Comparison of Outcomes using Pediatric Index of Mortality (PIM)-3 and PIM-2 Models in a Pediatric Intensive Care Unit

Objectives: To compare patient outcomes using the Pediatric Index of Mortality-3 (PIM-3) model with PIM-2 model for children admitted to the intensive care unit. Methods: We prospectively recorded the baseline characteristics, variables of PIM-3 and PIM-2 at admission, and outcomes of children <= 17 years over a period of 11 months. We used Area Under Receiver Operating Characteristics (AU-ROC) curves and Goodness-of-fit (GOF) tests to determine which of the two models had better discrimination and calibration. Results: Out of 202 children enrolled, 69 (34%) died. Sepsis and pneumonia were the common admitting diagnoses. The AU-ROC was better for PIM-3 (0.75) as compared to PIM-2 (0.69; P=0.001). The GOF-P value was 0.001 for both models, that indicated poor calibration of both (P<0.001). The AU-ROC curves were acceptable across different age and diagnostic sub-groups. Conclusion: PIM-3 had better discrimination when compared to PIM-2 in our unit. Both models had poor calibration across deciles of risk.