The aim of this study was to translate and adapt the original English-language versions of the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) and the Bath Ankylosing Spondylitis Functional Index (BASFI) into Ukrainian and validate the instruments by administering them to Ukrainian patients with ankylosing spondylitis (AS). After consensual translation, cultural adaptation, and back-translation into English, the Ukrainian versions of BASDAI and BASFI were transformed into numerical rating scales and tested on 87 Ukrainian AS patients meeting the modified 1984 New York criteria for AS. The Ukrainian versions were easily understood by the patients and displayed high levels of internal consistency and good reliability. The BASDAI (Ukrainian version) showed significant correlation with the duration of morning stiffness and the Maastricht Ankylosing Spondylitis Enthesitis Score (MASES) and weak correlation with CRP. The BASFI (Ukrainian version) showed significant correlations with Schober’s test, occiput-to-wall distance, and chest expansion measure. Both instruments were sensitive to modifications in the treatment regimen. Accordingly, the Ukrainian-language versions of BASDAI and BASFI reported here can be used to monitor the clinical status of Ukrainian patients with AS.
