title: Incidence and prognostic significance of thrombocytopenia in patients treated with prolonged heparin therapy.
abstract: BACKGROUND
  Despite widespread heparin use in clinical practice, the associated development of thrombocytopenia is an underrecognized and undertreated complication.
  
  
  METHODS
  We analyzed data from consecutive hospitalized patients treated with heparin (unfractionated or low molecular weight) for 4 days or longer to determine the incidence, predictors, prognostic significance, and management of "thrombocytopenia," defined as a platelet count less than 150 x 10(9)/L, reduction in platelet count of 50% or more from the admission level, or both.
  
  
  RESULTS
  We enrolled 2420 patients (median age, 65.2 years; 43.8% women) in 48 US hospitals. Thrombocytopenia occurred in 881 patients (36.4%; 95% confidence interval [CI], 34.5%-38.3%). Of those who developed thrombocytopenia, 5.1% died, compared with 1.6% of those without thrombocytopenia (odds ratio [OR], 3.4; 95% CI, 2.1-5.6; P< .001). Thrombocytopenia was also associated with greater risk of myocardial infarction (OR, 2.1; 95% CI, 1.5-2.8; P< .001) and congestive heart failure (OR, 1.3; 95% CI, 1.1-1.6; P= .01). After adjustment for important covariates, thrombocytopenia remained an independent predictor of thrombotic and hemorrhagic events. A relative reduction in platelet count of more than 70% was the strongest independent predictor of death (OR, 13.4; 95% CI, 6.5-27.6; P< .001), followed by a relative reduction in platelet count of 50% to 70%, worse Killip class, occurrence of thromboembolic complications, older age, and longer duration of heparin therapy.
  
  
  CONCLUSIONS
  Thrombocytopenia occurs frequently after prolonged heparin therapy and is strongly associated with worse short-term clinical outcome. The relative reduction in platelet count is a powerful independent predictor of all-cause mortality in hospitalized patients.
authors.affiliation: Duke Clinical Research Institute, Duke University Medical Center, 2400 Pratt St, Durham, NC 27705, USA.
authors.forename: Gustavo B F
authors.initials: GB
authors.lastname: Oliveira
authors.forename: Eric M
authors.initials: EM
authors.lastname: Crespo
authors.forename: Richard C
authors.initials: RC
authors.lastname: Becker
authors.forename: Emily F
authors.initials: EF
authors.lastname: Honeycutt
authors.forename: Charles S
authors.initials: CS
authors.lastname: Abrams
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Anstrom
authors.forename: Peter B
authors.initials: PB
authors.lastname: Berger
authors.forename: Linda D
authors.initials: LD
authors.lastname: Davidson-Ray
authors.forename: Eric L
authors.initials: EL
authors.lastname: Eisenstein
authors.forename: Neal S
authors.initials: NS
authors.lastname: Kleiman
authors.forename: David J
authors.initials: DJ
authors.lastname: Moliterno
authors.forename: Stephan
authors.initials: S
authors.lastname: Moll
authors.forename: Lawrence
authors.initials: L
authors.lastname: Rice
authors.forename: Jo E
authors.initials: JE
authors.lastname: Rodgers
authors.forename: Steven R
authors.initials: SR
authors.lastname: Steinhubl
authors.forename: Victor F
authors.initials: VF
authors.lastname: Tapson
authors.forename: E Magnus
authors.initials: EM
authors.lastname: Ohman
authors.forename: Christopher B
authors.initials: CB
authors.lastname: Granger
mesh_terms: D000368:Aged; D000925:Anticoagulants / Q000009:adverse effects*; D001792:Blood Platelets / Q000187:drug effects*; D005260:Female; D005500:Follow-Up Studies; D006493:Heparin / Q000009:adverse effects*; D017052:Hospital Mortality; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D010976:Platelet Count; D011379:Prognosis; D013921:Thrombocytopenia / Q000139:chemically induced* / Q000401:mortality*; D013997:Time Factors
chemical_list: D000925:Anticoagulants; D006493:Heparin