It is interesting to note that Behcet’s Disease (BD) is one of
those diseases which had an early diagnostic criteria (9 years after its
official recognition, with the Curth criteria in 1946), having one of the
largest number of classification/diagnosis criteria (17 sets, in 70 years, till
2016), among them only 2 real International Criteria (ISG and ICBD), and having
one of the largest international participation (27 countries for ICBD). The ISG
criteria were created by the collaboration of 7 countries (France, Iran, Japan,
Tunisia, Turkey, UK, and USA) in 1990. The ICBD was first presented in
2006 to the International Conference on Behcet’s Disease in Portugal and the
revised version in 2010 to the International Conference on Behcet’s Disease in
London, and published in 2014.
The sensitivity of ISG criteria was very good, at 92%, when
checked on the patients gathered from the 7 countries. The specificity was
excellent at 97%. Originally, the accuracy was not checked and instead the
relative value, which was 189 (the sum of sensitivity and specificity). When
the performance of the criteria was checked, for validation, in different
countries, the sensitivity was low, while the specificity was high. The
problem came from two main biases. First, as the majority of BD patients
gathered from the seven countries had oral aphthosis (OA), this manifestation
was put as a mandatory symptom to be present for diagnosis, while all over the
world, when patients are diagnosed by expert opinion, around 5% of patients
diagnosed as having BD miss OA. Second, the patients’ selection: overall 886 BD
patients and 97 control patients were selected from the seven collaborating
countries, with 366 (41.3%) from Iran, 285 (32.2%) from Turkey, and 141 (16.9%)
from Japan, which made 90.4% from 3 countries and less than 10% of the
remaining 4 countries. From Western countries, only 5% had BD. To be classified
as having BD, a patient must have oral aphthosis (mandatory), and two of he
following manifestations: genital aphthosis, skin manifestations (pseudo-folliculitis,
erythema nodosum), ophthalmologic manifestations (anterior uveitis, posterior
uveitis, retinal vasculitis), positive pathergy test.
For ICBD, patients were gathered from 27
countries, all over the world. This time, it was paid enough attention to not
make the same error in the patient selection, and to have enough patients from
the Western world. A total of 2556 BD and 1163 controls were gathered, with
35.1% from 9 countries of the Western world. The revised ICBD performance in
the cohort of the international patients was: sensitivity 96%, specificity
91.2%, and accuracy 94.5%. ICBD was validated in Germany, China, Iran, and
Italy. The revised ICBD was validated in Iran with sensitivity
96.8% (ISG 78.1%), specificity 97.2% (ISG 98.8%), and accuracy 97% (ISG 85.5%).
To be classified as having BD, a patient must get 4 points from the ICBD. Oral
aphthosis, genital aphthosis, and ophthalmologic manifestations (anterior
uveitis, posterior uveitis, retinal vasculitis) get each 2 points. Skin
manifestations (paseudo-folliculitis, erythema nodosum, skin aphthosis),
vascular manifestations, neurological manifestations, and positive pathergy
test get each one point.