ABSTRACT
Introduction: PrecISE is an ongoing Phase II clinical trial sponsored by the National Heart, Lung, and Blood Institute to investigate the efficacy of several treatments for severe asthma. The threat of COVID-19 has raised interest in obtaining reliable spirometry data for asthma research and clinical care in a remote, “no-touch” fashion. Prior studies of the accuracy of remote spirometry have not included real-time coaching. The PrecISE investigators hypothesized that remote spirometry with real-time video coaching could provide an accurate FEV1 for use as a study endpoint in a clinical trial setting. Methods: PrecISE network participants had remote spirometry post-bronchodilator (4 puffs of albuterol) measured with video coaching from trained research coordinators using the ZEPHYRx platform connected to MIR Spirobank Smart handheld spirometers. Remote spirometry measurements occurred within a +/- 3-day window from scheduled in-person PrecISE visits during which in-person spirometry with bronchodilator challenge was measured with standard equipment (Vyaire Medical). All measurements occurred during the screening/run-in period of the PrecISE protocol. Both remote and in-person spirometry was overread by the PrecISE Spirometry Core and only included in analysis if sessions met ATS acceptability and reproducibility criteria. Correlations between remote and in-person FEV1 and FVC were analyzed, and Bland-Altman plots generated. As a comparison, within subject biological variability was measured using data from separate in-person visits during the screening/run-in period. Results: A total of 128 pairs of remote/in-person spirometry data were obtained. The mean FEV1 for remote spirometry was 2.50 L (SD 0.81) and for inperson spirometry was 2.42 L (SD 0.80), with an estimated correlation of 0.95 (95% CI: 0.93, 0.97). The mean difference in FEV1 (in-person - remote) was -0.07 L (95% CI: -0.11, -0.03, SD 0.25). The mean FVC for remote spirometry was 3.72 L (SD 1.01) and for in-person spirometry was 3.53 L (SD 0.93), with an estimated correlation of 0.91 (95% CI: 0.87, 0.93). The mean difference in FVC (in-person - remote) was -0.19 L (95% CI: -0.27, -0.12, SD 0.42). A total of 142 pairs of repeated in-person spirometry measurements were performed (median time between measurements: 43 days), with mean difference in FEV1 of -0.01 L (95% CI: -0.06, 0.03) and FVC of -0.02 L (95% CI: -0.07, 0.03). Bland-Altman plots for FEV1 differences are shown in Figure 1. Conclusions: Remote spirometry with real-time video coaching provides a reliable FEV1 measurement which correlates closely with in-person spirometry and is suitable for use in clinical trials. (Figure Presented).
ABSTRACT
RATIONALE: The potential risk of acquiring COVID-19 has presented a particular challenge to delivering in-person outpatient care, especially to patients with chronic respiratory diseases who may be hesitant to come to clinic. Though much of an interdisciplinary visit for cystic fibrosis can be performed via telehealth, in-clinic spirometry is an important part of disease monitoring. Home spirometry has been proposed as a way to improve telehealth in cystic fibrosis care. Here we examine the reliability of home spirometers in an adult cystic fibrosis clinic. METHODS: Patients received home spirometers (Mir Spirobank Smart, n = 38) from the Cystic Fibrosis Foundation or obtained their own Microlife home spirometers (n = 2). They were instructed to bring their home spirometer to clinic for teaching and comparison with the calibrated clinical spirometer. Initial patient demographics, exacerbations in the last year, current symptoms, home airway clearance and inhaler regimen were recorded. After the initial visit, patients were emailed links to report symptoms and record home spirometry weekly or with worsening of their symptoms. Data was recorded in REDCap and analyzed in RStudio version 1.3.1056. RESULTS: A total of 40 patients have completed the initial clinic visit and teaching for their home spirometers. The clinic and home spirometers were very highly correlated when measuring forced expiratory volume in one second (FEV1) with a Pearson correlation coefficient 0.993 (P < 0.001) with the clinic spirometer recording a higher value, on average, of 0.072 ± 0.11 L (mean ± standard deviation). Of the 36 patients that had a home spirometer forced vital capacity (FVC) recorded, the correlation coefficient was 0.946 (P < 0.001) with the clinic spirometer recording a higher value of 0.134 ± 0.31 L on average. Measurements of percent predicted of FEV1 and FVC had Pearson correlation coefficients of 0.987 (P<0.001) and 0.953 (P<0.001), respectively, with clinic spirometers showing higher values, on average, of 0.806 ± 3.54 % and 1.31 ± 1.12 %, respectively. Peak expiratory flow (L/s), on the contrary, tended to be higher on the home devices by 0.542 ± 1.12 L/s on average, with a Pearson correlation coefficient of 0.857 between devices. Home spirometry measurements are ongoing. CONCLUSIONS: Home spirometry provide similar estimates of lung function compared to standard in-clinic devices and could play a useful role in the longitudinal telehealth care of cystic fibrosis patients. The reliability of their measurements in the home environment is currently ongoing.