Background: Knowledge of allergy patients' perception of own disease is inadequate, and understanding of the impact of local environment, including family and health-care system, on patients' management of disease is insufficient. We examined the potential of telephone-based survey techniques for establishing this knowledge in 10 European countries.
Methods: A two-phased questionnaire developed by use of focus groups in seven countries was translated into 10 languages. To ensure that the true values of the populations were restored in randomly selected populations, 75,343 telephone numbers selected for screening represented balanced national distributions of households.
Results: Eight thousand two hundred and sixty-eight respiratory allergy sufferers were identified by the telephone screening process. 85.4% accepted to participate in the survey and 89.6% completed both phases comprising 34 questions and rating of 49 statements. Data for each country were weighted in terms of age, sex and the recorded allergy prevalence within age intervals.
Conclusions: The telephone survey technique allowed for establishment of random representative samples, and application of mathematical weighting procedures assured that the true national values were restored in the data set. As all interviews were performed in a standardised manner we conclude that the telephone-based survey methodology enables national representative data set to be established and compared.