OBJECTIVE: To study the use of venous thromboembolism (VTE) prophylaxis and the incidence of thrombotic events in patients with acute gastrointestinal (GI) bleeding.METHODS: Individuals admitted with a primary diagnosis of a GI bleed along with any endoscopically confirmed source (over a two-year period) were included. Patient comorbidity and data regarding anticoagulation or antiplatelet agent use before hospitalization were collected, in addition to type of VTE prophylaxis and duration of treatment. The primary end point was the development of VTE (deep vein thrombosis or pulmonary embolism) within one year of presentation.RESULTS: Data from 504 patients admitted with GI bleeding were eligible for review. The total number of VTE events was 20 (4%) while the mortality rate during hospitalization was 4.6%; 397 patients were not given VTE prophylaxis during their hospitalization. Of the patients who were given VTE prophylaxis, 68 received prophylactic heparin or heparin derivatives during their admission. One hundred sixty-five patients had at least one other significant risk factor for VTE including recent or subsequent surgery, past thrombotic event or malignancy. The incidence of thrombosis in those with significant risk factors for VTE was significantly higher than those without (8.5% versus 1.8%; P=0.0009). Overall, there was no significant difference in thrombotic events between individuals receiving pharmacological prophylaxis (1.2%) and those who did not (2.8%) (P=0.4).CONCLUSION: Overall, VTE prophylaxis did not significantly affect thrombotic events in patients admitted for an active GI bleed.