Systematic review of laboratory parameters predicting severity and fatality of COVID-19 hospitalised patients

Background: We reviewed studies that reported changes in laboratory parameters in COVID-19 hospitalised patients to identify those parameters that predict disease severity with a high degree of sensitivity to aid early clinical decision which is essential for timely triaging of patients. Methods: An electronic search of four databases comprising PubMed/Medline, Google Scholar, AJOL and JSTOR was performed to identify studies reporting changes in laboratory parameters in COVID-19 patients using key words "laboratory" OR "haematological" OR "cardiac" and "coronavirus 2019" OR ''COVID-19" OR "2019-nCoV" OR "SARS-CoV-2". Results: A total of twenty-eight articles were reviewed out of 593 identified after duplicates removal. These 28 articles comprise 2,688 laboratory confirmed cases of COVID-19 patients comprising 1,418 male and 1,270 female patients with 32 different laboratory parameters identified. Comparing the mild to severe/critical cases our result showed a significant increase in lactate dehydrogenase (100%), D-dimer (100%), neutrophil to lymphocyte ratio (100%) as well as lymphocytopenia (96.0%), thrombocytopenia (83.3%), leukocytosis (71.4%) and neutrophilia (86.4%). Severe cases of COVID-19 had increased serum levels of myoglobin, cardiac troponin I, creatine kinase, creatine kinase-MB, N-terminal brain natriuretic peptide, urea, creatinine, cystatin C, platelet to lymphocyte ratio, international normalised ratio (NLR), platelet count, fibrin degradation products; and decreased levels of Hb, fibrinogen, uric acid, blood gases (PaO2 and PaCO2), and oxygenation index. Conclusions: The observations in this study provide evidence of multiple organ involvement in COVID-19 disease. D-dimer, lactate dehydrogenase, lymphocytes, neutrophils, platelets, fibrinogen, NLR, oxygen index, and blood gases should be considered important in risk stratification to predict severe and fatal COVID-19 outcome in hospitalised patients.