- Poster presentation
- Open Access
Is Paediatric Index of Mortality 2 already out of date?
© BioMed Central Ltd. 2004
- Published: 15 March 2004
- Similar Rate
- Temporal Trend
- Paediatric Intensive Care Unit
- Prospective Data
- Standardise Mortality Ratio
The Paediatric Index of Mortality (PIM) is the most widely used mortality-risk score in UK paediatric intensive care units (PICU). A recalibrated version, PIM 2, has recently been published. Although released in 2003, PIM 2 was derived from data collected between 1998 and 1999. We aimed to assess temporal changes in performance of both of these scores. Specifically, we hypothesised that the 6-year period between commencement of data collection (1998) and publication (2003) of the revised PIM 2 score may have allowed for significant decalibration.
A prospective data collection from a single, 20-bed tertiary PICU over 5 years (1999–2003). The standardised mortality ratio (SMR) was calculated using the standard formula, discrimination assessed via the area under the receiver–operating characteristic curve (ROC), and calibration using the Hosmer–Lemeshow goodness of fit test.
Both scores continue to discriminate well between survival and nonsurvival. As expected, PIM 2 is better calibrated than PIM, although both appear to be decalibrating at a similar rate. Because PIM 2 reflects the 1998–1999 standard of care, many PICUs will currently exhibit fewer deaths than expected (SMR < 1.00). More frequent calibration appears necessary.