Relationship of low-dose aspirin to GI injury and occult bleeding: a pilot study

Background: Low-dose aspirin is commonly used in patients with cardiovascular disease. However, little is known about the effect of aspirin on occult blood loss caused by gastrointestinal injury. Therefore, we studied endoscopic injury and fecal occult blood loss in patients ingesting different quantities of low-dose aspirin. Methods: Forty healthy volunteers were enrolled in a randomized, double-blind, prospective, pilot endoscopic study. Each volunteer underwent 30 days of treatment with daily aspirin 30 mg, 81 mg, 325 mg, or placebo. Subjects completed fecal occult blood test cards before and at the end of treatment of two types: guaiac impregnated (Hemoccult and Hemoccult SENSA) and immunochemical (HemeSelect and FlexSure OBT). Each volunteer underwent upper endoscopy at baseline and after completing 30 days of study medication. Results: Aspirin did not induce significant injury as determined by endoscopy when compared with placebo. Six of 30 volunteers taking aspirin developed erosions, whereas 1 of 10 subjects on placebo developed a new erosion (p = 0.66). Aspirin 325 mg was associated with a higher mean symptom score than the lower aspirin dosages and the placebo group (p = 0.12). Only one subject taking aspirin (325 mg) had fecal occult blood on a single HemeSelect card. No subject had a positive fecal occult blood test with Hemoccult II, Hemoccult II SENSA, or FlexSure OBT cards. Conclusions: Aspirin in dosages commonly used for cardiovascular prophylaxis does not generally cause significant gastric or duodenal mucosal endoscopic lesions. In the absence of frank ulceration, low-dose aspirin does not result in positive fecal occult blood tests. Low-dose aspirin should not interfere with fecal occult blood testing and probably should not be stopped during stool collection.