Description

Challen et al developed models for evaluating patients in the Emergency Department (ED). One model predicts the potential for benefit from a time-critical intervention. The authors are from the University of Sheffield.


 

Patient selection: patient in the ED

 

Outcome: benefit from a time-critical intervention

 

Parameters:

(1) pulse in beats per minute

(2) systolic blood pressure in mm Hg

(3) Glasgow Coma Score (GCS)

Parameter

Finding

Points

pulse

<= 70

0

 

71 to 110

2.373

 

> 110

9.533

systolic blood pressure

> 180 mm Hg

2.888

 

121 to 180

0

 

100 to 120

1.488

 

< 100

3.614

GCS

13 to 15

0

 

9 to 12

2.770

 

3 to 8

13.28

 

X =

= SUM(points for all 3 parameters)

 

probability of a potential to benefit =

= 1 / (1 + EXP((-1) * X))

 

Interpretation:

• The minimum value of X is 0 which occurs when all of the findings are normal. This gives a probability of 50%.

• The maximum value of X is 26.417 which has a probability of 100%.

• Although there is no factor mentioned in the text, many logistic regression models subtract a constant.

 

Performance:

• The area under the ROC curve was 0.74 in the derivation set and 0.71 in the validation set.

 


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