Newly diagnosed cases of AS at increased risk for IMIDs, lower risk for RA
Newly diagnosed patients with ankylosing spondylitis in Taiwan demonstrate increased risks for multiple immune-mediated inflammatory diseases, including acute anterior uveitis, psoriasis, thromboangiitis obliterans, Behcet’s disease and sarcoidosis, according to findings published in Arthritis Research & Therapy.
“In recent years, AS has been considered as a prototype of spondyloarthritis (SpA) that has been found to be associated with other [immune-mediated inflammatory diseases (IMIDs)] with shared immunopathogenesis referred to as extra-articular manifestations,” Hsin-Hua Chen, MD, PhD, of Taichung Veterans General Hospital, in Taiwan, and colleagues wrote. “Among the SpA concept-related extra-articular manifestations, acute anterior uveitis (AAU), psoriasis and inflammatory bowel disease (IBD), including Crohn’s disease (CD) and ulcerative colitis (UC), are most strongly associated with AS.”
“Several previous epidemiological studies reported the incidence and prevalence of extra-articular manifestations among AS patients,” they added. “However, to our knowledge, no prior study had concurrently assessed the risks of developing various IMIDs in addition to SpA concept-related IMIDs (ie, AAU, psoriasis, CD and UC) among AS patients.”
To assess the risk of IMIDs among patients with AS, Chen and colleagues studied 2003 to 2012 claims data from the Taiwanese National Health Insurance Research Database. The researchers identified 30,911 patients with newly diagnosed AS who required medical treatment from 2006 to 2012, as well as 309,110 randomly selected individuals without AS, who were matched based on age, sex and index year. Individuals with corresponding prior IMIDs were excluded from the study.
The researchers calculated incidence rates of multiple IMIDs in both the AS and non-AS groups, and estimated HRs with 95% confidence intervals after adjusting for age, sex, the Charlson comorbidity index, the frequency of ambulatory visits during the follow-up period and medications. Sensitivity analyses were conducted through excluding individuals who demonstrated IMIDs within three months following their index date.
According to the researchers, patients in the AS group demonstrated a significantly increased risk for acute anterior uveitis, psoriasis, Sjögren’s syndrome, thromboangiitis obliterans, Behcet’s disease and sarcoidosis. However, this increased risk for Sjögren’s syndrome was not present in the sensitivity analysis. In addition, there was no significant differences in the risks for Crohn’s disease, ulcerative colitis, systemic lupus erythematosus, systemic sclerosis, dermatomyositis, polymyositis, pemphigus and vitiligo between the two groups. Lastly, patients with AS had a significantly reduced risk for rheumatoid arthritis.
“These significant associations indicate potential shared or distinct genetic, pathogenic and clinical relationships between AS and these IMIDs and also suggest that physicians should survey symptoms and signs related to the positively correlated IMIDs when managing AS patients,” Chen and colleagues wrote. “Further clinical, genetic and pathogenic studies are also necessary to elucidate the role of AS in the development of uveitis, psoriasis, [thromboangiitis obliterans], [Behcet’s disease] and sarcoidosis and to identify the risk factors or predictors.” – by Jason LadayDisclosure: The researchers report no relevant financial disclosures.