Male smokers with HLA-B27 positivity, SI joints inflammation have more radiological damages and higher prevalence of AS while females have higher BASDAI scores: observations from cluster analyses of a group of SpA patients

Abstract

Abstract Objectives To describe the clinical characteristics and the relations with disease activity, functional status, and syndesmophytes formation in patients with axial spondyloarthritis (AxSpA) by categorizing them into different groups. Methods One hundred and sixty three patients with AxSpA were recruited. Clinical and blood parameters were collected. Patients were asked to complete the self-assessment questionnaires, Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), and Bath Ankylosing Spondylitis Functional Index (BASFI). Spinal mobility was measured according to Bath Ankylosing Spondylitis Metrology Index (BASMI). Radiographs of cervical and lumbosacral spine were performed for modified Stoke Ankylosing Spondylitis Spine Score (mSASSS). Radiological sacroiliitis was scored for ankylosing spondylitis (AS). Magnetic resonance imaging (MRI) of the sacroiliac (SI) joints was performed for spondyloarthritis research consortium of Canada (SPARCC) MRI inflammation score. Two-way cluster analyses were performed to determine the relationships between the parameters. Results Two cluster models were built using SPARCC scores of different scorers. Results were similar. The group of patients with highest mSASSS (20.33 vs 20.33) and prevalence radiological AS (85% vs 86%) were male patients (75% vs 75%), positive for HLA-B27 (70.0% vs 66.7%), smokers (87.5% vs 97.2%), and higher SPARCC SI joints score (5.32 vs 3.17). Higher BASDAI was observed among female sex. BASMI varies little but the group with highest BASMI (3.60 vs 3.62) also had highest mSASSS (20.33 vs 20.33). Conclusion Our data showed that male smokers with HLA-B27 positivity and SI joints inflammation have more radiological damage and higher prevalence of AS, consistent with known poor prognosis factors.