Incidence and prognostic significance of thrombocytopenia in patients treated with prolonged heparin therapy.
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.
Oliveira
Gustavo B F
GB
Duke Clinical Research Institute, Duke University Medical Center, 2400 Pratt St, Durham, NC 27705, USA.
Crespo
Eric M
EM
Becker
Richard C
RC
Honeycutt
Emily F
EF
Abrams
Charles S
CS
Anstrom
Kevin J
KJ
Berger
Peter B
PB
Davidson-Ray
Linda D
LD
Eisenstein
Eric L
EL
Kleiman
Neal S
NS
Moliterno
David J
DJ
Moll
Stephan
S
Rice
Lawrence
L
Rodgers
Jo E
JE
Steinhubl
Steven R
SR
Tapson
Victor F
VF
Ohman
E Magnus
EM
Granger
Christopher B
CB
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
D000925:Anticoagulants; D006493:Heparin