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 χ2 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.