Leung YY, et al. – This study was designed to adapt and validate the Singapore Chinese and Singapore English versions of the Ankylosing Spondylitis Quality of Life (ASQoL) scales. The ASQoL was successfully adapted into Singapore Chinese and English language versions. Moreover, it appeared to be culturally relevant, valid and reliable when used with combined samples of axial spondyloarthritis (AxSpA) patients who speak either Chinese or English.

Methods

• By professional and lay translation panels, translation of the ASQoL into Singapore Chinese and English was performed.
• Field–testing for face and content validity was performed by interviewing ten Chinese speaking and ten English speaking axial spondyloarthritis (AxSpA) patients.
• In validation surveys, AxSpA patients (either Chinese or English speaking) were enrolled.
• The Health Assessment Questionnaire (HAQ), Short Form Health Survey (SF–36), Bath Indices, and other measures of disease activity were used as comparator scales for convergent validity.
• In a test–retest postal study, a separate sample of AxSpA patients were invited to participate, with 2 weeks between administrations.

Results

• 183 patients (77% males, 82% English speaking), with a mean (SD) age of 39.4 (13.7) years were enrolled in this study.
• Findings suggested that the ASQoL had excellent internal consistency (Cronbach’s alpha = 0.88), and correlated moderately with all the comparator scales.
• The ASQoL was able to distinguish between patients grouped by disease activity and perceived general health.
• The ASQoL fulfilled the Rasch model analysis for fit, reliability and unidimensionality requirements.
• No significant differential item functioning was noted for gender, age below or above 50 years, and language of administration.
• Test–retest reliability was good (r = 0.81).