Changes in pulmonary function and patient-reported outcomes during COVID-19 recovery: a longitudinal, prospective cohort study

Objectives To compare respiratory and patient-reported outcome measures (PROMs) between 3 and 6 months after symptom onset and to identify features that predict these changes.

Methods This is a consecutive prospective cohort of 73 patients who were hospitalised with COVID-19. We evaluated the changes in pulmonary function tests (PFTs) and PROMs between 3 and 6 months and then investigated the associations between outcomes (change in diffusing capacity for carbon monoxide of the lung (DLCO), dyspnea, and quality of life (QOL)) and clinical and radiological features.

Results There was improvement in forced vital capacity (FVC), total lung capacity (TLC), and DLCO between 3 and 6 months by 3.25%, 3.82% and 5.69% respectively; however, there was no difference in PROMs. Reticulation and total CT scores were associated with lower DLCO %-predicted at 6 months (coefficients; −8.7 and −5.3 respectively). The association between radiological scores and DLCO were modified by time, with the degree of association between ground glass and DLCO having decreased markedly over time. There was no association between other predictors and change in dyspnea or QOL over time.

Conclusions There is improvement in pulmonary function measurements between 3 and 6 months after COVID-19 symptom onset; however, PROMs did not improve. A higher reticulation and total CT score are negatively associated with DLCO, but this association is attenuated over time. Lastly, there is a considerable proportion of patients with unexplained dyspnea at 6 months, motivating further research to identify the underlying mechanisms.