Severity of respiratory failure and computed chest tomography in acute COVID-19 correlates with pulmonary function and respiratory symptoms after infection with SARS-CoV-2: An observational longitudinal study over 12 months.

INTRODUCTION: Prospective and longitudinal data on pulmonary injury over one year after acute coronavirus disease 2019 (COVID-19) are sparse. We aim to determine reductions in pulmonary function and respiratory related quality of life up to 12 months after acute COVID-19. METHODS: Patients with acute COVID-19 were enrolled into an ongoing single-centre, prospective observational study and prospectively examined 6 weeks, 3, 6 and 12 months after onset of COVID-19 symptoms. Chest CT-scans, pulmonary function and symptoms assessed by St. Georges Respiratory Questionnaire were used to evaluate respiratory limitations. Patients were stratified according to severity of acute COVID-19. RESULTS: Median age of all patients was 57 years, 37.8% were female. Higher age, male sex and higher BMI were associated with acute-COVID-19 severity (p < 0.0001, 0.001 and 0.004 respectively). Also, pulmonary restriction and reduced carbon monoxide diffusion capacity was associated with disease severity. In patients with restriction and impaired diffusion capacity, FVC improved over 12 months from 61.32 to 71.82, TLC from 68.92 to 76.95, DLCO from 60.18 to 68.98 and KCO from 81.28 to 87.80 (percent predicted values; p = 0.002, 0.045, 0.0002 and 0.0005). The CT-score of lung involvement in the acute phase was associated with restriction and reduction in diffusion capacity in follow-up. Respiratory symptoms improved for patients in higher severity groups during follow-up, but not for patients with initially mild disease. CONCLUSION: Severity of respiratory failure during COVID-19 correlates with the degree of pulmonary function impairment and respiratory quality of life in the year after acute infection.

A prospective evaluation of lung function at three and six months in patients with previous SARS-COV-2 pneumonia.

OBJECTIVE: This study investigated the consequences of Coronavirus Disease 2019 (COVID-19) pneumonia on lung function in the first 6 months after hospital discharge. METHODS: A prospective lung function assessment in SARS-CoV2 patients with COVID-19 pneumonia, hospitalized between March and April 2020, was conducted with spirometry measurements including lung volumes, mainly total lung capacity (TLC), lung diffusion capacity for carbon monoxide (DLCO) collected at 3 months after hospital discharge. Patients with restrictive ventilatory defect or impaired DLCO or both were re-evaluated at 6 months with global spirometry and chest HRCT scan. RESULTS: Among 40 consecutive patients, 19 (48%) had normal pulmonary functional tests (group A), and 21 (52%) showed residual lung function abnormalities at 3 months after hospital discharge (group B). In group B, 4 patients (19%) had only loss of lung volume as shown by TLC reduction (group 1), 13 patients (62%) had decreased both TLC and DLCO (group 2), and 4 patients (19%) had isolated reduction in DLCO (group 3). At 6-month follow-up in group 1, although all patients improved, only one normalized total lung capacity (TLC). In group 2, TLC and DLCO increased significantly (p < 0.01), but only 3 patients reached normal values. In group 3, DLCO improved for most patients, normalizing in 50% of them. At 6-months significant correlations between an internal-built chest HRCT scan severity score and TLC (r2 = 0.33; p < 0.01) and DLCO (r2 = 0.32; p < 0.01) were found. CONCLUSIONS: Nearly 50% of patients recovered in the post-critical phase. Most of those with abnormal pulmonary function tests at 3 months improved subsequently, but only another 29% (6 out of 21) reached normal values at 6 months. These results indicate that lung function spontaneous recovery is faster at first and occurs more slowly thereafter, leaving more than one third (15 out of 40) of patients with abnormal lung function tests at 6 months.

Respiratory function in patients post-infection by COVID-19: a systematic review and meta-analysis.

BACKGROUND: Evidence suggests lungs as the organ most affected by coronavirus disease 2019 (COVID-19). The literature on previous coronavirus infections reports that patients may experience persistent impairment in respiratory function after being discharged. Our objective was to determine the prevalence of restrictive pattern, obstructive pattern and altered diffusion in patients post-COVID-19 infection and to describe the different evaluations of respiratory function used with these patients. METHODS: A systematic review was conducted in five databases. Studies that used lung function testing to assess post-infection COVID-19 patients were included for review. Two independent reviewers analysed the studies, extracted the data and assessed the quality of evidence. RESULTS: Of the 1973 reports returned by the initial search, seven articles reporting on 380 patients were included in the data synthesis. In the sensitivity analysis, we found a prevalence of 0.39 (CI 0.24-0.56, p < 0.01, I2 = 86%), 0.15 (CI 0.09-0.22, p = 0.03, I2 = 59%), and 0.07 (CI 0.04-0.11, p = 0.31, I2 = 16%) for altered diffusion capacity of the lungs for carbon monoxide (DLCO), restrictive pattern and obstructive pattern, respectively. CONCLUSION: Post-infection COVID-19 patients showed impaired lung function; the most important of the pulmonary function tests affected was the diffusion capacity.