Assessing paediatric asthma occurrence through dispensed prescription data and questionnaires

The prevalence of asthma, a common disorder in childhood, is often estimated by cross-sectional studies based on questionnaires, with the drawback that estimates are limited to certain age groups and areas. The use of electronic health data is increasingly allowing researchers to overcome these limitations. This study is aimed at assessing asthma occurrence of a school-aged population in Northeast Italy using two different data sources.

In 2004, a population-based survey using a standardized questionnaire was conducted to estimate asthma occurrence among a resident population of children aged 6-7 years and adolescents aged 13 years. A selection of dispensed asthma medications was extracted from electronic databases for a 4-year period prior to questionnaire completion (2000-03). Asthma prevalence was estimated by commonly used questionnaire classifications and compared with use of inhaled bronchodilators (alone or in combination) in various time periods. Correlations between the two approaches were calculated.

A total of 10 252 subjects were eligible for analysis (85% of the resident population). A total of 4747 subjects (38% of the resident population) were registered in the drug database during 2000-03. Asthma prevalence was higher in males and in children. Congruence between the two enquiry methods varied according to criteria applied and improved with the protraction of the observation period.

A longer period for the capture of medication data yielded higher congruence. A degree of mismatch was observed between the two methods most likely related to factors of drug use and questionnaire reliability. Nonetheless, the benefits of using easily accessible population data prevail, and further studies are warranted.