Evaluation of four comorbidity indices and Charlson comorbidity index adjustment for colorectal cancer patients.

INTRODUCTION

Cancer survival is related not only to primary malignancy but also to concomitant nonmalignant diseases. The aim of this study was to investigate the prognostic capacity of four comorbidity indices [the Charlson comorbidity index (CCI), the Elixhauser method, the National Institute on Aging (NIA) and National Cancer Institute (NCI) comorbidity index, and the Adult Comorbidity Evaluation-27 (ACE-27)] for both cancer-related and all-cause mortality among colorectal cancer patients. A modified version of the CCI adapted for colorectal cancer patients was also built.

METHODS

The study population comprised 468 cases of colorectal cancer diagnosed between 1 January 2000 and 31 December 2010 at a community hospital. Data were prospectively collected and abstracted from patients' clinical records. Kaplan-Meier method and multivariate logistic regression models were performed for survival and risk of death analysis.

RESULTS

Only moderate or severe renal disease [hazard ratio (HR) 2.71, 95% confidence interval (CI) 1.11-6.63] and AIDS (HR 3.27, 95% CI 1.23-8.68) were independently associated with cancer-specific mortality, with a population attributable risk of 5.18 and 4.36%, respectively. For each index, the highest comorbidity burden was significantly associated with poorer overall survival (NIA/NCI: HR 2.14, 95% CI 1.14-4.01; Elixhauser: HR 1.98, 95% CI 1.09-1.42; ACE-27: HR 1.78, 95% CI 1.07-1.23; CCI: HR 1.68, 95% CI 1.05-1.42) and cancer-specific survival. The modified version of the CCI resulted in a higher predictive power compared with other indices studied (cancer-specific mortality HR = 2.37, 95% CI 1.37-4.08).

CONCLUSIONS

The comorbidity assessment tools provided better prognostic prevision of prospective outcome of colorectal cancer patients than single comorbid conditions.