Description

van Straalen et al reported a model for identifying a patient with juvenile idiopathic arthritis (JIA). This can help to distinguish it from chronic musculoskeletal pain. The authors are from Children's Hospital of the University of Utrecht.


Parameters:

(1) sex

(2) age at first visit in years, from 0 to 18

(3) difficulty placing hands behind neck

(4) difficult looking over shoulder

(5) painful or swollen neck

(6) painful or swollen shoulder

(7) painful or swollen hip

(8) painful or swollen knee

(9) painful or swollen ankle

(10) skin rash

(11) VAS scale for disease activity, from 0 to 10

(12) difficulty with self-care

(13) depressed or feeling sad

 

points for age =

= 100 - (5.556 * (age))

 

points for disease activity with VAS scale =

= 2.19 * (VAS score)

 

Parameter

Finding

Points

sex

female

0

 

male

24.6

hands behind neck

no

3.1

 

yes

0

looking over shoulder

no

5.3

 

yes

0

painful/swollen neck

no

22.6

 

yes

0

shoulder

no

0

 

yes

27.3

hip

symmetric

0

 

asymmetric

9.7

 

none

32.6

knee

symmetric

0

 

asymmetric

41.4

 

none

14.4

ankle

yes

0

 

no

13.8

skin rash

no

0

 

yes

23.2

difficulty self-care

no

0

 

yes

28.2

depressed or sad

no

6

 

yes

0

 

total score =

= SUM(points for all of the parameters)

 

Interpretation:

• minimum score: 0

• maximum score: 349

 

value of X =-

= (0.03078 * (score)) - 4.402

 

probability of JIA =

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

 

Performance:

• The area under the ROC curve is 0.83.


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