Degenerative changes of lumbar spine and their clinical implications in patients with axial spondyloarthritis.

The objective of this study was to assess degenerative changes (DCs) on magnetic resonance imaging (MRI) of lumbar spine in axial spondyloarthritis (axSpA) and non-specific mechanical low back pain (mLBP). Patients were consecutively recruited and all underwent MRI of the lumbar spine in this cross-sectional study. Disk degeneration (DD, Pfirrmann classification), endplate changes (Modic, types 1, 2, and 3), annular fissure, disk bulging, and protrusion or extrusion at each lumbar spinal level were assessed using anonymized images. Patients with axSpA were assessed for disease activity, functioning, and quality of life. Univariate and subsequent multivariate logistic regression analyses with adjustments of various covariates were used to assess association between MRI findings and clinical variables. One hundred twenty-three patients had non-radiographic (nr-axSpA) and 144 had radiographic axSpA/ankylosing spondylitis (AS). Degenerative changes were more prevalent in patients with mLBP (n = 105) than axSpA. Disk degeneration was the most prevalent MRI finding, followed by annular fissure, disk herniation (protrusion or extrusion), and Modic changes (MCs) in axSpA. Disk herniation was more prevalent in patients with nr-axSpA compared to AS. Modic changes (OR = 6.455), lumbar disk herniation (OR = 2.278), annular fissure (OR = 2.842), conventional synthetic or biologic disease-modifying antirheumatic drugs (csDMARDs) non-users (OR = 2.225), and advanced age (OR = 31.556) were factors associated with an increased risk of DD in axSpA. Coexisting DD increased the burden of disease in axSpA. A considerable proportion of patients with axSpA had DD at the lumbar spine. These degenerative changes might explain some of the complaints and should not been overlooked in patients with axSpA. Key Points • Lumbar herniated nucleus pulposus (LHNP) is more frequent in nr-axSpA while MC is more frequent in AS. • DD may cause an increase in BASFI and BASMI scores in axSpA. • Spinal DCs might be an alternative explanation for low back complaints and should not been overlooked in patients with axSpA.

Serum prolidase level in ankylosing spondylitis: low serum levels as a new potential gold standard biomarker for disease activity.

Ankylosing spondylitis (AS) is a chronic inflammatory disorder that mainly affects the sacroiliac joints and axial skeleton. The aim of this study was to assess serum prolidase level (SPL) and its association with disease activity in patients with AS. This prospective study included 75 AS patients. Thirty age- and gender-matched healthy controls were enrolled. AS patients were considered as active if BASDAI score was ≥4 or inactive if BASDAI score was <4. There were 34 AS patients in the active group and 41 AS patients in the inactive group. Anti-TNF-monoclonal antibody treatment was started in patients in the active group. These active patients were reassessed 6 months later. BASDAI, ASDAS, visual analogue scale, short-form-general health survey questionnaire, C-reactive protein, erythrocyte sedimentation rate and SPL were measured in all AS patients before and after treatment. The SPL was significantly lower in inactive AS patients than in control group, and also, SPL was significantly lower in active AS patients than in inactive patients. All activity parameters were successful in separating active and inactive AS patients. However, the only parameter that could distinguish active patients from inactive patients was prolidase. The optimum cutoff point of SPL to identify patients with active AS was 23.13 ng/mL with sensitivity, specificity, positive predictive value and negative predictive value of 100 %. Serum prolidase level was successful in measuring disease activity and had as high sensitivity and specificity as BASDAI and was superior to other activity parameters.