Research article
Verifying a questionnaire diagnosis of asthma in children using health claims data
1 Division of Respiratory Medicine, Hospital for Sick Children, Toronto, Canada
2 Child Health Evaluative Sciences, Hospital for Sick Children, Toronto, Canada
3 Health Canada, Ottawa, Ontario, Canada
BMC Pulmonary Medicine 2011, 11:52 doi:10.1186/1471-2466-11-52
Published: 22 November 2011Abstract
Background
Childhood asthma prevalence is widely measured by parental proxy report of physician-diagnosed asthma in questionnaires. Our objective was to validate this measure in a North American population.
Methods
The 2884 study participants were a subsample of 5619 school children aged 5 to 9 years from 231 schools participating in the Toronto Child Health Evaluation Questionnaire study in 2006. We compared agreement between "questionnaire diagnosis" and a previously validated "health claims data diagnosis". Sensitivity, specificity and kappa were calculated for the questionnaire diagnosis using the health claims diagnosis as the reference standard.
Results
Prevalence of asthma was 15.7% by questionnaire and 21.4% by health claims data. Questionnaire diagnosis was insensitive (59.0%) but specific (95.9%) for asthma. When children with asthma-related symptoms were excluded, the sensitivity increased (83.6%), and specificity remained high (93.6%).
Conclusions
Our results show that parental report of asthma by questionnaire has low sensitivity but high specificity as an asthma prevalence measure. In addition, children with "asthma-related symptoms" may represent a large fraction of under-diagnosed asthma and they should be excluded from the inception cohort for risk factor studies.
