Validation of the Charlson Comorbidity Index for predicting functional outcome of stroke.
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.
Tessier
Annie
A
School of Physical and Occupational Therapy, Faculty of Medicine, McGill University, Montreal, QC, Canada. annie.tessier@mail.mcgill.ca
Finch
Lois
L
Daskalopoulou
Stella S
SS
Mayo
Nancy E
NE
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