Objectives: To investigate the longitudinal relationship between inflammatory lesions in sacroiliac joints on MRI (MRI-SI) and clinical disease activity measures (DA) in patients with axial spondyloarthritis (axSpA).
Methods: Two-year follow-up data from 167 patients (50% males, mean (SD) age 33 (9) years) fulfilling the Assessment of SpondyloArthritis international Society axSpA criteria in the DEvenir des Spondylarthopathies Indifférenciées Récentes cohort with MRI-SI at baseline, 1 year and 2 years were analysed. The relationship between MRI-SI (as dependent variable) and DA (Ankylosing Spondylitis Disease Activity Score (ASDAS), Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), patient's global DA, night pain, C reactive protein and erythrocyte sedimentation rate, as independent variables) was investigated using two types of generalised estimating equations (GEE) models: model of absolute scores and model of change scores.
Results: In the model of absolute scores, the relationship between DA and MRI-SI was different for males and females: in males, but not in females, a statistically significant relationship with MRI-SI was found for all DA except BASDAI. In the model of changes, only ASDAS (beta (95% CI): 2.79 (0.85 to 4.73) and pain at night (0.97 (0.04 to 1.90)) were significantly associated in males while again in females no significant relationship was found. ASDAS fitted the data best.
Conclusions: In male patients, but not in female patients, with axSpA, clinical DA, especially if measured by ASDAS, is longitudinally associated with MRI-SI inflammatory lesions.
Keywords: Ankylosing Spondylitis; Inflammation; Spondyloarthritis.
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