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The LOSE-AF study, funded by the National Institute for Health and Care Research, Oxford Biomedical Research Centre and the British Heart Foundation, enrolled 118 patients aged 60 to 85 with persistent AF and overweight or obesity. All the participants had been referred by their doctor for cardioversion (a medical procedure that involves using a controlled electrical shock to the heart to restore normal heart rhythm). Participants were randomly assigned either to a commercial low-calorie diet and behavioural support programme for eight months, or to usual care with written advice about weight loss for the same period.
After eight months, those in the diet programme had lost an around 10kg (approximately 10% of body weight), compared to around 3kg in the usual care group. A difference in weight between the groups was still evident at 3.5 years.
The dietary weight loss and behavioural support program was safe, with no reported serious adverse events related to the intervention or any reduction in physical performance. However, the intervention and associated weight loss did not result in any meaningful differences in AF-related symptoms, AF burden, or changes in the structure and function of participants' hearts. Participants allocated to the diet programme had similar rates of AF recurrence and requirements for repeat heart rhythm procedures as the control group over a median follow-up of approximately 3.5 years.
Dr Matteo Sclafani, first author of the study in the Radcliffe Department of Medicine, said: 'We demonstrated that weight loss in older adults with AF can be achieved safely - an important result in this population. Nevertheless, this did not lead to meaningful improvements in AF-related symptoms. This suggests that weight loss alone isn't enough to treat AF in this older population.'
Dr Rohan Wijesurendra, Senior Clinical Research Fellow at Oxford Population Health and Consultant Cardiologist and Electrophysiologist, said: 'AF is a growing health issue and many of the patients that we treat in the clinic are older. This trial provides important evidence on the effect of weight loss in this patient group. Whilst weight loss does have proven health benefits in individuals who are overweight or obese, the results of LOSE-AF show that additional treatments are also needed to tackle the factors that lead to AF and result in intrusive symptoms.'
AF is the most common heart rhythm disorder and a major cause of stroke, heart failure, and reduced quality of life. Its prevalence increases with age, affecting around one in ten people over 80. Excess weight is a known risk factor, and weight loss is currently recommended as part of AF treatment in clinical guidelines. However, most previous studies supporting this advice focused on younger patients. LOSE-AF is the first randomised trial to rigorously test weight loss as a treatment strategy for older people with persistent AF.
LOSE-AF: Weight Loss in Older Patients with Atrial Fibrillation was presented at the European Society of Cardiology (ESC) Congress 2025 in Madrid on Friday 29 August.