Objective: To evaluate association between biomarkers and outcomes in COVID-19 hospitalised patients. COVID-19 pandemic has been a challenge . Biomarkers have always played an important role in clinical decision making in various infectious diseases . It is crucial to assess the role of biomarkers in evaluating severity of disease and appropriate allocation of resources . Design and setting: Systematic review and meta-analysis . English full text observational studies describing the laboratory findings and outcomes of COVID-19 hospitalised patients were identified searching PubMed, Web of Science, Scopus, medRxiv using Medical Subject Headings (MeSH) terms COVID-19 OR coronavirus OR SARS-CoV-2 OR 2019-nCoV from 1 December 2019 to 15 August 2020 following Meta-analyses Of Observational Studies in Epidemiology (MOOSE) guidelines . Participants: Studies having biomarkers, including lymphocyte, platelets, D-dimer, lactate dehydrogenase (LDH), C reactive protein (CRP), aspartate aminotransferase (AST), alanine aminotransferase (ALT), creatinine, procalcitonin (PCT) and creatine kinase (CK), and describing outcomes were selected with the consensus of three independent reviewers . Main outcome measures: Composite poor outcomes include intensive care unit admission, oxygen saturation <90%, invasive mechanical ventilation utilisation, severe disease, in-hospital admission and mortality . The OR and 95% CI were obtained and forest plots were created using random-effects models . Publication bias and heterogeneity were assessed by sensitivity analysis .
Results: 32 studies with 10 491 confirmed COVID-19 patients were included . We found that lymphopenia (pooled-OR : 3.33 (95% CI : 2.51–4.41); p <0.00001), thrombocytopenia (2.36 (1.64–3.40); p <0.00001), elevated D-dimer (3.39 (2.66–4.33); p <0.00001), elevated CRP (4.37 (3.37–5.68); p <0.00001), elevated PCT (6.33 (4.24–9.45); p <0.00001), elevated CK (2.42 (1.35–4.32); p=0.003), elevated AST (2.75 (2.30–3.29); p <0.00001), elevated ALT (1.71 (1.32–2.20); p <0.00001), elevated creatinine (2.84 (1.80–4.46); p <0.00001) and LDH (5.48 (3.89–7.71); p <0.00001) were independently associated with higher risk of poor outcomes . Conclusion: Our study found a significant association between lymphopenia, thrombocytopenia and elevated levels of CRP, PCT, LDH, D-dimer and COVID-19 severity . The results have the potential to be used as an early biomarker to improve the management of COVID-19 patients, by identification of high-risk patients and appropriate allocation of healthcare resources in the pandemic.