The age-adjusted Charlson comorbidity index is a better predictor of survival in operated lung cancer patients than the Charlson and Elixhauser comorbidity indices

Abstract

Objectives: To compare the prognostic performance between different comorbidity assessments of survival in patients with operated lung cancer.

Methods: A total of 4508 lung cancer patients treated by surgery between 2003 and 2012 were identified through Taiwan's National Health Insurance Research Database. Information on pre-existing comorbidities prior to the cancer diagnosis was obtained and adapted to the Charlson comorbidity index, age-adjusted Charlson comorbidity index (ACCI) and Elixhauser comorbidity index scores. The influence on survival was analysed using a Cox proportional hazard model. The discriminatory ability of the comorbidity indices were evaluated using Akaike information criterion and Harrell's C-statistic.

Results: The mean age of the study cohort was 64.95 ± 11.15 years, and 56.28% of the patients were male. The median follow-up time was 2.59 years, and the 3-year overall survival was 73.94%. Among these patients, 2134 (47.3%) patients received adjuvant therapy. The Charlson comorbidity index and ACCI scores correlated well with survival and higher scores were associated with an increased 3-year mortality risk (hazard ratio = 1.21, 95% confidence interval = 1.03-1.42 and hazard ratio = 1.43, 95% confidence interval = 1.08-1.90, respectively) in multivariate analysis. The ACCI scores provided better discriminatory ability with a smaller Akaike information criterion and greater Harrell's C-statistic for 3-year overall survival compared to the Charlson comorbidity index or Elixhauser comorbidity index scores.

Conclusions: The operated lung cancer patients with severe comorbidities were associated with worse survival. The ACCI appears to be a more appropriate prognostic indicator and should be considered for use in clinical practice.

Keywords: Charlson comorbidity index; Elixhauser comorbidity index; Lung cancer; Surgery; age; survival.