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

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.