An automated computerized critical illness severity scoring system derived from APACHE III: modified APACHE

Abstract

Purpose: To evaluate the performance of an automated computerized ICU severity scoring derived from the APACHE III.

Materials and methods: Within a retrospective cohort of patients admitted to Veterans Health Administration ICUs between 2009 and 2015, we created an automated illness severity score(modified APACHE or mAPACHE), that we extracted from the electronic health records, using the same scoring as the APACHE III excluding the Glasgow Coma Scale, urine output, arterial blood gas components of APACHE III. We assessed the mAPACHE discrimination by using the area under the curve(AUC), and calibration by using the Hosmer-Lemeshow test and calculating the difference between observed and expected mortality across equal-sized risk deciles for death.

Results: The ICU and 30-day mortality was 5.07% of 7.82%, respectively (n = 490,955 patients). The AUC of mAPACHE for ICU and 30-day mortality was 0.771 and 0.786, respectively. The Hosmer-Lemeshow test was significant for both ICU and 30-day mortality (p < .001). The absolute difference between observed and expected mortality did not exceed ±1.53% across equal-sized deciles of risk for death. The AUC for ICU mortality was >0.7 in all admission diagnosis categories except in endocrine, respiratory, and sepsis. The AUC for 30-day mortality was >0.7 in every category.

Conclusion: mAPACHE has adequate performance to predict mortality.

Keywords: APACHE; Computerized; Critical care outcomes; Medical records systems; Mortality; Severity of illness index.