Validation of the Modified Pulmonary Functional Status and Dyspnea Questionnaire and the Medical Research Council scale for use in Brazilian patients with chronic obstructive pulmonary disease.

OBJECTIVE To determine the validity and reproducibility of two subjective instruments to assess limitations in activities of daily living (ADLs) in patients with chronic obstructive pulmonary disease (COPD) in Brazil: the Pulmonary Functional Status and Dyspnea Questionnaire - Modified version (PFSDQ-M) and the Medical Research Council (MRC) scale. METHODS Thirty patients with COPD (age, 67 +/- 10 years; males, 17; forced expiratory volume in one second, 42% +/- 13% of predicted) completed the Portuguese-language versions of the two instruments on two occasions, one week apart. The PFSDQ-M has three components: influence of dyspnea on ADLs, influence of fatigue on ADLs change in ADLs experienced by the patient. The MRC scale is simple, with only five items, in which patients report the degree to which dyspnea limits their performance of ADLs. The traditional Saint George's Respiratory Questionnaire (SGRQ), previously validated for use in Brazil, was used as a validation criterion. RESULTS The test-retest reliability (intraclass correlation coefficient) of the PFSDQ-M was 0.93, 0.92 and 0.90 for dyspnea, fatigue and change components, respectively, compared with 0.83 for the MRC scale. Bland-Altman plots showed good test-retest agreement for the PFSDQ-M. The components of the PFSDQ-M and the MRC scale correlated significantly with all of the domains and the total score of the SGRQ (0.49 < r < 0.80; p < 0.01 for all). CONCLUSIONS The Portuguese-language versions of the PFSDQ-M and the MRC scale proved reproducible and valid for use in patients with COPD in Brazil.