Table 15.20-1. Assessment of SpondyloArthritis International Society (ASAS) criteria for inflammatory back pain

– Age at onset < 40 years

– Insidious onset

– Improvement with exercise

– No improvement with rest

– Pain at night (with improvement upon getting up)

Inflammatory back pain present if ≥4 criteria are present. Sensitivity, 79.6%; specificity 72.4%.

Adapted from Ann Rheum Dis. 2009;68(6):784-8.