Background Relationship between inflammatory lesions on magnetic resonance imaging (MRI) and clinical disease activity measures is still unclear in patients (pts) with spondyloarthritis (SpA). In some studies MRI sacroiliac joints (SIJ) scores correlated negatively with the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) , but correlated neither with the Ankylosing Spondylitis Disease Activity Score (ASDAS) nor C-reactive protein (CRP) level. Another study showed a positive correlation between BASDAI and Spondyloarthritis Research Consortium of Canada (SPARCC) score .
Objectives To evaluate the disease activity and correlations between clinical indices, CRP, erythrocyte sedimentation rate (ESR) and SPARCC MRI score in SpA.
Methods 67 SpA pts (23 - axial (according to Assessment of Spondyloarthritis International Society (ASAS) 2009 criteria) and 44 – peripheral (according to ASAS 2011 criteria)) consulting a clinic for the first time were included. Mean age of pts (68.7% male) was 36.6+10.7, 88.4% of 43 pts were HLA-B27 positive. BASDAI (mm), Bath Ankylosing Spondilitis Functional Index (BASFI, mm), ASDAS, CRP (mg/l), ESR (mm/hr) and SPARCC MRI SIJ score (0–72, n=32) were evaluated. Spearman coefficients for correlation were calculated.
Results In all SpA pts mean value (M±σ) of indices and laboratory parameters were: BASDAI – 4.76±1.89, BASFI – 3.3±2.2, ESR – 26.21±19.63, CRP – 27.48±54.83, ASDAS-CRP 3.11±1.02 and ASDAS-ESR 3.07±0.97.
ASDAS-CRP, ASDAS-ESR and BASDAI were higher in peripheral SpA than in axial SpA: 3.32±1.05 vs 2.72±0.83 (p=0.016), 3.29±1.01 vs 2.66±0.75 (p=0.005) and 5.12±2.02 vs 4.07±1.4 (p=0.01) respectively. The level of inflammatory lesions of SIJ was high: SPARCC MRI SIJ score was 25.97±12.89, without significant differences between axial (27.83±12.92) and peripheral (23.57±12.92) SpA.
The correlation analysis revealed that for all SpA pts BASFI positively correlated with the both, ESR (r=0.388, p=0.01) and CRP (r=0.357, p=0.003), but BASDAI was only with CRP (r=0.428, p=0.001). All disease activity and functional indices for all SpA showed a high correlation with each other: ASDAS-CRP and ASDAS-ESR with BASDAI and BASFI (r value from 0.502 to 0.745, p=0.001), and BASDAI with BASFI (r=0.426, p=0.015).
In pts with axial SpA ASDAS-CRP and ASDAS-ESR but not BASDAI and BASFI were correlated with laboratory activity: ASDAS-ESR with ESR (r=0.620, p=0.002) and CRP (r=0.516, p=0.012), ASDAS-CRP only with CRP (r=0.785, p=0.001). All clinical indices of pts with the involvement of peripheral joints showed significant (p<0.05) correlation with ESR and CRP (r value from 0.302 to 0.779).
SPARCC MRI SIJ score showed correlation with CRP (r=0.358, p=0.004) in all SpA, with CRP (r=0.496, p=0.036) in axial SpA and with BASFI (r=0.556, p=0.039) in peripheral SpA pts.
Conclusions Disease activity according to ASDAS-CRP, ASDAS-ESR and BASDAI was significantly higher in pts with peripheral comparison with axial SpA. Clinical indices of pts with peripheral SpA showed better correlation with laboratory activity in comparison with axial SpA. SPARCC MRI score correlated with disease activity (only CRP level) of axial SpA pts and functional status (BASFI) of peripheral SpA pts.
Van der Heijde D. Arthritis Rheumatol. 2014;66(3):667–73.
Zhang P. Clin Radiol. 2015;70(1):62–6.
Disclosure of Interest None declared