Description

Van der Helm-van Mil et al developed a prediction rule for evaluating a patient with recent onset of undifferentiated arthritis. This can help identify a patient who may progress to rheumatoid arthritis or similar condition. The authors are from Leiden University in The Netherlands.


 

Parameter:

(1) age in years)

(2) gender

(3) involvement of small joints in hands and/or feet

(4) symmetry of involvement

(5) distribution of involved joints in the limbs

(6) morning stiffness as rated on a 100 mm visual analogue scale (VAS)

(7) number of tender joints (out of 44)

(8) number of swollen joints (out of 44)

(9) C-reactive protein (CRP) in mg/L

(10) rheumatoid factor

(11) anti-CCP antibody

Parameter

Finding

Points

gender of the patient

male

0

 

female

1

small joints of hands/feet

absent

0

 

present

0.5

involvement

asymmetrical

0

 

symmetrical

0.5

distribution

not in limbs

0

 

lower extremities only

0

 

upper extremities

1

 

upper and lower extremities

1.5

morning stiffness

<= 25 mm

0

 

26 - 90 mm

1

 

91 - 100

2

tender joint count

0 - 3

0

 

4 - 10

0.5

 

>= 11

1

swollen joint count

0 - 3

0

 

4 - 10

0.5

 

>= 11

1

C-reactive protein

< 5 mg/L

0

 

5 - 50 mg/L

0.5

 

>= 51 mg/L

1.5

rheumatoid factor

absent

0

 

present

1

anti-CCP antibodies

absent

0

 

present

2

 

where:

• The point assignment for small joints, symmetry and limb distribution seems to be the only way to get the maximum of 14+ points.

 

total score =

= (0.02 * (age in years)) + SUM(points for the other parameters)

 

Interpretation:

• minimum score: 0

• maximum score: 14-15

• The higher the score the greater the probability of the patient progressing to rheumatoid arthritis.

 

Total Score

Probability of RA

0 - 3

0%

4

7%

5

15%

6

26%

7

51%

8

67%

9

86%

10

92% (from Fig 2), 77% (Table 3)

>= 11

100%

from Table 3, page 437

 

Performance:

• The area under the ROC curve is around 0.89

 


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