Moderate Weight Loss Failed to Improve Persistent AF Outcomes: JAMA
UK: Researchers have found in a new study that among older overweight patients with persistent atrial fibrillation (AF), a low-calorie diet and behavioral support program achieved significant weight loss at 8 months without safety concerns. However, it did not improve AF symptoms, reduce AF burden, reverse cardiac remodeling, or lessen the need for further rhythm-control interventions, suggesting that moderate dietary weight loss alone was not an effective treatment strategy for persistent AF in this population.
The findings are from the LOSE-AF randomized clinical trial published in JAMA, led by Matteo Sclafani and colleagues from the University of Oxford. The study evaluated whether structured dietary weight reduction could improve clinical outcomes in older adults with persistent atrial fibrillation undergoing cardioversion.
A total of 118 participants aged 60 to 85 years with overweight or obesity were randomly assigned to either an 8-month low-calorie diet with behavioral support or usual care. The trial was conducted across two UK hospitals, with participants followed for changes in AF-related symptoms and clinical outcomes.
The trial revealed the following findings:
- The intervention group achieved greater weight loss than the control group by the end of the study.
- Mean body weight was 92.6 kg in the intervention group compared with 99.4 kg in the usual care group.
- The between-group difference in weight was approximately 6.9 kg and was statistically significant.
- This corresponded to a 9.7% weight reduction in the intervention group versus 3.1% in the control group.
- There was no significant difference in atrial fibrillation (AF) symptom severity between the two groups.
- AF Severity Scale scores were similar in both groups, with no meaningful improvement in the intervention arm.
- Overall symptom burden remained largely unchanged despite weight loss.
- No significant differences were observed in secondary outcomes, including AF burden, physical performance, blood pressure, lipid levels, cardiac imaging parameters, or repeat cardioversion/ablation rates.
- No serious adverse events related to the intervention were reported.
- The dietary program was found to be safe and well-tolerated in this older population.
The findings challenge the notion that weight loss alone can significantly alter disease progression in older patients with persistent atrial fibrillation. While prior studies in younger populations have shown benefits of weight reduction on arrhythmia outcomes, these results suggest the effect may not extend to older patients with more established disease.
The authors acknowledged several limitations, including the open-label design, disruptions due to the COVID-19 pandemic, and incomplete secondary assessments such as extended rhythm monitoring and imaging. The modest degree of weight loss achieved may also have limited the potential for broader cardiovascular benefits beyond weight reduction.
Overall, the LOSE-AF trial indicates that although dietary weight loss is safe and feasible in older patients with persistent AF, it does not independently improve arrhythmia-related outcomes. The findings highlight the need for more comprehensive, multimodal approaches to managing AF in this high-risk group.
Reference:
Sclafani M, Spartera M, Esmati Y, et al. Weight Loss in Older Patients With Persistent Atrial Fibrillation: The LOSE-AF Randomized Clinical Trial. JAMA. Published online May 20, 2026. doi:10.1001/jama.2026.5787
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