title: Are Hemorrhoids Associated with False-Positive Fecal Immunochemical Test Results?
abstract: OBJECTIVE
  False-positive (FP) results of fecal immunochemical tests (FITs) conducted in colorectal cancer (CRC) screening could lead to performing unnecessary colonoscopies. Hemorrhoids are a possible cause of FP FIT results; however, studies on this topic are extremely rare. We investigated whether hemorrhoids are associated with FP FIT results.
  
  
  METHODS
  A retrospective study was conducted at a university hospital in Korea from June 2013 to May 2015. Of the 34547 individuals who underwent FITs, 3946 aged ≥50 years who underwent colonoscopies were analyzed. Logistic regression analysis was performed to determine factors associated with FP FIT results.
  
  
  RESULTS
  Among 3946 participants, 704 (17.8%) showed positive FIT results and 1303 (33.0%) had hemorrhoids. Of the 704 participants with positive FIT results, 165 had advanced colorectal neoplasia (ACRN) and 539 had no ACRN (FP results). Of the 1303 participants with hemorrhoids, 291 showed FP results, of whom 81 showed FP results because of hemorrhoids only. Participants with hemorrhoids had a higher rate of FP results than those without hemorrhoids (291/1176, 24.7% vs. 248/2361, 10.5%; p<0.001). Additionally, the participants with hemorrhoids as the only abnormality had a higher rate of FP results than those experiencing no such abnormalities (81/531, 15.3% vs. 38/1173, 3.2%; p<0.001). In multivariate analysis, the presence of hemorrhoids was identified as an independent predictor of FP results (adjusted odds ratio, 2.76; 95% confidence interval, 2.24-3.40; p<0.001).
  
  
  CONCLUSIONS
  Hemorrhoids are significantly associated with FP FIT results. Their presence seemed to be a non-negligible contributor of FP results in FIT-based CRC screening programs.
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Nam Hee
authors.initials: NH
authors.lastname: Kim
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Jung Ho
authors.initials: JH
authors.lastname: Park
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Dong Il
authors.initials: DI
authors.lastname: Park
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Chong Il
authors.initials: CI
authors.lastname: Sohn
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Kyuyong
authors.initials: K
authors.lastname: Choi
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea. ys810.jung@samsung.com.
authors.forename: Yoon Suk
authors.initials: YS
authors.lastname: Jung
mesh_terms: D000368:Aged; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000175:diagnosis*; D016001:Confidence Intervals; D055088:Early Detection of Cancer / Q000379:methods; D005189:False Positive Reactions; D005260:Female; D006484:Hemorrhoids; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009780:Occult Blood; D016017:Odds Ratio; D012044:Regression Analysis; D056910:Republic of Korea; D012189:Retrospective Studies; D019564:Unnecessary Procedures
keywords: Hemorrhoids; false-positive; fecal immunochemical test