title: The American Society of Anesthesiologists' class as a comorbidity index in a cohort of head and neck cancer surgical patients.
abstract: 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.
authors.affiliation: Department of Oral Health Care Delivery, School of Dentistry, Room 3E-04, University of Maryland, 666 West Baltimore Street, Baltimore, Maryland 21203, USA. bcr001@dental.umaryland.edu
authors.forename: B C
authors.initials: BC
authors.lastname: Reid
authors.forename: A J
authors.initials: AJ
authors.lastname: Alberg
authors.forename: A C
authors.initials: AC
authors.lastname: Klassen
authors.forename: W M
authors.initials: WM
authors.lastname: Koch
authors.forename: J M
authors.initials: JM
authors.lastname: Samet
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D015897:Comorbidity; D005260:Female; D006258:Head and Neck Neoplasms / Q000145:classification* / Q000401:mortality*; D006801:Humans; D008297:Male; D011379:Prognosis; D016016:Proportional Hazards Models; D016019:Survival Analysis