Differences in the Impact of Obesity and Bariatric Surgery on Patients Hospitalized for Atrial Flutter and Atrial Fibrillation: A Nationwide Analysis, 2016-2020

Background: The "obesity paradox" claims that although obesity is a risk factor for atrial fibrillation, obese patients have lower inpatient mortality when admitted due to atrial fibrillation. This study aims to analyze if the obesity paradox still holds true after weight loss from bariatric surgery.  Methods: This study analyzed discharge data from the National Inpatient Sample, 2016-2020. Patients admitted due to atrial fibrillation or atrial flutter, with or without obesity, and with or without a past medical history of bariatric surgery were identified using ICD-10-CM and ICD-10-PCS codes. The primary outcome was mortality. Secondary outcomes included length of stay, resource utilization, necessity for endotracheal intubation, and necessity for cardioversion. STATA v.13 was used for univariate and multivariate analysis (StataCorp LLC, Texas, USA).

Results: Among 2,292,194 patients who had a primary diagnosis of atrial fibrillation or atrial flutter, 494,830 were obese and 25,940 had bariatric surgery. Mortality was not significantly different in post-bariatric surgery patients when compared to the general population (OR 0.76; 95% [CI 0.482-1.2; p=0.24]). Mortality was significantly lower in obese patients when compared to the general population (OR 0.646; 95% [CI 0.583-0.717; p<0.001]). Therefore, post-bariatric surgery patients had a higher mortality than obese patients when compared to the general population. Obese patients spent more days in the hospital (regression 0.219; 95% [CI 0.19-0.248, p<0.001]), had higher resource utilization (regression 3491.995; 95% [CI 2870.085-4113.905, p<0.001]), more cardioversions (OR 1.434; 95% [CI 1.404-1.465; p<0.001]), and no difference in endotracheal intubation rate (OR 1.02; 95% [CI 0.92-1.127; p=0.724]) when compared to the general population. Post-bariatric patients had no difference in length of stay (regression -0.053; 95% [CI -0.137-0.031; p=0.218]) and resource utilization (regression 577.297; 95% [CI -1069.801-2224.396; p=0.492]), fewer endotracheal intubations (OR 0.583; 95% [CI 0.343-0.99; p=0.046]), and more cardioversions (OR 1.223; 95% [CI 1.134-1.32; p<0.001]) when compared to the general population.

Conclusion: Compared to the general population, post-bariatric patients had higher inpatient mortality than obese patients when admitted due to atrial fibrillation or atrial flutter. This research reinforces the presence of the obesity paradox following bariatric surgery with respect to mortality.