PLATELET COUNT AND THE RISK OF BLEEDING IN HOSPITALIZED-PATIENTS WITHVENOUS THROMBOEMBOLISM STARTING ANTICOAGULANT-THERAPY

In a series of patients with pulmonary embolism (PE) we have previousl y demonstrated that the risk of recurrent PE was inversely correlated to platelet count (P1C) levels. To find out whether P1C levels were al so associated to a different incidence of heparin-related bleeding com plications, we report our experience with 1,103 consecutive patients w ith venous thromboembolism (VTE) receiving full-dose heparin therapy. Six points of clinical and laboratory information were recorded on adm ission and then compared to the development of bleeding: the patient's age and sex; the etiology of VTE; the type of heparin used (unfractio ned, UFH, vs. low-molecular-weight, LMWH), the presence or lack of PE findings on lung scan, and the P1C levels on admission. Bleeding occur red in 64/1,103 patients (6%). Patients who bled were significantly ol der than those who did not (72 +/- 11 vs. 64 +/- 17 years; p=0.0005). There were no significant differences in bleeding rate according to an y of the risk factors that could have predisposed to VTE, but patients treated with UFH bled significantly more frequently than those on LMW H (48/636 vs. 16/467; odds ratio: 2.30; 95% confidence interval: 1.25- 4.28). Finally, mean P1C levels were significantly lower at VTE diagno sis in patients who subsequently bled (227 +/- 112 vs. 262 +/- 110 x 1 0(9) liters(-1); p=0.01). The logistic regression analysis confirmed t hat all three variables were independent risk factors for bleeding com plications. This is the first study to demonstrate that P1C levels (wi thin the normal range) are inversely correlated with the risk of hepar in-related bleeding. These findings may be of interest not only from t he point of view of pathogenesis but also clinically, as they may be u sed in the decision as to which VTE patients could receive heparin the rapy at home.