Longer Diagnostic Delay Associated With Greater Incidence of Uveitis, IBD in AS

Extra-musculoskeletal manifestations (EMM), including uveitis and inflammatory bowel disease (IBD), may be more common in patients with ankylosing spondylitis (AS) who experience longer diagnostic delays than in those with psoriatic arthritis (PsA), according to study results published in Rheumatology (Oxford).

Ankylosing spondylitis and PsA share common characteristics, including EMMs such as uveitis and IBD.

Researchers aimed to assess the prevalence of EMMs in patients with AS and PsA and whether diagnostic delay influences their presence.

Data were collected from 2 single-center European cohorts and 1 Latin American multicenter cohort. Adult patients with a diagnosis of AS or PsA were included in the analysis. Cox proportional hazards were used to examine the association between diagnostic delay (defined as time between onset of musculoskeletal symptoms and disease diagnosis) and incidence of EMM.

A total of 3553 patients were included in the study (2097 with AS and 1456 with PsA). Patients in the Latin American cohort with AS were younger and had shorter disease duration than those in the European cohort. Diagnostic delay was similar among both cohorts.

The prevalence of uveitis vs IBD in the AS and PsA cohorts was 22.9% (95% CI, 21.1-24.8) and 3.8% (95% CI, 2.9-5.0) vs 8.1% (95% CI, 7.0-9.4) and 2.1 (95% CI, 1.3-2.9), respectively.

Overall, prevalence of EMMs was more common in patients with AS vs PsA (28.9% vs 5.8%).

For uveitis, 45.1% of patients with AS vs 33.3% of patients with PsA reported their first episode occurring before the diagnosis. In addition, 37.4% of patients report being diagnosed with IBD before AS, while 70% of patients with IBD and PsA report being diagnosed with IBD before AS.

Patients with AS with a diagnostic delay of at least 5 years reported more episodes of uveitis (hazard ratio [HR], 4.01) and IBD (HR, 1.85). This association was not observed among patients with PsA.

The study was limited by measurement bias because EMM characteristics were collected from clinical notes and patients’ memories. In addition, patient inclusion in the study was determined by clinician diagnosis instead of validated criteria.

Researchers noted, “Our results show that, despite some differences in demographic factors, the prevalence of uveitis and IBD is higher in AS when compared to PsA.”

“A longer diagnostic delay is associated with a greater probability of uveitis and IBD in AS, perhaps due to uncontrolled inflammation over time. These results highlight the need for multi-specialty collaboration to improve diagnostic strategies and referral pathways in order to reduce diagnostic delay in [spondyloarthritis].” they concluded.