BASDAI Calculator
Calculate the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) to assess disease activity in ankylosing spondylitis.
Formula
BASDAI = (Q1 + Q2 + Q3 + Q4 + (Q5+Q6)/2) ÷ 5
- Score range: 0–10. Score ≥ 4 indicates active disease.
- Questions 5 and 6 (morning stiffness) are averaged before inclusion.
- BASDAI ≥ 4 despite NSAIDs is generally a prerequisite for biologic therapy.
Moderate disease activity
Inputs
- Fatigue/tiredness (0-10): 6
- AS neck/back/hip pain (0-10): 7
- Non-neck/back joint pain/swelling (0-10): 4
- Discomfort from tender areas (0-10): 5
- Morning stiffness level (0-10): 6
- Morning stiffness duration (0-10, where 10=2+ hrs): 7
Morning stiffness avg = (6+7)/2 = 6.5. BASDAI = (6+7+4+5+6.5)/5 = 5.7 → Active disease.
Frequently asked questions
What does BASDAI measure?
It measures disease activity in ankylosing spondylitis (AS) across 6 domains on a 0–10 scale.
What score indicates active disease?
A BASDAI score of ≥ 4 is generally considered active disease.
How often should BASDAI be calculated?
Typically every 3–6 months to monitor treatment response.
Can patients self-report BASDAI?
Yes — BASDAI is a patient-reported outcome measure.