The impact of comorbidity on the overall survival and the cause of death in patients after colorectal cancer resection

Retrospective investigation to identify associations between certain patient characteristics and survival in 531 patients with resected colorectal cancer (CRC). Special reference is given to a standardized comorbidity. To compare different levels of exposure we determined hazard ratios (HR) in Cox proportional hazards models for survival times and odds ratios (OR) in logistic regression models. Overall survival was associated with tumor stages (III+IV vs. I+II; HR 7.48), tumor differentiation (low vs. high; HR 1.84), blood transfusions (>2 vs. < or =2; HR 1.88), and comorbidity (Charlson Comorbidity Index >2 vs. < or =2; HR 1.77). Low tumor stage (I+II vs. III+IV; OR 11.1), elevated Charlson Comorbidity Index (>2 vs. < or =2; OR 3.83), and longer ICU stay (>2 days vs. < or =2 days; OR 3.40) more frequently lead to non-cancer-related death than to cancer-related death. Standardized comorbidity should be considered as a factor in survival studies of CRC.