Incidence of thrombocytopenia in hospitalized patients with venous thromboembolism

Am J Med. 2009 Oct;122(10):919-30. doi: 10.1016/j.amjmed.2009.03.026. Epub 2009 Aug 13.


Purpose: To determine the incidence of heparin-associated thrombocytopenia in patients receiving prophylaxis or treatment for venous thromboembolism.

Methods: We assessed the database of the National Hospital Discharge Survey from 1979 through 2005 and complemented this with a meta-analysis of published literature.

Result: Among 10,554,000 patients discharged from short-stay hospitals throughout the US with venous thromboembolism during the 27 years of study, secondary thrombocytopenia was coded in 38,000 patients (0.36%). From 1979 through 1992, secondary thrombocytopenia was coded in only 0.15% of hospitalized patients with venous thromboembolism. The frequency increased sharply to 0.54% from 1993 through 2005. Secondary thrombocytopenia was rarely diagnosed among 1,446,000 patients aged <40 years and among 77,000 women who had venous thromboembolism with deliveries. Meta-analysis of published literature showed a higher incidence among patients who received unfractionated heparin (UFH) for prophylaxis than those who received low-molecular-weight heparin (LMWH) for prophylaxis. Treatment resulted in smaller differences of the incidence between UFH and LMWH.

Conclusion: Heparin-associated thrombocytopenia is rare among patients aged <40 years and women following delivery. The risk of heparin-associated thrombocytopenia is more duration-related than dose-related, and higher with UFH when used for an extended duration. Our findings and those of the literature suggest that although heparin-associated thrombocytopenia is uncommon, the incidence can be minimized by use of LMWH, particularly if extended prophylaxis or extended treatment is required.

Publication types

  • Meta-Analysis
  • Review

MeSH terms

  • Adult
  • Age Distribution
  • Anticoagulants / adverse effects
  • Anticoagulants / therapeutic use
  • Female
  • Follow-Up Studies
  • Heparin, Low-Molecular-Weight / administration & dosage
  • Heparin, Low-Molecular-Weight / adverse effects*
  • Hospitalization / statistics & numerical data*
  • Humans
  • Incidence
  • Male
  • Middle Aged
  • Pregnancy
  • Prognosis
  • Risk Assessment
  • Sex Distribution
  • Thrombocytopenia / chemically induced*
  • Thrombocytopenia / epidemiology*
  • Thrombocytopenia / physiopathology
  • United States / epidemiology
  • Venous Thromboembolism / diagnosis
  • Venous Thromboembolism / drug therapy*
  • Venous Thromboembolism / epidemiology*


  • Anticoagulants
  • Heparin, Low-Molecular-Weight