Redfern et al reported a risk index based on the Laboratory Decision Tree Early Warning Score (LDT-EWS) and National Early Warning Score (NEWS). The authors are from the Unversity of Portsmouth, University of Oxford, and Bournemouth University in England.
Patient selection: adult hospitalized after emergency medical admission
Parameters:
(1) laboratory decision tree early warning score (LDT-EWS)
(2) NEWS
(3) number of hours since blood specimen for laboratory tests drawn
factor =
= (beta value) - ((beta value) * (number of hours since labs drawn) / 120)
The authors used a beta factor of 0.26.
risk index =
= ((factor) * (LDT-EWS)) + ((1 - (factor)) * (NEWS))
Interpretation:
• The higher the index the greater the risk of unanticipated ICU admission.
• The supplement reports that the risk index ranges from 0 to 0.40. The thresholds reported were 0.27 and 0.36.
• The risk index as published would give results from 0 to 20.
• Dividing by 100 or creating a ratio between the 2 values does not clarify the issue.
Performance:
• The c-statistic was 0.90 and 0.92 in 2 cohorts.
