COVID-19's Radiologic, Functional, and Serologic Consequences at 6-Month and 18-Month Follow-up: A Prospective Cohort Study

J Korean Med Sci. 2024 Aug 19;39(32):e228. doi: 10.3346/jkms.2024.39.e228.

Abstract

Background: We evaluated the radiologic, pulmonary functional, and antibody statuses of coronavirus disease 2019 (COVID-19) patients 6 and 18 months after discharge, comparing changes in status and focusing on risk factors for residual computed tomography (CT) abnormalities.

Methods: This prospective cohort study was conducted on COVID-19 patients discharged between April 2020 and January 2021. Chest CT, pulmonary function testing (PFT), and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) immunoglobulin G (IgG) measurements were performed 6 and 18 months after discharge. We evaluated factors associated with residual CT abnormalities and the correlation between lesion volume in CT (lesionvolume), PFT, and IgG levels.

Results: This study included 68 and 42 participants evaluated 6 and 18 months, respectively, after hospitalizations for COVID-19. CT abnormalities were noted in 22 participants (32.4%) at 6 months and 13 participants (31.0%) at 18 months. Lesionvolume was significantly lower at 18 months than 6 months (P < 0.001). Patients with CT abnormalities at 6 months showed lower forced expiratory volume in 1 second (FEV1) and FEV1/forced vital capacity (FVC), and patients with CT abnormalities at 18 months exhibited lower FVC. FVC significantly improved between 6 and 18 months of follow-up (all P < 0.0001). SARS-CoV-2 IgG levels were significantly higher in patients with CT abnormalities at 6 and 18 months (P < 0.001). At 18-month follow-up assessments, age was associated with CT abnormalities (odds ratio, 1.17; 95% confidence interval, 1.03-1.32; P = 0.01), and lesionvolume showed a positive correlation with IgG level (r = 0.643, P < 0.001).

Conclusion: At 18-month follow-up assessments, 31.0% of participants exhibited residual CT abnormalities. Age and higher SARS-CoV-2 IgG levels were significant predictors, and FVC was related to abnormal CT findings at 18 months. Lesionvolume and FVC improved between 6 and 18 months.

Trial registration: Clinical Research Information Service Identifier: KCT0008573.

Keywords: COVID-19; Complications; Computed Tomography; Pulmonary Function Tests; Serologic Tests.

MeSH terms

  • Adult
  • Aged
  • Antibodies, Viral / blood
  • COVID-19* / diagnostic imaging
  • Female
  • Follow-Up Studies
  • Forced Expiratory Volume
  • Humans
  • Immunoglobulin G* / blood
  • Lung* / diagnostic imaging
  • Lung* / pathology
  • Male
  • Middle Aged
  • Prospective Studies
  • Respiratory Function Tests*
  • Risk Factors
  • SARS-CoV-2* / immunology
  • SARS-CoV-2* / isolation & purification
  • Tomography, X-Ray Computed*
  • Vital Capacity

Substances

  • Immunoglobulin G
  • Antibodies, Viral