Assessing the difference between radiographic and non-radiographic axial spondylarthritis in Mexican patients: The influence of clinical, demographic, laboratory and clinimetric features

Abstract Introduction/Objectives To compare the demographic, clinical, and laboratory characteristics, disease onset, and clinical features of radiographic axial Spondyloarthritis (r-AxSpA) and non-radiographic axial Spondyloarthritis (nr-AxSpA) patients. Method All patients who attended outpatient spondylarthritis clinics at Hospital General de Mexico and the Instituto Nacional de la Nutrición, from 1998 to 2005, and met the spondyloarthropathies study group criteria (EESG) were included. In addition, patients were reclassified according to The Assessment of SpondyloArthritis international Society (ASAS) criteria. We selected patients with nr-AxSpA and r-AxSpA and compared clinical, demographic, and clinimetric variables. Results 148 Mexican patients were included. 55 (37.2%) patients had r-AxSpA, and 70 (47.3%) had nr-AxSpA. Nr-AxSpA patients had a lower proportion of males (58.6% vs 78.2%, P < 0.05), lower HLA-B27 frequency (54.3%. vs. 92.7%, P < 0.05), older at disease onset (21 vs 16 years; P < 0.01), a higher frequency of infections at disease onset (32.9 .vs 9.1%, P < 0.05) than r-AxSpA. Logistic regression showed that the factors that most influenced the presentation of r-AxSpA were history of uveitis (OR 14, 95% CI 2.3 – 85), HLA-B27 (OR 7.97, 95% CI, 2.96 – 122), gender (male) (OR 6.16, 95% CI, 1.47 – 25.7), axial enthesopathy count (OR 1.17 95% CI, 1.03 – 1.33). Conclusions This study provides insight into the differences between nr-AxSpA and r- axSpA. Patients with r-AxSpA were mainly male, with a younger presentation age, a higher prevalence of HLA-B27, more history of uveitis, fewer episodes of dactylitis, more axial enthesopathy, and higher disease activity.