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)
where:
• 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.
