Aspirin therapy places burden on manage care system

Serious gastrointestinal (GI) events are common when antiplatelet therapy is prescribed for secondary cardiovascular disease (CVD) prevention, according to results released at Digestive Disease Week 2012. Hind T. Hatoum, PhD, owner of Hind T. Hatoum & Company and adjunct associate professor at the University of Illinois at Chicago, and colleagues calculated the likelihood of serious GI events associated with hospitalization or admission to an emergency room (ER) in newly diagnosed patients who used antiplatelet therapy for CVD prevention. Serious GI events necessitating hospitalization or ER admission included gastric, duodenal, or peptic ulcers (with or without hemorrhage or perforation), intestinal perforation, or GI hemorrhage. For the analysis, the investigators used medical claims data for the years 2001 through 2010 that were obtained from a large US claims database. Aspirin, with or without clopidogrel, is the cornerstone of antiplatelet therapy for secondary CVD prevention. The database included 2,470,371 patients with at least one diagnosis of a CVD index event, which included hospital or ER-associated stroke, acute myocardial infarction, coronary artery bypass grafting, or angiography. Of these, 54,215 patients were new users of antiplatelet agents; the agents included aspirin in 376 patients, aspirin/dipyridamole in 1,741 patients, and clopidogrel with or without aspirin in 52,098 patients. The mean length of follow-up from the index event to the last claim was 773 days, and to the end of the study was 580 days. Results showed that an average of 3.6% of patients without a history of GI events can be expected to experience a serious GI event within two years of initiating antiplatelet therapy for secondary CVD prevention. Use of aspirin only, older age, female gender, higher Charlson Comorbidity Index, GI history, the use of gastroprotective agents at baseline, and the use of non-steroidal anti-inflammatory drugs (NSAIDs) were associated with a higher risk of GI events. Of 246,777 claims for gastroprotective agents, 86.8% were for proton pump inhibitors; of 96,375 claims for NSAIDs, 25.2% were for cyclooxygenase (COX)-2 inhibitors. "The findings of this study suggest that GI events in people taking antiplatelet therapies such as aspirin are a significant burden on the managed care system," said John G. Fort, MD, Chief Medical Officer of POZEN and study co-author. "This underscores a need for additional treatment options for cardiovascular prevention with fewer upper gastrointestinal events than are associated with currently available therapies." The investigators caution that the analysis did not include over the-counter use of aspirin or common types of NSAIDs and gastroprotective agents, which may be substantial in relation to prescription rates. Therefore, claims databases may be limited in their ability to provide information that might be used to predict and avoid GI events by selectively managing patients' use of antiplatelet, NSAID, or gastroprotective agents. The study was funded by POZEN, which is a Chapel Hill, North Carolina-based pharmaceutical company which is developing PA32540 for the secondary prevention of cardiovascular disease in patients at risk of developing aspirin-associated gastric ulcers.