eP268 - The Impact of Obesity on Postoperative Outcomes Following Surgery for Colorectal Cancer: Analysis of the National Inpatient Sample 2015-2019

Purpose/Background: The global burden of obesity has reached epidemic proportions, placing great strain on the American healthcare system. In the case of colorectal cancer surgeries, higher volumes of subcutaneous and visceral fat can make accessing the abdominal cavity or bony confines of the pelvis much more difficult; thus, increasing the risk of patients with obesity experiencing worse postoperative outcomes due to an increased propensity for experiencing high levels of intraoperative blood loss, surgeon perceived operative difficulty, and longer operative time. To investigate this further, we designed a retrospective cohort database study comparing patients with and without obesity undergoing surgery for colorectal cancer in terms of postoperative morbidity and healthcare resource utilization.Methods/Interventions: Adult patients undergoing resection for colorectal cancer were identified from the 2015-2019 National Inpatient Sample (NIS) database. The timeline was chosen to capture the years that NIS started utilizing the International Classification of Diseases, 10th Revision, Clinical Modification (ICD-10-CM) codes. Patients were stratified according to obesity status (i.e., body mass index of 30 kg/m2). Propensity score matching (PSM) with 1:1 nearest-neighbor matching was performed according to demographic, operative, and hospital characteristics. The primary outcome was overall in-hospital postoperative morbidity. Secondary outcomes included system-specific postoperative complications such as respiratory, cardiovascular, gastrointestinal, genitourinary, wound, infections, and thromboembolic, as well as postoperative mortality, length of stay, total admission healthcare cost, and post-discharge disposition. McNemar’s and Wilcoxon matched-pairs signed rank tests were performed.Results/Outcomes: After PSM, 7,565 patients without obesity and 7,565 patients with obesity were included. Patients with obesity had a 10% increase in relative risk of overall in-hospital postoperative morbidity (23.1% vs. 25.6%, p=0.0015) and a $4,564 increase in hospitalization cost ($70,248 USD vs. $74,812 USD, p=0.0004). Analysis of system-specific in-hospital postoperative morbidity amongst patients with obesity demonstrated significant increases in genitourinary morbidity (11.9% vs. 15.0%, p < 0.0001), which was largely driven by significant differences in acute kidney injury (5.4% vs. 8.6%, p < 0.0001) and urinary tract infection (2.6% vs. 3.4%, p=0.0027). Patients with obesity were also more likely to require post-operative ICU admission (5.0% vs. 8.0%, p < 0.0001) and less likely to be discharged home after their index operation (68.3% vs. 64.2%, p=0.0022).Conclusion/

Discussion: Patients with obesity undergoing surgery for colorectal cancer may be at an increased risk of in-hospital postoperative and genitourinary morbidity. They may also be more likely to have increased hospitalization costs and post-operative ICU admissions. Additionally, they may be less likely to be discharged home from their acute care hospital stay, and rather require alternative level care (e.g., nursing home) prior to returning home. Preoperative optimization via weight loss strategies should be further explored for these patients through large, prospective trials. Lastly, preventative upstream interventions aimed at tackling obesity rates on a national level are required and will serve as the only means of definitive resolution.