Warfarin Use During Fecal Occult Blood Testing: A Meta-Analysis

BACKGROUND: Fecal occult blood testing (FOBT) is a widely used screening test for colorectal cancer (CRC). Given the limited data about the effects of warfarin on FOBT are inconclusive, current screening guidelines for CRC do not address whether warfarin should be discontinued before FOBT. Therefore, we conducted a meta-analysis to evaluate the influence of warfarin on the yield of FOBT. METHODS: Multiple medical databases were searched (April 2011). Studies examining the use of warfarin versus no warfarin for FOBT were included. Meta-analysis for the effect of warfarin or no warfarin for FOBT was performed by calculating pooled estimates of colonoscopy findings and detection of neoplasia, any adenoma, advanced adenoma, or colon cancer by odds ratio (OR) with fixed and random effects model. RevMan 5.1 was utilized for statistical analysis. RESULTS: Five studies (N = 11,244) met the inclusion criteria. No statistically significant difference was noted between FOBT with or without warfarin for colonoscopy findings (OR 0.88; 95% CI: 0.48 - 1.62, P = 0.67) or detection of neoplasia (OR 0.88; 95% CI: 0.58 - 1.35, P = 0.57), any adenoma (OR 1.08; 95% CI: 0.73 - 1.58, P = 0.71), advanced adenoma (OR 1.07; 95% CI: 0.69 - 1.65, P = 0.78), and colon cancer (OR 0.69; 95% CI: 0.38 - 1.23, P = 0.21). CONCLUSIONS: Among patients with positive FOBT, the yield of colonoscopy appears not to be altered by warfarin use.