Diabetes and Obesity and Treatment Effect of Early Rhythm Control vs Usual Care in Patients With Atrial Fibrillation: A Secondary Analysis of the EAST-AFNET 4 Randomized Clinical Trial

Importance: The EAST-AFNET 4 randomized clinical trial demonstrated that early rhythm control therapy added to anticoagulation therapy and therapy of concomitant conditions reduces the primary composite outcome of cardiovascular death, stroke, hospitalization because of heart failure, or acute coronary syndrome compared to usual care. However, the impact of body mass index (BMI, calculated as weight in kilograms divided by height in meters squared) and diabetes on outcomes in EAST-AFNET 4 is not known. Objective: To assess the effects of BMI and diabetes on outcomes in EAST-AFNET 4. Design, Setting, and Participants: EAST-AFNET 4 is an international, investigator-initiated, parallel-group, open, blinded outcome assessment randomized clinical trial conducted in 11 European countries. Patients who had early atrial fibrillation (AF, diagnosed ≤1 year before enrollment) and cardiovascular conditions were eligible for inclusion. The current analysis is a prespecified secondary analysis of the EAST-AFNET 4 trial performed in the final, locked dataset assigning patients to therapy group on the basis of randomization (intention-to-treat population). EAST-AFNET 4 was conducted from June 2010 to May 2020, and this secondary analysis of the final locked data base was performed in 2024. Intervention: EAST-AFNET 4 randomly assigned patients to either early rhythm control or usual care. Main Outcomes and Measure: The primary outcome of this analysis and the EAST-AFNET 4 trial is a composite of cardiovascular death, stroke, hospitalization because of heart failure, or acute coronary syndrome. Results: There were 1086 patients with obesity (BMI ≥30; mean [SD] BMI 34.5 [4.2]) and 1690 patients without obesity (BMI <30; mean [SD] BMI 25.9 [2.6]). Overall mean patient age was 70 years, and 1293 patients (46.6%) were female. Patients with obesity were younger (mean [SD] age, 68 [8.6] vs 72 [7.7] years) and had more frequently nonparoxysmal AF patterns (31% vs 24%) than patients without obesity. There was no difference in mean (SD) CHA2DS2-VASc score (3.4 [1.3] vs 3.3 [1.3]). Obesity did not change the effect of early rhythm control therapy on the first primary outcome (hazard rate point estimates: BMI <30, 0.84; BMI ≥30, 0.69; P for interaction = .22). Patients with diabetes were younger (mean [SD] age, 69 [8.6] vs 71 [8.2] years; P = .001) and had a higher mean CHA2DS2-VASC score (4.06 vs 3.11; P < .001). Diabetes did not interact with the treatment effect of early rhythm control (diabetes: hazard ratio [HR], 0.77; 95% CI, 0.57-1.05 vs no diabetes: HR, 0.78; 95% CI, 0.64-0.96; P for interaction = .93). There was no difference in safety outcomes between patients with and without diabetes (64 of 351 patients [18.2%] vs 167 of 1039 patients [16.1%]; P for interaction = .99). Conclusions and Relevance: This secondary analysis of the EAST-AFNET 4 randomized clinical trial shows that early rhythm control therapy retains its effectiveness and safety in patients with and without diabetes and patients with and without obesity. Trial Registration: ClinicalTrials.gov Identifier: NCT01288352.