Some psychological factors—helplessness and depression—account for significant variability in perceived disease activity in patients with ankylosing spondylitis (AS). Because medical variables—such as C-reactive protein (CRP) level and radiographic severity—are not associated with patient-reported disease activity, interpretation of AS disease status may need to occur in the context of evaluating psychological status.
Brionez and colleagues conducted a cross-sectional study of patients with AS from the Prospective Study of Outcomes in Ankylosing Spondylitis. Measurement of disease activity was achieved with the Bath AS Disease Activity Index (BASDAI), a self-report 6-item questionnaire. Medical variables included CRP level, number of patient-reported comorbidities, and disease duration. Six psychological variables were measured.
Psychological variables contributed significantly to variance in BASDAI scores, adding 33% to the overall R-square beyond that accounted for by demographic and medical variables. Arthritis helplessness and depression accounted for the most significant portion of variance in BASDAI scores; other psychological factors—internality and passive, active, and resilience coping—did not account for significant variance.
The authors noted that their findings have important clinical implications and suggest potential avenues of intervention.