Validation of the Airways Questionnaire 20 - AQ20 in patients with chronic obstructive pulmonary disease (COPD) in Brazil

introduction: a great emphasis has been placed on health-related quality of life of copd patients and specific questionnaires have been developed in order to measure it. objective: this study describes the language and cultural adaptation of a new (and short) disease-specific health status questionnaire developed for chronic obstructive pulmonary diseases: the airways questionnaire 20 (aq20). methods: in order to validate this questionnaire in brazil, it was initially translated into portuguese. the cultural adaptation was taken into consideration and then a back translation to english was undertaken, in order to obtain a final portuguese version. correlations were made with fev1, spo2, bmi and another disease-specific health status questionnaire, the saint george respiratory questionnaire (sgrq), previously validated in brazil. the interclass correlation ratio was done to test the reproducibility of aq20. results: the interclass correlation ratio for the total score was a = 0.90 (intra-observer variability) and a = 0.93 (inter-observer variability) (p < 0.05 for both). the correlation with total sgrq score was 0.76, with p < 0.001. the average time to answer the aq20 was 4 min and 6 s. conclusion: the brazilian portuguese version of aq20 is reproducible, of fast application and with good a correlation with sgrq total score, which makes it a valid questionnaire to measure health status in obstructive patients in brazil.