Abstract 19 — Treat-to-Target in Spondyloarthritis (SpA): Are There Sex-Related Differential Responses?

Background: Studies have reported that female patients with spondyloarthritis have different disease courses and treatment responses compared to male patients. Whether patients’ sex is associated with a different outcome after receiving one-year of tight control, treat-to-target (T2T) strategy remains uncertain. Thus, this study aimed to evaluate the differences in the clinical response between male and female patients from the APLAR SpA Registry. Methods: Patients who fulfilled the CASPAR 2006 classification criteria for PsA and 2009 ASAS classification for axSpA were recruited. They received 1 year of protocolized treatment aiming at 1) MDA or DAPSA-LDA for PsA patients, and 2) ASDAS-LDA for axSpA patients. Patients were assessed every 3-monthly and treatment was escalated if target was not reached. Results: Ninety-one male (age: 45.6±16.1, 43 PsA, 48 axSpA) and 52 female (age: 49.2±13.4, 36 PsA, 16 axSpA) patients were included. There was no significant difference between the 2 sexes at baseline, except a higher ESR and more severe enthesitis in female patients. During the study period, the use of csDMARDs and NSAIDs decreased slightly, whilst the use of bDMARDs significantly increased across both sexes (Fig. 1a). Considering the whole cohort, there were significant improvement in disease activity in PsA after 1-year and disease activity in axSpA remained low. Despite similar bDMARDs use at 1-year, female PsA patients had a lower MDA achievement rate (36% in female vs 51% in male). Female patients also remained to have a higher physician global assessment score (2.61±1.76 in female vs 1.98±1.57 in male, p=0.03), greater functional impairment (HAQ: 0.54±0.57 in female vs 0.32±0.46 in male, p=0.01) and more severe enthesitis (SPARCC: 0.83±1.67 in female vs 0.16±1.09 in male, p=0.005) at 1-year. There was also a trend of higher perceived disease burden and peripheral involvement in female (Fig. 1b). Conclusion: There may be differential treat-to-target responses between male and female SpA patients. The causes of such differential characteristics should be further explored to potentially implement a sex-specific treat-to-target strategy for spondyloarthritis.