CLINICAL PROFILE OF PATIENTS WITH EARLY AXIAL SPONDYLOARTHRITIS (RUSSIAN COHORT OF PATIENTS)

Abstract

Objective: to study clinical manifestations of axial spondyloarthritis (axSpA) fulfilling ASAS criteria and to evaluate Russian version of modified New York criteria for the diagnosis of AS in Russian patients. Subjects and methods . Authors examined 73 patients aged 18–45 years suffering from inflammatory back pain for a period from 3 months to 5 years. BASDAI and ASDAS-CRP were used to assess activity, whereas BASFI – to evaluate functional status. Examination included: assessment of HLA-B27 rate, X-ray of pelvis and lumbar spine, ultrasonography of hip joints and calcaneal regions, magnetic-resonance imaging (MRI) of sacroiliac joints, lumbar spine and hip joints (if clinical signs of injury are present), densitometry of lumbar spine (LII–IV) and femoral neck. Results . Mean age of patients was 28.3±6.4 years, mean duration of disease – 19.9±14.4 months. HLA-B27 was found in 94.5% of patients. Mean BASDAI value was 4.1±1.9; ASDAS – 2.7±1.3; BASFI – 2.6±2.1. Peripheral arthritis was observed in 65.8% of cases, coxitis – in 31.5%, calcaneal enthesitis – in 61.6%, dactylitis – in 19.2%, low bone mineral density – in 17.8%. MRI showed inflammatory changes of axial skeleton in 84.9% of patients, active sacroiliitis (SI) – in 72.6%. X-ray revealed definite SI in 49.3% of patients («classic» AS). According to MRI data, 30.1% of patients with active SI and without structural changes of sacroiliac joints had pre-radiological stage of AS (by Russian version of modified New York criteria). 74.0% of patients fulfilled both sets of ASAS criteria for axSpA, 5.5% – met only I criteria set, whereas 20.5% – only II criteria set. Three groups of patients were defined. The first included patients with radiologically proven SI, the second – with MRI-proven SI and the third – patients without SI. Significant difference between the groups was detected either by gender (number of males in groups I and II exceeded that in group III: p1–3=0.002, p2–=0.033) or by the rate of high activity according to ASDAS index (observed in groups I and II more frequently than in group III; p=0.02 in both cases) or by presence of inflammatory changes in spine in MRI scans (detected in 26% of patients of group III, not detected in patients of group II; p=0.05). Conclusion. Half of patients with axSpA symptoms longer than 20 months already have structural changes in sacroiliac joints, so they can be diagnosed as «classic» AS. 80% of patients who had axSpA for less than 5 years match the description of AS provided by Russian version of modified New York criteria; one third of them has pre-radiological stage of disease. Number of males with radiologically proven SI and MRI-proven SI was larger than that of patients without SI. SI is often accompanied with high activity according to ASDAS. MRI showed that, inflammatory processes in spine may precede active SI. No clinical differences were revealed between patients with radiogically proven AS and pre-radiological stage of AS described by Russian version of modified New York criteria.