Measurement of adherence to inhaled corticosteroids by self-report and electronic medication monitoring

Objective: Poor adherence to daily inhaled corticosteroids (ICS) is an important factor contributing to asthma morbidity. Assessing adherence in clinical settings using self-reported adherence often overestimates actual adherence. Electronic monitoring devices (EMDs) are objective means of assessing adherence, but are not routinely used in practice. Here, we aimed to establish adherence rates to ICS using EMDs in an inner-city, minority population in the Bronx, NY, and to compare two methods of self-reported adherence with EMD-measured adherence. Methods: Patients with physician-confirmed persistent asthma and daily ICS prescription were recruited. Self-reported adherence to ICS was measured by parental report for children and self-report for adults and the Medication Adherence Report Scale for Asthma (MARS-A). Two weeks after enrollment, EMD data were accessed for analysis. Daily adherence was calculated based on the number of puffs actuated per day as captured by EMD divided by the prescribed number of puffs. Results: 41 children and 40 adults participated. Median EMD-measured ICS adherence was 41% (children) and 43% (adults). This was significantly lower than the median self-reported adherence (100% for children, p < 0.001; 100% for adults, p < 0.001). MARS-A score in children did not correlate with EMD adherence data (p = 0.18), while in adults, this correlation tended to be more consistent (p = 0.07). Conclusions: Adherence to daily ICS as measured using EMD is low in this population. In both adults and children, self-reported adherence was a poor indicator of true adherence. Further efforts using objective measures of medication adherence for patients with high asthma morbidity may be warranted to guide therapeutic decisions.