The COGENT: Omeprazole with antiplatelet therapy reduces upper GI bleeding [Classics Series]

1. In patients being treated with dual antiplatelet therapy, the addition of omeprazole significantly decreases the rate of gastrointestinal events when compared with placebo.

2. The addition of omeprazole to clopidogrel and aspirin did not significantly change the rate of cardiovascular events as compared to placebo.

Original Date of Publication: November 2010

Study Rundown: Antiplatelet therapy is commonly prescribed to people who suffer from cardiovascular disease, including myocardial infarctions, transient ischemic attacks, and stroke. A common complication of antiplatelet therapy, however, is gastrointestinal bleeding and this risk is increased when patients are being treated with two antiplatelet agents. Moreover, evidence from observational studies were inconsistent with regards to potential interaction between clopidogrel, a commonly prescribed antiplatelet agent, and proton pump inhibitors. Thus, the purpose of the Clopidogrel and Optimization of Gastrointestinal Events Trial (COGENT) was to assess efficacy and safety of clopidogrel and proton pump inhibitors in patients with coronary artery disease.

Treatment with omeprazole in patients on dual antiplatelet therapy significantly reduced the rate of gastrointestinal events (HR 0.34; 95%CI 0.18-0.63) without a significant difference in the rate of cardiovascular events (HR 0.99; 95%CI 0.68-1.44). Notably, this trial was stopped prematurely, as there was an unexpected loss of funding. As a result, the intended study enrollment and event rates were not achieved. Nevertheless, this study provides evidence in support of the use of proton pump inhibitors in patients on dual antiplatelet therapy to reduce the rate of gastrointestinal events.

Click to read study in NEJM

In-Depth [randomized, controlled trial]: Originally published in NEJM in 2010, this randomized, controlled trial assessed the risk of gastrointestinal bleeding in patients receiving dual antiplatelet therapy with and without concomitant omeprazole. Cogentus Pharmaceuticals was involved in the design of the study. A total of 3,761 patients from 393 sites in 15 countries being treated with aspirin (75-325 mg daily) and clopidogrel (75 mg daily) were randomized to receive either omeprazole (20 mg daily) in addition or placebo. Patients were eligible for the study if they were ≥21 years of age and it was anticipated that they would require clopidogrel and aspirin therapy for the next 12 months. The primary endpoint was a composite of upper gastrointestinal events, including upper gastrointestinal bleeding, symptomatic uncomplicated gastroduodenal ulcers, obstruction, and perforation. The primary cardiovascular safety endpoint was a composite of death from cardiovascular causes, nonfatal myocardial infarction, coronary revascularization, or ischemic stroke.

The trial was stopped prematurely when the sponsor suddenly lost financial backing. At 180 days, the omeprazole group had a significantly lower rate of gastrointestinal events when compared to the placebo group (HR 0.34; 95%CI 0.18-0.63). The omeprazole group also experienced significantly less overall gastrointestinal bleeding as compared with placebo (HR 0.30; 95%CI 0.13-0.66). There was no significant difference between the two groups in terms of the rate of cardiovascular events (HR 0.99; 95%CI 0.68-1.44).

Image: PD

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