Original Article
High validity of mother-reported use of antiasthmatics among children: a comparison with a population-based prescription database

https://doi.org/10.1016/j.jclinepi.2010.10.014Get rights and content

Abstract

Objectives

To examine the validity of (1) maternal questionnaire report of children’s use of antiasthmatics using a prescription database as the reference standard and (2) dispensed antiasthmatics as a measure of asthma using maternal report of children’s asthma as the reference standard.

Study Design and Setting

A total of 3,394 children in the Norwegian Mother and Child Cohort Study aged 7 years were linked to the Norwegian Prescription Database. Maternal report of both children’s use of antiasthmatics during the preceding year and the presence of asthma was compared with data on dispensed antiasthmatics.

Results

A total of 2,056 mothers responded and reported use of antiasthmatics during the previous year in 125 of 147 children who had been dispensed antiasthmatics (sensitivity 85.0%). Of the 1,909 children with no dispensed antiasthmatics, 1,848 had no maternal report of antiasthmatic use (specificity 96.8%). Mothers reported current asthma in 133 (6.5% of 2,056) children, including in 122 (5.9%) reported as verified by a doctor. Of these 122, 98 had been dispensed antiasthmatics during the preceding year (sensitivity 80.3%). Only 1.2% of the children without reported asthma were dispensed antiasthmatics.

Conclusion

Mother-reported use of antiasthmatics during the previous year among 7-year-old children is highly valid. Dispensed antiasthmatics would be a useful proxy for the presence of current asthma when disease data are not available.

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.

Section snippets

Materials and methods

The present study is based on the MoBa conducted by the Norwegian Institute of Public Health, which is a prospective nationwide pregnancy cohort enrolling pregnant women and their partners throughout Norway [12]. Data from MoBa on the children’s use of antiasthmatics and asthma history as reported by mothers in the year after the child turned 7 years were compared with data on dispensed antiasthmatics recorded in the nationwide NorPD. Data from MoBa and NorPD were linked using the unique

Prevalence of dispensed antiasthmatics as recorded in NorPD

The 1-year prevalence of dispensed antiasthmatics in 2008 recorded in NorPD was 7.6% (95% CI: 5.9, 9.4) among responders and 7.9% (95% CI: 5.8, 9.9) among nonresponders to the MoBa 7-year questionnaire.

Mother-reported overall use of antiasthmatics vs. dispensed antiasthmatics

Mothers reported use of antiasthmatics among their children during the preceding year in 125 of 147 children (Table 2) who redeemed prescriptions in NorPD giving a sensitivity of 85.0%. Of 1,909 children with no record of dispensed antiasthmatics in NorPD, 1,848 had no maternal report of

Discussion

In this large population-based sample, we showed that mother-reported use of antiasthmatics in general and of specific brand names of antiasthmatics in children aged 7 years had high sensitivity and specificity when using NorPD as the reference standard.

In addition, we showed that the sensitivity for dispensed antiasthmatics during the past year recorded in NorPD was 80% for children with current physician-diagnosed asthma, increasing to 94% when taking into account antiasthmatics dispensed

Conclusion

Our study confirms that mother-reported use of antiasthmatics during the previous year among 7-year-old children is highly valid. In addition, our data suggest that prescription data on dispensed antiasthmatics would be a useful proxy for the presence or absence of current asthma when disease data are not available.

Acknowledgments

The MoBa is supported by the Norwegian Ministry of Health, National Institutes of Health/National Institute of Environmental Health Sciences (NIH/NIEHS) (contract no. ES-044008), NIH/National Institute of Neurological Disorders and Stroke (grant no. UO1 NS 047537-01), and the Norwegian Research Council (NRC)/Functional genomics (FUGE) (grant no. 151918/S10). Dr London is supported by the Intramural Research Program, NIEHS, NIH, Department of Health and Human Services. Ph D student Karlstad is

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