Performance effectiveness of pediatric index of mortality 2 (PIM2) and pediatricrisk of mortality III (PRISM III) in pediatric patients with intensive care in single institution: Retrospective study

Hwang, Hui Seung; Lee, Na Young; Han, Seung Beom; Kwak, Ga Young; Lee, Soo Young; Chung, Seung Yun; Kang, Jin Han; Jeong, Dae Chul

Abstract

PURPOSE: To investigate the discriminative ability of pediatric index of mortality 2 (PIM2 ) and pediatric risk of mortality III (PRISM III) in predicting mortality in children admitted into the intensive care unit (ICU).
METHODS
We retrospectively analyzed variables of PIM2 and PRISM III based on medical records with children cared for in a single hospital ICU from January 2003 to December 2007. Exclusions were children who died within 2 h of admission into ICU or hopeless discharge. We used Students t test and ANOVA for general characteristics and for correlation between survivors and non-survivors for variables of PIM2 and PRISM III. In addition, we performed multiple logistic regression analysis for Hosmer-Lemeshow goodness-of-fit, receiver operating characteristic curve (ROC) for discrimination, and calculated standardized mortality ratio (SMR) for estimation of prediction.
RESULTS
We collected 193 medical records but analyzed 190 events because three children died within 2 h of ICU admission. The variables of PIM2 correlated with survival, except for the presence of post-procedure and low risk. In PRISM III, there was a significant correlation for cardiovascular/neurologic signs, arterial blood gas analysis but not for biochemical and hematologic data. Discriminatory performance by ROC showed an area under the curve 0.858 (95% confidence interval; 0.779-0.938) for PIM2, 0.798 (95% CI; 0.686-0.891) for PRISM III, respectively. Further, SMR was calculated approximately as 1 for the 2 systems, and multiple logistic regression analysis showed chi-square(13)=14.986, P=0.308 for PIM2, chi-square(13)=12.899, P=0.456 for PRISM III in Hosmer-Lemeshow goodness-of-fit. However, PIM2 was significant for PRISM III in the likelihood ratio test chi-square(4)=55.3, P<0.01).
CONCLUSION
We identified two acceptable scoring systems (PRISM III, PIM2 ) for the prediction of mortality in children admitted into the ICU. PIM2 was more accurate and had a better fit than PRISM III on the model tested.