title: Clinical outcomes in a cohort of patients with heparin-induced thrombocytopenia.
abstract: BACKGROUND
  Heparin-induced thrombocytopenia (HIT) is a thrombotic disorder usually prompting treatment with non-heparin anticoagulants. The benefits and risks of such treatments have not been fully assessed.
  
  
  METHODS
  We analyzed data for 442 patients having a positive heparin-platelet factor 4 antibody test and recent heparin exposure. The primary outcome was a composite endpoint (death, limb amputation/gangrene, or new thrombosis). Secondary outcomes included bleeding and the effect of anticoagulation.
  
  
  RESULTS
  Seventy-one patients (16%) had HIT with thrombosis (HIT-T); 284 (64%) had HIT without thrombosis (isolated HIT); 87 (20%) did not have HIT. An intermediate or high "4T" score was found in 85%, 58%, and 8% of the three respective groups. Non-heparin anticoagulation was begun in 80%, 56%, and 45%. The composite endpoint occurred in 48%, 36%, and 17% (P = .01) of which 61%, 38%, and 40% were receiving non-heparin anticoagulation. Compared with the no HIT group, the composite endpoint was significantly more likely in HIT-T [HR 2.48 (1.35-4.55), P = .003)] and marginally more likely in isolated HIT [HR 1.66 (0.96-2.85), P = .071]. Importantly, risk increased (HR 1.77, P = .02) after platelet transfusion. Major bleeding occurred in 48%, 36%, and 16% of the three groups (P = .005). Non-heparin anticoagulation was not associated with a reduction in composite endpoint events in either HIT group.
  
  
  CONCLUSIONS
  HIT patients have high risks of death, limb amputation/gangrene, thrombosis, and bleeding. Non-heparin anticoagulant treatment may not benefit all patients and should be considered only after careful assessment of the relative risks of thrombosis and bleeding in individual patients.
authors.affiliation: Massachusetts General Hospital, Boston, Massachusetts, USA.
authors.forename: David J
authors.identifier: http://orcid.org/0000-0002-7855-2409
authors.initials: DJ
authors.lastname: Kuter
authors.affiliation: Puget Sound Blood Center and University of Washington Medical Center, Seattle, Washington, USA.
authors.forename: Barbara A
authors.initials: BA
authors.lastname: Konkle
authors.affiliation: New England Research Institutes, Watertown, Massachusetts, USA.
authors.forename: Taye H
authors.initials: TH
authors.lastname: Hamza
authors.affiliation: Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA.
authors.forename: Lynne
authors.initials: L
authors.lastname: Uhl
authors.affiliation: New England Research Institutes, Watertown, Massachusetts, USA.
authors.forename: Susan F
authors.initials: SF
authors.lastname: Assmann
authors.affiliation: University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
authors.forename: Joseph E
authors.initials: JE
authors.lastname: Kiss
authors.affiliation: Brigham and Women's Hospital, Boston, Massachusetts, USA.
authors.forename: Richard M
authors.initials: RM
authors.lastname: Kaufman
authors.affiliation: University of North Carolina, Chapel Hill, North Carolina, USA.
authors.forename: Nigel S
authors.initials: NS
authors.lastname: Key
authors.affiliation: New York Blood Center, New York, New York, USA.
authors.forename: Bruce S
authors.initials: BS
authors.lastname: Sachais
authors.affiliation: University of Maryland, Baltimore, Maryland, USA.
authors.forename: John R
authors.initials: JR
authors.lastname: Hess
authors.affiliation: Johns Hopkins University, Baltimore, Maryland, USA.
authors.forename: Paul
authors.initials: P
authors.lastname: Ness
authors.affiliation: Cleveland Clinic, Cleveland, Ohio, USA.
authors.forename: Keith R
authors.initials: KR
authors.lastname: McCrae
authors.affiliation: Tulane University Hospital and Clinics, New Orleans, Louisiana, USA.
authors.forename: Cindy
authors.initials: C
authors.lastname: Leissinger
authors.affiliation: University of Iowa, Iowa City, Iowa, USA.
authors.forename: Ronald G
authors.initials: RG
authors.lastname: Strauss
authors.affiliation: Froedert Memorial Lutheran Hospital, Milwaukee, Wisconsin, USA.
authors.forename: Janice G
authors.initials: JG
authors.lastname: McFarland
authors.affiliation: Children's Hospital, Boston, Massachusetts, USA.
authors.forename: Ellis
authors.initials: E
authors.lastname: Neufeld
authors.affiliation: Weill Cornell Medicine, New York, New York, USA.
authors.forename: James B
authors.initials: JB
authors.lastname: Bussel
authors.affiliation: Duke University, Durham, North Carolina, USA.
authors.forename: Thomas L
authors.initials: TL
authors.lastname: Ortel
mesh_terms: D000328:Adult; D000368:Aged; D000925:Anticoagulants / Q000627:therapeutic use; D001323:Autoantibodies / Q000097:blood / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006493:Heparin / Q000009:adverse effects* / Q000276:immunology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009026:Mortality; D063868:Patient Outcome Assessment; D010976:Platelet Count; D010978:Platelet Factor 4 / Q000276:immunology; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D013921:Thrombocytopenia / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology* / Q000628:therapy
chemical_list: D000925:Anticoagulants; D001323:Autoantibodies; D010978:Platelet Factor 4; D006493:Heparin