Greek adaptation and validation of the Ankylosing Spondylitis Quality of Life (ASQoL) measure

Background: Ankylosing Spondylitis (AS) is a chronic rheumatic disease that has a significant impact on patient's quality of life (QoL). The Ankylosing Spondylitis Quality of Life (ASQoL) questionnaire is a disease-specific patient-reported outcome measure for assessing QoL in AS. While the ASQoL has been adapted for use in 46 countries worldwide, a Greek language version of the measure has not been available and was required for an international clinical trial. Aim: The aim was to develop and assess the psychometric properties of a Greek language version of the ASQoL. Methods: The adaptation of the ASQoL into Greek involved three procedures: translation, assessment of face and content validity, and formal validation. The measure was translated into Greek using two translation panels. Cognitive debriefing interviews were employed to determine face and content validity. Finally, the translation's psychometric properties were examined by administering it on two occasions, with a 14-day interval. The Nottingham Health Profile (NHP) was used as a comparator measure. Results: The ASQoL proved straightforward to translate into Greek and interviewees found it relevant, comprehensible and easy to complete. The measure had good internal consistency (alpha = 0.92) and test-retest reliability (r = 0.98). Predicted correlations with the NHP provided evidence of the convergent validity of the two measures. Construct validity was confirmed by the measure's ability to distinguish groups of AS patients varying by perceived disease severity and general health. Conclusions: The Greek ASQoL has been shown to be well-accepted, reliable and valid and can be recommended for use in clinical studies and routine clinical practice in AS.