title: Validation of the Charlson Comorbidity Index for predicting functional outcome of stroke.
abstract: OBJECTIVE
  To determine whether a separate comorbidity index is needed to predict functional outcome after stroke, we compared the predictability of the Charlson Comorbidity Index (CMI) and the Functional Comorbidity Index (FCI) to that of a stroke-specific comorbidity index with function quantified with a measure developed with a Rasch model as outcome.
  
  
  METHODS
  Two prospective inception cohort studies, in 1996 through 1998 and in 2002 through 2005, with up to 9 months of follow-up.
  
  
  METHODS
  Participants enrolled in 2 studies were recruited from acute care hospitals in the Montreal area.
  
  
  METHODS
  For study one, 1027 persons with a first stroke discharged into the community were eligible; the 437 who were interviewed a second time at 6 months were included in the analysis. In study two, 235 of 262 patients with stroke were enrolled.
  
  
  METHODS
  Not applicable.
  
  
  METHODS
  To predict recovery, we developed 3 stroke-specific comorbidity algorithms based on the estimated strength of association between comorbidities and stroke function. The various indices were compared on the basis of their predictive ability with a c statistic.
  
  
  RESULTS
  In study 1, the c statistics were .758, .763, .766, and .763 for the stroke-specific algorithms 1, 2, and 3 and the CMI, respectively. In study 2, the c statistics were .680, .700, .704, .714, and .714 for the algorithms 1, 2, and 3, the CMI, and the FCI, respectively.
  
  
  CONCLUSIONS
  For purposes of case-mix adjustment, the CMI seems to be more than adequate.
authors.affiliation: School of Physical and Occupational Therapy, Faculty of Medicine, McGill University, Montreal, QC, Canada. annie.tessier@mail.mcgill.ca
authors.forename: Annie
authors.initials: A
authors.lastname: Tessier
authors.forename: Lois
authors.initials: L
authors.lastname: Finch
authors.forename: Stella S
authors.initials: SS
authors.lastname: Daskalopoulou
authors.forename: Nancy E
authors.initials: NE
authors.lastname: Mayo
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D015897:Comorbidity; D005260:Female; D006305:Health Status Indicators; D006801:Humans; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D017063:Outcome Assessment, Health Care; D020127:Recovery of Function; D012720:Severity of Illness Index; D000071939:Stroke Rehabilitation