medwireNews: Researchers have identified factors that may signal increased axial spondyloarthritis (axSpA) risk among family members of patients with ankylosing spondylitis (AS), including the presence of acute anterior uveitis (AAU).
This family study spanning 35 years represents “the longest longitudinal study in axSpA to date,” say Sjef van der Linden (University of Bern, Switzerland) and co-authors.
They evaluated data from 360 first-degree relatives of 125 patients with AS who underwent clinical examination in 1985 and completed a follow-up questionnaire about axSpA features in 2018–2019.
In all, 25.9% of the 162 relatives with human leukocyte antigen B27 (HLA-B27) positivity developed axSpA (either AS or nonradiographic axSpA) during follow-up. This compared with just 0.7% of the 141 HLA-B27-negative relatives of HLA-B27-positive probands, and 3.4% of the 29 HLA-B27-negative relatives of HLA-B27-negative probands.
Overall, relatives who developed axSpA were significantly more likely to report symptoms suggestive of AAU (≤1 episode of unilateral painful inflamed red eye and prescription of steroid eye drops) than those who did not, at rates of 38.2% versus 11.6% and an odds ratio (OR) of 4.74. The researchers note that the prevalence of AAU in relatives was similar to that in HLA-B27-positive probands with AS (38.2 vs 44.3%).
These findings suggest that “[o]ccurrence of AAU among [relatives] of patients with axSpA calls for screening for the disease,” say van der Linden and team.
They also evaluated whether pain symptoms were associated with axSpA risk among the relatives, finding that having chronic inflammatory back pain at baseline was not a significant predictor. However, a combination of chronic inflammatory back pain and pain/discomfort in the thoracic spine and the anterior chest wall predicted axSpA with 83.1% sensitivity and 87.2% specificity.
“Paying attention to prevailing symptoms of pain and discomfort at the thoracic spine and the frontal chest wall in addition to [chronic inflammatory back pain] may improve the diagnostic yield and classification of axSpA,” write the researchers in the Annals of the Rheumatic Diseases.
They note, however, that “this triad needs to be fully validated as a potential diagnostic tool.”
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