title: Evaluation of internal consistency and re-test reliability of Bath ankylosing spondylitis indices in a large cohort of adult and juvenile spondylitis patients in Taiwan.
abstract: The Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Bath Ankylosing Spondylitis Functional Index (BASFI), and Bath Ankylosing Spondylitis Global Score (BAS-G) have been recommended for evaluating function and disability in patients with ankylosing spondylitis (AS). The aim of this study was to develop a Chinese version of the BASDAI, BASFI, and BAS-G and assess their reliability and validity. The Chinese version was obtained after a translation and back-translation process. A total of 447 patients with adult and juvenile AS were assessed using these three instruments. Reliability was tested by internal consistency and test-retest reliability. Internal consistency of the instrument was given as Cronbach's alpha. Test-retest reliability was assessed by intraclass correlation coefficient. To assess the sensitivity to change, 153 patients were included in an 8-week follow-up study. In our analysis, the reliability of these three instruments-the BASDAI, BASFI, and BAS-G-for a 24-h test-retest showed acceptable intraclass correlation coefficients (0.92-0.94). Our Chinese versions of the BASDAI, BASFI, and BAS-G also showed 0.87, 0.94, and 0.90, respectively, with Cronbach's alpha coefficient, indicating good reliability. For sensitivity to change in 8-week follow-up, all three instruments showed 5.0 to 5.4% changes. Our Chinese versions of the BASDAI, BASFI, and BAS-G showed adequate reliability, validity, and responsiveness to clinical change. Thus, disease activity and functional status in Chinese-speaking patients with AS may be adequately evaluated with these versions of the original instruments.
authors.affiliation: Institute of Medicine, Chung Shan Medical University, Taichung, Taiwan.
authors.forename: James Cheng-Chung
authors.initials: JC
authors.lastname: Wei
authors.forename: Ruey-Hong
authors.initials: RH
authors.lastname: Wong
authors.forename: Jun-Huang
authors.initials: JH
authors.lastname: Huang
authors.forename: Chen-Tung
authors.initials: CT
authors.lastname: Yu
authors.forename: Chung-Tei
authors.initials: CT
authors.lastname: Chou
authors.forename: Ming-Shiou
authors.initials: MS
authors.lastname: Jan
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Tsay
authors.forename: Ming-Chih
authors.initials: MC
authors.lastname: Chou
authors.forename: Hong-Shen
authors.initials: HS
authors.lastname: Lee
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002624:Chemistry, Clinical / Q000379:methods; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013167:Spondylitis, Ankylosing / Q000097:blood / Q000175:diagnosis* / Q000208:ethnology*; D013624:Taiwan