Comparison of the BASDAI and the miniBASDAI in assessing disease activity in patients with ankylosing spondylitis.

The BASDAI (Bath Ankylosing Spondylitis Disease Activity Index) is the most widely used instrument for the assessment of disease activity in ankylosing spondylitis (AS). Objective. The aims to investigate whether the alternative BASDAI, here termed as the miniBASDAI [(Question (Q) 1 fatigue + Q2 spinal pain) + mean of (Q5 strength morning stiffness + Q6 duration morning stiffness)] / 3], measures disease activity more accurately in the subgroup of AS patients without peripheral manifestations.