Risk factors for unfavorable clinical outcome in patients with documented heparin-induced thrombocytopenia.
BACKGROUND
Prognostic factors for unfavorable clinical outcome in patients with heparin-induced thrombocytopenia (HIT) are largely unknown.


METHODS
In this multicenter, retrospective, case-control study, all HIT patients were treated with danaparoid. Study cases were HIT patients with an unfavorable clinical outcome. Controls were HIT patients who were not study cases. Unfavorable clinical outcome was defined as the occurrence of at least one of the following clinical events: death within 60 days after HIT start date, or venous or arterial thromboembolism, amputation, major bleeding, or disseminated intra-vascular coagulation between 48 hours and 60 days after HIT start date.


RESULTS
Compared with controls (n=65), thrombotic episodes within 48 hours of HIT start date were more frequent (59.2% versus 32.3%; p=0.004), the median time between HIT start date and initiation of danaparoid infusion was longer (3.0 versus 1.0 days; p=0.001), and this treatment was more frequently underdosed (43.8% versus 18.8%; p=0.004) in study cases (n=49). Upon multivariate analysis, all these three parameters were significant predictive factors for unfavorable clinical outcome. The adjusted odds ratios [95% confidence interval] were 6.6 [2.5-17.3] for time between HIT start date and danaparoid initiation over 48 hours, 4.3 [1.5-12.0] for danaparoid underdosing, and 3.2 [1.3-8.0] for presence of a thromboembolic episode at HIT start date.


CONCLUSIONS
This study supports the recommendations concerning the management of HIT patients, namely discontinuation of all heparin administration once the diagnosis is suspected and prompt initiation of an alternative anticoagulant drug with a strict adherence to doses specifically recommended for these patients.
Elalamy
Ismail
I
University Hospital Tenon, ER2 UPMC Paris. ismail.elalamy@tnn.aphp.fr
Tardy-Poncet
Brigitte
B
Mulot
Agnès
A
de Maistre
Emmanuel
E
Pouplard
Claire
C
Nguyen
Philippe
P
Cleret
Bénédicte
B
Gruel
Yves
Y
Lecompte
Thomas
T
Tardy
Bernard
B
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000009:adverse effects*; D016022:Case-Control Studies; D002809:Chondroitin Sulfates / Q000627:therapeutic use; D003871:Dermatan Sulfate / Q000627:therapeutic use; D006493:Heparin / Q000009:adverse effects*; D006497:Heparan Sulfate / Q000627:therapeutic use; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011379:Prognosis; D012189:Retrospective Studies; D012307:Risk Factors; D013921:Thrombocytopenia / Q000139:chemically induced* / Q000175:diagnosis / Q000188:drug therapy*; D016896:Treatment Outcome; D055815:Young Adult
D000925:Anticoagulants; D002809:Chondroitin Sulfates; D003871:Dermatan Sulfate; D006493:Heparin; D006497:Heparan Sulfate; C035838:danaparoid