Reliability of a questionnaire for evaluating the understanding of asthma.

The present study was designed to evaluate the repeatability of a questionnaire developed to assess the understanding that asthma patients have of their disease and, on the basis of its variability, estimate the sample size necessary for determining the efficacy of a future structured program on asthma knowledge. The repeatability of the Asthma Questionnaire (AQ) was evaluated by asking 89 patients to complete it twice within a period of 7-10 days without the subject being exposed to any programme on asthma knowledge between the two administrations. The AQ was demonstrated to have good content and face validity. Results showed that neither age nor sex had a significant influence on total scores, and that the degree of reliability was adequate (R = 0.769). The mean percentage of correct answers was observed to be approximately 70% in both sessions, suggesting a consistent area for possible improvement which could be targeted by means of an appropriately structured programme on asthma knowledge. For comparative purposes before and after the programme, or for measuring its efficacy, the AQ should be recommended. In conclusion the Asthma Questionnaire could provide a useful tool for the general practitioner, chest physician and other health professionals, to assess what the patient really does understand or does not, concerning asthma management, and hence be the starting point for a well-tailored educational intervention.