Evaluation of lactate dehydrogenase (LDH) in predicting the severity of lung involvement and pneumomediastinum in hospitalized COVID-19

BACKGROUND: COVID-19 is a health crisis that triggered the need to find a rapid and sensitive tool to screen populations with a high risk of complications. Lactate dehydrogenase (LDH) is an enzyme found in almost all body cells, particularly pneumocytes, and appears to be associated with worst outcome. Pneumomediastinum (PM), which results from ruptured alveoli, can occur in non-ventilated patients. Acute pneumocytes injury induces the release of serum LDH. OBJECTIVE: This study evaluates the role of baseline serum LDH levels in predicting COVID-19 lung necrosis. METHODS: This retrospective study was conducted among 524 COVID-19 patients admitted to Hôtel-Dieu de France university hospital, Lebanon, between March 2020 and March 2021. Baseline serum LDH was retrieved from patients’ medical records. Radiological severity outcomes were assessed at admission and during follow-up by non-contrast computed tomography (NCCT) of the chest. RESULTS: The mean age of participants was 63 ± 16 years, with 359 males (68.5%) and median (IQR) LDH levels upon admission of 328 (248–430). LDH was correlated with lobar involvement at both admission and NCCT follow-up (Spearman’s rho 0.527 and 0.264, respectively) and the development of a PM (p = 0.035) in 3% of the patients. Using ROC analysis, a baseline LDH value higher than 395 U/L was associated with the presence of a PM on admission and follow-up chest CT, with a sensitivity of 75% and a specificity of 60.1%. CONCLUSION: Baseline LDH levels could serve as a tool for early diagnosis of severe pulmonary injury with poor radiological outcomes in hospitalized COVID-19 patients.