June 3, 2009
HOUSTON – Researchers from the Michael E. DeBakey VA Medical Center (MEDVAMC) unveiled data during the Digestive Disease Week® (DDW®) 2009 conference held in Chicago this week examining the potential risks associated with a commonly-used treatment, particularly among the elderly, antithrombotics. DDW is the largest international gathering of physicians and researchers in the field of gastroenterology, hepatology, endoscopy, and gastrointestinal surgery.
“As individuals age, the number of medications they take to control chronic and short-term diseases increases,” said Nicholas J. Shaheen, M.D., M.P.H., A.G.A.F., University of North Carolina School of Medicine. “Patients need to talk to their doctors about the potential risks involved with all medications and how the combinations of drugs they are taking may interact, leading to gastrointestinal or other serious distress.”
Complex antithrombotic therapy (CAT) is the combination of dual or triple antithrombotic agents. Typically, they are prescribed to patients with a history of heart attack, stroke, or peripheral vascular disease. However, these drugs are independently associated with clinically significant upper gastrointestinal events (UGIE), such as bleeding or perforation that require immediate medical attention. The elderly are one of the largest population groups for whom these drugs are prescribed, and the magnitude of CAT-related UGIE risk remains unknown.
MEDVAMC investigators used the Department of Veterans Affairs national pharmacy and administrative databases to identify veterans (60-99 years old) who, from Jan. 1, 2003 to Sept. 30, 2006, were prescribed anticoagulant-antiplatelet (ACAP) therapy, aspirin-antiplatelet (ASAP) therapy, aspirin-anticoagulant (ASAC) therapy, or TRIP (aspirin-anticoagulant-antiplatelet) therapy.
Among 78,084 patients, 30.4 percent were prescribed CAT, with 1,061 UGIE occurring within one year of prescription. Those prescribed ASAP and ASAC were two to two and a half times more likely to suffer UGIE. The least harmful combination of CAT was ACAP.
Younger patients, between 60 and 69 years of age, prescribed CAT are at highest risk of experiencing UGIE. These patients are the most likely to receive TRIP because they are more likely to have a history of ischemic heart disease, hypertension, diabetes, and peripheral artery disease. When adjusted for prescription channeling and confounders, TRIP patients had a four-fold increased risk of bleeding within one year of taking these drugs.
“The fact that triple therapy is most commonly prescribed to younger patients reflects the changes in current cardiac care,” said Neena S. Abraham, M.D., lead investigator, staff physician, and gastroenterologist. “The observed magnitude of UGIE risk suggests an unfavorable risk/benefit profile for CAT in the short term. Gastroenterologists and cardiologists alike need to further evaluate the risk/benefit ratio of these therapies given the observed absolute two- to four-fold increased UGIE risk.” Abraham is also an assistant professor at Baylor College of Medicine, a top-ranked medical school.
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