Post COVID-19 Chronic Parenchymal Lung Changes

Abstract

Introduction: Persistent parenchymal lung changes are an important long-term sequela of COVID-19. There are limited data on this COVID-19 infection sequela characteristics and trajectories. This study aims to evaluate persistent COVID-19-related parenchymal lung changes 10 weeks after acute viral pneumonia and to identify associated risk factors.

Methods: This is a retrospective case-control observational study involving 38 COVID-19 confirmed cases using nasopharyngeal swab reverse transcriptase-polymerase chain reaction (RT-PCR) at King Abdullah Medical City (KAMC) Hospital, Makkah. Patients were recruited from the post-COVID-19 interstitial lung disease (ILD) clinic. Referral to this clinic was based on the pulmonology consultant's assessment of hospitalized patients suspected of developing COVID-19-related ILD changes during hospitalization.

Results: Thirty-eight patients with parenchymal lung changes were evaluated at the ILD clinic. Nineteen patients who had persistent parenchymal changes 10 weeks after the acute illness (group 1) were compared with 19 control patients who had accelerated clinical and/or radiological improvement (group 2). Group 1 was found to have the more severe clinical and radiological disease, with a higher peak value of inflammatory biomarkers. Two risk factors were identified, neutrophil-lymphocyte ratio (NLR) > 3.13 at admission increases the odds ratio (OR) of chronic parenchymal changes by 6.42 and 5.92 in the univariate and multivariate analyses, respectively. Invasive mechanical ventilation had a more profound effect with ORs of 13.09 and 44.5 in the univariate and multivariate analyses, respectively.

Conclusion: Herein, we found that only receiving invasive mechanical ventilation and having NLR >3.13 at admission were strong risk factors for persistent parenchymal lung changes. Neither the clinical severity of the acute illness nor the radiological one is found to predict this outcome. None of the medications received during the acute illness were found to alter the risk for this post-COVID-19 infection sequelae.

Keywords: complication; covid-19; interstitial lung disease; long covid; post-covid-19 fibrosis.

Figure 1. Representative CT scan of severe COVID19 infection in "group 1"

(A, B) Initial CT chest, while (C, D) The follow-up CT (after 10 weeks) showing significant improvement, however, residual minimal patchy ground-glass opacities (yellow arrows), thickening of the interlobular septa, and linear opacities (red arrows) are noted in the bilateral lung.

Figure 2. Representative CT scan of moderate COVID19 infection in "control group"

(A, B) Initial CT chest shows patchy ground-glass opacities and focal consolidations (yellow arrows), with thickened interlobular septa (red arrows), in the bilateral lung. (C, D) Lesions were resolved in the follow-up CT.