At-Home Telespirometry (AHT) in Amyotrophic Lateral Sclerosis (ALS): Digital Health Technology and Quality Control
Bhavya Narapureddy1, Benjamin Brooks4, Jenny Meyer1, Dongliang Wang2, Birendra Sah3, Dragos Manta3, Urvi Desai4, Eufrosina Young1
1Department of Neurology, 2Biostatistics, 3Department of Pulmonary, Upstate Medical University, 4Department of Neurology, Atrium Health
Objective:
Smart phone mobile application (Breathe Easy app) with data dashboard (https://www.zephyrx.com/) receive and display results of remote Forced Vital Capacity (FVC), accelerated in use during COVID-19 pandemic. We assessed the reliability of FVC as reported with in-clinic conventional (Viaire and Vyasis, USA) and in-clinic and at-home portable (MIR Spirobank Smart, Italy) spirometers that calculated FVC as percentage of predicted values based on Global lung initiative (GLI)-2012 reference standard.
Design/Methods:
In this retrospective study, 22 out of 99 ALS patients seen in clinic between July 2020 to June 2021 were analyzed . Independent analysis of FVC % predicted values acquired with portable spirometer was performed using GLI-2012 online calculator equations based on age, height, gender and ethnicity. To confirm that the same reference standard GLI-2012 was displayed by the software application, a web-based tool was used to calculate % predicted FVC to confirm that spirometric values were standardized according to GLI-2012 (gli-calculator.ersnet.org).
Results:
A third of dashboard-reported measurements were found to be 1% less than calculated measurements (29 out of 87 portable spirometry measurements) and appeared to be a fairly consistent difference in the first 1/3 of FVC followed longitudinally. Query was brought to the attention of the ZephyRx software development team. Dashboard algorithm was assessed to investigate for possible systematic error to account for the difference. The automated dashboard reporting of age using exact birth date to one decimal place on the day of testing as opposed to birth year used with manual calculations was confirmed to result in the 1% predicted difference in manually calculated FVC.
Conclusions:
Reported difference in spirometric values can be due to systematic difference in spirometric reference standards or a true difference in pulmonary function. ALS-specific digital health technology require vetting by independent ALS neuromuscular and pulmonary researchers and quality testing needs to occur within the clinical realm.