Adaptation and validation of the ankylosing spondylitis quality of life (ASQOL) questionnaire for use in serbia

M. I. Zlatkovic-Svenda, M. M. Radak-Perovic, J. Milicevic, R. Stojanovic, B. Lazovic, P. Ostojic, J. Wilburn, S. McKennaInstitute of Rheumatology, University of Belgrade School of medicine, Belgrade Hospital Center Uzice, General hospital Pozega, Uzice University Clinical Hospital Center Zemun, University of Belgrade School of Medicine, Belgrade, Serbia 4Galen Research Ltd School of Health Sciences, University of Manchester, Oxford Road, Manchester, United Kingdom  Objectives: To translate and adapt a Serbian version of the Ankylosing Spondylitis Quality of Life (ASQoL) questionnaire and to validate it in Serbian speaking AS patients. Methods: The ASQoL development was conducted in three stages. The first stage comprised of a dual-panel translation: a bilingual panel (to provide the initial translation into the target language) and a lay panel (where items are assessed by people of average and below average education levels for comprehension and “naturalness” of language). The second stage involved cognitive debriefing interviews to assess the applicability, relevance and comprehensiveness of the new questionnaire. The third stage was a psychometric evaluation of the new questionnaire to assess construct validity, convergent validity and known-group validity. Convergent validity determined associations between ASQoL and NHP section scores by using Spearman’s rank correlation coefficients. Known-group validity was evaluated by testing of the ASQoL ability to distinguish between groups of patients who differed according to perceived general health, incidence of flare-ups and perceived disease severity. Nonparametric tests for independent samples (Mann-Whitney U test for two groups or Kruskal–Wallis one-way analysis of variance for three or more groups) were used. Internal consistency was assessed using Cronbach’s alpha coefficient. Reproducibility was measured by test-retest reliability. Results: Cognitive debriefing interviews were conducted with 10 AS individuals (50% male), aged 38,4 (8,8) years. A few items (i.e. chronically and ‘I get frustrated…’) were not fully understood by all participants and were amended to be more natural sounding in Serbian. The Serbian ASQoL was deemed relevant, clear and easy to complete. Psychometric evaluation was conducted in 60 patients (70% male), aged 37,9 (11,1) years. No significant differences in ASQoL scores were found between males and females or between older and younger patients (p=0.41, p=0.16). Considering convergent validity, the ASQoL correlated the most strongly with the Pain (r=0.79) and Emotional reactions (r=0.78) sections of the NHP. The ASQoL highly correlated with the Physical mobility (r=0.77) and Energy scales (r=0.75), indicating the importance of these factors on QoL in AS. The ability of the Serbian ASQoL to detect meaningful differences was demonstrated by ASQoL scores according to patients perceived general health (p<0.05) and disease severity (p<0.05). Cronbach’s alpha coefficient for the ASQoL was 0.95 at Time 1 and 0.91 at Time 2, indicating good internal consistency. Test-retest reliability was good, with a correlation coefficient of 0.84. Conclusions: The Serbian version of the ASQoL demonstrated good psychometric properties proving it to be a valid and reliable tool for use in routine clinical practice and in clinical trials. Disclosure of Interest: None declared DOI: 10.1136/annrheumdis-2018-eular.4012 Citation: Ann Rheum Dis, volume 77, supplement Suppl, year 2018, page A856Session: Validation of outcome measures and biomarkers