Can generic paediatric mortality scores calculated 4 hours after admission be used as inclusion criteria for clinical trials?
BACKGROUND
Two generic paediatric mortality scoring systems have been validated in the paediatric intensive care unit (PICU). Paediatric RISk of Mortality (PRISM) requires an observation period of 24 hours, and PRISM III measures severity at two time points (at 12 hours and 24 hours) after admission, which represents a limitation for clinical trials that require earlier inclusion. The Paediatric Index of Mortality (PIM) is calculated 1 hour after admission but does not take into account the stabilization period following admission. To avoid these limitations, we chose to conduct assessments 4 hours after PICU admission. The aim of the present study was to validate PRISM, PRISM III and PIM at the time points for which they were developed, and to compare their accuracy in predicting mortality at those times with their accuracy at 4 hours.


METHODS
All children admitted from June 1998 to May 2000 in one tertiary PICU were prospectively included. Data were collected to generate scores and predictions using PRISM, PRISM III and PIM.


RESULTS
There were 802 consecutive admissions with 80 deaths. For the time points for which the scores were developed, observed and predicted mortality rates were significantly different for the three scores (P < 0.01) whereas all exhibited good discrimination (area under the receiver operating characteristic curve >or=0.83). At 4 hours after admission only the PIM had good calibration (P = 0.44), but all three scores exhibited good discrimination (area under the receiver operating characteristic curve >or=0.82).


CONCLUSIONS
Among the three scores calculated at 4 hours after admission, all had good discriminatory capacity but only the PIM score was well calibrated. Further studies are required before the PIM score at 4 hours can be used as an inclusion criterion in clinical trials.
Paediatric Intensive Care Unit, University Hospital of Lille, Lille, France. s-leteurtre@chru-lille.fr <s-leteurtre@chru-lille.fr>
Stéphane
S
Leteurtre
Francis
F
Leclerc
Jessica
J
Wirth
Odile
O
Noizet
Eric
E
Magnenant
Ahmed
A
Sadik
Catherine
C
Fourier
Robin
R
Cremer
D000293:Adolescent; D002648:Child; D046688:Child Mortality; D002675:Child, Preschool; D002986:Clinical Trials as Topic; D005260:Female; D005602:France / Q000453:epidemiology; D017052:Hospital Mortality; D006785:Hospitals, University; D006801:Humans; D007223:Infant; D007226:Infant Mortality; D015278:Intensive Care Units, Pediatric / Q000706:statistics & numerical data*; D008297:Male; D010343:Patient Admission; D018579:Patient Selection; D011379:Prognosis; D018570:Risk Assessment / Q000379:methods*; D012720:Severity of Illness Index; D013997:Time Factors