The Bath metrology index as assessed by a trained and an untrained rater in patients with spondylarthropathy: a study of intra- and inter-rater agreements

The Bath ankylosing spondylitis metrology index (BASMI; range 0–10) has gained widespread use in daily clinical practice as an objective measure of spinal stiffness not only in patients with ankylosing spondylitis (AS) but also in patients with other spondylarthropathies (Sp A ). We examined intra-rater and inter-rater reproducibility of BASMI scoring in 30 Danish patients with Sp A (median age 40 years, range 22–56 years) fulfilling the European Spondylarthropathy Study Group criteria, 25 of them satisfying the modified New York Criteria for AS. Measurements were performed twice on two different days (median interval 7 days, range 4–11) by a trained physiotherapist (PT) and by an untrained nurse who had undergone a single 1-h training session with the PT. The median BASMI score obtained by the PT on the two test days was 3.5 (range 1–8) and 3.0 (range 1–8), respectively (NS). Test–retest BASMI scores from the PT were significantly correlated ( r s = 0.95, p