Rheumatology
Bath Ankylosing Spondylitis Disease Activity Index
The BASDAI is a patient-reported outcome capturing fatigue, spinal pain, joint symptoms, enthesitis, and morning stiffness. Each is rated 0–10; higher scores indicate more active disease.
Overall level of fatigue/tiredness over the last week
Overall level of spinal (back, neck) pain over the last week
Overall level of joint pain/swelling (other than spine) over the last week
Discomfort from areas tender to touch or pressure (entheses) over the last week
Severity of morning stiffness over the last week
Duration of morning stiffness over the last week
0 = 0 hours, 10 = 2 or more hours
BASDAI score
4.30
High disease activityBASDAI ≥ 4 indicates active disease—consider adjusting therapy, evaluating NSAID response, or initiating biologics per ASAS/EULAR guidance.
How to Use This Calculator
Explain the 0–10 scale to patients
0 represents no symptoms; 10 represents worst imaginable symptoms for each domain.
Record each domain rating
Ensure responses reflect the last week, consistent with BASDAI methodology.
Interpret the average score
Use BASDAI alongside BASFI, CRP/ESR, and imaging to guide treatment decisions.
Formula
BASDAI = (Q1 + Q2 + Q3 + Q4 + ((Q5 + Q6) ÷ 2)) ÷ 5
Each question scored 0–10. Thresholds: ≥ 4 indicates active disease warranting treatment escalation.
Full Description
The BASDAI is a validated instrument capturing axial spondyloarthritis activity from the patient perspective. It integrates musculoskeletal symptoms and morning stiffness, mirroring disease burden. BASDAI complements objective measures (CRP, imaging) when assessing response to NSAIDs, biologics, or JAK inhibitors.
Repeat BASDAI regularly (e.g., every 3–6 months). Combine with functional indices (BASFI) and physician global assessments to tailor therapy per ASAS/EULAR recommendations.
Frequently Asked Questions
What BASDAI score triggers biologic therapy?
Guidelines often use BASDAI ≥ 4 despite NSAID therapy as a threshold for biologic initiation, alongside objective inflammation.
Can BASDAI be used in non-radiographic axSpA?
Yes. BASDAI applies to both radiographic and non-radiographic axial spondyloarthritis cohorts.
How does BASDAI differ from ASDAS?
ASDAS incorporates CRP/ESR and has defined cut-offs for disease states. BASDAI is fully patient-reported. Many clinicians use both.
Should morning stiffness duration be recorded in minutes?
BASDAI uses a 0–10 scale where 0 represents no stiffness and 10 corresponds to stiffness lasting ≥ 2 hours.