Background/Purpose: Recent data suggest differences between men and women with axial spondyloarthritis (axSpA), in terms of disease activity, disease progression and treatment response [1-3]. Overall, women tend to show higher perceived disease activity (mostly on the Bath Ankylosing Spondylitis Disease Activity Index: BASDAI) and extra-articular manifestations (mostly enthesitis), whereas men with axSpA tend to show more structural progression [2-3]. The objective of this study was to determine gender differences in disease activity in recent axSpA over 6 years of follow-up.

Methods: We analysed data collected during the first 6 years of follow-up of the prospective national multicentric DESIR cohort for patients with early inflammatory back pain suggestive of axial SpA and fulfilling the ASAS classification criteria for axSpA at any time (1) (n= 494). Self-reported gender was collected at baseline. Three main outcomes were compared between men and women: ASDAS-CRP (to assess disease activity), patient global assessment (PGA: ranging from 0-10), and CRP. To compare genders longitudinally and account for repeated measures over time (mo 6, 12, 18, 24, 36, 48, 60 and 72), a linear mixed-effect model analysis (LMM) was performed (using lme4 R package) with gender and time as fixed effects and subjects as random effect. There was no imputation of missing data.

Results: Of 708 at baseline, 494 patients (70%) were analysed: mean age was 31.9±7.5 years, mean disease duration 20.7±11.7 months; 50.4% were men. At baseline, mean ASDAS-CRP score was 2.6±1.0 in men versus 2.6± 0.9 in women (p=0.75), mean PGA score was 4.6±2.6 and 5.2±2.6 (p< 0.0001) and mean CRP was 10.7 ± 16.5 and 6.2 ± 8.3 (p< 0.0001) respectively. Over time, ASDAS-CRP, PGA and CRP all decreased in both men and women. However, there was more decrease in all aspects in men than women (Figure 1). The difference was significant in LMM for ASDAS-CRP and PGA (both p< 0.0001) but not for CRP (p=0.089). As an illustration, the mean ASDAS-CRP score was 1.8±1.0 in men versus 2.3±0.9 in women at 6 years, with mean PGA score of 2.9±2.6 versus 4.2±2.7 respectively.

Conclusion: Although disease activity was similar between genders at baseline, there were more improvements in all aspects of disease in men than in women over 6 years of follow-up, leading to higher disease activity and symptoms in women at 6 years, with similar CRP levels. Further research is needed to explore differences in disease activity between genders using imaging data. Gender is an important contextual factor in axSpA and should be taken into account.

References
[1] Tournadre A et al. Arthritis Care Res 2013;65:1482–9.
[2] Rusman T et al. Rheumatol Oxf Engl 2020;59:iv38–46.
[3] De Jong H et al. Scand J Rheumatol 2020;49:28–32.

ACR Meeting Abstracts - https://acrabstracts.org/abstract/is-there-a-difference-in-disease-activity-between-genders-in-axial-spondyloarthritis-6-year-longitudinal-data-from-a-large-national-cohort/