Thrombocytopenia Is Associated with COVID-19 Severity and Outcome: An Updated Meta-Analysis of 5637 Patients with Multiple Outcomes

Lab Med. 2021 Jan 4;52(1):10-15. doi: 10.1093/labmed/lmaa067.


The COVID-19 pandemic is persistent worldwide. A prior meta-analysis suggested the association of thrombocytopenia (TCP) with more severe COVID-19 illness and high mortality. Considering newly published studies, we updated the previous meta-analysis to confirm and explain the association of TCP with COVID-19 severity and multiple outcomes. Twenty-four studies with 5637 patients with COVID-19 were included in this study. The weighted incidence of TCP in COVID-19 was 12.4% (95% confidence interval [CI], 7.9%-17.7%). Data synthesis showed that the platelet number was lower in patients with either more severe illness or poor outcomes and even lower in nonsurvivors, with weighted mean differences of -24.56 × 109/L, -22.48 × 109/L, and -49.02 × 109/L, respectively. The meta-analysis of binary outcomes (with and without TCP) indicated the association between TCP and 3-fold enhanced risk of a composite outcome of intensive care unit admission, progression to acute respiratory distress syndrome, and mortality (odds ratio [OR], 3.49; 95% CI, 1.57-7.78). Subgroup analysis by endpoint events suggested TCP to be significantly associated with mortality (OR, 7.37; 95% CI, 2.08-26.14). Overall, the present comprehensive meta-analysis indicated that approximately 12% of hospitalized patients with COVID-19 have TCP, which also represents a sign of more severe illness and poor outcomes.

Keywords: COVID-19; SARS-CoV-2; coronavirus disease 2019; platelet; prognosis; thrombocytopenia.

Publication types

  • Meta-Analysis
  • Review

MeSH terms

  • Blood Platelets / pathology*
  • COVID-19 / complications
  • COVID-19 / diagnosis
  • COVID-19 / mortality
  • COVID-19 / pathology*
  • Disease Progression
  • Hospitalization / statistics & numerical data
  • Humans
  • Intensive Care Units
  • Platelet Count
  • Prognosis
  • Respiratory Distress Syndrome / complications
  • Respiratory Distress Syndrome / diagnosis
  • Respiratory Distress Syndrome / mortality
  • Respiratory Distress Syndrome / pathology*
  • SARS-CoV-2 / pathogenicity*
  • Severity of Illness Index
  • Survival Analysis
  • Thrombocytopenia / complications
  • Thrombocytopenia / diagnosis
  • Thrombocytopenia / mortality
  • Thrombocytopenia / pathology*