Measures of symptoms and disease status in ankylosing spondylitis: Ankylosing Spondylitis Disease Activity Score (ASDAS), Ankylosing Spondylitis Quality of Life Scale (ASQoL), Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Bath Ankylosing Spondylitis Functional Index (BASFI), Bath Ankylosing Spondylitis Global Score (BAS‐G), Bath Ankylosing Spondylitis Metrology Index (BASMI), Dougados Functional Index (DFI), and Health Assessment Questionnaire for the Spondylarthropathies (HAQ‐S)

Outcome measurement in spondylarthritis, particularly ankylosing spondylitis (AS) has been a rapidly growing field over the last decade, with enormous progress being made in patient-reported outcomes, clinical assessments, physical measurements and composite scoring of disease state, and response to treatment. Many of these advances arose out of need, when anti–tumor necrosis factor therapies were found to have a role in the treatment of AS patients and therefore required appropriate clinical assessment. The Assessment of SpondyloArthritis international Society (ASAS) was first formed in 1995 as a group of clinicians and methodologists with a shared interest in outcome measurement in AS patients, and has grown to incorporate early diagnosis, classification, development and validation of outcome measures, and evaluation of therapeutic modalities. The instruments reviewed here include those recommended in the ASAS core sets for clinical record keeping (in daily clinical practice) and for clinical research, as over time these have been extensively validated and implemented across different clinical settings. The core sets describe those health-related domains that should be measured in AS patients in different settings, and recommend appropriate instruments that can be used for that domain. Additional measures included are the AS Quality of Life scale and the Health Assessment Questionnaire for the Spondylarthropathies, which cover health domains not included in the original core sets but have been shown to be important to AS patients through the World Health Organization International Classification of Functioning, Disability and Health projects (1). Finally, the AS Disease Activity Score has also been presented, as an alternative to the Bath Ankylosing Spondylitis Disease Activity Index, as one of the newest measures constructed to assess disease activity.