Comprehensive Complication Index Versus Clavien–Dindo Classification After CRS-HIPEC for Colorectal Peritoneal Metastases: Associations with 30- and 90-Day Readmission

Abstract

Background and Objectives: To compare the Comprehensive Complication Index (CCI) with the conventional Clavien–Dindo (CD) classification for association with readmission after cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) for colorectal peritoneal metastases. Materials and Methods: Single-center retrospective cohort of 26 patients treated with CRS-HIPEC for peritoneal metastases of colonic or rectal origin. The patient-level CD grade was the highest of the individually graded complications of the index admission; the CCI was calculated with the standard formula. A prespecified threshold of CCI ≥ 26.2—the value of a single CD grade IIIa complication—defined a high cumulative burden. Unplanned readmission was assessed at 30 and 90 days after discharge as co-primary outcomes; classification agreement and correlates of CCI level were exploratory, without adjustment for multiplicity. Results: Agreement was moderate (kappa = 0.54, 95% confidence interval [CI] 0.25–0.83). Six of 26 patients (23.1%) had no major complication by the CD classification yet a high cumulative burden by the CCI (exact McNemar p = 0.031). Readmission occurred in 32.0% by 30 days and 44.0% by 90 days. For 90-day readmission the CCI gave a numerically higher area under the curve than the CD classification (0.672 vs. 0.555; DeLong p = 0.074), and readmission was more frequent above the CCI threshold (55.6% vs. 14.3%; odds ratio 6.95, 95% CI 0.64–378.69); neither comparison was significant. CCI level correlated with body mass index (rho = 0.541) and the Peritoneal Cancer Index (rho = 0.423), both p < 0.05. Conclusions: The CCI identified a high cumulative burden in six patients recorded as having no major complication by the CD classification, but its numerically higher discrimination for readmission was not statistically demonstrated. These exploratory findings require confirmation in larger cohorts.