Impact of Morbid Obesity on Post-esophagectomy Leak Rate: a NSQIP Analysis

Background: Morbid obesity is becoming more prevalent and is a known risk factor for esophageal cancer. Esophagectomy in this population is technically more challenging than the non-obese, thus increasing the risks of surgery. This study hypothesizes that higher body mass index (BMI) is associated with higher anastomotic leak rates after esophagectomy. Methods: This study is a retrospective review of patients undergoing esophagectomy in the National Surgical Quality Improvement Program (NSQIP) Targeted Esophagectomy database from 2016 to 2019. Patients were stratified by BMI < 35 versus BMI > 35, with the primary outcome being leak post-esophagectomy. Univariate analyses were performed for demographics and post-operative outcomes, and multivariate analyses were performed specifically for the primary outcome of anastomotic leak (all diagnoses and malignancy/dysplasia subgroup). This study was approved by the Institutional Review Board. Results: Of 4165 patients, 439 (10.5%) had a BMI > 35. Patients with BMI > 35 were often younger (mean age 60 vs 64 years, p < 0.001), White (p < 0.001), female (p < 0.001), non-smoker (p < 0.001), diabetic (p < 0.001), with hypertension (p < 0.001), and ASA ≥ 3 (p < 0.001). There were no differences between BMI groups with regard to indication for esophagectomy (malignancy/dysphasia vs other), conversion to open, mortality, or length of stay. The BMI > 35 cohort reported higher operative times (p < 0.001), open operative approach (p = 0.04), superficial surgical site infection (p < 0.001), return to operating room (p = 0.01), and leak (13.5% vs 10.1%, p = 0.01). BMI > 35 was not an independent predictor of leak for all diagnoses; however, the subgroup analysis of esophagectomy for malignancy/dysplasia demonstrated that BMI > 35 was predictive of leak (OR 1.42, 95% CI 1.05–1.91), as well as operative time and hypertension. Conclusion: Patients with a BMI > 35 and who undergo esophagectomy have a higher rate of anastomotic leak. BMI > 35 was also an independent predictor of leak when esophagectomy was performed for malignancy/dysplasia, but not for all diagnoses. The risk of anastomotic leak should be considered in morbidly obese patients undergoing esophagectomy, particularly for malignancy.