248 Analysis of Antiplatelet/Anticoagulant Agents Exposure in Patients With Positive Fecal DNA Test

Abstract

INTRODUCTION: Due to the increased risk of gastrointestinal bleeding (obscure and overt), antiplatelet/anticoagulant agents may increase the chances of a positive stool DNA test, leading in an increased false positive rate. To date, there have been no published studies to evaluate if anticoagulants/anti-platelet agents can affect the results of the stool DNA test. METHODS: A retrospective chart review of 1413 patients who had a positive stool DNA followed by documented colonoscopy was performed. Two patients were excluded because of finding of “other carcinoma.” Attention was given to the patient's medication list at the time of the test. All patients on clopidogrel or other antiplatelet agents, warfarin, direct thrombin inhibitors were included in the analysis and patients on aspirin were excluded. Patients who met the inclusion criteria were divided in 2 groups. Group one (1) included patients who were not exposed to antiplatelet/anticoagulant therapy while group two (2) included patients who were exposed to at least 1 antiplatelet/anticoagulant therapy. Only the index lesion was recorded. Advanced adenoma was defined as an adenoma that is larger than 10 mm or had high risk features such as villous transformation or high grade dysplasia. Non-advanced adenoma was defined as an adenoma that is smaller than 10 mm and had no high-risk features. Statistical analysis with Chi- square and Fisher exact was done to compare the proportions. A P-value < 0.05 was considered to be statistically significant. RESULTS: Out of the 1411 patients included in the study, 1221 (86.53%) patients were not exposed to antiplatelet/anticoagulant agents while 190 (13.47%) were exposed to at least one antiplatelet/anticoagulant agent. Colonoscopy findings between group 1 and group 2 were compared. “Adenocarcinoma” was found in 1.64% vs. 2.11% respectively (P = 0.55). “Advanced adenoma” was found in 23.01% vs. 27.89% respectively (P = 0.14). “Non-advanced adenoma” was found in 28.67% vs. 34.74% respectively (P = 0.09). Finally, no adenomas were found in 39.39% vs. 28.95% respectively (P = 0.006), which was statistically significant. CONCLUSION: Previously published studies noted higher prevalence of colorectal neoplasms in patients with coronary artery disease. In our study, patients who are exposed to antiplatelet/anticoagulant therapy were found to have about 10% more cancerous/precancerous lesions on colonoscopy which could be due to higher cardiovascular comorbidities in patients on this therapy.