Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) Score

Evaluates disease activity in Ankylosing Spondylitis based on major symptoms of this rheumatological condition.

Refer to the text below the calculator for more information about the index and its clinical use.

The use of the Bath Indices (in particular the BASDAI) is a key feature in the NICE criteria for anti-TNF medications for the treatment of Ankylosing Spondylitis in the UK.

BASDAI scores of 4 or greater are internationally recognised to suggest suboptimal control of disease. These patients may be candidates for new medical therapy or enrolment in clinical trials.

BASDAI evaluates six dimensions of Ankylosing Spondylitis:

Fatigue;
Spinal pain;
Joint pain / swelling;
Areas of localized tenderness;
Morning stiffness duration;
Morning stiffness severity.

Send Us Your Feedback

Steps on how to print your input & results:

1. Fill in the calculator/tool with your values and/or your answer choices and press Calculate.

2. Then you can click on the Print button to open a PDF in a separate window with the inputs and results. You can further save the PDF or print it.

Please note that once you have closed the PDF you need to click on the Calculate button before you try opening it again, otherwise the input and/or results may not appear in the pdf.

BASDAI Explained

The Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) is simple and quick to administer and helps evaluate disease activity in six dimensions, as follows:

Fatigue;
Spinal pain;
Joint pain / swelling;
Areas of localized tenderness (also called enthesitis, or inflammation of tendons and ligaments);
Morning stiffness duration;
Morning stiffness severity.

The first five items consist of a visual analogue scale 1 to 10 scale, where 1 indicates no problem and 10 indicates the most severe problem. The sixth item, related to the duration of morning stiffness is scored as 0 for 0 hours, 5 for one hour and 10 for two or more hours.

The total score is computed by:

BASDAI = ((Q1 + Q2 + Q3 + Q4) + ((Q5 + Q6) / 2)) / 5

BASDAI scores of 4 or greater are internationally recognised to suggest suboptimal control of disease. These patients may be candidates for new medical therapy or enrolment in clinical trials.

Calin et al. demonstrated that the individual symptoms and the index as a whole demonstrated good score distribution, using 95% of the scale.

BASDAI demonstrated statistically significant (p<0.001) reliability.

BASDAI may be used to monitor disease activity in time and response to treatment as it has demonstrated a sensitivity to change (i.e. in a group of 154 patients, following a 3 week physiotherapy course, the BASDAI showed a significant (p=0.009) 16.4% score improvement).

In a subsequent study, the index’ content validity was further confirmed on a cohort of 473 patients with AS who received placebo or active non-steroidal anti-inflammatory drug (NSAID) for 6 weeks and evaluated as start and end of trial.

The use of the Bath Indices (in particular the BASDAI) is a key feature in the NICE criteria for anti-TNF medications for the treatment of AS in the UK.

Another index (also part of the Bath indices) for use in evaluating Ankylosing Spondylitis is BASFI (Bath Ankylosing Spondylitis Functional Index) which determines the degree of functional limitation in those with AS.