OBJECTIVES: Many agents used in treating AF have potential gastrointestinal (GI) tolerability issues. Treatment-related adverse GI events are a common reason for noncompliance to treatment. The current analysis describes the prevalence of dyspepsia in relation to anticoagulant use among AF patients. METHODS: Data were obtained from the 2009 National Health and Wellness Survey (N=75,000), an annual cross-sectional Internet-based survey of US adults. Respondents answered general demographic and health-related questions. A CHADS2 score (an index of stroke risk) was calculated for each patient using demographic and clinical characteristics. RESULTS: A total of 1297 patients (1.7%) reported a diagnosis of AF. Of these patients, 535 (41%) also reported a physician-diagnosed GI condition; 449 of these (84%) were consistent with dyspepsia (ulcers, abdominal bloating, abdominal pain, gastroesophageal reflux disease/acid reflux, or heartburn). Compared with AF patients without dyspepsia (n=848), those with dyspepsia were younger (mean 62.9 vs. 66.0 years, p<0.05) and more likely to be female (43% vs. 31%, p<0.05). AF patients with dyspepsia were in poorer health than those without dyspepsia, as evidenced by a higher CHADS2 score (1.9 vs. 1.4, p<0.05); this difference was more pronounced in patients aged >65 years and in those with CHADS2 score >2. Despite this, significantly fewer AF patients with than without dyspepsia were taking a prescription medication to treat AF (67% vs. 73%, p<0.05) or an anticoagulant for stroke prevention (35% vs. 47%, p<0.05). CONCLUSIONS: One-third of AF patients in this analysis had dyspepsia. These patients reported a greater disease burden and stroke risk relative to AF patients without dyspepsia. Significantly fewer AF patients with than those without dyspepsia were taking a prescription to treat AF or an anticoagulant for stroke prevention. Poor GI tolerability may be significant in the AF population and should be considered when adherence to medication is critical, such as in high-risk populations.