Early diagnosis and treatment of ankylosing spondylitis in Africa and the Middle East

Abstract

Ankylosing spondylitis (AS) is the prototype for spondyloarthritis primarily affecting young men. Geographic and ethnic variations exist in the prevalence and severity of AS and relate to the wide disparity in the frequency of human leukocyte antigen (HLA)-B27, a major genetic risk factor. The strength of the disease association with HLA-B27 is lower in most Arab populations (25-75 %) than in Western European populations (>90 %), and there is no association in sub-Saharan Africa, where the prevalence of HLA-B27 is <1 %. Other epidemiologic differences between European and African populations are the apparent later age at presentation in sub-Saharan Africa, and the high rate of spondyloarthropathies associated with human immunodeficiency virus infection. Diagnosis of AS is often delayed 8-10 years; potential reasons for the delay in Africa and the Middle East include low awareness among physicians and patients, the requirement for radiographic evidence of sacroiliitis for diagnosis, and limited access to magnetic resonance imaging in some countries. Treatment should be initiated early to prevent or reduce skeletal deformity and physical disability. Nonsteroidal anti-inflammatory drugs are effective first-line treatment and anti-tumor necrosis factor-α drugs are indicated for patients who have an inadequate response to first-line therapy. In Africa and the Middle East, such treatments may be precluded either by cost or contraindicated because of the high prevalence of latent tuberculosis infection. Research is sorely needed to develop cost-effective tools to diagnose AS early as well as effective, inexpensive, and safe treatments for these developing regions.

HLA B27 antigen in Middle Eastern and Arab countries: systematic review of the strength of association with axial spondyloarthritis and methodological gaps

“…Therefore, HLA-B27 plays a central role in SpA classification and can be pivotal in referral strategies and early diagnosis [9, 10]. The association of axial SpA with HLA-B27 seems to be lower in most Arab populations compared to Western European populations [11], possibly due to genetic backgrounds. This may affect the diagnostic value of HLA-B27 antigen, and impact the local application of published referral strategies, which were studied in Western populations with high HLA-B27 prevalence [9].…”

Evaluation of multiple referral strategies for axial spondyloarthritis in the SPondyloArthritis Caught Early (SPACE) cohort

“…HLA-B27 as a screening parameter is appealing as it is easy to interpret (either present or absent), but the value of HLA-B27 for screening is, among others, dependent on its prevalence in the general population,33 which varies widely geographically and ethnically 34…”

Spondyloarthritis: Criteria, limitations, and perspectives throughout history

“…Second, the patients used to develop these criteria had arthritis, enthesitis, or dactylitis of less than 1 year's duration. Third, the use of the HLA-B27 antigen is associated with the same limitations discussed above for axial spondyloarthritis [25,26]. Fourth, the ASAS criteria set does not perform well for detecting recent-onset spondyloarthritis [26].…”

“…Sixth, the place of prominence given to the HLA-B27 antigen in the ASAS criteria might prompt inexperienced physicians to increase testing for this feature, perhaps to excessive levels, in patients with a small number of strictly subjective symptoms. In addition, HLA-B27 is not associated with spondyloarthritis in some populations, such as those from sub-Saharan Africa [25]. Thus, the ASAS criteria may have a limited ability to detect recent-onset spondyloarthritis, particularly in populations with a low prevalence of the HLA-B27 antigen and/or when MRI is not available [25,26].…”

“…In addition, HLA-B27 is not associated with spondyloarthritis in some populations, such as those from sub-Saharan Africa [25]. Thus, the ASAS criteria may have a limited ability to detect recent-onset spondyloarthritis, particularly in populations with a low prevalence of the HLA-B27 antigen and/or when MRI is not available [25,26].…”