PO:04:048 | Assessment of chronic and residual pain in axial spondyloarthritis in a single-center cohort of patients treated with anti-tnf agents

Valentina Fornero^1|2, Niccolò Melis¹, Emanuela Salustro¹, Mattia Congia¹, Elisabetta Chessa¹, Alberto Floris¹, Matteo Piga¹, Alberto Cauli¹ | ¹Rheumatology unit, AOU e Università di Cagliari; ²Asl Biella, Ospedale degli Infermi, Ponderano (BI), Italy

Materials and Methods: Patients diagnosed with AxSpA (according to the ASAS 2009 criteria) who had been treated with anti-TNF agents for at least six months and had undergone a minimum of two outpatient visits spaced by at least six months were included. The following definitions were applied: chronic pain—VAS pain ≥40 at the last two outpatient visits at least three months apart; residual pain—VAS pain ≥20 and ASDAS <1.3 at the last visit. Collected variables included BASMI, ASDAS-CRP, patient VAS, last-week VAS (0–100), HAQ, BASFI, BASDAI, age, sex, BMI, disease duration, radiographic damage, and comorbidities. Statistical analyses were performed using Student’s t-test or Mann–Whitney test for quantitative variables and the Chi-square or Fisher’s exact test for qualitative variables.

Results: A total of 264 patients were enrolled (see Table). Among them, 33 (12.5%) had residual pain and 67 (25.5%) had chronic pain. In patients with residual pain, no significant differences were observed compared with controls regarding age (52 ± 45.4 vs. 53 ± 52 years; p = 0.43), male sex (66.6% vs. 61%; p = 0.57), disease duration (14.2 vs. 14.9 years; p = 0.94), or HLA-B27 positivity (66.7% vs. 87%; p = 0.48). Residual pain was less frequent in patients with non-radiographic AxSpA (21.2% vs. 39.8%; p = 0.019) and was associated with significantly higher VAS scores (30 [20–46] vs. 10 [10–20]; p = 0.0008). No significant differences were found for BASMI, BMI, CRP, or comorbidities. In the chronic pain group, males were more represented (52% vs. 16%; p = 0.008), with later disease onset (33 vs. 29.3 years; p = 0.03) and higher HLA-B27 positivity (58% vs. 11.6%; p = 0.04). These patients showed increased values for ASDAS-CRP (2.59 vs. 0.92; p < 0.0001), BASDAI (5.8 vs. 1.5; p < 0.0001), and VAS at the last visit (50 [50–70] vs. 10 [10–10]; p < 0.001). The presence of fibromyalgia (34% vs. 7%; p < 0.001) and discopathies (61% vs. 39%; p < 0.001) was significantly associated with chronic pain. No significant differences were observed in other clinical or radiographic variables.

Conclusions: Despite effective disease control with biologic therapy, patients with AxSpA may continue to experience pain, which can be classified as either chronic pain - often associated with comorbidities such as fibromyalgia or discopathies that affect pain mechanisms - or residual pain, reflecting a mismatch between perceived pain and disease activity indices (ASDAS-CRP, BASDAI) and indicating a suboptimal response to therapy. These findings highlight the need for comprehensive patient management in clinical practice, emphasizing strategies to minimize pain through accurate clinical assessment and appropriate multimodal pharmacological treatment in patients with AxSpA.