Cross-cultural adaptation and assessment of reproducibility of the duke activity status index for COPD patients in Brazil

Abstract

Objective: To cross-culturally adapt the Duke Activity Status Index (DASI) for use in Brazil and evaluate the reproducibility of the new (Brazilian Portuguese-language) version. Methods: We selected stable patients with clinical and spirometric diagnosis of COPD. Initially, the DASI was translated into Brazilian Portuguese, and the cross-cultural adaptation was performed by an expert committee. Subsequently, 12 patients completed the questionnaire, so that their questions and difficulties could be identified and adjustments could be made. An independent translator back-translated the final version into English, which was then submitted to and approved by the original author. The final Brazilian Portuguese-language version of the DASI was applied to 50 patients at three distinct times. For the assessment of interobserver reproducibility, it was applied twice within a 30-min interval by two different interviewers. For the assessment of intraobserver reproducibility, it was applied again 15 days later by one of the interviewers. Results: The mean age of the patients was 62.3 ± 10.0 years, the mean FEV1 was 45.2 ± 14.7% of the predicted value, and the mean body mass index was 26.8 ± 5.8 kg/m2. The intraclass correlation coefficients for intraobserver and interobserver reproducibility were 0.95 and 0.90, respectively. The correlations between the DASI and the Saint George's Respiratory Questionnaire (SGRQ) domains were all negative and statistically significant. The DASI correlated best with the SGRQ activity domain (r = -0.70), the total SGRQ score (r = -0.66), and the six-minute walk distance (r = 0.55). Conclusions: The Brazilian Portuguese-language version of the DASI is reproducible, fast, and simple, correlating well with the SGRQ.