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

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

• Kim C
• Seok H
• Kim J
• Park DW
• Assen Mv
• Cecco CND
• Choi H
• Kim C
• Hwang SH
• Yong HS
• Oh YW
• Choi WS

• KMID: 2558528
• DOI: http://doi.org/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 (lesion_volume ), 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. Lesion_volume 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 lesion_volume 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. Lesion_volume and FVC improved between 6 and 18 months.

Keyword

COVID-19; Complications; Computed Tomography; Pulmonary Function Tests; Serologic Tests

Figure

• 

  Fig. 1 Graphs comparing changes between 6 months (6M) and 18 months (18M), with specific changes in (A) lesionvolume, (B) FVC (L), (C) FVC (%), and (D) FEV1/FVC.lesionvolume = lesion volume percentage, FVC = forced vital capacity, FEV1 = forced expiratory volume in 1 second.Comparisons were performed with the paired t-test and Wilcoxon signed rank test.***P < 0.001; ****P < 0.0001.

• 

  Fig. 2 The ROC curves of SARS-CoV-2 IgG levels for predicting CT abnormalities at 6 or 18 months. (A) ROC curves were used to test the performance of SARS-CoV-2 IgG level at 6 months for predicting residual CT abnormalities at 6 months, showing an AUC of 0.688 (95% CI, 0.798–0.908; P < 0.001). The cut-off IgG level at 6 months for predicting CT abnormalities at 6 months was 10.25 (sensitivity, 70.5%; specificity, 90.5%). (B) The ROC curve of IgG level at 6 months for predicting residual CT abnormalities at 18 months showed an AUC of 0.734 (95% CI, 0.849–0.964; P < 0.001). The cut-off value was 10.1 (sensitivity, 69.0%; specificity, 100%). (C) The ROC curve of IgG level at 18 months for predicting residual CT abnormalities at 18 months showed an AUC of 0.823 (95% CI, 0.823–0.909; P < 0.001). The cut-off value was 2.35 (sensitivity, 75.0%; specificity, 100%).ROC = receiver operating characteristic, SARS-CoV-2 = severe acute respiratory syndrome coronavirus 2, IgG = immunoglobulin G, CT = computed tomography, AUC = area under the curve, CI = confidence interval.

• 

  Fig. 3 The correlations between lesionvolume and PFT, as well as between lesionvolume and SARS-CoV-2 IgG levels.(A) lesionvolume at 6 months and FEV1 (L) at 6 months, (B) lesionvolume at 6 months and SARS-CoV-2 IgG level at 6 months, (C) lesionvolume at 18 months and SARS-CoV-2 IgG level at 6 months, and (D) lesionvolume at 18 months and SARS-CoV-2 IgG level at 18 months.lesionvolume = lesion volume percentage, PFT = pulmonary function testing, SARS-CoV-2 = severe acute respiratory syndrome coronavirus 2, IgG = immunoglobulin G, FEV1 = forced expiratory volume in 1 second.

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