Study of biomarkers to determine severity and lung damages in COVID-19 patients.

Introduction: Identifying inflammation and lung damage markers is crucial in reducing morbidity and mortality of coronavirus disease 2019 (COVID-19). This study aimed to examine the validity and reliability of severity and post-infection lung damage and analyse their relationship.

Methodology: This was a prospective analysis study at the Airlangga University Hospital, Surabaya, Indonesia, from March to August 2021. The infection`s severity was measured by examining angiotensin-converting enzyme 2 (ACE2) levels and complete blood count. Lung damage was estimated by reviewing Krebs von de Lungen (KL)-6, matrix metalloproteinase (MMP)-9, tissue inhibitor metalloproteinase (TIMP)-1, and MMP-9/TIMP-1. Two-factor confirmatory factor analysis (CFA) and canonical correlation were calculated using Lisrel and SPSS (version 25).

Results: The research sample included 76 patients. The t count loading factor values were calculated: ACE2 (6.00), neutrophils (-0.80), lymphocytes (-0.63), neutrophil-lymphocyte ratio (NLR, 1.27), eosinophils (-1.52), basophils (1.72), monocytes (0.05), platelets (0.53), leukocytes (-0.51), platelet-lymphocyte ratio (PLR, -1.15), KL-6 (10.47), MMP-9 (11.91), TIMP-1 (11.79), and MMP-9/TIMP-1 (-0.24). The t values were: neutrophil covariance error (6.11), lymphocytes (6.12), NLR (6.10), eosinophils (6.08), basophils (6.07), monocytes (6.12), platelets (6.12), leukocytes (6.12), PLR (6.10), ACE2 (0.97), KL-6 (5.63), MMP-9 (2.08), TIMP-1 (2.77), and MMP-9/TIMP-1 (6.12). t value canonical correlation of 7.04 (t count > 1.96) indicated a correlation between the severity of the patient and post-infection lung damage.

Conclusions: The severity was adequately measured through ACE2, IL-6, IL-10, neutrophils, lymphocytes, leukocytes, and NLR. Lung damage was measured with KL-6, MMP-9, and TIMP-1. There was a correlation between disease severity and lung damage.