Comparison of the pediatric risk of mortality, pediatric index of mortality, and pediatric index of mortality 2 models in a pediatric intensive care unit in China A validation study

This study was designed with the aim of comparing the performances of the pediatric risk of mortality (PRISM), pediatric index of mortality (PIM), and revised version pediatric index of mortality 2 (PIM2) models in a pediatric intensive care unit (PICU) in China. A total of 852 critically ill pediatric patients were recruited in the study between January 1 and December 31, 2014. The variables required to calculate PRISM, PIM, and PIM2 were collected. Mode l performance was evaluated by assessing the calibration and discrimination. Discrimination between death and survival was assessed by calculating the area under the receiver-operating characteristic curve (AUC). Calibration across deciles of risk was evaluated using the Hosmer-Lemeshow goodness-of-fit chi(2) test. Of the 852 patients enrolled in this study, 745 patients survived until the end of the PICU stay (107 patients died, 12.56%). The AUCs (95% confidence intervals, CI) were 0.729 (0.670-0.788) for PRISM, 0.721 (0.667-0.776) for PIM, and 0.726 (0.671-0.781) for PIM2. The Hosmer-Lemeshow test revealed a chi-square of 7.26 (P=0.51, v=10) for PRISM, 26.28 (P=0.0009, v=10) for PIM, and 10.28 (P=0.21, v=10) for PIM2. The standardized mortality rate was 1.14 (95% CI: 0.93-1.36) for PRISM, 1.89 (95% CI: 1.55-2.27) for PIM, and 2.13 (95% CI: 1.75-2.55) for PIM2. The PRISM, PIM, and PIM2 scores demonstrated an acceptable discriminatory performance. With the exception of PIM, the PRISM and PIM2 models had good calibrations.