Objective: To determine the physical function and the quality of life (QOL) of Spanish patients with ankylosing spondylitis (AS), and to study the reliability of the Spanish version of the Bath Ankylosing Spondylitis Functional Index (BASFI).
Methods: Clinimetric variables, including Spanish BASFI (test-retest), Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), QOL instruments (Short Form 36 [SF-36] and European Quality of Life Questionnaire [EuroQol]), Bath Ankylosing Spondylitis Metrology Index (BASMI), and chest expansion, were assessed.
Results: A total of 92 patients were included: 69 males (75%), age (mean +/- SD) 40.7 +/- 9.1 years, and disease duration 11 +/- 7.8 years. The scores (mean +/- SD) were (from 0 the best to 10 the worst): BASFI 4.3 +/- 2.4; BASDAI 4.5 +/- 2.2; global SF-36 5.5 +/- 2.1; SF-36 physical function 3.8 +/- 2.5; SF-36 physical scale 4.9 +/- 2.7; SF-36 mental scale 3.7 +/- 2.7; SF-36 physical role limitations 5.6 +/- 4.4; SF-36 general health 5.5 +/- 2.1; SF-36 pain 5.4 +/-2.8; SF-36 vitality 5.1 +/- 2; EuroQoL rating scale 3.9+/-2.1; EuroQol health profile (from 0 the best to 2 the worst) 0.6 +/- 0.4; and BASMI 4.7 +/- 1.6. Significant association was found between BASFI and SF-36 physical function domain (r = 0.75, R(2) = 0.56, P < 0.0001). BASFI Cronbach's alpha was 0.92, Spearman's rho = 0.91, P < 0.0001.
Conclusions: Physical function and QOL are deteriorated in AS. The physical domain is more impaired than the mental one. The SF-36 and the health profile of the EuroQol may be used as generic instruments to measure health-related QOL. Spanish BASFI index is a reliable instrument.