Performance of Pediatric Risk of Mortality (PRISM), Pediatric Index of Mortality (PIM), and PIM2 in a pediatric intensive care unit in a developing country

Abstract

To determine the discriminative ability and calibration of existing scoring systems in predicting the outcome (mortality) in children admitted to an Indian pediatric intensive care unit (PICU). Prospective cohort study. Pediatric Intensive Care Unit, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, from July 1, 2002, to July 31, 2003. A total of 246 patients were admitted. After exclusion of 29 neonates and two patients who stayed in the PICU for <or=2 hrs, 215 patients were enrolled in the study. Of these 215 patients, 139 patients survived at the end of the PICU stay. None. Discrimination between death and survival was assessed by calculating the area under the receiver operating characteristic curve for each model. The areas under the curve (95% confidence intervals) for Pediatric Risk of Mortality (PRISM), Pediatric Index of Mortality (PIM), and PIM2 were 0.80 (0.74-0.86), 0.82 (0.76-0.88), and 0.81 (0.75-0.87), respectively. The area under the receiver operating characteristic curves was significantly greater for older children compared with infants. The existing scores underpredicted the mortality; the standardized mortality ratios (SMRs) (95% confidence interval) using PRISM, PIM, and PIM2 models were 1.20 (0.94-1.50), 1.57 (1.24-1.96), and 1.57 (1.24-1.59), respectively. The SMRs were higher in children with severe malnutrition, those with underlying illness, and those with serum albumin <or=2.5 g/dL. The area under the receiver operating characteristic curve for all the models evaluated was >0.8. However, all the models underpredicted mortality. The likely reasons for this could be differences in the patient profile and greater load of severity of illness being managed with lesser resources--both physical and human--and differences in the quality of care.