Validação e reprodutibilidade do teste de avaliação da DPOC (CAT) em português para uso no Brasil e comparação entre duas versões de aplicação do questionário

Abstract

Background: The COPD assessment test (CAT) can provide a simple, efficient and reliable tool for assessing and monitoring COPD patients. It’s important to perform the validation study of the Brazilian version of the instrument and therefore may become available for studies with the Brazilian population. The literature indicates the existence of different modes of questionnaires administration (selfadministered, interview, telephone), however there are many ways to influence the responses obtained from these instruments, culminating in the appearance of bias, especially in countries with low educational levels. Objectives: to perform the validation and reproducibility of the Brazilian version of CAT (group 1) and to compare psychometric properties of two forms of the questionnaire application: face to face interview and telephone. Methods: Group 1- There were selected patients with stable COPD from two hospitals in Fortaleza-Ceará. CAT was administered in 50 patients on two occasions with an interval of 30 minutes, and a third time after one week. CAT has eight components: coughing, mucus production, chest tightness, capacity for exercise and activities, confidence, sleep quality and energy levels. Also the following tests were performed: Saint George questionnaire for respiratory diseases (SGRQ), pulmonary function tests, six-minute walk distance test (6MWD), modified index of dyspnea (MMRC) and hospital anxiety and depression scale (HADS). Group 2 – 100 patients were randomly assigned to either the face-to-face interviewer administered CAT (CAT-FFIA) or telephone interviewer administered CAT (CAT-TIA) group to asses internal consistency reliability, cross-sectional validity and test-retest reliability of the questionnaires. The patients answered the questionnaires twice, one week apart. In the same occasion, the patients answered the following questionnaires: SGRQ, HADS and MMRC. Results: Group 1 – CAT demonstrated excellent reproducibility, with an inter-rater ICC of 0.96 (95% CI: 0.93-0.97; p< 0.001) and an intra-rater ICC coefficient of 0.98 (95% CI: 0.96-0.98; p< 0.001). Bland-Altman plots showed good test-retest agreement for the CAT. The total score presented a significant correlation with SGRQ, espirometric values, 6MWDT, MRC and depression scores of HADS (p< 0.05). Group 2: For both administration formats, we found good internal consistency reliability (Crohnbach's alpha between 0,89 and 0.74 for the CAT-FFIA and CAT-TIA, respectively). In general, moderate-to-high correlations of CAT with SGRQ were observed, independent of the format of administration. For the test-retest reliability, the intraclass correlation coefficients were very similar for both CAT-FFIA and CAT-TIA group : 0,96 (95%CI 0,93-0,97) vs 0,98 (95%CI 0,96-0,98) respectively. In relation to discriminative properties of the CAT, it was observed that the questionnaire is able to assess the severity of COPD. The results showed significant differences in the scores of CAT in patients with moderate to severe COPD in both CAT-FFI and CAT-TIA. Conclusions: the Brazilian Portuguese version of CAT is a valid, reproducible and reliable instrument to evaluate the impact of COPD on patient’s lives. There were similarities in the psychometric properties when compared the format application of CAT (face to face interview versus telephone).