The burden of ankylosing spondylitis in Spain.
OBJECTIVE: To investigate the burden of ankylosing spondylitis (AS) in Spain, as baseline for economic evaluation of the use of biological agents. METHODS: A cross-sectional retrospective observational study was performed in 601 patients with AS in Spain, using a methodology developed in studies in the United Kingdom and Canada. Patients were mailed a questionnaire asking about their health-care c
