A Phase 3 interventional study of Omeprazole 20 mg Oral Tablet and Placebo in Venous Thromboembolism, Gastro Intestinal Bleeding and Blood Clot, sponsored by Ottawa Hospital Research Institute. Recruiting at 7 sites in Canada. Open to participants aged 65 Years and older. Per ClinicalTrials.gov, last updated 2026-07-22.
Sponsored by Ottawa Hospital Research Institute · Phase 3, Interventional, and Treatment
The investigators are studying whether treatment with a proton pump inhibitor called omeprazole reduces gastrointestinal bleeding in older adults taking blood thinners for a blood clot (venous thromboembolism). The purpose of this study, a pilot study or a feasibility study, is to test the study plan and determine whether enough participants will join a larger study and accept the study procedures.
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:
712 studies on the registry are indexed under Venous Thromboembolism; 146 are open to participants now.
This study's planned enrollment of 360 is above the median of 240 across 401 interventional studies indexed under Venous Thromboembolism.
Browse Venous Thromboembolism studies →Ottawa Hospital Research Institute is the lead sponsor of 547 studies on the registry; 99 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
The study doctor’s estimate of how long someone is likely to live. Criteria use it so that people can stay in the study long enough for it to answer its question.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Life expectancy
The study doctor’s estimate of how long someone is likely to live. Criteria use it so that people can stay in the study long enough for it to answer its question.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants randomized to the experimental arm will take one omeprazole 20 mg tablet by mouth every day for the duration of their participation in the study.
Drug: Omeprazole 20 mg Oral Tablet
Participants randomized to the control arm will take one placebo tablet by mouth every day for the duration of their participation in the study.
Other: Placebo
Omeprazole once daily for 90 days
Also known as: Omeprazole
Placebo once daily for 90 days
Study feasibility at participating centres
The mean number of participants recruited per site per month
Time frame: 24 months
Eligibility Rate
Proportion of screened patients who are eligible
Time frame: 24 months
Consent Rate
Proportion of eligible patients who provide consent
Time frame: 24 months
Retention Rate
Proportion of participants who completed all study procedures
Time frame: 27 months
Adherence Rate
adherence to study drug measured by pill count or assessing the patient diary at the end of follow-up
Time frame: 27 months
Risk Factors
The proportion of participants with the following risk factors for bleeding at baseline: decreased kidney function (defined as estimated glomerular filtration rate \[eGFR\] \<60 mL/min/1.73 m2), active cancer, concurrent antiplatelet and/or NSAID therapy, chronic liver disease, chronic anemia.
Time frame: 24 months
Patients already prescribed proton pump inhibitor
The proportion of screened patients already receiving prescribed proton pump inhibitor therapy
Time frame: 24 months
Reasons for Declining Participation
Patients are not required to provide a reason for declining to participate. However, for those patients who are willing to share, reasons for declining participation will be reviewed
Time frame: 24 months
New PPI prescription
The proportion of participants with new prescription for proton pump inhibitor during the study
Time frame: 27 months
Recurrent VTE
The proportion of patients that have a recurrent venous thromboembolism during the study
Time frame: 27 months
Mortality
The proportion of patients who die from gastrointestinal bleeding, and all-cause mortality during the study
Time frame: 27 months
Serious Adverse Events
The proportion of patients who have a serious adverse event during the study
Time frame: 27 months
Change in health-related quality of life
Change in health-related quality of life as measured by the EuroQol EQ-5D-5L Quality of Life questionnaire at 90 days compared to baseline. This questionnaire includes the patient's thoughts about their health, including mobility, self-care, usual activities, pain or discomfort, and anxiety or depression. The lowest possible score is 5 and the highest is 25. A lower score represents a worse quality of life. The questionnaire also includes a Visible Analog Scale where patients are asked to picture a vertical line that is numbered from 0 to 100. 100 at the top of the line means the best health the patient can imagine and 0 at the bottom of the line means the worst health the patient can imagine. Patients are asked to provide a number that best represents their health at the time of completing the questionnaire.
Time frame: 27 months
Change in functional status
Change in functional status as measured by the Standard Assessment of Global Activities in the Elderly (SAGE) scale at 90 days compared to baseline. The SAGE questionnaire measures what patients are doing in their community and their homes. Patients are asked to indicate the level of difficulty they have with each of the questions in the past month with a response of no difficulty, mild, moderate, or severe difficulty. Mild = minimal/occasional difficulty that does not affect the ability to perform the activity or task; Moderate = some/regular difficulty that does affect the ability to perform the task, although they may still be able to perform the task; Severe = extreme/constant difficulty performing the task or the task is not completed and/or is completed by someone else because of its difficulty.
Time frame: 27 months
Clinically Relevant Upper Gastrointestinal Bleeding Events
Adjudicated clinically relevant upper gastrointestinal bleeding (major upper gastrointestinal bleeding plus clinically relevant non-major \[CRNM\] upper GI bleeding, adapted from International Society on Thrombosis and Haemostasis (ISTH) criteria for major bleeding and CRNM bleeding).
Time frame: 27 months
Rate of endoscopically confirmed upper gastrointestinal bleeding
Proportion of patients who have upper gastrointestinal bleeding as confirmed by endoscope at 30, 60, and 90 days post randomization
Time frame: 27 months
Rate of lower gastrointestinal bleeding
Proportion of patients who have lower gastrointestinal bleeding at 30, 60, and 90 days post randomization
Time frame: 27 months
All major gastrointestinal bleeding
Proportion of patients who have confirmed major gastrointestinal bleeding by adjudication at 30, 60, and 90 days post randomization
Time frame: 27 months
All clinically relevant non-major gastrointestinal bleeding
Proportion of patients who have confirmed clinically relevant non-major gastrointestinal bleeding by adjudication at 30, 60. 90 days
Time frame: 27 months
All major bleeding
Proportion of patients who have confirmed major bleeding by adjudication, including major GI bleeding) at 30, 60, 90 days post randomization
Time frame: 27 months
All clinically relevant non-major bleeding
Proportion of patients who have confirmed clinically relevant non-major bleeding (including CRNM GI bleeding) at 30, 60, and 90 days post randomization
Time frame: 27 months
Hospitalization for gastrointestinal bleeding
Proportion of patients hospitalized for gastrointestinal bleeding at 30, 60. and 90 days post randomization
Time frame: 27 months
Plan to share: Yes — CONVERGE trials will be conducted within specific research domains under a core protocol outlining shared elements, including broad inclusion criteria, a minimum set of core outcomes, event adjudication, and data sharing to the CONVERGE shared data repository. Patients meeting domain-specific inclusion criteria can be enrolled in individual trials based on pre-defined additional characteristics. RADIANT will be the first trial conducted within the Acute VTE Treatment Domain.
Supporting information: Study protocol
Time frame: Starting after study completion
Access criteria: Select members of the International Network of VENous Thromboembolism Clinical Research Networks (INVENT) participating in CONVERGE trials will enter into an agreement to enhance data-sharing and meta-analysis across trials. Access will be restricted by strict authentication processes and data will be maintained on secure servers.
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Studies of the drug tested here: Omeprazole
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