Handling of and preferences for available dry powder inhaler systems by patients with asthma and COPD.

The correct handling of dry powder inhalers (DPIs) is crucial for efficient therapy, and acceptance of the device can improve compliance. The handling of seven different dry powder inhalers was studied in 72 patients with asthma and chronic obstructive pulmonary disease (COPD). The aim of this study was to identify possible handling errors and investigate patient preferences. Patients inhaled twice with each inhaler; first after reading the device leaflet, and second after device handling was explained by the investigator. The investigator identified handling errors and critical handling errors, which might lead to insufficient or no dose delivery. Afterward, the patients selected their preferred device and judged different aspects of device handling. The lowest number of patients with critical handling errors was observed for the Diskus/Accuhaler, the highest numbers for the Jethaler and the Easyhaler (% of patients during first/second use): Diskus/Accuhaler 25%/13.9% (group A) and 38.9%/8.3% (group B); Clickhaler 50.0%/52.8%, Cyclohaler 58.3%/13.9%, Jethaler 66.7%/30.6% (group A) and Benosid N Inhaler 52.8%/22.2%, Novolizer 52.8%/25.0%, Easyhaler 72.2%/47.2% (group B). Device handling improved after instruction by the investigator. Device handling and preferences of patients closely correlated in this study. Both devices producing the lowest numbers of handling errors (Diskus/Accuhaler and Clickhaler) had the highest preference by the subjects (score from 1 = very good to 7 = very bad): Diskus/Accuhaler 2.21 (group A) and 2.02 (group B); Clickhaler 2.21, Cyclohaler 2.80, Jethaler 3.16 (group A); Novolizer 2.33, Easyhaler 2.37, Benosid N Inhaler 2.43 (group B). Critical handling errors may reduce therapy outcome due to a reduced dose delivery. In addition, reduced patients acceptance of a device, being dependent on device handling, may have a similar effect by reducing patients' compliance.