Reducing Gastrointestinal Bleeding With Proton Pump Inhibitor Therapy in Acute Venous Thromboembolism

Venous thromboembolism (VTE) refers to blood clots that form in the veins of the body, including the arms or legs (deep vein thrombosis \[DVT\]), abdomen (portal vein thrombosis), or lungs (pulmonary embolism \[PE\]). These blood clots are treated with medication to reduce blood clotting called anticoagulants. The main complication of anticoagulants is bleeding, the majority of which comes from the stomach or intestines (gastrointestinal tract). Anticoagulants do not cause bleeding, but they may make bleeding worse. Uncommonly, serious gastrointestinal (GI) bleeding can happen leading to hospitalization and even death. The chance of bleeding is highest in the first few months after starting anticoagulants. Proton pump inhibitors (PPIs) are medications that lower the acid content of the stomach. The medication in this study, a type of proton pump inhibitor called omeprazole, is approved in Canada for treating stomach ulcers, heartburn, and a stomach infection called Helicobacter pylori. The use of omeprazole in this study is considered investigational. This means that Health Canada has not approved the use of omeprazole as a treatment for preventing gastrointestinal bleeding in patients taking anticoagulants. Some studies suggest that they may reduce gastrointestinal bleeding for people taking anticoagulants. The investigators are studying whether treatment with a proton pump inhibitor called omeprazole reduces gastrointestinal bleeding in older adults taking anticoagulants for venous thromboembolism. The investigators plan to do a large, randomized trial which is the best way to test the effect of a treatment. To do this, some of the participants in this study will get omeprazole and others will get a placebo (a substance that looks like the study omeprazole but does not have any active or medicinal ingredients). The placebo in this study is not intended to have any effect on bleeding. A placebo is used to make the results of the study more reliable. Primary Objective To assess the feasibility of a full-scale double-blind placebo-controlled randomized trial to determine whether omeprazole reduces the risk of upper GI bleeding in older adults receiving anticoagulation for acute VTE compared to placebo. Secondary Objectives: 1. To measure additional feasibility outcomes 2. To measure informative outcomes 3. To measure key clinical outcomes