Using comorbidity indexes to predict costs for head and neck cancer.

Objective: To determine whether the general Charlson Comorbidity Index (CCI) and the head and neck cancer-specific Washington University Head and Neck Cancer Comorbidity Index (WUHNCCI) were useful for predicting cost of treatment for elderly patients with head and neck cancer.

Design: Retrospective, observational study.

Patients: A total of 1780 Medicare patients with head and neck cancer, who were treated between 1984 and 1994, were analyzed using the Surveillance, Epidemiology, and End Results (SEER)-Medicare-linked database.

Main Outcome Measures: Total Medicare payments were accumulated for each patient up to 1 and 5 years. Linear regression was used to estimate the impact of the comorbidity indexes on costs, controlling for demographics, site, stage, and treatment modality.

Results: Neither the WUHNCCI nor the CCI was significantly associated with 1-year costs. However, the effect of the WUHNCCI on 5-year costs was statistically significant (P<.001). A 1-point increase in the WUHNCCI from 4 to 5 was associated with an increase in 5-year costs of $2105. A 1-point increase in the WUHNCCI from 9 to 10 was associated with an increase in 5-year costs of $2837.

Conclusion: These results suggest that comorbidity indexes for head and neck cancer may be useful for prognostication of patient outcomes and predicting costs.