Validation of the Korean Ankylosing Spondylitis Quality of Life Questionnaire

BACKGROUND: Measuring accurate and reliable scores of quality of life in patients with ankylosing spondylitis (AS) is important in both decision-making and treatment planning for the disease. Questionnaire, The ankylosing spondylitis quality of life (ASQoL), is one of the representative tools for assessing how seriously AS patients view their disease severity, activity, as well as their overall health. To make these types of questionnaires readable and understandable, local language translation of surveys should be required. A Korean version of the ASQoL questionnaire has accordingly been developed. This study assessed the Korean version of the ASQoL survey to evaluate the reliability and validity of it. METHODS: Translation and reverse translation of the English ASQoL survey were conducted. A total of 120 consecutive AS patients received a mail including the Korean-translated 36-Item Short Form Survey (SF-36), the ASQoL survey, and the visual analog scale (pain). The coefficient of intraclass correlation and Cronbach’s alpha were computed, and factor analysis, as well as reliability assessments utilizing the kappa agreement statistics for each item, was undertaken. By analyzing the responses to SF-36 and ASQoL questionnaire utilizing Pearson’s correlation coefficient, construct validity was calculated. RESULTS: Factor analysis was performed regarding pain, physical function, and mental function. The kappa statistic of agreement was larger than 0.6 for all items. The ASQoL questionnaire had adequate test and re-test reliability (0.814). Furthermore, Cronbach’sα, the internal consistency, was very good (0.877). The Korean-translated ASQoL questionnaire demonstrated a significantly strong correlation between the single domain and total SF-36 scores. CONCLUSIONS: The Korean version of the ASQoL questionnaire showed acceptable properties of measurement and successful translation. Thus, it can be said that the questionnaire is appropriate for evaluating the outcomes of Korean patients with AS.