Diagnostic delay is associated with uveitis and inflammatory bowel disease in AS: a study of extra-musculoskeletal manifestations in SpA.

Objectives: To examine the prevalence of extra-musculoskeletal manifestations (EMM) and the association between diagnostic delay and their incidence in AS and PsA.

Methods: This was a retrospective, cohort study comprising two single centre cohorts in Europe and one multicentre cohort in Latin America (RESPONDIA). Crude prevalence of EMMs (uveitis, IBD and psoriasis) was calculated across geographic area and adjusted by direct standardization. Cox proportional hazard analysis was performed to assess the association between diagnostic delay and EMM incidence.

Results: Of 3553 patients, 2097 had AS and 1456 had PsA. The overall prevalence of uveitis was 22.9% (95% CI: 21.1, 24.8) in AS and 3.8% (95% CI: 2.9, 5.0) in PsA; 8.1% (95% CI: 7.0, 9.4) and 2.1% (1.3, 2.9), respectively, for IBD; and 11.0% (95% CI: 9.7, 12.4) and 94.6% (93.0, 95.9), respectively, for psoriasis. The EMM often presented before the arthritis (uveitis 45.1% and 33.3%, and IBD 37.4% and 70%, in AS and PsA, respectively). In the multivariable model, longer diagnostic delay (≥5 years) associated with more uveitis (hazard ratio [HR] 4.01; 95% CI: 3.23, 4.07) and IBD events (HR 1.85; 95% CI: 1.28, 2.67) in AS. Diagnostic delay was not significantly associated with uveitis (HR 1.57; 95% CI: 0.69, 3.59) or IBD events (HR 1.59; 95% CI: 0.39, 6.37) in PsA.

Conclusion: EMMs are more prevalent in AS than PsA and often present before the onset of the articular disease. A longer diagnostic delay is associated with the 'de novo' appearance of uveitis and IBD in AS, highlighting the need to enhance diagnostic strategies to shorten the time from first symptom to diagnosis in SpA.