Thrombocytopenia is associated with severe coronavirus disease 2019 (COVID-19) infections: A meta-analysis

Clin Chim Acta. 2020 Jul;506:145-148. doi: 10.1016/j.cca.2020.03.022. Epub 2020 Mar 13.


Background: Coronavirus disease 2019 (COVID-19) is a novel infectious disease with lack of established laboratory markers available to evaluate illness severity. In this study, we investigate whether platelet count could differentiate between COVID-19 patients with or without severe disease. Additionally, we evaluate if thrombocytopenia is associated with severe COVID-19.

Methods: An electronic search in Medline, Scopus and Web of Science was performed to identify studies reporting data on platelet count in COVID-19 patients. A meta-analysis was performed, with calculation of weighted mean difference (WMD) of platelet number in COVID-19 patients with or without severe disease and odds ratio (OR) of thrombocytopenia for severe form of COVID-19.

Results: Nine studies with 1779 COVID-19 patients, 399 (22.4%) with severe disease, were included in the meta-analysis. The pooled analysis revealed that platelet count was significantly lower in patients with more severe COVID-19 (WMD -31 × 109/L; 95% CI, from -35 to -29 × 109/L). A subgroup analysis comparing patients by survival, found an even lower platelet count was observed with mortality (WMD, -48 × 109/L; 95% CI, -57 to -39 × 109/L. In the four studies (n = 1427) which reported data on rate of thrombocytopenia, a low platelet count was associated with over fivefold enhanced risk of severe COVID-19 (OR, 5.1; 95% CI, 1.8-14.6).

Conclusions: Low platelet count is associated with increased risk of severe disease and mortality in patients with COVID-19, and thus should serve as clinical indicator of worsening illness during hospitalization.

Keywords: Coronavirus, COVID-19; Platelets; Thrombocytopenia.

Publication types

  • Meta-Analysis

MeSH terms

  • Betacoronavirus / isolation & purification
  • COVID-19
  • Coronavirus Infections / blood*
  • Coronavirus Infections / complications*
  • Humans
  • Pandemics
  • Platelet Count
  • Pneumonia, Viral / blood*
  • Pneumonia, Viral / complications*
  • Risk Factors
  • SARS-CoV-2
  • Thrombocytopenia / blood*
  • Thrombocytopenia / etiology*