Comparative analysis of readmission drivers in right- versus left-sided colorectal cancer: Insights from a national database.

Abstract

49 Background: Colorectal cancer is the third leading cause of cancer death in men and the fourth in women. The American Cancer Society projects 107,320 new cases in 2025. Right-sided cancers have distinct biology and worse prognosis than left-sided disease. We examined reasons for readmission, comorbidity prevalence, healthcare utilization, and socioeconomic factors in right- versus left-sided colorectal cancer. Methods: Patients admitted in 2022 were identified from the Nationwide Readmissions Database and categorized into four groups: (1) right-sided colorectal cancer, (2) left-sided colorectal cancer, (3) right-sided with readmission within 90 days, and (4) left-sided with readmission within 90 days. Readmitted and non-readmitted patients were compared. Multivariate regression adjusted for confounders. Results: Among 35,245 right-sided patients, 5,411 (15.3%) were readmitted within 90 days versus 2,892 (14.1%) of 20,515 left-sided cases. In right-sided disease, mean cost and stay were $26,400 and 6.56 days for non-readmitted versus $27,675 and 7.32 days for readmitted patients. In left-sided disease, values were $28,346 and 6.37 days versus $30,631 and 8.0 days. Sepsis was the leading non-malignant cause in both groups. Right-sided cases more often involved postprocedural complications, AKI, obstruction/ileus, pulmonary embolism, COVID-19, pneumonia, hemorrhage, and peritoneal abscess. Left-sided cases more often showed ostomy complications, E. coli sepsis, chemotherapy encounters, wound disruption, and peritoneal abscess. On multivariate analysis, thrombosis (HR 1.27), AKI (HR 1.19), CHF (HR 1.23), thrombophilia (HR 1.43), and COPD (HR 1.20) increased readmission risk, while smoking, CKD, cirrhosis, diabetes, CAD, CVA, and obesity did not. Conclusions: Ninety-day readmission rates were similar between right- and left-sided colorectal cancer, though slightly higher in right-sided disease. Causes varied by location, with infection and procedural complications most common. Comorbidities including thrombosis, AKI, CHF, thrombophilia, and COPD independently increased risk. Targeted strategies may reduce readmissions in high-risk patients. Characteristics and Comorbidities Right-sided Colorectal Index Right-sided Colorectal Readmission p value Left-sided Colorectal Index Left-sided Colorectal Readmission p value Mean Age 63.03 64.41 69.94 70.3 Female 53.59% 51.22% 0.0255 44.38% 41.42% 0.0351 Iron Deficiency Anemia 20.44% 27.72% < 0.001 18.73% 11.04% < 0.001 Smoking 24.12% 24.2% 0.9262 23.07% 22.48% 0.6325 Thrombosis 3.56% 5.59% < 0.001 2.48% 5.96% < 0.001 CKD 12.94% 17.22% < 0.001 8.79% 14.21% < 0.001 CHF 9.15% 14.24% < 0.001 5.75% 11.04% < 0.001 Obesity 20.12% 20.28% 0.8692 21.11% 21.16% 0.9699 DM 25.09% 27.15% 0.0345 20.5% 25.05% 0.001 AKI 11.34% 15.2% < 0.001 9.86% 17.26% < 0.001 COPD 8.1% 11.1% < 0.001 5.25% 7.24% 0.0029