Original articleValidation of the Charlson Comorbidity Index for Predicting Functional Outcome of Stroke
Section snippets
Methods
First, we developed predictive models linking comorbidity to function; comorbidities were defined through a list of stroke-specific conditions and were weighted according to their impact on function. The predictive ability of the stroke-specific functional outcome comorbidity algorithms was then compared with the predictive ability of the CMI.9 The second step consisted of confirming the comparative predictability of stroke-specific algorithms to the CMI9 and FCI13 in a separate sample.
Results
Selected characteristics of both samples are presented in table 1. The mean age of the participants was 70 and 72 years for studies 1 and 2, respectively. They were predominantly men, with ischemic stroke. About 80% had a moderate or severe stroke, and the main discharge destination was home at the time of follow-up after 14.7 and 16.9 days in the hospital for studies 1 and 2, respectively. Hypertension and diabetes were among the most common conditions. People in study 1 had on average 4
Discussion
Comorbidities can compromise recovery from a stroke. The CMI9 is widely used in studies predicting function,25, 26, 27 although its use can be questioned because it was developed to predict mortality and morbidity. To account better for the effect of comorbidities when assessing rehabilitation programs, several comorbidity indices have been recently developed to predict functional outcomes.13, 14, 15, 16, 20 To verify the need for a stroke-specific comorbidity index, we developed 3
Conclusions
The CMI, although originally developed for predicting mortality and subsequently validated for some indicators of morbidity, predicted function as well as, if not better than, stroke-specific comorbidity indices. For purposes of case-mix adjustment, the CMI seems to be more than adequate for explaining variability in functional outcome poststroke; it is widely known and easily obtained from either clinical or administrative data. Use of standard assessments for comorbidity will facilitate
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