Clinical research study
Incidence of Thrombocytopenia in Hospitalized Patients with Venous Thromboembolism

https://doi.org/10.1016/j.amjmed.2009.03.026Get rights and content

Abstract

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.

Section snippets

Data Sources

The number of patients discharged from short-stay non-Federal hospitals throughout the US with a diagnostic code for pulmonary embolism, deep venous thrombosis, or the combination of pulmonary embolism and deep venous thrombosis, venous thromboembolism, from 1979 through 2005 was obtained from the National Hospital Discharge Survey.2 Among these patients, the number with secondary thrombocytopenia was determined. The National Hospital Discharge Survey consists of data obtained annually from

Results

Over the 27 years of study, among 10,554,000 patients discharged from short-stay hospitals with venous thromboembolism, secondary thrombocytopenia was coded in 38,000 patients (0.36%, 95% CI, 0.32-0.40%) (Table 2). During the 14-year interval from 1979 through 1992, secondary thrombocytopenia was rarely coded in patients with venous thromboembolism. During that time interval, only 7000 cases of secondary thrombocytopenia were recorded on discharge codes among 4,823,000 patients with venous

Discussion

We assumed that the vast majority of patients with pulmonary embolism or deep venous thrombosis would have been treated with heparin, and thrombocytopenia in such patients, therefore, was heparin-associated. The diagnosis of immune heparin-induced thrombocytopenia is usually based on a fall of the platelet count below 150 × 109/L,6 or either a decrease in platelet count of more than 50% from baseline or a platelet count <100 × 109/L7 or <150 × 109/L.8 We assume that these criteria were the basis for

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  • Cited by (0)

    Funding: None.

    Conflict of Interest: Russell Hull has received research support from Sanofi-Aventis and Leo-pharma. He has been on advisory boards for Sanofi-Aventis, Boehringer Ingelheim, Bayer, and Pfizer. None of the authors have any conflict of interest with the content of this article.

    Authorship: All authors had access to the data and a role in writing the manuscript.

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