Radiographic axial versus nonradiographic axial spondyloarthritis: Comparison of the disease activity parameters and the disease activity and functional scores: RBSMR study

Abstract

Background: A new terminology based on the Assessment of SpondyloArthritis International Society (ASAS) 2009 classification criteria has been proposed to describe the phenotype of patients with axial spondyloarthritis (axSpA). This classification defines two subgroups: radiographic axial spondyloarthritis (r-axSpA) patients and non-radiographic axial spondyloarthritis (nr-axSpA) patients. Methods and findings: The aim of this study is to describe and analyse the differences and the similarities between r-axSpA and nr-axSpA concerning the demographic and clinical characteristics of patients and the disease features according to the Moroccan registry of biological therapies in rheumatic diseases RBSMR (Registre des Biotherapies de la Societe Marocaine de Rhumatologie) database. A cross-sectional, multicenter and analytical study based on the RBSMR registry database, which included 194 patients with SpA, among them 186 patients had axSpA fulfilling the 2009 ASAS criteria with 170 patients having r-axSpA and 16 patients having nr-axSpA. The demographic characteristics and the disease features were compared using descriptive statistics. Among 186 patients having axSpA, 91.4% had r-axSpA and 8.6% had nr-axSpA. The two subgroups shared respectively similar demographic characteristics with a mean age at 39 versus 38.5 years and had male gender predominance. We didn’t find significant differences between the two subgroups concerning the disease features which are the disease duration, the HLA B27, the family history of SpA, the extra-articular manifestations (uveitis and inflammatory bowel disease), the peripheral arthritis, the visual analogue scale for fatigue (VAS-F), the Schober’s test, the radiographic and ultrasonographic coxitis, except for the psoriasis which was significantly more frequent in patient with r-axSpA (p=0.027). We didn’t note significant differences between the two subgroups concerning the disease activity (erythrocyte sedimentation rate, C-reactive protein) parameters and the disease activity (BASDAI, ASDAS-CRP) and functional (BASFI) scores. Conclusions: Our study didn’t find significant differences in the demographic, clinical characteristics of the patients and the disease features between the two subgroups r-axSpA versus nr-axSpA included in the Moroccan biotherapy registry RBSMR except for the psoriasis which was significantly more frequent in r-axSpA patients. These results differ from those reported in the literature because the registry included only the severe forms of SpA, which were referred to tertiary centers for treatment by biotherapy.