A U-shaped relationship of body mass index on atrial fibrillation recurrence post ablation: A report from the Guangzhou atrial fibrillation ablation registry

Background: Obesity or overweight is related to worse outcomes in patients with atrial fibrillation (AF) following catheter ablation (CA). The role of being underweight in relation to recurrent arrhythrnias post AF ablation is less certain. We conducted a retrospective study to investigate the association of body mass index (BMI) with arrhythmia outcomes in AF patients undergoing CA. Methods: In a cohort of 1410 AF patients (mean age 572 +/- 11.6 years; 68% male) undergoing single CA, the association between BMI and AF ablation outcome was analyzed using BMI as a continuous variable and by four BMI categories (<18.5 kg/m(2), 18.5-24 kg/m(2), 25-29 kg/m(2), and 30 kg/m(2)). Result: We observed a positive association between a cut off value of BMI and risk of AF recurrence post AF ablation. BMI 26.36 kg/m(2) was related to more AF recurrence (c-statistic 0.55, 95%CI 0.51-0.58; P <0.01) with 50% increased risk of AF recurrence (HR 1.50, 95% CI 122-1.86; P < 0.01). Recurrence rates in the four BMI categories were 333%, 232%, 272 and 41.8%, respectively (P < 0.01). Kaplan-Meier analysis showed that BMI categories of <18.5 kg/m(2) and 30 kg/m(2) were all associated with more AF recurrence ( P = 0.01). Both underweight (HR 1.85, 95%CI 1.12-3.08; P = 0.02) and obesity (HR 1.78, 95%CI 1.17-2.72; P = 0.01) significantly increased the risk of AF recurrence in a Cox proportional hazard model. Conclusion: BMI had good predictive value for AF ablation outcomes with a cut off value of >= 26.36 kg/m(2). Apart from being obese/overweight, being underweight might also be a risk factor for AF recurrence post ablation. (C) 2018 The Authors. Published by Elsevier B.V.