COVID-19 and the effects on pulmonary function following infection: A retrospective analysis

Abstract

Background: The coronavirus disease 2019 (COVID-19) has been identified in over 110 million people with no studies comparing pre-infection pulmonary function to post-infection. This study's aim was to compare preinfection and post-infection pulmonary function tests (PFT) in COVID-19 infected patients to better delineate between preexisting abnormalities and effects of the virus. Methods: This was a retrospective multi-center cohort study. Patients were identified based on having COVID-19 and a pre-and post-infection PFT within one year of infection during the time period of March 1, 2020 to November 10, 2020. Findings: There was a total of 80 patients, with an even split in gender; the majority were white (n = 70, 87¢5%) and never smokers (n = 42, 52¢5%). The majority had mild to moderate COVID-19 disease (n = 60, 75¢1%) with 25 (31¢2%) requiring hospitalization. There was no difference between the pre-and post-PFT data, specifically with the forced vital capacity (FVC) (p = 0¢52), forced expiratory volume in 1 s (FEV1) (p = 0¢96), FEV1/FVC(p = 0¢66), total lung capacity (TLC) (p = 0¢21), and diffusion capacity (DLCO)(p = 0¢88). There was no difference in the PFT when analyzed by hospitalization and disease severity. After adjusting for potential confounders, interstitial lung disease (ILD) was independently associated with a decreased FEV1 (-2¢6 [95% CI, -6¢7 to -1¢6] vs. -10¢3 [95% CI, -17¢7 to -2¢9]; p = 0¢03) and an increasing age (p = 0¢01) and cystic fibrosis (-1¢1 [95% CI, -4¢5 to-2¢4] vs. -36¢5 [95% CI, -52¢1 to -21¢0]; p < 0¢01) were associated with decreasing FVC when comparing pre and post infection PFT. Only increasing age was independently associated with a reduction in TLC (p = 0¢01) and DLCO (p = 0¢02) before and after infection. Interpretation: This study showed that there is no difference in pulmonary function as measured by PFT before and after COVID-19 infection in non-critically ill classified patients. There could be a relationship with certain underlying lung diseases (interstitial lung disease and cystic fibrosis) and decreased lung function following infection. This information should aid clinicians in their interpretation of pulmonary function tests obtained following COVID-19 infection.

Comparison of pulmonary function test, diffusion capacity, blood gas analysis and CT scan in patients with and without persistent respiratory symptoms following COVID-19

“…It must be noted that no PFT taken prior to acute COVID-19 that could serve as a reference was available. However, this seems to play a minor role, as no significant difference between lung function test prior to and following COVID-19 could be found in a study cohort of 80 patients [ 16 ]. Comparing symptomatic and asymptomatic patients, the patients with ongoing respiratory symptoms who were younger than the asymptomatic patients had a significantly lower FVC (%), TLC (L) and TLCO SB (%) compared to asymptomatic patients and thus indicating an association between perceived symptoms and pathological findings in medical examinations.…”

Deep learning identified genetic variants associated with COVID-19 related mortality

“…The genes LASTR and AGAP3 have been reported to be associated with pulmonary function (FEV1/FVC), while the gene GLI3 has also been found to be related to the pulmonary function (FVC) [46]. COVID-19 virus has been shown to affect many organs, with the lung being one of the most affected [47, 48]. In particular, one study find that severe COVID-19 patients had an abnormal FVC over a half-year following discharge [49].…”

Risk factors for impaired pulmonary diffusion function in convalescent COVID-19 patients: A systematic review and meta-analysis

“…also showed that older age was independently associated with a decrease in DLCO following SARS-CoV-2 infection. 57 In an editorial on the pathogenesis of COVID-19, Prof. Mason commented that immune response disorders in elderly patients may make it easier for the virus to spread to the gas exchange units in the lungs. 58 The specific mechanism of elderly patients being more likely to have DLCO damage is uncertain.…”