Effect of comorbidity assessed by the Charlson Comorbidity Index on the length of stay, costs, and mortality among colorectal cancer patients undergoing colorectal surgery

Objective: Charlson Comorbidity Index (CCI) is a good predictor for hospitalization cost and mortality among patients with chronic disease. However, the impact of CCI on patients after colorectal cancer surgery is unclear. This study aims to investigate the influence of comorbidity assessed by CCI on length of stay, hospitalization costs, and in-hospital mortality in patients with colorectal cancer (CRC) who underwent surgical resection. Methods: This historical cohort study collected 10,271 adult inpatients for CRC undergoing resection surgery in 33 tertiary hospitals between January 2018 and December 2019. All patients were categorized by the CCI score into four classes: 0, 1,2, and >= 3. Linear regression was used for outcome indicators as continuous variables and logical regression for categorical variables. EmpowerStats software and R were used for data analysis. Results: Of all 10,271 CRC patients, 51.72% had at least one comorbidity. Prevalence of metastatic solid tumor (19.68%, except colorectal cancer) and diabetes without complication (15.01%) were the major comorbidities. The highest average cost of hospitalization (86,761.88 CNY), length of stay (18.13days), and in-hospital mortality (0.89%) were observed in patients with CCI score >= 3 compared to lower CCI scores (p < .001). Multivariate regression analysis showed that the CCI score was associated with hospitalization costs (beta, 7340.46 [95% confidence interval (CI) (5710.06-8970.86)1, p < .001), length of stay (beta, 1.91[95%CI (1.52-2.30)], p < .001), and in-hospital mortality(odds ratio (OR),16.83[95%CI (2.23-126.88)], p = .0062) after adjusted basic clinical characteristics, especially when CCI score >= 3. Notably, the most specific complication associated with hospitalization costs and length of stay was metastatic solid tumor, while the most notable mortality-specific comorbidity was moderate or severe renal disease. Conclusion: The research work has discovered a strong link between CCI and clinical plus economic outcomes in patients with CRC who underwent surgical resection.