Comparing Approaches to Teaching Patients How to Use an App-Based Home Spirometer: Randomized Controlled Trial.

Background: Bluetooth-enabled, app-based home spirometry has been validated for use in the diagnosis and monitoring of respiratory disease. Remote teaching (virtual or self-directed) of patients on how to use an app-based home spirometry offers the opportunity to deliver diagnostics safely and at scale. However, the most appropriate method of teaching home spirometry to patients is unknown. Objective: The aim of this pragmatic study undertaken during the COVID-19 pandemic was to determine whether virtual or self-directed teaching were valid methods for deploying home spirometry to patients referred for outpatient lung physiology testing. Methods: REACH-SPIRO is a single-center, unblinded, randomized controlled trial of adults referred for spirometry. Participants were randomized (1:1:1) to be taught to use a Bluetooth, app-based spirometer either (A) face-to-face, (B) virtually (live video conferencing), or (C) self-directed. Forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1) were recorded. Home spirometry (Spirobank Smart Spirometer) readings for each training modality were compared with gold standard hospital measurements (Vyaire Medical) using Bland-Altman Limits of Agreement (LoA). Patients' feedback questionnaires on acceptability and adherence were also collected, and common themes were described using content analysis. Results: A total of 106 participants were randomized. Bland-Altman analysis between hospital and home FEV1 measurements for group A showed a mean difference of 0.108L, LoA -0.331L to 0.548L, group B 0.152L, LoA -0.358L to 0.661L, and group C 0.153L, LoA -0.358L to 0.661L. FVC measurements in group A showed a mean difference of 0.123L, LoA -0.402L to 0.648L, group B 0.249L, LoA -0.297L to 0.795L, and group C 0.340L, LoA -0.556L to 1.235L. There was no significant difference between randomized arms for either mean FEV1 (P=.41) or FVC (P=.84). Patient feedback was similar across all groups, with more positive feedback for face-to-face and virtual teaching methods. Conclusions: There is no meaningful difference in spirometry measurement between patients taught to use a home spirometer remotely (virtual or self-directed) versus traditional face-to-face treatment. Patients' feedback was favorable to all three methods of teaching. This study supports the use of either virtual or self-directed teaching of home spirometry for the monitoring of respiratory disease. In doing so, we can improve access to spirometry in communities facing barriers to health care and clinically vulnerable populations.