Weight Loss Did Not Improve Outcomes in LOSE-AF Trialed article

An 8-month low-calorie diet and behavioral support program produced significantly greater weight loss but did not improve atrial fibrillation (AF) symptom severity in older adults with overweight and persistent AF, according to the LOSE-AF randomized clinical trial published in JAMA.

Investigators noted that excess body weight is a strong risk factor for AF and that clinical guidelines recommend weight loss for patients with obesity and AF. They evaluated the intervention in older adults because earlier evidence came from younger patients and weight loss later in life could increase the risk of frailty.

The parallel-group, unblinded trial was conducted at 2 UK hospitals from November 14, 2018, through April 25, 2025. Among adults aged 60 to 85 years undergoing electrical cardioversion, 118 participants with a body mass indexof 27 or greater were randomized equally to an 8-month low-calorie diet and behavioral support program or usual care. The main outcome was the intention-to-treat change in Atrial Fibrillation Severity Scale score at 8 months.

Participants had a mean age of 68 years, and 33% were female. At 8 months, baseline-adjusted mean weight was 92.6kg in the intervention group and 99.4kg in the control group, an estimated difference of −6.9kg. Weight decreased by 9.7% and 3.1%, respectively (P<.001). However, the adjusted symptom severity scores were 7.9 and 8.9, respectively, a nonsignificant difference of −0.9.

No significant intervention effects were observed for physical performance, AF burden, cardiac imaging measures, blood pressure, lipid profile, repeat cardioversion, or AF ablation. No serious adverse events related to trial participation were reported. The authors concluded that the program achieved significant weight loss without identified safety concerns but did not improve AF symptoms, AF burden, cardiac remodeling, or the need for additional rhythm-control interventions. Moderate dietary weight loss was not an effective AF treatment strategy in this trial.

Sources: Sclafani M, Spartera M, Esmati Y, et al. Weight loss in older patients with persistent atrial fibrillation: the LOSE-AF randomized clinical trial. JAMA. 2026;336(3):205-214. doi:10.1001/jama.2026.5787