Diagnostic Yield of Colonoscopy in Young Adults with Lower Gastrointestinal Symptoms in a Multicenter Midwest Cohort

Background/Aims: Serious gastrointestinal (GI) pathologies are common in older adults compared to young adults (≤40 years). Data on the diagnostic yield (DY) of colonoscopy in young adults with lower GI symptoms are lacking. We aimed to evaluate the overall DY of colonoscopy; and the DY stratified by the presence or absence of bright red blood per rectum (BRBPR) in young adults ≤40 years. Methods: We reviewed diagnostic colonoscopies performed in young adults by 18 gastroenterologists at 2 different institutions from ­October 2016 to April 2019. Patients with familial colorectal cancer (CRC) syndromes were excluded. DY was calculated based on the proportion of abnormal colonoscopy defined as having inflammatory bowel disease (IBD), microscopic colitis (MC), advanced adenoma, or CRC. Results: We included 454 patients, mean (SD) age was 31 (3) years, 162 (36%) were males and mean (SD) BMI was 30 (8.5). BRBPR was the indication for colonoscopy in 194 (43%) patients, 260 (57%) patients had colonoscopy for other lower GI symptoms (abdominal pain, chronic diarrhea, constipation) but without BRBPR. Overall DY of colonoscopy in young adults with lower GI symptoms was 15%; IBD was seen in 43 (10%) patients, MC 10 (2%), and advanced neoplasia/CRC 20 (4%). Overall DY in patients with BRBPR was significantly higher than in patients without BRBPR (22 vs. 11%, p = 0.001). The DY for IBD was also higher in young adults with BRBPR versus without BRBPR (15 vs. 6%, p = 0.003). The DY of patients with both BRBPR and abdominal pain was 34%, for BRBPR and diarrhea was 40%, and for all 3 symptoms of BRBPR, diarrhea, and abdominal pain was 52%. Conclusions: Significant proportion of young adults with BRBPR have abnormal pathology (22%) justifying evaluation by colonoscopy. For other lower GI symptoms without BRBPR, the necessity of endoscopic evaluation should be determined clinically on a case-to-case basis due to the low overall DY.