The American Society of Anesthesiologists' class as a comorbidity index in a cohort of head and neck cancer surgical patients

BACKGROUND: We assessed the American Society of Anesthesiologists' (ASA) class, as a measure of comorbidity in comparison to the commonly used Charlson index for prognostic ability in a HNCA population. METHODS: Proportional hazards methods were applied to head and neck cancer patients whose treatment included surgery by the Johns Hopkins Otolaryngology service (n = 388). RESULTS: The Charlson index and ASA class were modestly correlated (Spearman 0.36, p <.001). Compared with patients with ASA class 1 or 2, those with ASA class 3 or 4 had a two-fold elevated mortality rate (Relative Hazard (RH) = 2.00, 95% CI, 1.38-2.89). This association was stronger than observed for a Charlson index score of 1 or more compared with 0 (RH = 1.59, 95% CI, 1.17-2.17). Both the Charlson index and ASA class adjusted RHs displayed dose-response patterns (p value for trend <.001). CONCLUSIONS: Compared with the Charlson index, the ASA class had comparable if not greater prognostic ability for mortality in this elderly HNCA population.