Anticoagulation update

February 15, 2011

The latest info on VTE in HIV; intracerebral hemorrhage; and antiplatelet/warfarin combinations

Key Points

Risk factors for VTE in HIV

According to the literature, a higher rate of VTE occurs in patients with HIV who are younger than 50 years (3.31% vs. 0.53% in age-matched healthy controls), have a CD4+ cell count less than 200 cells/mm3 , or have a diagnosis of acquired immunodeficiency syndrome. Both protein S and C deficiencies are considered risk factors. These deficiencies are thought to be secondary to immunosuppression. In addition, the use of protease inhibitors (specifically indinavir and saquinavir) and the presence of active opportunistic infections or antiphospholipid antibodies may be associated with VTE in HIV.

Many cases of VTE are preventable. In light of the expense associated with VTE cases, it is imperative that all VTE risk factors be identified and incorporated into medical decision-making for high-risk patients, including those with HIV, in order to decrease the burden on the healthcare system. Risk factors associated with HIV are not well understood; therefore, long-term prospective studies assessing these are needed.

Source: Kiser KL, Badowski ME. Risk factors for venous thromboembolism in patients with human immunodeficiency virus infection. Pharmacotherapy. 2010;30(12):1292–1302.

Previous antiplatelet therapy results in poorer outcomes in cases of intracerebral hemorrhage

A recent meta-analysis of patients with intracerebral hemorrhage who were taking antiplatelet drugs showed a modest but significantly higher mortality rate in those who were receiving these agents.

Researchers performed a meta-analysis of 25 cohort studies comprising 9,900 patients with intracerebral hemorrhage; 23% of patients had been taking antiplatelet drugs (usually aspirin) at the time of the hemorrhage. In a multivariable-adjusted pooled analysis, previous antiplatelet therapy was associated with significantly higher mortality (odds ratio, 1.27; P=.001) but not worse functional outcomes (OR, 1.10).

In this analysis, too few patients were taking nonaspirin antiplatelet drugs or dual antiplatelet therapies to allow confident conclusions about different antiplatelet regimens. The authors commented that this report serves to remind us that antiplatelet drugs, including aspirin, are not necessarily benign and should be prescribed only if the benefit outweighs the risk of treatment.

Source: Thompson BB, Béjot Y, Caso V, et al. Prior antiplatelet therapy and outcome following intracerebral hemorrhage: A systematic review. Neurology. 2010;75:1333–1342.