Predictive accuracy of severity scoring system: a prospective cohort study using APACHE III in a Korean intensive care unit

Aim: To evaluate the discrimination, calibration, and uniformity of fit by age group, operative status, and location before ICU admission of APACHE III in a single-center ICU population. Design and setting: Prospective data collection in a 25 bed mixed (surgical and medical) ICU of 850-bed teaching hospital in Pusan, South Korea. Subjects and methods: The worst values on APACHE III variables during 24 h following ICU admission were collected from the patient's charts and clinical flow sheets of 284 consecutively admitted subjects. Results: The mortality rate was 31.0%, and showed a strong positive correlation between APACHE III score (r = 0.97, p<0.0001 for entire population, r = 0.97, p<0.0001 for medical patients, r = 0.91, p<0.0001 for surgical patients). Hospital mortality was significantly higher for medical patients than surgical patients (OR = 7.23, 95% CI = 3.76-13.88), and for patients located in the operating room than at ward before admitting ICU (OR = 0.09, 95% CI = 0.04-0.23). At the predicted risk of 0.5 (66 of APACHE III score), sensitivity was 0.72, specificity 0.91, and correct classification rate 0.85. Area under the ROC curve was 0.905 (95%, CI = 0.867-0.943). Correlation coefficient (r) between observed and expected mortality rate was 0.99. The value (chi-square) of Lemeshow-Hosmer (L-H) goodness-of-fit statistic was 6.54 (p = 0.59). In patients stratified according to age groups, operative status, and location in the hospital before ICU admission, discrimination was generally good in all subgroups (area under the ROC curve > 0.85), and the chi-squared of L-H goodness-of -fit statistic showed a good fit for all subgroup, especially for operative status. Conclusions: The predictive accuracy of the APACHE III scoring system showed better discrimination, as well as uniformity of fit. So, it was thought that could be utilized for the subject hospital. (C) 2003 Elsevier Science Ltd. All rights reserved.