ALERT Scale Calculation

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ALERT Scale Calculation

Binary logistic regression resulted in the following outcome model:

  • LN(R/1-R) = Y

Y =

  • -3.8390 + (0.1570 x male gender)
  • +(0.0712 x Charlson Comorbidity Index)
  • +(0.0532 x #ADLs
  • -(0.1720 x Glasgow Coma Scale (GCS))
  • +(0.0678 x age)
  • -(0.0004 x (age x age)
  • +(0.0175 x heart rate)
  • +(0.0631 x respiratory rate)
  • +(0.0289 x white blood cell count)
  • -(0.0410 x systolic blood pressure)
  • +(0.000121 x (systolic blood pressure x systolic blood pressure)

Where R is the risk of bad outcome and the categorical variable gender, is coded female=0 and male=1.

How to calculate R:

  • R=exp(Y)/1 + exp(Y)
  • Heart rate, respiratory rate, White Blood cell Count (WBC), systolic Blood Pressure (sBP) - are continuous data

The cut-off probability for R is 0.088 . "A cut-off point of 0.088, or a predicted probability of adverse outcome of 8.8%, was used to classify patients into two groups; high-risk and low-risk of adverse outcome." (from publication)

ADLs

Activity of Daily Living Score (ADLS)

  • Activity of Daily Living Score:
    • 0 - independent
    • 3 - minor dependence
    • 6 - major dependence