title: Interrater reliability of APACHE II scores for medical-surgical intensive care patients: a prospective blinded study.
abstract: BACKGROUND
  Despite widespread use of the Acute Physiology and Chronic Health Evaluation II (APACHE II), its interrater reliability has not been well studied.
  
  
  OBJECTIVE
  To determine interrater reliability of APACHE II scores among 1 intensive care nurse and 2 research clerks.
  
  
  METHODS
  In a prospective, blinded, observational study, 3 raters collected APACHE II scores on 37 consecutive patients in a medical-surgical intensive care unit. One research clerk was blinded to the study's start date to minimize observer bias. The nurse and the other research clerk were blinded to each other's scores and did not communicate with the first research clerk about the study. The data analyst was blinded to the identity and source of all 3 raters' scores. Intraclass correlation coefficients and 95% confidence intervals were assessed.
  
  
  RESULTS
  Mean (standard deviation) APACHE II scores were 21.8 (9.2) for the nurse, 20.4 (7.7) for research clerk 1, and 20.5 (8.1) for research clerk 2. Among the 3 raters, the intraclass correlation coefficient (95% confidence interval) was 0.90 (0.84, 0.94) for the APACHE II total score. Within APACHE II score components, the highest reliability was for age (0.98 [0.97, 0.99]), with lower reliabilities for the Chronic Health Index (0.64 [0.50, 0.80]) and the verbal component of the Glasgow Coma Scale (0.40 [0.20, 0.60]). Results were similar between pairs of raters.
  
  
  CONCLUSIONS
  Use of trained nonmedical personnel to collect illness severity scores for clinical, research, and administrative purposes is reasonable. This method could be used to assess reliability of other illness severity scores.
authors.affiliation: Health Research Methodology Program, at McMaster University, Hamilton, Ontario, Canada. khome@mcmaster.ca
authors.forename: Michelle E
authors.initials: ME
authors.lastname: Kho
authors.forename: Ellen
authors.initials: E
authors.lastname: McDonald
authors.forename: Paul W
authors.initials: PW
authors.lastname: Stratford
authors.forename: Deborah J
authors.initials: DJ
authors.lastname: Cook
mesh_terms: D018806:APACHE; D003422:Critical Care / Q000706:statistics & numerical data; D006801:Humans; D009726:Nurses; D015588:Observer Variation; D009864:Ontario; D011446:Prospective Studies; D015203:Reproducibility of Results; D012108:Research Personnel; D012720:Severity of Illness Index