The Brazilian Portuguese-language version of the Manchester Respiratory Activities of Daily Living questionnaire: construct validity, reliability, and measurement error

OBJECTIVE: To test the construct validity, reliability, and measurement error of the Brazilian Portuguese-language version of the Manchester Respiratory Activities of Daily Living (MRADL) questionnaire in patients with COPD. METHODS: We evaluated 50 patients with COPD, among whom 30 were men, the mean age was 64 ± 8 years, and the median FEV(1) as a percentage of the predicted value (FEV(1)%predicted) was 38.4% (interquartile range, 29.1-57.4%). Pulmonary function and limitations in activities of daily living (ADLs) were assessed by spirometry and by face-to-face application of the MRADL, respectively. For the construct validity analysis, we tested the hypothesis that the total MRADL score would show moderate correlations with spirometric parameters. We analyzed inter-rater reliability, test-retest reliability, inter-rater measurement error, and test-retest measurement error. RESULTS: The total MRADL score showed moderate correlations with the FEV(1)/FVC ratio, FEV(1) in liters, FEV1%predicted, and FVC%predicted, all of the correlations being statistically significant (r = 0.34, r = 0.31, r = 0.42, and r = 0.38, respectively; p < 0.05 for all). For the reliability and measurement error of the total MRADL score, we obtained the following inter-rater and test-retest values, respectively: two-way mixed-effects model intraclass correlation coefficient for single measures, 0.92 (95% CI: 0.87-0.96) and 0.89 (95% CI: 0.81-0.93); agreement standard error of measurement, 1.03 and 0.97; smallest detectable change at the individual level, 2.86 and 2.69; smallest detectable change at the group level, 0.40 and 0.38; and limits of agreement, −2.24 to 1.96 and −2.65 to 2.69. CONCLUSIONS: In patients with COPD in Brazil, this version of the MRADL shows satisfactory construct validity, satisfactory inter-rater/test-retest reliability, and indeterminate inter-rater/test-retest measurement error.