RESUMO
Objective:To explore the clinical characteristics of adult-onset non-radiographic axial spondyloarthritis (nr-axSpA) in different genders.Methods:A total of 662 patients with adult-onset nr-axSpA (age at disease onset ≥16 years) who visited the Rheumatology Department of the First Affiliated Hospital of Shantou University Medical College from 1999 to 2020 were included in the study. Comparisons of baseline demographic and clinical characteristics between different genders were performed.Results:Overall, the male-to-female ratio was 1.17∶1, and the prevalence of human leukocyte antigen-B27 (HLA-B27) positivity was 71.8%(475/662). The median baseline disease duration and age at diagnosis was 1.6 (0.5, 4.0) years and 25.0 (21.0, 33.0) years respectively. The males had a significantly earlier age at disease onset and diagnosis [21.0 (18.0, 28.0) vs 25.0 (21.0, 30.0), Z=5.63, P<0.001; 24.0 (19.0, 32.0) vs 27.0 (23.0, 34.5), Z=4.90, P<0.001, respectively] than females. HLA-B27 positivity was more frequent in males than in females [78.4% (280/357) vs 63.9%(195/305), χ2=17.06, P<0.001]. The prevalence of inflammatory back pain (IBP), morning stiffness, nocturnal pain, enthesitis, hip and groin pain were higher in males, whereas females showed a higher prevalence of small joint involvement of the hands. At baseline, males had higher median ankylosing spondylitis disease activity score (ASDAS)-C-reaction protein (CRP) [3.0(2.3, 3.8) vs 2.4(2.0, 3.0), Z=5.59, P<0.001] and a greater prevalence of high disease activity ASDAS-CRP>2.1 [81.9%(185/227) vs 67.9%(133/195), χ2=11.08, P=0.001] than females. The proportions of male patients with elevated CRP levels and erythrocyte sedimentation rate (ESR) were also higher than those of female patients [49.0%(175/357) vs 27.9%(85/305), χ2=30.85, P<0.001; 49.3%(176/357) vs 33.4%(102/305), χ2=16.98, P<0.001, respectively]. Conclusion:The adult-onset nr-axSpA in China is characterized by a comparable sex ratio. Males have an earlier age at disease onset and are higher HLA-B27 positivity with higher prevalence of IBP, enthesitis, hip and groin pain, as well as high disease activity.