Elalamy et al identified risk factors associated with an unfavorable outcome in patients with heparin-induced thrombocytopenia (HIT). Aggressive management may be able to reduce serious complications for these patients. The authors are from multiple hospitals in France participating in the Groupe d'Etude sur l'Hemostase et la Thrombose de la SFH-Thrombopenie Induite par l'Heparine (GEHT-TIH).


Patient selection: adult exposed to any form of heparin


Onset of HIT was defined as either a drop in platelet count by >= 40% from baseline or a thromboembolic event (arterial or venous).


Unfavorable outcomes: death within 60 days of HIT onset; venous or arterial thromboembolism, amputation, major bleeding, or DIC occurring 2 to 60 days after HIT onset.


Risk factors for unfavorable outcome based o multivariate analysis:

(1) thrombotic episode within 48 hours of HIT onset

(2) delay in starting a danaparoid (or alternative anticoagulant) infusion

(3) underdosing the danaparoid (or alternative anticoagulant)



• Failure to discontinue heparin immediately would also be a risk factor and appears to be inferred in the second parameter.

• The odds ratio was 6.6 if there was a delay > 48 hours from the start of the HIT before starting alternative anticoagulation.

• The odds ratio was 4.3 if the alternative anticoagulant was underdosed.

• The odds ratio was 3.2 if there was an early thrombotic event.


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