A Prospective Cohort Study for the Comparison of Two Prognostic Scores-Prism 3 and Pim 2 in a Paediatric Intensive Care Unit

Abstract

BACKGROUND AND OBJECTIVES: Various prognostic scores are used to evaluate the outcome in the PICU. Among these scores PRISM (Pediatric Risk of Mortality) and PIM (Pediatric Index of Mortality), are the most recent versions. The objectives of this study were to compare performance of PIM II and PRISM III scores at a general pediatric intensive care unit, relation between observed mortality and survival and predicted mortality and survival. METHODS: Present prospective cohort study was conducted at Pediatric Intensive Care Unit, KLES, Dr. Prabhakar Kore Hospital and Medical Research Centre, Belgaum during period of July-2009 to October-2009. Ethical clearance was obtained from Ethical and Research Committee of Jawaharlal Nehru Medical College, Belgaum. A total of 316 patients were enrolled out of 350 admissions during study period. Within first hour of admission PIM II was assessed and at 24 hours PRISM III score was assessed. Patients were followed up for outcome measured in form of survivors and non survivors. RESULTS: A total 316 patients were enrolled, 28 patients were excluded as their outcome was not known. Among the 288 patients 261 were survivors and 27 were non-survivors. Majority of survivors and non survivors were males but there was no statistical significant influence on outcome. The overall number of estimated mortality was 13.2 and 16.5 with PIM II and PRISM III respectively compared to observed mortality of 27. PIM II (x 2 =16.34; p<0.001) and PRISM III (x 2 =6.78; p=0.009) had poor calibration. PRISM III showed the better discrimination (ROC=0.892) followed by PIM II 0.871 (0.827 to 0.907). PIM II and PRISM III (0.850 to 0.925) revealed positive and significant correlation, with spearman's rank correlation (r= 0.318; p<0.0001). INTERPRETATION AND CONCLUSION: In this study PIM II and PRISM III under predicted mortality and also had poor calibration with good discrimination. Overall both scores exhibited good capacity to discriminate between survivors and non survivors and can be used as a tool with comparable performance for prognostic evaluation.