitations, and exercise function, as well as reductions in weight, CRP, and NT-proBNP in people with and without AF and across AF types. The magnitude of semaglutide-mediated improvements in HF-related symptoms and physical limitations was more pronounced in those with AF vs without AF at baseline.(Research Study to Investigate How Well Semaglutide Works in People Living With Heart Failure and Obesity [STEP-HFpEF; NCT04788511; Research Study to Look at How Well Semaglutide Works in People Living With Heart Failure, Obesity and Type 2 Diabetes [STEP-HFpEF DM; NCT04916470]).