The risk of developing ankylosing spondylitis is significantly higher following past episodes of anterior uveitis, a type of eye inflammation, according to researchers.
This finding emphasizes the importance of a multidisciplinary approach in the diagnosis and management of ankylosing spondylitis (AS).
The study, “Recurrent anterior uveitis and subsequent incidence of ankylosing spondylitis: a nationwide cohort study from 2002 to 2013,” was published in the journal Arthritis Research and Therapy.
Anterior uveitis, which is defined as the inflammation of the middle layer of the eye, including the iris, occurs in about a quarter of AS patients and is considered the most common extra-articular (outside the joints) manifestation of the disease.
Despite this association, no conclusive studies have been conducted to provide a quantitative risk assessment of subsequent ankylosing spondylitis in patients with uveitis.
South Korean researchers analyzed data from the Korean National Health Insurance Service based on claims submitted by healthcare providers from 2002 to 2013.
Data from 10,483 patients with newly developed anterior uveitis and 52,415 people without uveitis (matched controls) was used to calculate incidence rates of AS using the number of uveitis episodes. Risk ratios were determined based on the incidence rates from the control group.
Researchers also identified a subgroup of patients with recurrent uveitis — defined as a 120-day interval between consecutive uveitis reports — who were treated with steroids or immune-modifying drugs.
Anterior uveitis and ankylosing spondylitis development were assessed using the appropriate International Classification of Disease (ICD) codes. However, an active uveitis episode was defined using the ICD code in addition to a prescription for either steroids or immunosuppressive agents.
Out of the 10,483 patients in the “all uveitis” group, 2,038 were found to have recurrent uveitis. From the “all uveitis” group, 0.54% subsequently developed ankylosing spondylitis.
Statistical analyses showed there was a significant risk of AS in the recurrent uveitis group compared to controls, with 1.03% and 0.08% developing AS, respectively. The median interval between the first episode of uveitis and the development of AS was about two years.
Taken together, the results indicate that the incidence rate of ankylosing spondylitis increases 7.4-fold after one uveitis episode and 17.7-fold after two episodes.
The researchers concluded that “the incidence of ankylosing spondylitis increased proportionally with the number of episodes of uveitis.”
Therefore, the study “emphasizes the importance of multidisciplinary collaboration in the diagnosis and management of ankylosing spondylitis,” they wrote.