Late Breaking Abstract - The use of a digital inhalation coach reduces inhalation error rates in a clinical trial.

<bold>Background:</bold> Inhalation errors are a common source of underdosing in asthma patients, leading to poor asthma control. Thus, regular inhalation training is recommended. The Kata^® app is a digital inhalation coach that provides step-by-step guidance on how to inhale correctly. <bold>Objective:</bold> Evaluate the effect of the Kata^® app on inhalation technique and clinical endpoints (e.g., FeNO; ACQ-5) in a clinical trial. <bold>Methods:</bold> This post hoc analysis of Kata^® app data collected during a phase II randomized controlled trial, included adult patients with moderate to severe, uncontrolled type-2 high asthma (N=78). Patients were followed for up to 12 weeks. A smartphone with the Kata^® app was provided at study start. Patients were asked to record each inhalation of their asthma maintenance treatment. Inhalation errors were scored according to predefined criteria. Rates for total and critical errors (significantly affect drug delivery) were calculated as the number of errors per inhalation. Analysis of clinical endpoints used data from the run-in phase only. <bold>Results:</bold> Univariate regression analysis showed a significant total error rate decrease of 1.4% per study day (p<.001; 95%CI: 0.8-1.9). Similarly, a significant decrease of the critical error rate of 2.0% per study day was found (p<.001; 95%CI: 1.0-2.6). There was a significant improvement of the ACQ-5 (p=.036; N=59). No significant improvement of FeNO was found (p=.170; N=60), but 26 of 60 patients (43%) showed a clinically relevant decrease (>20%) of FeNO. <bold>Conclusion:</bold> The Kata^® app improves inhalation technique in a clinical trial and is associated with improved asthma control. The Kata^® app is a useful tool for patients using inhalers to treat their asthma.