Severity of Illness

VPS Work with Severity of Illness Scoring Tools

Over 130 Research Publications

Over 1.7 Million Records Available for Research
Validated Severity of Illness Scores

PIM3 North American Development [calibration, validation and comparison to PIM3]

  • The original PIM3 model from Straney et al [1] did not calibrate well with the VPS data. This type of behavior is well-known in the medical literature, Leteurtre et al [2] and Brady et al [3] published papers were models built on a specific population did not calibrate well when applied in different populations. These authors [2,3] suggested to recalibrate models when applied to different datasets.
  • In collaboration with Dr. Straney, the main author in the PIM3 paper [1], VPS recalibrated the original PIM3 model, and utilized a novel calibration technique known as the GiViTI calibration belt [4]. Good calibration results were found with the North American VPS units.



[1]. Straney L, Clemens A, Parslow RC, et al, Paediatric Index of Mortality 3: An Updated Model for Predicting Mortality in Pediatric Intensive Care, Pediatric Critical Care Medicine (2013) 14: 673-681.

2]. Leteurtre S, Grandbastien B, Leclerc F, et al, International comparison of the performance of the paediatric index of mortality (PIM) 2 score in two national data sets, Intensive Care Med (2012) 38: 1372-1380.

3]. Brady AR, Harrison D, Black S, et al, Assessment and Optimization of Mortality Prediction Tools for Admission to Pediatric Intensive Care in the United Kingdom, PEDIATRICS (2006) 117: e733-e742.

4]. Finazzi S, et al, Calibration Belt for Quality-of-Care Assessment Based on Dichotomous Outcomes, PLoS ONE (2011) 6:e16110.

2014 Length of Stay – PRISM Model

  • VPS has observed that the PRISM III Length of Stay (LOS) model as defined in [1] has become less precise in predicting Pediatric Intensive Care Unit (PICU) length of stay. The model’s standardized length of stay ratios (SLOSR), defined as a ratio of observed to predicted LOS, are now much greater than 1.
  • VPS has developed a new PRISM III LOS model, which performs better. The model’s SLOSRs are now distributed around 1



[1]. Pollack MM. Recalibration of the Length of Stay (LOS) Algorithm: 2006. Personal Communication. 2006.