Clinical profile and treatment utilisation based on HLA-B*27 status in axial spondyloarthritis: results from ASAS-PerSpA study

OBJECTIVE: We aimed to characterize differences of clinical features, extra-musculoskeletal manifestations and treatment utilizations based on the patients’ HLA-B*27 status in a global axSpA cohort and identify predictors of HLA-B*27 negativity in these patients. METHODOLOGY: In post-hoc analysis of the ASAS-PerSpA study, patients fulfilling the 2009 ASAS classification criteria for axSpA and typed for HLA-B*27 were included. The patient characteristics cwere compared between the HLA-B*27(+) and HLA-B*27(-) subgroups. Multivariablete logistic regression was conducted to identify predictors of HLA-B*27 negativity. RESULTS: Of 2910 patients with axSpA from 24 countries, 2269 were tested for HLA-B*27 [1753 HLA-B*27(+) and 516 HLA-B*27(-)]. The proportion of males was higher in the HLA-B*27 (+) compared to the HLA-B*27 (-) subgroup (72.1 vs 54.3%). Patient population with HLA-B*27 (+) more often had positive family history for axSpA (29.8 vs 15.3%), and younger age at diagnosis, 31.6 years (SD 10.9) vs 37.7 years (SD 12.1). HLA-B*27 (-) patients had significantly higher peripheral arthritis (47.5 vs 42.1%, p<0.05), psoriasis (19.4 vs 10.2), enthesitis (56.6 vs 49.8%) and IBD (12.8 vs 3.4) (p<0.001). The exposure to csDMARDS in HLA-B*27 (-) patients was higher (61.2 vs 55.0%, p< 0.05). On multivariable analysis, HLA-B*27 (-) status was positively associated with enthesitis, psoriasis and IBD with an OR 1.27 (1.02-1.57), 1.84 (1.36-2.48) and 4.84 (3.23-7.30) respectively, and inversely associated with uveitis, OR 0.37 (0.27-0.50). CONCLUSION: HLA-B*27 (-) axSpA patients had a longer delay in diagnosis, more frequently had peripheral arthritis, enthesitis, IBD, psoriasis, and were more often treated with csDMARDs compared to HLA-B*27 (+) subgroup.