Pulmonary function test results and radiological findings 90-120 days after COVID-19 pneumonia: a single-center retrospective study

Background: Survivors of Coronavirus Disease 2019 (COVID-19) pneumonia may have permanent loss of lung function and radiological sequelae. There is a need for markers that predict patients for whom follow-up is required. Aim of the study: To identify the risk factors associated with post-COVID-19 radiological and functional findings. Material and Methods: This is a single-center retrospective study performed in a university hospital. We obtained the data from all hospitalized patients with COVID-19 pneumonia. We included those who underwent pulmonary function tests (PFT) and chest computerized tomography (CT) 90-120 days later. We analyzed initial and peak laboratory results (C-reactive protein (CRP), d-dimer, ferritin, and fibrinogen), and the length of hospital and intensive care unit (ICU) stay. We examined the relationship between baseline data and radiological findings and PFT. Results: Fifty-six patients were included in this study. Of these, 31 (55.4%) were women. The mean age of the patients was 55.05 ± 13.29 years. The mean peak ferritin, fibrinogen, d-dimer, and CRP values recorded during hospitalization follow-up were 285.56 ± 339.82, 518.59 ± 186.93, 1.99 ± 5.69, and 98.94 ± 80.77, respectively. The mean length of hospital and ICU stay were 10.21 ± 8.01 and 8.38 ± 8.90 days, respectively. In 18 (32.1%) patients, we observed a restrictive pattern on PFT, and 22 (39.3%) patients had an abnormal diffusion test. In 21 (37.5%) patients we observed ground glass opacities and in 4 (7.1%) patients reticulation was seen on their chest CT. A multivariate logistic regression analysis revealed that the first visit and peak fibrinogen values were significantly associated with abnormal PFT (p = 0.049, R2 = 0.272), while ferritin and CRP levels at the first visit and peak levels were significantly associated with an abnormality on chest CT (p < 0.001, p = 0.05, respectively). Conclusions: High initial and peak ferritin, fibrinogen, and CRP levels were associated with persistent radiological findings on chest CT and abnormal PFT at 90–120 follow-up after COVID-19 pneumonia.