Background and objective: Adherence with preventive asthma medication by young children is an important factor when evaluating a suboptimal response to treatment. However, few data exist regarding the accuracy of subjective measures of adherence and factors associated with adherence in young children.
Methods: Fifty-one asthmatic children aged 18 months to 7 years had their use of preventive asthma medication monitored using an electronic monitoring device (Smartinhaler) for 1 month. At a follow-up visit the child's parent was asked how often medication had been given and they also completed a confidential questionnaire that included questions about medication usage, barriers to optimal adherence and parenting. The treating physician made an estimate of the child's likely use of medication.
Results: The median use of medication as determined by the Smartinhaler was 70.5% (range 21.4-100%). The parents' verbal reports (85.1%) and questionnaire responses (84.2%) overestimated medication usage. The physician was not able to determine which parents correctly estimated their child's use of medication (P = 0.28). The child's age, level of parental education and annual family income did not influence adherence. Parents reported simply 'forgetting' or their child's 'reaction to being given medication' as the principal barriers to adherence. There was a significant association between how stressful the parent found parenting and adherence (P = 0.05).
Conclusion: Adherence with preventive medication, even within the context of a research study, was generally low and highly variable. Subjective measures of adherence were found to overestimate adherence in young asthmatics.