Cardiac-specific comorbidity index beats generic indexes

(HealthDay)—For patients admitted to the hospital with a cardiac condition, a cardiac-specific comorbidity index outperforms generic indexes for predicting mortality, according to study published online March 18 in CMAJ, the journal of the Canadian Medical Association.

Lorenzo Azzalini, M.D., Ph.D., from the Université of Montréal, and colleagues derived a cardiac-specific comorbidity index from consecutive patients admitted to a tertiary care cardiology hospital. Age, sex, and 22 clinically relevant comorbidities were incorporated to build the index. The cardiac-specific index was compared to the refitted Charlson-Deyo and Elixhauser comorbidity indexes.

The researchers found that for predicting in-hospital mortality, the novel cardiac-specific comorbidity index outperformed the refitted generic Charlson-Deyo and Elixhauser comorbidity indexes in the derivation population (10,137 individuals: C-statistic, 0.95 versus 0.81 and 0.86, respectively) and in the validation population (17,877 individuals: C-statistic, 0.92 versus 0.76 and 0.82, respectively). In the validation cohort, the cardiac-specific comorbidity index also outperformed the Charlson-Deyo and Elixhauser comorbidity indexes for predicting one-year mortality (C-statistic: 0.78 versus 0.75 and 0.77). Better fit for the prediction of length of stay was also seen for the cardiac-specific comorbidity index. The net reclassification improvement for the prediction of death was 0.29 and 0.192, respectively, for the cardiac-specific comorbidity index versus the Charlson-Deyo and Elixhauser comorbidity indexes.

"Our cardiac-specific comorbidity index outperformed generic comorbidity indexes to predict all-cause death and length of stay in patients admitted to hospital for a cardiac condition," the authors write.

One author disclosed financial ties to the pharmaceutical and medical device industries.