Six patient-reported questions assessing fatigue, spinal and hip pain, peripheral joint pain, entheseal discomfort, and morning stiffness. No lab values required. Historically used when ASDAS-CRP cannot be calculated. Score of 4 or more indicates active disease warranting treatment escalation.
Original Development
Garrett S, Jenkinson T, Kennedy LG, et al.
J Rheumatol, 1994
ASAS 2022 Note: ASDAS-CRP is now the preferred tool when CRP is available. Use BASDAI when CRP is unavailable or when historical comparison requires it.
1
Questions 1-4: Fatigue & Pain
Rate each on a scale of 0 (none/not severe) to 10 (very severe). Answers reflect the past week.
1. How would you describe the overall level of fatigue/tiredness you have experienced? (Past week)
5
0 (None)10 (Very severe)
2. How would you describe the overall level of AS neck, back, or hip pain? (Past week)
5
0 (None)10 (Most severe)
3. How would you describe the overall level of pain/swelling in joints other than neck, back, hips? (Past week)
5
0 (None)10 (Most severe)
4. How would you describe the overall level of discomfort you have had from any areas tender to touch or pressure? (Past week)
5
0 (None)10 (Most severe)
2
Questions 5-6: Morning Stiffness
Note: Questions 5 and 6 are averaged together, then that average is combined with Q1-4 for the final BASDAI score.
5. How would you describe the overall level of morning stiffness you have had from the time you wake up? (Past week)
5
0 (None)10 (Most severe)
6. How long does your morning stiffness last from the time you wake up? (Past week)
5
0 (No stiffness)10 (2 hours or more)
📊 Interpreting the Score
BASDAI
Status
Clinical Meaning
< 2.5
Inactive / Low
Correlates approximately with ASDAS inactive disease. Well-controlled SpA.
2.5 to 3.9
Moderate
Correlates approximately with ASDAS moderate activity (1.3-2.1).
4.0 to 5.9
Active
Historical threshold for biologic eligibility. Consider escalation.
≥ 6.0
Very Active
Correlates approximately with ASDAS very high (≥3.5). Prompt escalation warranted.
Note: The traditional BASDAI ≥ 4 threshold for biologic eligibility was set empirically. The 2024 ACR/EuroSpA cutoffs (inactive <2.5, low ≤2.8-4, high >5.9) reflect more recent validation.
💡 Pearls and Pitfalls
✓
Use ASDAS-CRP when CRP is available. Per ASAS/EULAR 2022 recommendations, ASDAS-CRP is the preferred instrument. BASDAI should be reserved for situations where CRP cannot be obtained. If switching from BASDAI to ASDAS mid-treatment, establish a new ASDAS baseline rather than comparing to prior BASDAI values.
⚠
Q1 (fatigue) and Q4 (tenderness) are heavily confounded by fibromyalgia. Patients with coexisting fibromyalgia will frequently report high scores on Q1 and Q4 without underlying inflammatory disease. This is the most common cause of BASDAI-positive / ASDAS-low discordance. These patients typically respond poorly to biologics.
⚠
The formula averages Q5 and Q6 before including them. A common scoring error is to add all six questions and divide by 6. The correct formula averages Q5 and Q6 first, then calculates the mean of Q1, Q2, Q3, Q4, and that average of Q5+Q6, divided by 5.
🔬 Evidence
BASDAI was developed by Garrett, Jenkinson, Kennedy, and colleagues and published in the Journal of Rheumatology in 1994. It was the dominant disease activity measure for axial SpA for nearly 15 years before ASDAS was developed. Validation studies demonstrated good reliability (test-retest r=0.98) and responsiveness to anti-TNF treatment.
View References▾
1
Garrett S, Jenkinson T, Kennedy LG, et al.A new approach to defining disease status in ankylosing spondylitis: the Bath Ankylosing Spondylitis Disease Activity Index. J Rheumatol. 1994;21(12):2286-2291.
2
Goswami RP, Chatterjee M, Das S.Defining objective BASDAI cut-offs for disease activity states in axial spondyloarthritis. Int J Rheum Dis. 2024 Nov;27(11):e15418. 2024 BASDAI cutoff validation.
For clinical decision support only. ASAS 2022 recommends ASDAS-CRP as the preferred instrument over BASDAI when CRP is available. BASDAI is a monitoring tool, not a diagnostic instrument.