The assessment of pulmonary impairment and clinical correlations in patients survived from SARS-CoV-2 infection: A 3-month follow-up study

Abstract

During the coronavirus disease 2019 (COVID-19), the extent of pulmonary impairment associated with initial clinical parameters remained controversial. The notion is valuable for the recovery and prognosis of COVID-19. This study investigated the long-term pulmonary sequelae of severe acute respiratory syndrome coronavirus 2 infection, focusing on pulmonary function and clinical parameters during the 3 months after diagnosis. This is a retrospective, single-center observational study of 229 patients who tested positive for COVID-19 and made the 3rd-month follow-up visit between June 2020 and May 2021. The demographic and clinical characteristics of patients and treatment outcomes were recorded. The obstructive, restrictive pulmonary dysfunction patterns were analyzed to associate with the radiological findings, disease severity, and clinical parameters. The median age of the patients was 46 years. The most common residual symptoms were dyspnea (38%), dry cough (34.5%), and fatigue (29.4%). The obstructive and restrictive pulmonary dysfunction patterns were observed in 38.9% and 2.2% of the patients, respectively. Two-fifth of patients had some form of pulmonary dysfunction. A significant rate (35.8%) of patients had reduced diffusing capacity for carbon monoxide values. Obstructive pulmonary dysfunction was more common among older patients, whereas hypertension was more common among patients with extended hospital stays. Long-term pulmonary dysfunction was a frequent complication in patients recovering from severe severe acute respiratory syndrome coronavirus 2 infection. Understanding these long-term effects is essential for providing appropriate medical care for COVID-19 survivors. Therefore, further research is needed to elucidate the postinfection changes in the lung.

Keywords: obstructive; pulmonary diseases; pulmonary function tests; respiratory system; restrictive; severe acute respiratory syndrome coronavirus 2.

Figure 1.

Multi-parameter pulmonary function assessment at 3-month post-COVID-19 follow-up. Box plot analysis demonstrating spirometric parameter distributions in COVID-19 survivors (n = 229). Each panel represents median values, interquartile ranges, and extreme distributions for: (A) Forced vital capacity (FVC, mL), (B) forced expiratory volume in 1 s (FEV₁, mL), (C) FEV₁/FVC ratio (%), (D) mid-expiratory flow 25–75% (MEF25–75%, mL/s), (E) diffusion capacity for carbon monoxide (DLCO, mL/min/mm Hg), and (F) transfer coefficient (KCO, %). Data illustrate heterogeneous respiratory recovery patterns with significant inter-parameter variability, supporting individualized therapeutic strategies in post-COVID respiratory sequelae management. Whiskers represent minimum-maximum ranges; boxes denote 25th to 75th percentiles; horizontal lines indicate median values.