The persistent lung alterations caused by the 2019 coronavirus disease (COVID-19) due to severe disease are already common knowledge. This research aimed to identify potential contributors to interstitial lung disease among hospitalized patients with COVID-19 pneumonia. Retrospective studies were conducted on patients hospitalized with COVID-19 pneumonia between June 2020 and March 2021. Information such as smoking habits, co-existing conditions, results of reverse transcriptase polymerase chain reaction testing results, laboratory parameters at the time of diagnosis, oxygen support, corticosteroid use (including dosage and duration of use), and the need for intensive care unit care were documented. At their 3-6 month checkup, participants in the study had taken high-resolution computed tomography (HRCT) scans. If a follow-up HRCT showed parenchymal abnormalities other than pure ground-glass opacities, the patients were diagnosed with residual parenchymal lung disease (the residual disease group). Patients with normal chest radiographs or HRCTs at their follow-up appointments or with only pure ground-glass opacities served as a control group. Patients in 2 groups were compared across various variables, including demographics, aberrant laboratory results, diagnoses, and treatments administered in the intensive care unit (ICU). There were 446 participants in total. The distribution was clearly male at a mean ± SD of 58.4 ± 13.87 years, with 257 males (57.6%) making up the total. The HRCT findings in 55 of the individuals were normal, but 157 of the lung parenchyma were abnormal. Age, sex, corticosteroid medication, and ICU admission were all significant predictors of the development of interstitial lung disease in a univariate logistic regression analysis (P<.001, P=.003, P<.001, and P<.001, respectively). The residual disease group had significantly higher leukocyte and neutrophil counts and lower lymphocyte counts (P < .001, P < .001, P = .004, respectively). Correlated with these findings, neutrophil-to-lymphocyte ratios and platelet-to-lymphocyte ratios were significantly higher in the residual disease group (P < .001 and P = .008, respectively).

About 1/3rd of patients hospitalized with COVID-19 pneumonia had residual parenchymal illness 3 months after being released. Males of advanced age and those with more severe disease criteria were shown to be at increased risk for developing interstitial lung disease.