Home Spirometry is a Valid and Effective Tool for Tracking Recovery in Pulmonary Function Tests of COVID-19 Pneumonia Survivors

<bold>Background:</bold> COVID-19 pneumonia survivors may have pulmonary function impairments. The clinical validity of an ultrasonic home-based spirometer was assessed in post-COVID patients' home pulmonary function testing. Material-Methods: This 12-week prospective study assessed COVID-19 survivors' lung function using home- and clinic-based spirometry. Clinical spirometry was done at baseline, 4, 8, and 12 weeks. At baseline, participants received home spirometry equipment and training. Weekly home spirometry was required for 12 weeks. Results: The last group of 30 post-COVID patients (M/F:21/9) had a mean age of 48.6 ± 10.5 years. FVC, FEV1, and FEV1/FVC mean values by clinical and home spirometry at weeks 4, 8, and 12 were similar. The mean differences between clinical and home spirometry readings at weeks 4, 8, and 12 were small for FVC (−0.18 ± 0.22, 0.14 ± 0.21, −0.05 ± 0.15), FEV1 (0.00 ± 0.18, 0.02 ± 0.15, −0.00 ± 0.13), and FEV1/FVC (0.58 ± 3.08, 0.09 ± 3.12, 1.02). Bland-Altman plots of clinical and home spirometry results agreed well. Bland-Altman plots for FVC and FEV1 at four, eight, and twelve weeks favored the null hypothesis (β = −0.04, P = 0.63; β = −0.05, P = 0.72; β = −0.05, P = 0.08). Both clinical and home spirometry demonstrated significant FVC and FEV1 improvements from week 4 to week 12 (p=0.002, p=0.002, respectively). A 65.5% majority of online satisfaction survey respondents preferred home spirometry to clinical. <bold>Conclusion:</bold> Home spirometry is a valid and effective method for determining COVID-19 pneumonia survivors' progress. Most subjects preferred home spirometry over clinical.