BASDAI

Overview
The BASDAI is important because it is a validated diagnostic test which allows a physician (usually a rheumatologist) to determine the effectiveness of a current drug therapy, or the need to institute a new drug therapy for the treatment of ankylosing spondylitis. The BASDAI consists of a one through 10 scale (one being no problem and 10 being the worst problem) in response to 6 questions pertaining to the 5 major symptoms of AS:


 * 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

To give each symptom equal weighting, the average of the two scores relating to morning stiffness is taken. The resulting 0 to 50 score is divided by 5 to give a final 0 – 10 BASDAI score. Scores of 4 or greater suggest suboptimal control of disease, and patients with scores of 4 or greater are usually good candidates for either a change in their medical therapy, eligible for treatment with powerful biologic therapies such as etanercept, infliximab and adalimumab, or may be eligible for enrollment in clinical trials evaluating new drug therapies directed at Ankylosing Spondylitis.

History
Garrett and coworkers writing in the Journal of Rheumatology in December 1994 described a self-administered 6-question measurement tool which was to become the gold standard for measuring and evaluating disease activity in Ankylosing Spondylitis (AS). This validated tool is the BASDAI, or the Bath Ankylosing Spondylitis Disease Activity Index. A research team consisting of rheumatologists, physiotherapists, and research associates with a special interest in AS developed the index in Bath, England, hence the reason for "Bath" in the name.

Validation
BASDAI is a quick and simple index (taking between 30 secs and 2 mins to complete) BASDAI demonstrated statistically significant (p<0.001) reliability. BASDAI encorporates a reasonable scale. The individual symptoms and the index as a whole demonstrated good score distribution, using 95% of the scale. BASDAI demonstrates a sensitivity to change within a short period of time. Following a 3 week physiotherapy course, the BASDAI showed a significant (p=0.009) 16.4% score improvement.

Tools and references

 * BASDAI automated calculation tool