An intensive weight reduction and risk factor management program helped reduce atrial fibrillation (AF) symptoms more effectively than written and verbal weight reduction and exercise advice, according to a study published online Nov. 20 in JAMA.
“Although population aging is regarded as an important contributor, obesity may account for a substantial proportion of the increasing prevalence,” explained the authors, led by Hany S. Abed, BPharm, MBBS, of Adelaide Hospital in Adelaide, Australia.
The researchers randomized 150 participants to either the weight management group or the general lifestyle advice group, which served as the control. All participants were between 21 and 75 years old, had symptomatic paroxysmal or persistent AF, a body mass index (BMI) greater than 27 and a waist circumference greater than 100 cm for men or greater than 90 cm for women.
The weight loss and management intervention was broken into two phases—weight loss followed by weight management. Participants followed an eight-week very low-calorie diet (800 to 1200 kcal/day) and received very low-calorie meal replacements for two meals. For the third meal, they ate low-calorie, low glycemic index foods with high levels of animal and plant proteins. Participants also followed an exercise plan that consisted of walking or cycling three days a week.
After the eight weeks, the weight management phase began and lasted 13 months. Low-glycemic index meals replaced the very low calorie meals and more intense exercise was implemented. Participants in this group maintained diet, activity and blood pressure diaries.
The primary endpoint was AF symptom burden as measured by the Atrial Fibrillation Severity Scale, which also measures symptom severity. Secondary outcomes were number of AF episodes and their duration as measured by a Holter monitor and echocardiographic measurements of left atrial area and left ventricular wall thickness.
Those in the control group received written and verbal diet and exercise advice at the start of the study. Patients taking dual antiplatelet medications or oral anticoagulants also took prescribed three grams of fish oil per day. There were no diaries required for anyone in this group.
Weight reduction was significantly higher in the intervention group compared with the control group (14.3 kg vs. 3.6 kg). The intervention group also experienced significantly greater AF symptom burden scores (11.8 points vs. 2.6 points), symptom severity scores (8.4 vs. 1.7 points), number of AF episodes (2.5 vs. no change) and cumulative duration (decline of 692 minutes vs. 419 minute increase).
Cardiac remodeling was also significantly better in the intervention group. The reduction in interventricular septal thickness was greater in the intervention group (1.1 mm, compared with 0.6 mm in the control group) as was the reduction in left atrial area (3.5 cm, compared with 1.9 cm in the control group).
The authors acknowledged that their study limitations included a small sample size and the single-center design. However, they argued that their findings suggest this type of weight reduction intervention is effective and practical.
“The lifestyle and comprehensive metabolic risk factor management program was feasible to deliver, effective, associated with a limited risk of serious adverse events, and resulted in a substantial reduction in the symptom burden and symptom severity of atrial fibrillation,” they wrote.