Brazilian version of airways questionnaire 20: a reproducibility study and correlations in patients with COPD.

This study describes the correlations and reproducibility of AQ20, a simple health status questionnaire with 20 questions, which was designed to be useful especially in time sparing situations. A formal language validation process was done, in order to validate the AQ20 before studying its reproducibility. Thirty stable COPD patients answered the final version twice within 15 days. To test the reproducibility of AQ20, the interclass correlation coefficient and Bland-Altman display were used. Results were correlated with FEV1, SpO2, BMI, Mahler BDI, and the Saint George Respiratory Questionnaire (SGRQ). Twenty-five patients (83.3%) were male, with a mean age of 68.6 years. The mean predicted FEV1 (%) was 56.8%. The interclass correlation ratio for the total score was alpha=0.90 for the intraobserver variability and alpha=0.93 for the interobserver variability. The correlation with total SGRQ score was 0.76, with P<0.001. The mean application time for AQ20 was 4 min and 6 s, and the score calculation time, was 8 s. It can be concluded that AQ20 is reproducible, with an excellent correlation with SGRQ total score, and also having the advantage of taking just a few minutes to be applied and to have its score calculated.