Delayed diagnosis is linked to worse outcomes and unfavourable treatment responses in patients with axial spondyloarthritis.

The diagnosis of spondyloarthritis (SpA) has a lengthy delay; we investigated the outcomes and factors associated with the delayed diagnosis of SpA. This was a cross-sectional study on patients with SpA who visited a rheumatology clinic at a single tertiary centre. The data were collected from face-to-face interviews, physician assessments of disease status and reviews of medical records. In total, 105 patients with SpA were consecutively enrolled. Of the included patients, 94 had axial SpA and 11 had peripheral SpA. The median diagnostic delay was 8 years (interquartile range, 3-14) for axial SpA. Comparisons between the early and late diagnosis groups were performed to identify the factors related to delayed diagnosis in axial SpA. A definite diagnosis of SpA led to proper management and clinical improvements. The patients with delayed diagnosis showed worse outcomes in disease activity, function, spinal mobility and/or radiographic damage. These patients also demonstrated a less favourable treatment response according to the Bath Ankylosing Spondylitis Disease Activity Index and the rate of radiographic progression. Multivariate analysis indicated that a prior diagnosis of mechanical back pain was an independent factor associated with diagnostic delay. The diagnosis of SpA is often delayed. Delayed diagnosis is associated with worse outcomes and poor treatment responses in SpA patients. Physician and patient awareness of inflammatory back pain are essential for the early diagnosis of SpA, and a referral guideline for patients with suspected SpA is needed.