The Clinical Effectiveness and Validity of Home Spirometry in Children with Cystic Fibrosis

ABSTRACT

Aims During the COVID-19 pandemic, home spirometry became essential for continued monitoring of cystic fibrosis patients, however, the clinical effectiveness was unknown.The aims of this study were to assess the success rate of testing patients at home and to compare the results to the gold standard testing (in lab spirometry). Methods 147 home spirometry devices (Air Next, NuvoAir, USA) were given out to cystic fibrosis patients (MF 6780;mean age 11.8 [4.7 - 17.3]) who had previous experience of spirometry and deemed to be competent to perform spirometry at home. Patients were asked to perform 4 tests in the first month, then 1 test per month unless clinically requested. When Lab spirometry resumed, 28 (MF 1216;mean age 13.1 [8.0-17.0]) patients tested on NuvoAir within 5 days (mean 0.7 days (1.0)) of Lab spirometry (Vyntus Spiro, Vyaire Medical, USA). Correlation between spirometry indices were analysed using linear regression. Results 142 patients (96.6%) successfully onboarded onto the NuvoAir platform. Between July 2020 and Jan 2022, 1854 tests were performed, with 1711 (92.3%) tests over-read to be valid. 54 patients (36.7%) performed >=15 tests requested. FEV1 (R2 = 0.93, p = <0.00), Ratio (R2 = 0.70, p = <0.00), FVC (R2 = 0.91, p = <0.00), MMEF (R2 = 0.87, p = <0.00) and PEF (R2 = 0.88, p = <0.00) all showed significant correlation between Lab spirometry and Home spirometry. Conclusion Our results show that home spirometry is well adopted by cystic fibrosis patients, however, continual encouragement may be required. We have also shown that valid spirometry loops can be performed by cystic fibrosis patients on this device. There is also close agreement between this home spirometry device and the gold standard of lab spirometry and therefore, results can be deemed valid and reliable.