Background: Inhaler mishandling is a common issue among patients suffering from asthma and is associated with poor clinical outcomes and greater consumption of health-care resources. Ease of use can improve inhaler technique and, possibly, patients' preference for their inhaler device, which in turn may lead to better adherence to therapy.
Methods: This study investigated usability characteristics of NEXThaler(®) versus two other dry powder inhalers (DPIs; Diskus(®) and Turbuhaler(®)). Sixty-six adult patients with asthma (mean age 42.9±17.7 years) and with no previous experience of using a DPI were included in a randomized crossover comparison of the three devices. The main measures of usability were the number of steps failed for each device and the number of people who were able to use the device successfully (effectiveness), the time it took patients to set up the device and the time to read the instructions for use (IFU; efficiency), and patient preferences (satisfaction). Inhaler technique was evaluated after the IFU leaflet was read.
Results: NEXThaler was found to be superior to the other two DPIs in terms of the number of device use failures (p<0.001), time to set up (p<0.001), and time to read IFU (p<0.001). Additionally, the proportion of participants who completed a successful inhalation without any errors at all was significantly higher for NEXThaler than for Diskus and Turbuhaler (p<0.001). Patients rated NEXThaler as the easiest to use and most preferred inhaler to own (p<0.001).
Conclusions: NEXThaler displayed better usability compared with Diskus and Turbuhaler. The improved usability and higher satisfaction with the device may contribute to increased patient adherence to asthma treatment.
Keywords: asthma; dry powder inhaler; error; preference; usability.