Evaluation of spondylarthritis activity by patients and physicians: ASDAS, BASDAI, PASS, and flares in 200 patients

Objectives: In patients with spondyloarthritis, to determine Ankylosing Spondylitis Disease Activity Score (ASDAS) cutoffs matching the patient-acceptable symptom state (PASS) and patient-reported levels of disease activity, to assess associations between disease activity levels and presence of depression, and to identify ASDAS and Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) cutoffs indicating a flare and indicating a remission.

Methods: Prospective single-center study of patients meeting ASAS criteria for spondyloarthritis receiving follow-up at the Besançon teaching hospital, France, between February 2011 and February 2012. In each patient, the BASDAI, ASDAS, Bath Ankylosing Spondylitis Functional Index (BASFI), patient-acceptable symptom state (PASS) and signs of depression were assessed. Receiver-operating characteristic (ROC) curves were drawn to identify the ASDAS cutoffs separating different levels of disease activity. The kappa coefficient was computed to evaluate agreement between patients and physicians regarding the presence of flares.

Results: Two hundred patients with a mean age of 44.4 ± 12.5 years and mean disease duration of 12.9 ± 10.5 years were included. Mean BASDAI was 4.1 ± 2.2, mean ASDAS-C-reactive protein (CRP) was 2.4 ± 1, mean BASFI was 3.3 ± 2.7, and 58.9% of patients reported being in the PASS. The PASS was associated with BASDAI values inferior or equal to 4.1 and ASDAS-CRP values inferior or equal to 2.3. Mild patient-reported disease activity was associated with BASDAI values inferior or equal to 3.8 and ASDAS-CRP values inferior or equal to 2.3; corresponding values for high patient-reported disease activity were superior to 5.2 and superior to 3.1. Among patients reporting high disease activity, 64.5% had Beck Depression Inventory scores consistent with severe depression. At the time of the visit, 36.9% of the patients and 28.3% of the physicians felt there was a flare. Cutoffs indicating a flare were superior or equal to 5.2 for the BASDAI and superior or equal to 2.3 for the ASDAS-CRP. Agreement between patients and physicians regarding flares was good (Kappa, 0.61). An evaluation in 43 patients indicated that an ASDAS-CRP cutoff inferior or equal to 2.2 separated the 25.6% of patients who reported being in remission from the other patients.

Conclusion: Our results show a significant association between disease activity and depression severity, as well as good agreement between BASDAI and ASDAS. The ASDAS cutoffs for the various levels of patient-reported disease activity differed from the cutoffs suggested by ASAS; a 2.3 cutoff was found for both patient-reported absence of disease activity and PASS, indicating that achieving PASS should be included among our treatment objectives.