Use of Pediatric Index of Mortality (PIM) and the Pediatric Risk of Mortality (PRISM) III-24 for prediction of mortality.

To the Editor—I read with interest the article by Choi et al regarding the use of the Pediatric Index of Mortality (PIM) and the Pediatric Risk of Mortality (PRISM) III-24 score for predicting mortality in a paediatric intensive care unit (PICU) in Hong Kong. I agree with the authors that mortality prediction models are useful for audit purposes and allow comparison of disease severity and clinical outcomes in different PICUs to be made. Nonetheless proper validation of such systems is essential.