title: Administrative data outperformed single-day chart review for comorbidity measure.
abstract: OBJECTIVE
  The purpose of this article is to compare the Charlson comorbidity index derived from a rapid single-day chart review with the same index derived from administrative data to determine how well each predicted inpatient mortality and nosocomial infection.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  The study was conducted in the context of the Swiss Nosocomial Infection Prevalence (SNIP) study in six hospitals, canton of Valais, Switzerland, in 2002 and 2003.
  
  
  METHODS
  We included 890 adult patients hospitalized from acute care wards.
  
  
  METHODS
  The Charlson comorbidity index was recorded during one single-day for the SNIP study, and from administrative data (International Classification of Disease, 10th revision codes). Outcomes of interest were hospital mortality and nosocomial infection.
  
  
  RESULTS
  Out of 17 comorbidities from the Charlson index, 11 had higher prevalence in administrative data, 4 a lower and two a similar compared with the single-day chart review. Kappa values between both databases ranged from - 0.001 to 0.56. Using logistic regression to predict hospital outcomes, Charlson index derived from administrative data provided a higher C statistic compared with single-day chart review for hospital mortality (C = 0.863 and C = 0.795, respectively) and for nosocomial infection (C = 0.645 and C = 0.614, respectively).
  
  
  CONCLUSIONS
  The Charlson index derived from administrative data was superior to the index derived from rapid single-day chart review. We suggest therefore using administrative data, instead of single-day chart review, when assessing comorbidities in the context of the evaluation of nosocomial infections.
authors.affiliation: Health Observatory, Canton of Valais, Switzerland. jean-christophe.luthi@ichv.ch
authors.forename: Jean-Christophe
authors.initials: JC
authors.lastname: Luthi
authors.forename: Nicolas
authors.initials: N
authors.lastname: Troillet
authors.forename: Marie-Christine
authors.initials: MC
authors.lastname: Eisenring
authors.forename: Hugo
authors.initials: H
authors.lastname: Sax
authors.forename: Bernard
authors.initials: B
authors.lastname: Burnand
authors.forename: Hude
authors.initials: H
authors.lastname: Quan
authors.forename: William
authors.initials: W
authors.lastname: Ghali
mesh_terms: D015897:Comorbidity; D003428:Cross Infection / Q000453:epidemiology / Q000401:mortality; D003430:Cross-Sectional Studies; D006739:Hospital Administration / Q000379:methods*; D017052:Hospital Mortality; D006801:Humans; D008499:Medical Records; D019984:Quality Indicators, Health Care / Q000458:organization & administration; D013557:Switzerland