Central sensitization has major impact on quality of life in patients with axial spondyloarthritis.

INTRODUCTION: Persistent pain has large potential impact on quality of life (QoL). During the course of the disease, many patients with axial spondyloarthritis (axSpA) report persistent pain. Central sensitization (CS) may explain part of this chronic pain. However, the role of CS in relation to QoL has been sparsely studied in axSpA. Therefore, our aim was to explore the relationship between CS and QoL in patients with axSpA. METHODS: Consecutive outpatients from the Groningen Leeuwarden axSpA (GLAS) cohort completed the Central Sensitization Inventory (CSI; range 0-100) and the AS Quality of Life (ASQoL; range 0-18). Multivariable linear regression analysis was used to explore the relationship between CSI and ASQoL scores correcting for potential confounders. RESULTS: Of the 178 included axSpA patients, mean CSI score was 38.0 ± 14.1 and 45% scored ≥40, which indicates a high probability of CS. Mean ASQoL score was 6.0 ± 5.3 and mean ASDASCRP 2.1 ± 1.0. A CSI score ≥40 was significantly associated with higher ASQoL score (mean 9.7 vs. 3.3), higher ASDASCRP (mean 2.6 vs. 1.7), female gender (60% vs. 29%) and more often entheseal involvement (61% vs. 26%). In univariable analysis, CSI score explained a large proportion of the variation in ASQoL (B = 0.06, 95%CI: 0.05-0.07; R2=0.46). This association remained significant after correction for ASDASCRP, gender, entheseal involvement, comorbidities, symptom duration, smoking status, BMI class and educational level (B = 0.04, 95%CI: 0.03-0.05). CONCLUSION: CS is strongly related to patient-reported QoL in patients with axSpA independently from other patient- and disease-related aspects.

Central sensitization, illness perception and obesity should be considered when interpreting disease activity in axial spondyloarthritis.

OBJECTIVES: Many patients with axial spondyloarthritis (axSpA) report persistent pain even when treated with anti-inflammatory agents. Our aim was to explore the presence of central sensitization (CS) and different types of illness perceptions in patients with axSpA, and to assess their associations with disease activity assessments. METHODS: Consecutive outpatients from the Groningen Leeuwarden Axial Spondyloarthritis (GLAS) cohort were included. Besides standardized assessments, patients filled out the Central Sensitization Inventory (CSI), Illness Perception Questionnaire (IPQ-R) and Pain Catastrophizing Scale (PCS). Univariable and multivariable linear regression analyses were used to investigate the association between questionnaire scores, patient characteristics and disease activity assessments ASDASCRP, BASDAI and CRP. RESULTS: We included 182 patients with a mean symptom duration of 21.6 years. Mean ASDASCRP was 2.1, mean BASDAI 3.9, and median CRP 2.9. Mean CSI score was 37.8 (scale 0-100) and 45% of patients scored ≥40, indicating a high probability of CS. CSI score, IPQ-R domain identity (number of symptoms the patient attributes to their illness), and IPQ-R domain treatment control (perceived treatment efficacy), and obesity were significantly and independently associated with both ASDASCRP and BASDAI, explaining a substantial proportion of variation in these disease activity scores (R2=0.35 and R2=0.47, respectively). Only obesity was also independently associated with CRP. CONCLUSION: CS may be common in patients with long-term axSpA. CS, as well as specific illness perceptions and obesity were all independently associated with the widely used (partially) patient-reported disease activity assessments ASDASCRP and BASDAI. Treating physicians should take this into account in the follow-up and treatment of their patients.

Ankylosing spondylitis disease activity score is related to NSAID use, especially in patients treated with TNF-α inhibitors.

BACKGROUND: Non-steroidal anti-inflammatory drugs (NSAIDs) are regarded as the cornerstone of conventional treatment for AS. However little is known about concomitant NSAID use during treatment (with TNF-α inhibitors) in daily clinical practice. METHODS AND FINDINGS: Consecutive patients from the GLAS cohort were included. NSAID use and ASAS-NSAID index were evaluated at group level and at individual patient level during 52 weeks of follow-up. Analyses were stratified for treatment regimen. Generalized estimating equations (GEE) was used to evaluate NSAID use in relation to assessments of disease activity over time. In patients starting TNF-α inhibitors (n = 254), 79% used NSAIDs at baseline and this proportion decreased significantly to 38% at 52 weeks. ASAS-NSAID index also decreased significantly from median 65 to 0. In patients on conventional treatment (n = 139), 74% used NSAIDs at baseline with median ASAS-NSAID index of 50 and this remained stable during follow-up. At each follow-up visit, approximately half of the patients changed their type or dose of NSAIDs. GEE analysis over time showed that NSAID use was associated with AS disease activity score (p<0.05). This relation was more pronounced in patients treated with TNF-α inhibitors compared to conventional treatment (B = 0.825 vs. B = 0.250). CONCLUSIONS: In this observational cohort of established AS patients, there was no difference in baseline NSAID use between patients with and without indication for TNF-α inhibitors. NSAID use decreased significantly after starting TNF-α inhibitors. During conventional treatment, NSAID use remained stable at group level. However, NSAID use changed frequently at individual patient level and was significantly associated with disease activity.