Objective: To evaluate knowledge of and techniques for using prescribed inhalation devices among patients with asthma or COPD treated at a tertiary teaching hospital. Methods: Patients were assessed after medical visits, and their physicians were blinded to this fact. Patients were asked to demonstrate their inhaler technique and were then interviewed regarding their knowledge of inhalation devices, control of the disease and instructions received during medical visits. Results: We included 120 volunteers: 60 with asthma and 60 with COPD. All of the asthma patients and 98.3% of the COPD patients claimed to know how to use inhaled medications. In the sample as a whole, 113 patients (94.2%) committed at least one error when using the inhalation device. Patients committed more errors when using metered-dose inhalers than when using the dry-powder inhalers Aerolizer® (p < 0.001) or Pulvinal® (p < 0.001), as well as committing more errors when using the Aerolizer® inhaler than when using the Pulvinal® inhaler (p < 0.05). Using the metered-dose, Pulvinal® and Aerolizer® inhalers, the COPD group patients committed more errors than did the asthma group patients (p = 0.0023, p = 0.0065 and p = 0.012, respectively). Conclusions: Although the majority of the patients claimed to know how to use inhalation devices, the fact that 94.2% committed at least one error shows that their technique was inappropriate and reveals a discrepancy between understanding and practice. Therefore, it is not sufficient to ask patients whether they know how to use inhalation devices. Practical measures should be taken in order to minimize errors and optimize treatment.

Keywords: Metered dose inhalers; Nebulizers and vaporizers; Asthma; Pulmonary disease, chronic obstructive.

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.

Keywords: Asthma; Questionnaires; Validation studies; Reproducibility of results.