Doward, L.C., Spoorenberg, A., Cook, S.A., Whalley, D., Helliwell, P.S., Kay, L.J., McKenna, S.P., Tennant, A., van der Heijde, D. and Chamberlain, M.A. (2003) Development of the ASQoL: a quality of life instrument specific to ankylosing spondylitis. Annals of the Rheumatic Diseases, 62 (1). pp. 20-26. ISSN 0003-4967
Background: Although disease-specific health status measures are available for ankylosing spondylitis (AS), no instrument exists for assessing quality of life (QoL) in the condition.
Objective: To produce an AS-specific QoL measure that would be relevant and acceptable to respondents, valid, and reliable.
Methods: The ASQoL employs the needs-based model of QoL and was developed in parallel in the UK and the Netherlands (NL). Content was derived from interviews with patients in each country. Face and content validity were assessed through patient field test interviews (UK and NL). A postal survey in the UK produced a more efficient version of the ASQoL, which was tested for scaling properties, reliability, internal consistency, and validity in a further postal survey in each country.
Results: A 41 item questionnaire was derived from interview transcripts. Field testing interviews confirmed acceptability. Rasch analysis of data from the first survey (n=121) produced a 26 item questionnaire. Rasch analysis of data from the second survey (UK: n=164; NL: n=154) showed some item misfit, but showed that items formed a hierarchical order and were stable over time. Problematic items were removed giving an 18 item scale. Both language versions had excellent internal consistency (α=0.89–0.91), test-retest reliability (r(s)=0.92 UK and r(s)=0.91 NL), and validity.
Conclusions: The ASQoL provides a valuable tool for assessing the impact of interventions for AS and for evaluating models of service delivery. It is well accepted by patients, taking about four minutes to complete, and has excellent scaling and psychometric properties.
|Copyright, Publisher and Additional Information:||© 2003 by Annals of the Rheumatic Diseases. Supplementary material is available from the ARD website at http://ard.bmjjournals.com/cgi/reprint/62/1/20|
|Keywords:||ankylosing spondylitis, quality of life, questionnaire, health status|
|Institution:||The University of Leeds|
|Academic Units:||The University of Leeds > Faculty of Medicine and Health (Leeds) > Institute of Molecular Medicine (LIMM) (Leeds) > Section of Musculoskeletal Disease (Leeds)|
|Depositing User:||Repository Officer|
|Date Deposited:||13 Mar 2006|
|Last Modified:||16 Sep 2016 15:52|