title: Comparison of comorbidity collection methods.
abstract: BACKGROUND
  Multiple valid comorbidity indices exist to quantify the presence and role of comorbidities in cancer patient survival. Our goal was to compare chart-based Adult Comorbidity Evaluation-27 index (ACE-27) and claims-based Charlson Comorbidity Index (CCI) methods of identifying comorbid ailments and their prognostic abilities.
  
  
  METHODS
  We conducted a prospective cohort study of 6,138 newly diagnosed cancer patients at 12 different institutions. Participating registrars were trained to collect comorbidities from the abstracted chart using the ACE-27 method. The ACE-27 assessment was compared with comorbidities captured through hospital discharge face sheets using ICD coding. The prognostic accomplishments of each comorbidity method were examined using follow-up data assessed at 24 months after data abstraction.
  
  
  RESULTS
  Distribution of the ACE-27 scores was: "none" for 1,453 (24%) of the patients; "mild" for 2,388 (39%); "moderate" for 1,344 (22%), and "severe" for 950 (15%) of the patients. Deyo's adaption of the CCI identified 4,265 (69%) patients with a CCI score of 0, and the remaining 31% had CCI scores of 1 (n = 1,341 [22%]), 2 (n = 365 [6%]), or 3 or more (n = 167 [3%]). Of the 4,265 patients with a CCI score of zero, 394 (9%) were coded with severe comorbidities based on ACE-27 method. A higher comorbidity score was significantly associated with higher risk of death for both comorbidity indices. The multivariable Cox model, including both comorbidity indices, had the best performance (Nagelkerke's R(2) = 0.37) and the best discrimination (C index = 0.827).
  
  
  CONCLUSIONS
  The number, type, and overall severity of comorbid ailments identified by chart- and claims-based approaches in newly diagnosed cancer patients were notably different. Both indices were prognostically significant and able to provide unique prognostic information.
authors.affiliation: Clinical Outcomes Research Office, Department of Otolaryngology-Head and Neck Surgery, Washington University in St Louis, St Louis, MO.
authors.forename: Dorina
authors.initials: D
authors.lastname: Kallogjeri
authors.affiliation: Clinical Outcomes Research Office, Department of Otolaryngology-Head and Neck Surgery, Washington University in St Louis, St Louis, MO.
authors.forename: Sheila M
authors.initials: SM
authors.lastname: Gaynor
authors.affiliation: Clinical Outcomes Research Office, Department of Otolaryngology-Head and Neck Surgery, Washington University in St Louis, St Louis, MO.
authors.forename: Marilyn L
authors.initials: ML
authors.lastname: Piccirillo
authors.affiliation: Clinical Outcomes Research Office, Department of Otolaryngology-Head and Neck Surgery, Washington University in St Louis, St Louis, MO.
authors.forename: Raymond A
authors.initials: RA
authors.lastname: Jean
authors.affiliation: Department of Mathematics, Washington University in St Louis, St Louis, MO.
authors.forename: Edward L
authors.initials: EL
authors.lastname: Spitznagel
authors.affiliation: Clinical Outcomes Research Office, Department of Otolaryngology-Head and Neck Surgery, Washington University in St Louis, St Louis, MO. Electronic address: piccirilloj@ent.wustl.edu.
authors.forename: Jay F
authors.initials: JF
authors.lastname: Piccirillo
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D059019:Clinical Coding; D015897:Comorbidity; D003625:Data Collection / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000453:epidemiology*; D063886:Patient Discharge Summaries / Q000706:statistics & numerical data; D015995:Prevalence; D011379:Prognosis; D011446:Prospective Studies