Bariatric Surgery-Induced Weight Loss Is Associated With Improved Colorectal Cancer Surgical Outcomes in Morbidly Obese Patients

Abstract

Introduction: We have shown previously that morbid obesity leads to worse post-operative colorectal cancer (CRC) surgical outcomes. However, no literature exists on whether these outcomes are ameliorated after bariatric surgery. Aim was to evaluate the impact of bariatric surgery-induced weight loss on post-operative outcomes of CRC surgery. Methods: Retrospective cohort study of 20,288 patients who underwent CRC surgery between the years of 2008-2012. Patients were identified using the Nationwide Inpatient Sample, a 20% sample of United States of America hospitals. We compared patients who lost weight due to bariatric surgery [body mass index (BMI) < 35 kg/mr2] to morbidly obese patients (BMI ≥ 40 kg/mr2). Results: During the five year study period, there were 1,235 patients in the bariatric surgery group and 19,053 morbidly obese patients who underwent CRC surgery. Significant demographic and clinical characteristics are shown in Table 1. Bariatric surgery-induced weight loss was associated with younger age, female gender and White race in patients undergoing CRC surgery (p < 0.05). Furthermore, bariatric surgery patients were less likely to have congestive heart failure, Diabetes Mellitus, hypertension and renal failure (p < 0.05). On multivariate linear regression, after adjusting for significant covariates and comorbidities, morbidly obese patients had a prolonged length of hospital stay 1.81 days [95% confidence interval (CI):1.81-1.82, P < 0.001], a $5,967 increase in total hospital costs $5,967 (95% CI: 5,965-5,968, P < 0.001) and a twofold increase in disposition to short term rehab facilities, odds ratio (OR) 2.1 (95% CI: 1.2-3.6, p < 0.006) as opposed to bariatric surgery patients. There was also a trend towards increased mortality in the morbidly obese patients, although not significant OR 3.9 (95% CI: 0.5, 29.3). Finally, trend analysis (Figure 1) showed increasing volume of CRC surgeries performed in morbidly obese patients over time as opposed to patients with history of bariatric surgery.Figure 1Table 1: Univariate analysis of patients with and without obesity undergoing CRC surgery.Conclusion: With the increasing volume of morbidly obese patients undergoing CRC surgery, bariatric surgery-induced weight loss seems to improve health care utilization in these patients, with a trend towards lower mortality, possibly due to improved obesity- induced comorbidities.