Adaptation of the osteoarthritis-specific quality of life scale (the OAQoL) for use in Germany, Hungary, Italy, Spain and Turkey

The Osteoarthritis Quality of Life scale (OAQoL) is specific to individuals with osteoarthritis. The present study describes the adaptation of the OAQoL for use in the following five European languages: German, Hungarian, Italian, Spanish and Turkish. The study involved three stages in each language; translation, cognitive debriefing (face and content validity) and validation. The validation stage assessed internal consistency (Cronbach's alpha), reproducibility (test-retest reliability using Spearman's rank correlations), convergent and divergent validity (correlations with the Health Assessment Questionnaire, The Western Ontario and McMaster Universities Index of osteoarthritis and Nottingham Health Profile) and known group validity. The OAQoL was successfully translated into the target languages with minimal problems. Cognitive debriefing interviewees found the measures easy to complete and identified few problems with content. Internal consistency ranged from 0.94 to 0.97 and test-retest reliability (reproducibility) from 0.87 to 0.98. These values indicate that the new language versions produce very low levels of measurement error. Median OAQoL scores were higher for patients reporting a current flare of osteoarthritis in all countries. Scores were also related, as expected, to perceived severity of osteoarthritis. The OAQoL was successfully adapted for use in Germany, Hungary, Italy, Spain and Turkey. The addition of these new language versions will prove valuable to multinational clinical trials and to clinical practice in the respective countries.