Lung function variability in one year after COVID-19 pneumonia

ABSTRACT

The SARS-CoV-2 virus causes pneumonia which can result in lung function (LF) impairment. Impaired LF shortly after the disease is not commonly observed, but the LF substantially fluctuates even when its value remains within the limits of the norm. The aim of the study was to determine the variability scope of LF during the first year after COVID-19 pneumonia. Material(s) and Method(s) LF measurements (spirometry, body-plethysmography, transfer factor) were conducted up to 1 month, 3, 6, and 12 months after hospitalization in a group of consecutive patients recovered from moderate to severe COVID-19 pneumonia requiring hospitalization. The coefficient of variation (CV) was calculated to assess the stability of LF. Result(s) 113 patients were included, with a lung involvement median of 40% (IQR30-60%). Shortly after hospitalization, we detected 3.5% airway obstructions, 12.4% restrictions, and 26.5% lung transfer factor impairments. During one year significant changes were observed in lung volumes but not flow indices. The most pronounced improvements were observed in lung transfer factor (TLco) and they were associated with volume changes (VA), but not Kco improvements (figure 1). Stable LF (CV<4%) was observed only in 21% of patients. Conclusion(s) Impaired LF shortly after COVID-19 was detected in a quarter of patients with significant improvement in the next months. However, lung function remained unstable in the majority of examined patients.