Background: Research data on hospitalized coronavirus 2019 (COVID-19) survivors indicate the persistence of symptoms, radiological abnormalities, and physiological disorders months after the initial infection. Given the scale of the ongoing pandemic, a substantial number of patients with severe residual pulmonary fibrosis (PF) and oxygen dependence are anticipated. Currently, the search for risk factors associated with the development of fibrotic radiological abnormalities after moderate to severe COVID-19 is underway. Furthermore, the extent to which computed tomography (CT) data correlate with postdischarge symptoms and physical functions remains unclear. This study aimed to characterize patients experiencing persistent pulmonary consequences after hospital discharge. We examined clinical, radiological, and laboratory predictors of pulmonary fibrosis after COVID-19 infection.
Methods: We retrospectively evaluated fibrosis-like lung changes and their prognostic factors in COVID-19 survivors. Our study included 77 patients with laboratory-confirmed COVID-19 who received inpatient treatment at City Clinical Hospital No. 1 in Almaty between November and December 2020. We assessed patients during the acute phase of the disease and again 6 to 8 months after discharge using high-resolution computed tomography (CT). Patients were classified into 2 cohorts based on semi-quantitative analysis of subsequently added tomograms-those with radiological fibrosis-like abnormalities (main group) and those who had recovered (control group).
Results: Parenchymal cords, irregular interfaces, reticulation, and traction bronchiectasis were common CT findings among all COVID-19 patients. Our study focused on patients who developed pulmonary fibrosis within 1 month after the onset of the disease. After 6 to 8 months, fibrosis-like lung changes persisted in 49.35% of patients (leading group), while 50.65% showed disease resolution (control group). Age, body mass index, high interleukin-6 (IL-6) levels, low IO levels, and the need for mechanical ventilation were identified as prognostic indicators for the persistence of pulmonary fibrosis.
Conclusion: Our study revealed that pulmonary function can return to normal in over half of COVID-19 patients 8 months after infection onset. Despite advancements in COVID-19 treatment, there remains a significant knowledge gap in managing long-term effects, especially pulmonary fibrosis. Continued clinical trials and research on post COVID-19 fibrosis are essential to prevent early mortality due to the long-term impacts on these patients.
Keywords: COVID-19; Interleukin-6; Lung Function; Pulmonary Fibrosis; Ventilator.
© 2023 Iran University of Medical Sciences.