Reliability and validity of a German asthma quality of life questionnaire
Swiss Medical Weekly
The Asthma Quality of Life Questionnaire (University of Sydney [AQLQ-Sydney]) is a self-administered questionnaire that has been developed in Australia and validated in different languages in Australia, the USA and Spain. We developed a German translation of this questionnaire by applying a sequential forward and backward translation approach. The objective of this study was to validate a German translation of the AQLQ-Sydney questionnaire in an outpatient population of asthmatic patients in
... atic patients in Switzerland. Outpatients were assessed for a diagnosis of asthma and those who consented were selected for the validation study. All patients had spirometry, methacholine challenge testing, fractional exhaled nitric oxide recorded and answered the German AQLQ-Sydney. A subgroup of 17 patients answered the questionnaire for a second time after receiving asthma treatment with combined steroids and bronchodilators for two months. Test-retest-reliability was tested in 12 stable asthmatic patients without treatment modification. Of 90 patients assessed, 57 were diagnosed with asthma and participated in the validation study. The total score did not significantly correlate with any of the objective measures of severity of asthma. However, the "Breathlessness" subscale score correlated weakly with PD20 methacholine. Internal consistency was high with Cronbach's alpha of 0.97 for the total score and 0.91-0.97 for the subscale scores. Test-retest reliability was also high for the total score and the subscale scores. The questionnaire detected a significant improvement in total quality of life score and "Breathlessness" and "Mood" subscale scores after a period of combined treatment with inhaled steroids and long acting bronchodilators. The German translation of the AQLQ-Sydney had a good internal consistency and test-retest-reliability in stable asthmatic patients. It shows responsiveness to treatment. Some correlations with objective markers were detected.