Colonoscopic Yield after Positive Fecal Occult Blood Testing

Abstract

Purpose: Fecal occult blood testing (FOBT) is accepted as one method of colon cancer screening, and a positive result is an indication for colonoscopy. However, the utility of FOBT in the inpatient setting is not clear. We sought to describe the yield of colonoscopy in inpatients whose sole pre-op indication was positive FOBT. Methods: This is a retrospective study. Using an electronic GI endoscopy database, we identified all inpatients who underwent colonoscopy from 2008-2013 with a positive FOBT listed as the indication on the order form. Patient charts were reviewed for demographics, clinical presentation, prep quality, and for colonoscopic findings including quality of bowel preparation and adverse events. The type of FOBT, location of testing and presence of iron-deficiency anemia were also recorded. Results: Five hundred twenty-five inpatients undergoing colonoscopy were identified. Of these, 96 (18%) had a positive FOBT as the sole indication for colonoscopy (median age 75; 43% female). Sixty-three patients (66%) had a normal colonoscopy, six were found to harbor colorectal cancer (6%), eight had one or more colonic adenomas ≥ 1cm (6%), 4 had angiodysplasia ≥ 5 in number and ≥ 8 mm in size (4%), five had active colitis (5%), 6 had one/more ulcers ≥ 1cm (6%) and 4 had an incomplete exam (4%). Only one patient experienced a procedural adverse event (sedation-related hypotension). Thirty-one patients (32%) were found to have a poor colonoscopic preparation. After chart review, we identified clinical indications for colonoscopy other than positive FOBT in nearly all patients (98%). These included anemia (65 patients; 68%), history of melena or hematochezia (28 patients; 29%) or concern for carcinoma (1 patient; 1%). Conclusion: Only 44% of inpatients undergoing colonoscopy with positive FOBT as the listed indication had clinically significant findings. However, nearly all patients had at least one other reason to undergo colonoscopy. We believe that FOBT should not be used to decide whether screening colonoscopy should be performed in inpatients.