PMD179 - PATIENTS’ USABILITY OF SIX MOST USED DRY-POWDER INHALERS IN ASTHMA AND COPD

Abstract

Preference and usability of Inhalation devices, affect per sé the effectiveness and the outcomes of treatment in persistent airway obstruction, independently of the drug(s) administered. The Global Usability Score (GUS) Questionnaire was used to assess, rank, and compare the real usability of six devices. The questionnaire was administered to consecutive patients suffering from persistent asthma or COPD, from October to December 2017. Six devices were compared: Breezhaler, Diskus, Ellipta, Nexthaler, Spiromax, and Turbohaler. The predicted power of GUS was measures using ROC curve and the area under the curve (AUC) was calculated. A Bayesian Indirect Comparison (IC) model was built to assess the usability and to rank each device in a “global usability” classification. The cost-of-usability, defined as the cost due to nurse-training for ensuring a proper actuation and the device cost, was also calculated for each device. 110 patients tested Breezhaler, Spiromax, Nexthaler, and Ellipta, and 112 tested Breezhaler, Spiromax, Diskus, and Turbohaler. Predicted power of GUS questionnaire resulted high in predicting the most preferred/easiest/difficult device (AUC>0.90, p-value<0.001) and in ordering devices according to both patient and nurse judgment (AUC 0.929 and 0.874, respectively, p<0.001). Results of IC analysis proved Ellipta be the most preferred device (rank 1 to 3), while Breezhaler resulted the least preferred device ranked 5 to 6. Cost-of-usability, considering time needing to instruct at least one patient to achieve the proper inhalation at the first attempt, reflected this ranking. The usability of inhalers is a complex and multifaceted issue that should include the role of patients’ beliefs and other objective determinants which are unrelated to the sole patients’ viewpoint. The GUS represents the first comprehensive score for assessing, ranking, and comparing objectively the contribution of all main components of inhaler usability, and then provide an effective and motivated standard of choice.