Comparison of non-radiographic axial spondyloarthritis and ankylosing spondylitis patients in Malaysia

Abstract

Aim of the workThis study aimed to compare the clinical features, associated comorbidities and treatment patterns of ankylosing spondylitis (AS) patient to those with non-radiographic axial spondyloarthritis (nr-axSpA) in Malaysia. Patients and methodsThis study was conducted in multiple rheumatology centre in Malaysia. Patients with axial spondyloarthritis (axSpA) were included. The AS and nr-axSpA group were compared. ResultsA total of 302 AS patients and 43 nr-axSpA patients were included. The age was comparable (41.7 ± 12.4 vs 38.5 ± 14.3 years; p = 0.13) however the male:female in those with AS was 4.8:1 vs 1.2:1 (p < 0.0001). The diagnostic delay was longer in AS patients (6.04 ± 6.6 vs 3.4 ± 7.3; p = 0.03), more were frequently smoking (50.3 % vs 25.6 %; p = 0.003), were Chinese (56.6 % vs 37.2 %; p = 0.02), had a higher frequency of HLA-B27 (p < 0.0001) and family history of axSpA (p = 0.04).More AS patients experienced inflammatory back pain (p < 0.0001), had higher Bath AS Metrology Index (BASMI) (p < 0.0001) and Bath AS functional index (BASFI) (p = 0.04). Nr-axSpA patients more likely to experience dactylitis (16.3 % vs 5.6 %; p = 0.014) but no significant differences in frequency of enthesitis. The frequency of comorbidities was similar in both groups. The use of non steroidal anti inflammatory drugs was more frequent in AS (p = 0.038) while nr-axSpA patients more likely to receive conventional disease modifying antirheumatic drug (p = 0.002). ConclusionAS and nr-axSpA shared some characteristics but also had some significant difference especially on gender, inflammatory back pain and HLA-B27. This study offers a better understanding of both the subtypes of axSpA in Malaysia.