Which Metrological Index, the BASMI or EDASMI, is Best Correlated with Disease-Related Parameters in Spondylarthritis Patients?

Abstract

This study aimed at comparing the Edmonton Ankylosing Spondylitis Metrology Index (EDASMI) and Bath Ankylosing Spondylitis Metrology Index (BASMI) to determine which of the two is best correlated with disease-related parameters in axial spondyloarthritis (axSpA) patients. A cross-sectional study was carried out involving 86 patients with radiographic axSpA. Sociodemographic data, the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), the Ankylosing Spondylitis Disease Activity Score (ASDAS), the Bath Ankylosing Spondylitis Functional Index (BASFI), and the Ankylosing Spondylitis Quality of Life (ASQoL) questionnaire were applied. Spinal mobility was assessed by two indices: the BASMI and the EDASMI. Structural damage of the spine was also evaluated by two indices: the Bath Ankylosing Spondylitis Radiology Index (BASRI) and the modified Stoke Ankylosing Spondylitis Spine Score (mSASSS). Eighty-six patients with an average age of 43.21 ± 11.43 years (20-79) were included. Impaired spinal mobility, which corresponds to higher BASMI scores, was correlated with prolonged disease duration (p < 0.01, r = 0.310), higher ASDAS-CRP (p < 0.001, r = 0.386), severe functional disability on the BASFI (p < 0.01, r = 0.505) and poorer quality of life according to the ASQoL (p < 0.01, r = 0.369). However, the EDASMI score did not correlate with any disease parameter. The BASMI was correlated with the total BASRI (p < 0.01, r = 0.634) and mSASSS (p < 0.01, r = 0.388). Unlike the BASMI, the EDASMI was neither correlated with the BASRI (p = 0.520, r = 0.245) nor the mSASSS (p = 0.252, r = -0.120). Our results indicate that among the studied metrological indices, the BASMI is more contributory since it is correlated with clinical disease parameters and structural damage, unlike the EDASMI.