Lu et al reported a model for differentiating Crohn's disease from intestinal tuberculosis. The authors are from Sun Yat-Sen University in China.
Parameters:
(1) interferon-gamma release assay (IGRA)
(2) number of segments involved
(3) longitudinal ulcer
(4) circular ulcer
(5) aphthous ulcer
(6) Comb sign, target sign, adipose creeping sign
(7) rectum involvement
|
Paramter
|
Finding
|
Beta Coefficient
|
|
IGRA
|
negative
|
0
|
|
|
positive
|
-3.62
|
|
segments involved
|
1 to 3
|
0
|
|
|
>= 4
|
2.87
|
|
longitudinal ulcer
|
no
|
0
|
|
|
yes
|
2.06
|
|
circular ulcer
|
no
|
0
|
|
|
yes
|
-2.52
|
|
aphthous ulcer
|
no
|
0
|
|
|
yes
|
2.52
|
|
Comb sign, etc
|
no
|
0
|
|
|
yes
|
0.53
|
|
rectum involvement
|
no
|
0
|
|
|
yes
|
-0.31
|
value of X =
= SUM(all of the beta-coefficients) - 0.05
probability of Crohn's disease =
= 1 / (1 + EXP((-1) * X))
Since only allows for 2 diagnoses
probability of tuberculosis =
= 1 - (probability of Crohn's disease)
The authors also prepared a CART analysis of the most important variables (#1, #2, #3, #4, #5).
