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Emergency care
Biomarkers and outcomes of COVID-19 hospitalisations: systematic review and meta-analysis
  1. Preeti Malik1,
  2. Urvish Patel1,
  3. Deep Mehta2,
  4. Nidhi Patel3,
  5. Raveena Kelkar2,
  6. Muhammad Akrmah4,
  7. Janice L Gabrilove5,
  8. Henry Sacks6
  1. 1Public Health, Icahn School of Medicine at Mount Sinai, New York, New York, USA
  2. 2Clinical Research Program, Icahn School of Medicine at Mount Sinai, New York, New York, USA
  3. 3MS3, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
  4. 4Pathology, Hartford Hospital, Hartford, Connecticut, USA
  5. 5Medicine, Hematology and Medical Oncology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
  6. 6Environmental Medicine and Public Health, Icahn School of Medicine at Mount Sinai, New York, New York, USA
  1. Correspondence to Dr Preeti Malik, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA;{at}


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.

  • critical care
  • evidence-based practice
  • global health
  • infectious disease medicine
  • prognosis

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  • Contributors PM and UP contributed to conceptualisation and methodology. PM and DM contributed to acquisition of data, PM contributed to formal analysis and investigation. PM, UP, DM, NP, RK and MA contributed to writing-original draft preparation. JLG and HS contributed to writing-review, critical feedback and editing. HS contributed to supervision.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Ethics approval Though this article does not contain any studies with direct involvement of human participants or animals performed by any of the authors, all procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement All data relevant to the study are included in the article or uploaded as supplementary information. Data are collected from the studies published online, publicly available, and specific details related to data and/or analysis will be made available upon request.

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