Colorectal cancer readmissions: Identifying high-risk patients and drivers of cost.

52 Background: Colorectal cancer was the second highest contributor to treatment costs in 2020, accounting for 11.6% of all cancer-related expenditures according to the CDC. Risk factors include excess body weight, smoking, alcohol use, and demographic variables such as age, sex, and race. We aimed to investigate risk factors for readmission, evaluate the impact of readmissions on healthcare utilization, and identify the most common causes. Methods: Patients admitted in 2022 were identified from the Nationwide Readmissions Database and categorized into two groups using ICD-10 codes: colorectal cancer (index admission), colorectal cancer with readmission within 90 days. Readmitted and non-readmitted patients were compared. Multivariate regression adjusted for confounders. Results: The study population included 47,457 index admissions and 8,303 readmissions within 90 days. Mean age was 67.3 years in the index group and 68.2 in the readmission group. Mean length of stay and hospital costs were 6.49 days and $27,399 in the index group versus 7.55 days and $28,704 in the readmission group. Baseline characteristics and comorbidities are summarized in the table. The most frequent cause of readmission was sepsis, followed by postprocedural complications and acute kidney injury. Other common causes included infections following a procedure, intestinal obstruction/ileus, and colostomy-related care. Less frequent but notable causes were pulmonary embolism, toxic gastroenteritis/colitis, COVID-19, hypertensive heart and chronic kidney disease with heart failure, C. difficile enterocolitis, sepsis due to E. coli , and peritoneal abscess. On multivariate analysis, iron deficiency anemia (HR 1.35, p