Relation of Obesity to Recurrence Rate and Burden of Atrial Fibrillation

Study Questions:

Does obesity increase the risk for recurrent atrial fibrillation (AF)?

Methods:

A limited access data set from the AFFIRM (Atrial Fibrillation Follow-up Investigation by Rhythm Management) trial was used for the present analysis. Of the 4,060 patients enrolled in AFFIRM, 1,542 were excluded for missing data on body mass index (BMI). Among the 2,518 patients, data on 22,753 follow-up visits and 1,094 cardioversions were available. The primary outcomes were AF recurrence (cardioversions were used as a surrogate marker of recurrence) and AF burden (defined as the number of follow-up visits in which the patient was in AF).

Results:

Among 2,518 patients included, BMI, left atrial size, age, and history of hypertension were independently associated with higher AF burden. Patients with a higher BMI were associated with a higher number of cardioversions (odds ratio [OR] 1.017, 95% confidence interval [CI] 1.005-1.029 for a BMI increase of 1 kg/m2; OR 1.088, 95% CI 1.024-1.155 for a BMI increase of 5 kg/m2; OR 1.183, 95% CI 1.049-1.334 for a BMI increase of 10 kg/m2; p = 0.006 for each). Increased BMI was also associated with a higher likelihood of being in AF on follow-up (OR 1.020, 95% CI 1.002-1.038 per 1 kg/m2 increased BMI, p = 0.028; OR 1.104, 95% CI 1.011-1.205 per 5 kg/m2 increased BMI, p = 0.028; OR 1.218, 95% CI 1.021-1.452 per 10 kg/m2 increased BMI, p = 0.028). In a multivariate analysis, left atrial size but not BMI was an independent predictor of AF recurrence and AF burden. Because left atrial size was correlated with BMI, the effect of BMI on AF can likely be explained by greater left atrial size in subjects with higher BMIs.

Conclusions:

The authors concluded that obesity is associated with a higher incidence of recurrent AF and greater AF burden.

Perspective:

This informative study suggests that BMI is associated with both recurrence and burden of AF. An important next question to address is whether weight loss would result in reductions in AF.

Clinical Topics: Arrhythmias and Clinical EP, Prevention, EP Basic Science, Atrial Fibrillation/Supraventricular Arrhythmias, Hypertension

Keywords: Odds Ratio, Follow-Up Studies, Heart Atria, Weight Loss, Electric Countershock, Incidence, Recurrence, Body Mass Index, Biological Markers, Obesity, Atrial Fibrillation, Probability, Hypertension


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