Introduction
What is new?
The mother’s report of children’s overall use of antiasthmatics during the preceding year was highly valid compared with records of dispensed antiasthmatics in a nationwide prescription database. The mothers also reliably reported the brand names of the drugs used.
In addition, dispensed antiasthmatics showed high sensitivity in identifying children with maternal report of current asthma. Furthermore, in children with no report of asthma, the prevalence of dispensed antiasthmatics was very low. Thus, a nationwide prescription database of dispensed drugs can be a valuable data source in epidemiologic studies on asthma.
Asthma is the most common chronic disease among children in developed countries. In epidemiologic studies, questionnaire reports of asthma diagnosis and medication use have been a central source of information for assessing the prevalence of asthma [1], [2]. However, self-report or parental report of asthma may not be a sufficient way of defining asthma in studies of risk factors [3], [4]. The validity of parental reporting of pediatric asthma and asthma drug exposure has also been questioned because of possible recall bias, which may influence the prevalence estimates and surveillance of trends in asthma [5], [6], [7]. Therefore, it is useful to have more objective data to compare with parental reports in different populations. In large birth cohorts of children, rates of response to questionnaires may decrease over time as children get older. Thus, the availability of population-based prescription registry data can serve as surrogate disease endpoints among nonresponders and enable the assessment of nonresponse bias. Prescription data are a source of objective data that have become available in some countries, recently also in Norway [8].
Most studies on the validity of self-reported drug use have been performed in adult populations [7], [9]. Worldwide, there are very few validation studies on maternal reporting of drug use among children using registry data as the reference source. Pharmacy data in prescription databases may be a feasible reference standard in validity studies of parental reporting on children’s use of antiasthmatics [10]. Norway has had a complete nationwide prescription database since January 2004 [11].
The objectives of this study were to examine
- 1.
the validity of maternal report of children’s use of antiasthmatics in a pregnancy cohort, the Norwegian Mother and Child Cohort Study (MoBa), using the Norwegian Prescription Database (NorPD) as the reference standard and
- 2.
the validity of dispensed antiasthmatics recorded in NorPD as a measure of asthma using maternal report of children’s asthma in MoBa as the reference standard.