1) To validate European Spondylarthropathy Study Group (ESSG) and B. Amor's criteria for spondylarthropathies in Lebanon. 2) To evaluate the frequency of spondylarthropathies in rheumatological practice in Lebanon.
Cases of definite and probable spondylarthropathy were diagnosed based on the clinical judgement of participating rheumatologists, without reference to the two criteria sets under study. The first two patients without spondylarthropathy seen after each spondylarthropathy case were included into the control group. Criteria in the ESSG and B. Amor sets were looked for in the patient and control groups. The frequency of spondylarthropathy meeting each criteria set was determined.
Of the 841 patients evaluated during the study period, 68 met B. Amor's criteria and 72 met ESSG criteria. There were 29 cases of ankylosing spondylitis (40.3%), ten of peripheral psoriatic arthritis (13.8%), two of reactive arthritis (2.8%), two of enteropathic arthropathy (2.8%), and 29 of undifferentiated spondylarthropathy (40.3%). In the definite spondylarthropathy group, sensitivity and specificity were 77.19% and 97.55% for B. Amor's criteria versus 91.23% and 100% for ESSG criteria. The frequency of spondylarthropathy was 8.1% (95% confidence interval [CI], 6.3-9.9) or 8.56% (CI 6.6-10.5) according to B. Amor and ESSG criteria, respectively.
Our data validate both criteria sets in the Lebanese population, demonstrating that they are useful in populations that are genetically different from the European populations used to develop them. Spondyloarthropathy is the most common in our rheumatology practice.