Improved pulmonary function and exercise tolerance despite persistent pulmonary fibrosis over 1 year after severe COVID-19 infection

Abstract

We conducted a prospective single-centre cohort study of 104 multi-ethnic severe COVID-19 survivors from the first wave of the pandemic 15 months after hospitalisation. Of those who were assessed at 4 and 15 months, improvement of ground glass opacities correlated with worsened fibrotic reticulations. Despite a high prevalence of fibrotic patterns (64%), pulmonary function, grip strength, 6 min walk distance and frailty normalised. Overall, dyspnoea, cough and exhaustion did not improve and were not correlated with pulmonary function or radiographic fibrosis at 15 months, suggesting non-respiratory aetiologies. Monitoring persistent, and often subclinical, fibrotic interstitial abnormalities will be needed to determine their potential for future progression.

Keywords: COVID-19; clinical epidemiology; imaging/CT MRI; interstitial fibrosis; respiratory measurement; viral infection.

Figure.

A. Chest CT pattern scores for 104 post-COVID survivors at 15 months. B. Change in individual CT pattern scores for 57 individuals who had imaging studies at 4 and 15 months. Each line represents an individual. C. Scatter plot with a best linear fit line of the change in reticulation scores (y-axis) with the change ground glass opacity scores (x-axis) for individuals who had imaging studies at both 4 and 15 months. Each dot represents an individual. D. Example of one individual whose CT chest scan showed improvement at 15 months.