Effect of Obesity on Atrial Fibrillation
Abstract & Commentary
By Harold L. Karpman, MD, FACC, FACP
Clinical Professor of Medicine, UCLA School of Medicine
Dr. Karpman reports no financial relationships relevant to this field of study.
Synopsis: Weight reduction with intensive risk factor management resulted in a reduction in atrial fibrillation symptom burden
and severity, and in beneficial cardiac remodeling.
Source: Abed HS, et al. Effect of weight reduction and cardiometabolic risk factor management on symptom burden and severity in patients with atrial fibrillation: A randomized clinical trial. JAMA 2013;310:2050-2060.
Atrial fibrillation is an extremely common arrhythmia. it has been projected that by 2050 the arrhythmia will affect 12-15 million individuals in the United States1 with a direct economic cost estimated to be $6 billion annually.2 Risk factors such as hypertension, hyperlipidemia, glucose intolerance, sleep apnea, and alcohol and tobacco use may all contribute to the increased incidence of atrial fibrillation. In addition, it has been determined that obesity has been associated with and actually may account for a substantial proportion of the increasing prevalence of atrial fibrillation.3 Therefore, Abed and his colleagues decided to evaluate the effect of a structured weight reduction and risk factor management program on the atrial fibrillation burden in a randomized, controlled trial.4
Abed et al performed a single-center, partially blinded, randomized, controlled study in overweight and obese patients with symptomatic atrial fibrillation. The primary outcomes were symptom burden and severity and the secondary outcomes consisted of total atrial fibrillation episodes and cumulative duration measured by 7-day Holter studies. Both groups were treated with intensive management of cardiometabolic risk factors, whereas only the intervention group received weight management advice and support. Weight loss was induced over 8 weeks using a modified very low calorie diet (800-1200 calories per day) and a carefully structured exercise program. The results demonstrated that weight reduction with intensive risk factor management resulted in a reduction in atrial fibrillation symptom burden and severity. The authors concluded that the findings support therapy directed at weight and risk factor management in the overall treatment strategy of patients with atrial fibrillation.
COMMENTARY
In this study, the authors used the Atrial Fibrillation Severity Scale that evaluates the frequency, duration, and global episode severity and symptom severity of atrial fibrillation to measure primary outcomes.5 Since obesity is frequently accompanied by other atrial fibrillation risk factors such as hypertension, impaired glucose tolerance, obstructive sleep apnea, etc., it should be carefully noted that the active intervention group, besides demonstrating a favorable effect on weight loss, also demonstrated favorable effects on the other risk factors, which probably at least partially contributed to the observed substantial reduction in the symptom burden and severity of atrial fibrillation. Study limitations included a relatively small sample size and that the study was conducted in a single center with a highly motivated, predominantly Caucasian male (67%) population. Finally, the study could not be completely blinded because the weight loss program counselors could not be blinded to the patient allocation.
The study results suggest that weight reduction and improvement of multiple cardiometabolic risk factors benefited cardiac structure, reduced atrial fibrillation events observed on ambulatory rhythm recordings, and reduced the atrial fibrillation symptom burden.4 In addition, the results demonstrated that an effective lifestyle and comprehensive metabolic risk factor management program was feasible and resulted in a substantial reduction in the symptom burden and severity produced by atrial fibrillation.
References
- Miyasaka Y, et al. Secular trends in incidence of atrial fibrillation in Olmsted County, Minnesota, 1980-2000, and implications on the projections for future prevalence. Circulation 2006;114:119-125.
- Koyne KS, et al. Assessing the direct costs of treating nonvalvular atrial fibrillation in the United States. Value Health 2006;9:348-356.
- Wanahita N, et al. Atrial fibrillation and obesity results of a meta-analysis. Am Heart J 2008;155:310-315.
- Abed HS, et al. Effect of weight reduction and cardiometabolic risk factor management on symptom burden and severity in patients with atrial fibrillation: A randomized clinical trial. JAMA 2013;310:2050-2060.
- Dorian P, et al. The impairment of health-related quality of life in patients with intermittent atrial fibrillation: Implications for the assessment of investigational therapy. J Am Coll Cardiol 2000;36:1303-1309.
