Background The association of axial involvement with peripheral arthritis activity and skin lesion severity in early psoriatic arthritis (ePsA) patients (pts) has not been studied properly.
Objectives to study the prevalence of axial involvement detected by magnetic resonance imaging (MRI) and X-ray of sacroiliac joints (SIJs) and its correlation with peripheral arthritis activity and skin lesion severity in peripheral ePsA pts.
Methods 89 pts (M/F–42 /47) with peripheral ePsA according to CASPAR criteria were included; mean age 36.5±10.9 yrs, disease duration 12.1±10.1 mo., disease activity index (DAS)28 8.8±1.7, patient's pain VAS 55.0±17.9, patient's global disease activity VAS 56.9±17.1, C-RP16.1 [6.6; 31.0] mg/l, ESR 22.5±19.2 mm/h. All patients were evaluated for the presence of inflammatory back pain (IBP) by ASAS criteria. In pts having IBP disease activity was measured by BASDAI. The examination included X-ray of sacroiliac joints (SIJs), HLA B27 antigen, MRI of SIJs was performed in 79 pts, both with and without IBP, on Signa Ovation 0,35T. Bone marrow edema on MRI (STIR), considered as active MRI sacroiliitis (MRI-SI), was evaluated by an independent reader. Radiographic sacroiliitis (R-SI) was defined at 2 grade changes, at least in one SIJ, while definite radiographic SI (dR-SI) was considered according to New York criteria (unilateral grade ≥3 or bilateral grade ≥2). Skin lesion area was measured according to BSA. BSA >10% was defined as extensive.
Results IBP was found in 58 out of 89 (65.1%) pts, 35 (60.3%) of them had short-term (episodic) IBP, and 23 (39.7%) pts had long-term IBP. MRI-SI was observed in 28 out of 79 (35.4%) pts. R-SI was determined in 42 out of 89 (47.2%) pts, while dR-SI was found in 27 out of 89 (30.3%) pts. 34 (38. 2%) pts were HLA-B27 positive. In pts having IBP disease activity by BASDAI was 4.5±1.6. An association was detected between the presence of MRI-SI and activity of peripheral arthritis by DAS28 (r=0.25; p=0.03). Correlation was detected between the presence of MRI-SI and the value of patient's global disease activity (r=0.23; p=0.047) as well as patient's pain (r=0.31; p=0.007). An association was found between the presence of MRI-SI and the skin lesion area. Among the group of 28 pts with MRI-SI, 6 (21.0%) pts had an extensive skin lesion area, while out of the group of 51 pts without MRI-SI only 2 (4.0%) pts had an extensive skin lesion area (p=0.033). A positive trend has been found between the presence of R-SI and erosive arthritis of hands and feet. Among the 42 pts having R-SI erosive arthritis was found in 18 (43.2%) pts while in 47 pts without R-SI–in 11 (23.9%) pts (p=0.06).
Conclusions in the Russian cohort of early peripheral PsA pts, careful examination quite often revealed high prevalence of axial involvement. Active inflammation of the SIJ detected by MRI (in 35% of pts) is more often found in pts with higher peripheral arthritis activity measured by DAS28, with higher values of patient's pain /patient's global disease activity, with more extensive skin lesion area. There is a tendency that pts with more severe (erosive) peripheral arthritis more often develop R-SI.
Disclosure of Interest None declared
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