False-positive fecal immunochemical test results in colorectal cancer screening and gastrointestinal drug use

Purpose The study aimed to determine the influence of drug treatments (proton pump inhibitors [PPIs] combined with other drugs) on the false-positive (FP) rate in the fecal immunochemical test (FIT). Methods Patients undergoing colonoscopy in the setting of a CRC screening program due to a positive FIT result were included prospectively. Demographic data and drug intake of PPIs, antiplatelet therapy (APA), anticoagulants, selective serotonin reuptake inhibitors (SSRIs), and nonsteroidal anti-inflammatory drugs (NSAIDs) were collected. An FP FIT result was considered normal colonoscopy or with nonneoplastic pathology (NNP). Logistic regression models were used to evaluate the effect of these drugs on the rate of FP FIT results. Results We included 515 patients, and 59% (304/515) were males. The rate of FP FIT results was 48% (249/515). Study drug use was higher in patients > 60 years old and females than in those < 60 years old and males (p < 0.001 and p = 0.049, respectively). Multivariate logistic regression revealed that female sex (OR = 2.7 95% CI 1.9-3.9), NNP (OR = 1.5 95% CI 1.1-2.2), and the use of any of the study drugs (OR = 1.4 95% CI 0.9-2.0) were independent risk factors for FP FIT results. The risk of FP FIT results was significantly higher in PPI users than in nonusers (OR = 1.8 95% CI 1.1-2.9), specifically when PPIs were combined with other drugs (OR = 2.01 95% CI 1.1-3.6) only in men. Conclusion Female sex, NNP, and PPIs combined with other drugs in males were identified as independent risk factors for FP FIT results.