Lactate dehydrogenase and C-reactive protein as predictors of respiratory failure in CoVID-19 patients

Erika, Poggiali; Domenica, Zaino; Paolo, Immovilli; Luca, Rovero; Giulia, Losi; Alessandro, Dacrema; Marzia, Nuccetelli; Giovanni Battista, Vadacca; Donata, Guidetti; Andrea, Vercelli; Andrea, Magnacavallo; Sergio, Bernardini; Chiara, Terracciano

OBJECTIVE: The dramatic worldwide CoVID-19 infection requires the identification of a reliable and inexpensive tool to quickly discriminate patients with a more unfavorable outcome. METHODS: We performed routine laboratory tests suitable to identify tissue damage and inflammatory status in 123 consecutive CoVID-19 patients admitted to the Emergency Department of the hospital of Piacenza (Emilia-Romagna, Northern Italy). The results were correlated with patients’ respiratory function evaluated by the partial pressure of arterial oxygen to fraction of inspired oxygen ratio (PaO2/FiO2). Results: The most common laboratory abnormalities were lymphocytopenia and elevated values of C-reactive protein (CRP) and lactate dehydrogenase (LDH). Aspartate aminotransferase (AST), alanine aminotransferase (ALT) and creatine kinase (CK) were also increased. The respiratory performance (PaO2/FiO2) showed a strong inverse correlation with LDH (r= 0.62, r(2) 0.38, p value< 0.0001) and CRP (r= 0.55, r(2) 0.31, p value< 0.0001). PaO2/FiO2 values also showed a significant inverse correlation with age (r= -0.37, p< 0.0001), AST (r= -0.31, p<0.01), WBC (r= -0.49, p<0.0001), neutrophils count (r= -0.5, p<0.001). ROC curves showed a sensitivity of 75% and specificity of 70% for the LDH cut-off value of 450 U/L and a sensitivity of 72% and specificity of 71% for the CRP cut-off value of 11 mg/dl in identifying CoVID-19 with moderate-severe ARDS. CONCLUSIONS: LDH and CRP may be related to respiratory function (PaO2/FiO2) and be a predictor of respiratory failure in CoVID-19 patients. LDH and CRP should be considered a useful test for the early identification of patients who require closer respiratory monitoring and more aggressive supportive therapies to avoid poor prognosis.