Home Spirometry in Clinical Trials: Evaluating Adherence and Quality in Patients with Asthma

<bold>Introduction:</bold> Home spirometry (HS) is gaining interest for use in clinical trials, as part of a decentralized strategy and as a way to gain additional insights on treatment efficacy. Defining barriers and enablers for its implementation is therefore important. We aimed to evaluate (1) the adherence to HS assessment and (2) the quality of unsupervised HS. <bold>Methods:</bold> HS data from a 26-week multicenter, randomized double-blind asthma study were evaluated. Two HS sessions were scheduled once weekly (pre and post-dose). Adherence to HS was evaluated according to 3 definitions with increasing stringency: a) at least 1 session/week, b) 2 sessions /week or c) 2 sessions on the same day of the week. Adherence was considered adequate if the above criteria were met for > 75% of the 26 weeks. Over-reading was performed at session and trial level using the artificial intelligence (AI) software ArtiQ.QC following modified 2005 ATS/ERS standards. <bold>Results:</bold> 236 patients (33.9% male, age 53.4±12 yr) were included in the analysis. 66%, 37% and 36% of the patients were adherent based on the a, b and c definitions, respectively. 66% and 62% of the sessions were of acceptable quality (A or B) for FEV1 and FVC, respectively. At the trial level, 97% of FEV1 and 75% of FVC measures were acceptable. The most common errors were: short effort lasting <6s (24%), lack of plateau (89%), and leaks (10%). <bold>Conclusion:</bold> A stringent schedule for HS can be challenging for patients to follow. Two thirds of sessions of HS were of good quality; and, patients were able to perform good quality HS at trial level, especially for FEV1. Training to ensure adequate end of forced expiration (EOFE) should be emphasized.