Comparison of clinical manifestations according to HLA-B(27) genotype in ankylosing spondylitis patients: real-world evidence from smart management system for spondyloarthritis

Abstract

Objective: The aim of this study was to set up a large, longitudinal and prospective database to compare the clinical manifestations in human leucocyte antigen (HLA)-B(27) positive and negative patients with ankylosing spondylitis(AS) based on real-world evidence in Chinese population. Methods: A total of 897 outpatients with confirmed AS were recruited consecutively by smart management system for spondyloarthritis (SMSP) from April 13, 2016 to June 6, 2017 in Chinese PLA General Hospital from 30 provinces and autonomous regions. 801 patients with HLA-B(27) data were included in the analysis. Demographic and clinical parameters including Bath ankylosing spondylitis disease activity index (BASDAI), Bath ankylosing spondylitis functional index (BASFI), ankylosing spondylitis disease activity score (ASDAS), arthritis, enthesitis, Bath ankylosing spondylitis metrology index (BASMI), erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were compared between HLA-B(27) positive and negative groups. Results: A total of 801 patients were included in the analysis with an average age of (30.7±8.8) years. There were 659 males and 142 females and HLA-B(27) was present in 88.0%(705/801). Males were significantly more in HLA-B(27) positive patients [83.3%(587/705) vs. 75.0%(72/96); P=0.047].The average age at disease onset was (22.3±7.6)years in HLA-B(27) positive patients and (24.4±8.7) years in HLA-B(2)7 negative ones (P=0.028).There was significant difference in diagnose delay between two groups [14.3(2.5,43.6)months in HLA-B(27) positive patients vs. 20.3(5.0,67.4) months in HLA-B(27) negative ones, P=0.041]. Anterior uveitis was found to be significantly more common in HLA-B(27) positive patients [18.9% (133/705)vs.7.3%(7/96),P=0.005], and knee involvement less common in HLA-B(27) positive patients [4.0%(27/682) vs.10.0%(9/90), P=0.010], conversely. CRP[6.5(3.0, 16.4)mg/L vs. 3.5(1.6, 12.3)mg/L] and ESR[11.0(4.0, 24.0)mm/1h vs. 7.0(3.0, 16.0)mm/1h] were significantly higher in HLA-B(27) positive patients(P=0.005,0.013, respectively).But no differences in BASDAI,ASDAS,BASFI and BASMI were obtained between two groups. Conclusions: HLA-B(27) positive patients had a higher proportion of males, a younger age of onset and a greater risk for occurrence of anterior uveitis, suggesting a poorer prognosis.