Almost half of the patients with axial spondyloarthritis reporting an acceptable symptom state have high disease activity; data from two standard-of-care cohorts

Objectives: To assess the proportion of axial spondylarthritis (axSpA) patients reporting PASS, explore variables associated with PASS and determine the relation with axSpA Disease Activity Score (ASDAS) to predict PASS in two Dutch standard-of-care cohorts. 

Methods: Patients from the GLAS cohort were included in this cross-sectional analysis. External validation was performed in the SpA-Net cohort. Univariable and multivariable logistic regression were performed to identify determinants of PASS. The predictive accuracy and threshold of the ASDAS for predicting PASS were determined using AUC and highest Youden’s index. 

Results: Of 673 included GLAS patients, 63 % were male, mean age was 48 (±14) years, and mean ASDAS 2.3 (±0.9). In total, 77 % perceived their symptom state as acceptable. Of these patients, 44 % had an ASDAS ≥2.1. In multivariable regression, lower ASDAS, absence of tender entheses and older age were independently associated with reported PASS (R² = 0.39). The ASDAS showed good accuracy in predicting PASS, with AUC of 0.84 (95 % CI 0.80-0.85) and optimal cut-off value of 2.6 (sensitivity 78 %, specificity 77 %). Similar results were found in the 159 patients from SpA-Net. 

Conclusion: In daily clinical practice, 3 out of 4 axSpA patients report an acceptable symptom state, although almost half of them have high disease activity. In line, the ASDAS threshold for predicting PASS is 2.6. Our results show that the PASS question provides additional information to disease activity, which can contribute to better shared decision making.