Wa. Ghali et al., SEARCHING FOR AN IMPROVED CLINICAL COMORBIDITY INDEX FOR USE WITH ICD-9-CM ADMINISTRATIVE DATA, Journal of clinical epidemiology, 49(3), 1996, pp. 273-278
Citations number
17
Categorie Soggetti
Public, Environmental & Occupation Heath","Medicine, General & Internal
We studied approaches to comorbidity risk adjustment by comparing two
ICD-9-CM adaptations (Deyo, Dartmouth-Manitoba) of the Charlson comorb
idity index applied to Massachusetts coronary artery bypass surgery da
ta. We also developed a new comorbidity index by assigning study-speci
fic weights to the original Charlson comorbidity variables. The 2 ICD9
-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). Mean
while, the study-specific comorbidity index identified a 10% subset of
patients with 15% mortality, whereas the 5% highest risk patients acc
ording to the Charlson index had only 8% mortality (p = 0.01). A model
using the new index to predict mortality had better validated perform
ance 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 w
ith the Charlson variables substantially improved the power of these d
ata to predict mortality.