title: Incidence of thrombocytopenia among patients receiving heparin venous thromboembolism prophylaxis.
abstract: BACKGROUND
  Heparin is commonly used for venous thromboembolism prophylaxis; however, the incidence of acquired thrombocytopenia in this setting has not been well described.
  
  
  METHODS
  The Complications After Thrombocytopenia Caused by Heparin (CATCH) Registry was designed to evaluate the risk of thrombocytopenia among patients receiving heparin in diverse clinical settings. We examined the incidence, management, and outcomes of thrombocytopenia (platelet count decrease ≥50% or to nadir <150×10(9)/L) among patients with normal admission platelet counts (≥150×10(9)/L) who received ≥72 hours of heparin venous thromboembolism prophylaxis.
  
  
  RESULTS
  Among 1017 patients receiving heparin venous thromboembolism prophylaxis, 190 (19%) developed thrombocytopenia. Factors significantly associated with the development of thrombocytopenia include higher admission platelet count, ventilator use, prolonged heparin exposure, unfractionated heparin use, lower admission blood pressure, and cardiac surgery. For thrombocytopenic patients, only 5% received serologic testing for heparin-induced thrombocytopenia, and a hematology consult was obtained in 3%, but none were switched to a direct thrombin inhibitor. Acquired thrombocytopenia was not associated with increased in-hospital risk of mortality or thromboembolic events (adjusted odds ratio 1.06; 95% confidence interval, 0.57-1.95); however, it was associated with increased Global Use of Strategies to Open Occluded Coronary Arteries (GUSTO) moderate or severe bleeding risk (adjusted odds ratio 4.49; 95% confidence interval, 2.24-9.02).
  
  
  CONCLUSIONS
  Thrombocytopenia occurs frequently in patients on heparin venous thromboembolism prophylaxis, yet its diagnosis has minimal impact on downstream management. The development of thrombocytopenia is associated with increased bleeding risk.
authors.affiliation: Duke Clinical Research Institute, Durham, NC 27705, USA. tracy.wang@dm.duke.edu
authors.forename: Tracy Y
authors.initials: TY
authors.lastname: Wang
authors.forename: Emily F
authors.initials: EF
authors.lastname: Honeycutt
authors.forename: Victor F
authors.initials: VF
authors.lastname: Tapson
authors.forename: Stephan
authors.initials: S
authors.lastname: Moll
authors.forename: Christopher B
authors.initials: CB
authors.lastname: Granger
authors.forename: E Magnus
authors.initials: EM
authors.lastname: Ohman
mesh_terms: D000368:Aged; D000925:Anticoagulants / Q000008:administration & dosage / Q000009:adverse effects*; D001794:Blood Pressure; D001026:Coronary Artery Bypass / Q000706:statistics & numerical data; D005260:Female; D006470:Hemorrhage / Q000453:epidemiology; D006493:Heparin / Q000008:administration & dosage / Q000009:adverse effects*; D006760:Hospitalization; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000453:epidemiology; D010976:Platelet Count; D012042:Registries; D012121:Respiration, Artificial; D012737:Sex Factors; D013921:Thrombocytopenia / Q000139:chemically induced* / Q000175:diagnosis / Q000453:epidemiology*; D054556:Venous Thromboembolism / Q000517:prevention & control*
chemical_list: D000925:Anticoagulants; D006493:Heparin