INTRODUCTION: Axial spondyloarthritis (axSpA) is a chronic inflammatory condition associated with considerable pain and impaired health-related quality of life (HRQoL) for affected patients. Despite the documented increase in healthcare resource utilization (HRU) related to axSpA, few studies have explored the impact of diagnostic delays on these outcomes. This study sought to determine the association between diagnostic delay of axial spondyloarthritis (axSpA) and costs in the 3 years after diagnosis. METHODS: This is a retrospective, observational study based on routine follow-up data from adult patients with confirmed axSpA diagnosis in three tertiary Spanish hospitals. Sociodemographic and clinical variables were collected at diagnosis. Direct and indirect healthcare costs were estimated from healthcare resource use (HRU) and productivity losses. The correlation between diagnostic delay and total healthcare costs was analyzed. RESULTS: Eighty-two patients (62.2% men
mean age: 39.3 years at diagnosis) were included, mostly with radiographic axSpA (r-axSpA) (67.1%). The mean (standard deviation, SD) diagnostic delay was 10.1 (9.3) years, with a median (interquartile range, IQR) of 5.4 (2.3, 17.2) years. The mean total healthcare cost per patient accumulated over 3 years was €25,812.6 (direct: €16,384.7
indirect: €9427.9). Patients with longer diagnostic delay (>
5.4 years) had 57% higher total healthcare cost (€31,717.7 vs. €20,188.7, p = 0.029) and higher disease activity at diagnosis (BASDAI score 4.7 vs. 3.4, p = 0.007) and after 3 years (3.9 vs. 2.9, p = 0.042) compared to those with shorter delay (≤ 5.4 years). CONCLUSIONS: The diagnostic delay in axSpA remains high and is associated with an increase in healthcare costs post-diagnosis. Actions to reduce diagnostic delay should be prioritized by healthcare systems to potentially improve outcomes and reduce long-term costs.