Influence of Adherence to Inhaled Corticosteroids and Inhaler Handling Errors on Asthma Control in a Japanese Population

OBJECTIVE: High adherence to medications and accurate handling of inhaler devices are important for asthma management. However, few reports to date have simultaneously evaluated adherence and handling errors. We therefore investigated the adherence to inhaled corticosteroid (ICS) and inhaler handling errors in the same patients in cooperation with pharmacists. METHODS: Data were derived from a survey of physicians and pharmacists treating asthma patients who visited participating hospitals and pharmacies from July 2012 to January 2013. The patients were evaluated for asthma control using the Asthma Control Test (ACT) and for inhaler handling errors using checklists. ICS adherence was evaluated based on pharmaceutical records. RESULTS: Adherence among participants (n=290) was 33.3% (mean), and the percentage of inhaler handling errors was 20.0% (mean). Total inhalation times in the high-adherence group were fewer than those in the low-adherence group. In a comparison by device, adherence to pressurized metered dose inhalers was significantly lower than that to Diskus(Ⓡ) inhalers, presumably attributable to the total number of inhalations per day. Adherence, handling errors, and total number of inhalations per day were significantly different between the asthma-controlled group and the uncontrolled group. A multivariate analysis showed that adherence and handling errors were independent factors contributing to asthma control. CONCLUSION: Our data indicated that both adherence to ICS and device handling errors contributed to asthma control in this population.