Validation of Pediatric Index of Mortality-2 Scoring System in a Single Pediatric Intensive Care Unit in Iran

Objective: A study to validate and calibrate Pediatric Index of Mortality-2 (PIM2) in children admitted to our pediatric intensive care unit (PICU).
Methods: This is a prospective cohort study performed in Bahrami Children’s Hospital affiliated to Tehran University of Medical Sciences. We studied the patients admitted to PICU from May 2007 to November 2008. Clinical measures were identified upon arrival in PICU. We used PIM2 score and logistic regression analysis to compare expected mortality risk with observed mortality rate. Receiver operating characteristics (ROC) curve analysis was done and standardized mortality ratio was calculated. PIM2 Index assessment was performed by use of Hosmer and Lemeshow goodness-of-fit test.
Findings: 240 patients were included in this study. The model fit was achieved adequately (P value = 0.741). The area under the ROC curve was 0.795 (0.715-0.875 for 95% confidence interval) and standardized mortality ratio was 1.8 (1.28-2.465 for 95% confidence interval) High-risk group diagnosis with adjusted odds ratio (AOR)=14.75, pupil reaction to light (AOR=0.13) and duration of stay in PICU (AOR=1.03) had significant statistical association to pediatric mortality.
Conclusion: PIM2 is a good index for prediction of mortality in our pediatric intensive care unit. This study revealed that there is significant statistical association between the children mortality and the length of hospitalization, pupillary light reflex and the risk level category on admission.

Keywords
Mortality; Pediatric intensive care unit; Pediatric Index of Mortality-2 (PIM2); Iran