Measurement of children's asthma medication adherence by self report, mother report, canister weight, and Doser CT

Background: Accurate assessment of medication adherence has been difficult to achieve but is essential to drug evaluation in clinical trials and impro ved outcomes in clinical care. Objective: This study was conducted to compare four adherence assessment me thods: child report, mother report, canister weight, and electronic measure ments of metered dose inhaler (MDI) actuation. Methods: Participants included 27 children with mild-to-moderate asthma who were followed prospectively for 6 months. All patients used an MDI equippe d with an electronic Doser attached to their inhaled steroid. At each 2-mon th follow up visit, Doser and canister weight data were recorded, while chi ld and mother were interviewed separately regarding medication use. Results: Children and mothers reported, on average, over 80% adherence with the prescribed inhaled steroid. Canister weight revealed, on average, adhe rence of 69%, significantly lower than self-report. When adherence recorded by the electronic Doser was truncated to no more than 100% of prescribed d aily use, average adherence was 50%. Older children and adolescents, nonwhi te children, and these from poorer functioning families were least adherent . Conclusions: Electronic adherence monitoring was significantly more accurat e than self-report or canister weight measures. Such accuracy is an essenti al prerequisite to increasing understanding of the treatment, setting, and patient factors that influence adherence, and to the consequent design of e ffective intervention strategies.