OP0046 CAN PATIENTS WITH AXIAL SPONDYLOARTHRITIS INDICATE WHETHER PAIN IS MAINLY RELATED TO INFLAMMATION OR STRUCTURAL DAMAGE?
Authors: A. Kampman, F. Wink, M. Carbo, F. Maas, A. Spoorenberg, S. Arends
Journal: Annals of the Rheumatic Diseases (2021)

Background: Patients with axial spondylarthritis (axSpA) mainly rate disease activity on experienced symptoms such as pain (1). Pain is also included in the assessments (ASDAS and BASDAI) used to monitor disease activity in axSpA. However, besides disease activity, also other factors including the presence of structural damage may be related to experienced pain and discomfort. Objectives: To explore to what extent axSpA patients relate their experienced pain in neck, back and hips to inflammation and/or structural damage. Methods: Patients from the Groningen Leeuwarden Axial Spondyloarthritis (GLAS) cohort visiting the out-patient clinic between May 2016 and October 2019 were included in this cross-sectional analysis. Patients filled out two additional questions related to question 2 of the BASDAI: To what extent do you think pain in your neck, back and hips is related to: 1. inflammation caused by axSpA?, 2. damage of spine and joints caused by axSpA? These questions were answered on a NRS from 0 (none) to 10 (very much). A difference of ≥2 points was considered as clinically relevant. Patients who differentiated the cause of their pain were allocated to an inflammation or damage group, in favour of their highest score. Furthermore, patient characteristics and clinical assessments were compared between the inflammation and damage groups. Results: In total, 688 axSpA patients were included, 62.4% were male, mean age was 47.9 years, median symptom duration was 19 years, 77.9% were HLA-B27+, mean BASDAI was 3.9 and mean ASDAS CRP was 2.3. Respectively 13% and 14% of the patients reported a score of 0 on the additional questions about inflammation or damage. In total, 517 (75%) patients could not differentiate between inflammation or damage. 102 (15%) patients interpreted experienced pain as mainly related to inflammation and 69 (10%) patients interpreted their pain as mainly related to structural damage. Patients who interpreted pain as mainly related to inflammation were significantly younger, had shorter symptom duration, were more frequently diagnosed as non-radiographic axSpA and had higher ASDAS CRP , which was driven by the patient-reported questions as the objective marker CRP was not significantly different between both groups (Table 1). Table 1. Patients characteristics and clinical assessments of axSpA patients who related pain mainly to inflammation versus to structural damage. Inflammation group (n = 102 ) Structural damage group (n = 69 ) P-value Age (years) 39.5 ± 12.4 48.9 ± 12.4 &lt;0.001 Symptom duration (years) 12 (6 – 20) 28 (17 – 35) &lt;0.001 Diagnosis non-radiographic axSpA 39 (40%) 8 (13%) &lt;0.001 Male gender 60 (59%) 44 (64%) 0.627 BASDAI 4.2 ± 1.8 3.9 ± 2.0 0.371 BASDAI – Q2 6 (3 – 7) 4 (2 – 6) 0.005 Patient global disease activity 4 (3 – 7) 3 (2 – 5) &lt;0.001 ASDAS CRP 2.6 ± 0.9 2.2 ± 0.8 0.003 CRP 3.0 (2.0 – 8.0) 2.5 (2.0 – 4.4) 0.094 Occiput wall distance (cm) 0.0 (0.0 – 4.0) 4.0 (0.0 – 10.0) &lt;0.001 Chest expansion (cm) 5.8 (4.0 – 7.0) 4.0 (3.0 – 6.0) 0.006 Modified Schober test (cm) 14.0 ± 1.6 13.5 ± 1.6 0.052 Lateral flexion mean (cm) 15.3 ± 6.5 12 ± 5.9 0.001 Cervical rotation mean (degrees) 80 (70 – 90) 70 (45 - 81) &lt;0.001 mSASSS * 3.0 (0.0 – 9.0) 8.0 (1.8 – 26.0) 0.061 * only available in a subgroup of patients. Inflammation group (n=31), structural damage group (n=39). Patients who reported their pain as mainly related to structural damage showed significantly worse spinal mobility on almost all spinal mobility tests. In the subgroup of patients with available mSASSS data, there was also a trend towards more spinal radiographic damage (Table 1). Conclusion: In our large observational cohort of axSpA patients, the vast majority (75%) could not rate whether experienced pain in neck, back and hips was more related to inflammation or structural damage. However, if patients were able to relate pain to inflammation or damage, it seems in accordance with the outcome of their clinical assessments. References: [1]Spoorenberg A et al . Rheumatology (Oxford), 2005;44(6):789-95. Disclosure of Interests: None declared