Tradução para a língua portuguesa, adaptação cultural e análise das propriedades de medidas da escala de fadiga de Manchester para uso em indivíduos com doença pulmonar obstrutiva crônica no Brasil

Abstract

Introduction: Chronic obstructive pulmonary disease (COPD) is a preventable and treatable respiratory disease characterized by chronic airflow obstruction that is not fully reversible. Fatigue is one of the main symptoms reported by individuals with COPD when performing activities that require physical effort. However, there are still no specific, translated, and validated instruments for the assessment of fatigue in the Brazilian population with COPD. The Manchester COPD Fatigue Scale (MCFS) may fill this gap. Aim: To perform the translation into Brazilian Portuguese, the cultural adaptation and to analyze the properties of the MCFS measures. Materials and methods: Cross-sectional study carried out in two phases: (1) translation and cross-cultural adaptation of the scale and (2) evaluation of measurement properties. The first Phase of the study, after the consent of the researcher holding the MCFS rights, involved translation and cross-cultural adaptation. In the second Phase, validation was performed through the analysis of measurement properties. Fatigue was assessed using the MCFS and the Functional Assessment of Chronic Illness Therapy Fatigue Scale (FACIT-F); pulmonary function was assessed using spirometry; dyspnea was measured by the modified Medical Research Council Dyspnea Scale (mMRC); the impacts of the disease on daily life was assessed by the COPD Assessment Test (CAT); the effort tolerance was measured by the sixminute step test (6MST). Psychometric analyzes included internal consistency, reliability, reproducibility, validity concurrent, convergent, discriminant and interpretability. Results: 130 participants diagnosed with COPD were evaluated, 30 in Phase 1 and 100 in Phase 2 (69.9 ± 8.9 years, 60% women). The instrument showed adequate internal consistency (Cronbach's alpha = 0.97), test-retest coefficients (intraclass correlation coeficiente- ICC) were high (ICC from 0.88 to 0.97), significant correlations were observed for concurrent validity with the CAT (r = 0.80) and with FACIT-F (r = -0.87) and convergent validity with the mMRC (r = 0.74), the correlation with the 6MST was low (r = -0.37). MCFS was effective in discriminating groups with different sensation of dyspnea (p<0.0001). The standard error of the measurement was 0.81 and the smallest detectable difference was 2.48. There was no floor and ceiling effect. Conclusions: The MCFS translated and cross-culturally adapted for the Brazilian population is a reliable and valid instrument for assessing fatigue in individuals with COPD in Brazil.