🦴 BASDAI Ankylosing Spondylitis Activity Index
The Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) is a patient-reported measure of axial spondyloarthritis activity scored 0–10.
BASDAI Ankylosing Spondylitis Activity Index
① Fatigue/tiredness level (0–10)
② Neck/back/hip pain (0–10)
③ Peripheral joint pain/swelling (0–10)
④ Discomfort on touch/pressure (enthesitis) (0–10)
⑤ Morning stiffness severity (0–10)
⑥ Morning stiffness duration (0–10)
When to use
Enter the six 0–10 items (fatigue, spinal pain, peripheral joint pain/swelling, enthesitis, morning-stiffness severity, morning-stiffness duration) over the past week; the tool returns the index.
How it works
BASDAI = (Q1 + Q2 + Q3 + Q4 + (Q5 + Q6)/2) / 5. A value ≥4 generally indicates active disease.
Key points
- The two morning-stiffness items (severity and duration) are averaged before being combined, so they together carry the weight of a single item (original synthesis · not guideline verbatim).
- A BASDAI ≥4 is a common threshold for active disease and is often part of the assessment before starting or escalating a biologic.
- It is increasingly paired with or replaced by ASDAS, which incorporates CRP and better reflects objective inflammation.
References
Decision support for licensed clinicians only; not a substitute for clinical judgement, diagnosis or local protocols.