Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) Calculator

Overview

Calculates patient-reported disease activity in axial spondyloarthritis from six 0–10 questions.

Clinical Significance

Higher scores indicate greater disease activity; a BASDAI of 4 or more is often used as a threshold for active disease in treatment pathways.

When to Use

• Use as structured clinical decision support when the required data are available and reliable.

How It Is Calculated

• The displayed variables are combined using the published equation or weighted point system.

Interpretation

• Higher scores indicate greater disease activity; a BASDAI of 4 or more is often used as a threshold for active disease in treatment pathways.

Worked Example

Enter verified patient data in the displayed units; MedicalC applies the published equation or point system.

Limitations

• Classification and prognostic tools can be misapplied outside their validated population.
• Missing, estimated or non-contemporaneous data may materially change the result.

Clinical Pearls

• Document the input values, units, date and clinical setting with the result.
• Use serial scores only when the same instrument and measurement method are used consistently.

Common Mistakes

• Using the tool without confirming entry criteria.
• Selecting overlapping findings that should be represented by the highest-scoring item only.
• Treating a classification threshold as a standalone diagnosis.

References

1. Garrett S et al. J Rheumatol. 1994;21:2286-2291. — Primary or supporting reference for the implemented model.