Development and validation of an asthma knowledge questionnaire for use in Brazil.

OBJECTIVE To develop and validate an asthma knowledge questionnaire for use in adult asthma patients in Brazil. METHODS A 34-item self-report questionnaire was constructed and administered to adult asthma patients and adult controls. The maximum total score was 34. RESULTS The questionnaire was shown to be discriminatory, with good reliability and reproducibility. The mean score for asthma patients and controls was, respectively, 21.47 +/- 4.11 (range: 9-31) and 17.27 +/- 5.11 (range: 7-28; p < 0.001). The Kaiser-Meyer-Olkin measure of sampling adequacy was 0.53, and the Bartlett's test of sphericity demonstrated a satisfactory suitability of the data to factor analysis (p < 0.001). There was no significant difference between the total scores obtained in the first and in the second application of the questionnaire within a two-week interval (p = 0.43). The internal consistency reliability (KR-20 coefficient) was 0.69. CONCLUSIONS This study has validated an asthma knowledge questionnaire for use in Brazil.