Evaluating the reliability of Persian version of ankylosing spondylitis quality of life (ASQoL) questionnaire and related clinical and demographic parameters in patients with ankylosing spondylitis

Abstract

Ankylosing spondylitis quality of life (ASQoL) is an instrument for assessing quality of life (QoL). The aims of this study were to assess the reliability of Persian version of ASQoL questionnaire and evaluation of QoL status and related factors in ankylosing spondylitis (AS). One hundred and sixty-three Iranian patients with AS who fulfilled modified New York criteria were enrolled. Patients were evaluated using questionnaires including demographic and clinical variables, Bath AS Disease Activity Index (BASDAI), Bath AS Functional Index (BASFI), fatigue, Bath AS Metrology Index, pain and ASQoL. Reliability and validity of Persian version of ASQoL were evaluated by test-re-test agreement, internal consistency and correlation with specific scales. Relationship of parameters with ASQoL was analyzed by multiple regression. Age, disease duration and ASQoL score (mean ± SD) were 37.74 ± 9.88, 14.49 ± 8.47 and 8.02 ± 5.28 years, respectively. Test-re-test reproducibility for ASQoL was good as assessed by intra-class correlation coefficient (ICC: 0.97, P < 0.001). Internal consistency was high (Cronbach's alpha: 0.91). Convergent validity was confirmed by correlation of ASQoL score with specific scales (BASFI, r = 0.74, BASDAI, r = 0.6, fatigue, r = 0.56, depression, r = 0.24, intermalleolar distance, r = -0.44 and educational level, r = -0.37). Persian version of ASQoL is a valid and reliable scale to assess QoL in AS. Function, fatigue, mood, hip mobility and education are the factors which should be noted to achieve the best QoL.