We studied approaches to comorbidity risk adjustment by comparing two ICD-9-CM adaptations (Deyo, Dartmouth-Manitoba) of the Charlson comorbidity index applied to Massachusetts coronary artery bypass surgery data.
We also developed a new comorbidity index by assigning study-specific weights to the original Charlson comorbidity variables.
The 2 ICD-9-CM coding adaptations assigned identical Charlson comorbidity scores to 90% of cases, and specific comorbidities were largely found in the same cases (kappa values of 0.72-1.0 for 15 of 16 comorbidities).
Meanwhile, the study-specific comorbidity index identified a 10% subset of patients with 15% mortality, whereas the 5% highest-risk patients according to the Charlson index had only 8% mortality (p=0.01).
A model using the new index to predict mortality had better validated performance than a model based on the original Charlson index (c=0.74 vs. 0.70).
Thus, in our population, the ICD-9-CM adaptation used to create the Charlson score mattered little, but using study-specific weights with the Charlson variables substantially improved the power of these data to predict mortality.
Mots-clés Pascal : Artère coronaire, Chirurgie, Dérivation, Mortalité, Association morbide, Risque, Evaluation, Echelle évaluation, Homme, Méthode calcul, Modèle mathématique, Appareil circulatoire
Mots-clés Pascal anglais : Coronary artery, Surgery, Bypass, Mortality, Concomitant disease, Risk, Evaluation, Evaluation scale, Human, Computing method, Mathematical model, Circulatory system
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Inist-CNRS - Institut de l'Information Scientifique et Technique
Cote : 96-0420694
Code Inist : 002B25E. Création : 10/04/1997.