Patient-acceptable Symptom State as an Outcome Measure in the Daily Care of Patients with Ankylosing Spondylitis

Objective. We assessed the prevalence of patients with ankylosing spondylitis (AS), rating their state as acceptable (patient-acceptable symptom state; PASS), among 190 patients with AS seen in daily practice. Factors associated with PASS status and PASS thresholds for outcome measures were also analyzed. Methods. The characteristics of patients with affirmative and negative assignment to PASS were compared. Associated factors were estimated by logistic regression models and PASS thresholds by the 75th percentile and receiver-operating characteristic curve methods. Results. A total of 77% of patients rated their state as acceptable (95% CI 62-91). These patients were taking fewer nonsteroidal antiinflammatory drugs and corticosteroids, practiced more exercise, had less anxiety and depression, and had lower values of all patient-reported outcome measures, physicians' assessment, AS Disease Activity Score (ASDAS) and C-reactive protein. Lower values of Bath AS Disease Activity Index and physician's global assessment were independent factors associated with acceptable symptom state. High rates of anxiety and depression were found in patients not in PASS. The thresholds with the 75th percentile approach were 4.55 for the BASDAI and 2.84 for the ASDAS. Fifty-three percent of patients in PASS had a high or very high disease activity state according to ASDAS cutoff values. Conclusion. A high percentage of patients with AS in daily practice declared that their symptom state was acceptable. PASS status correlated with physician global assessment and BASDAI. PASS thresholds for common recommended outcome measures were relatively high and many patients in PASS had unacceptably high disease activity states according to ASDAS. Other factors such as psychological problems may influence a negative PASS state. (First Release June 1 2012; J Rheumatol 2012;39:1424-32; doi:10.3899/jrheum.111481)