Objective: There are few data to guide the choice between colonoscopy and flexible sigmoidoscopy in patients with nonacute rectal bleeding, especially in younger age groups. Our aim was to determine the yield of colonoscopy for significant proximal large bowel disease in the absence of significant distal disease, with special reference to young patients.
Methods: This was a retrospective study of data collected prospectively in 1766 patients (median age 57 yr, 711 women). The endoscopic database (GI-Trac) contained 152 discrete fields for data input. Multiple logistic regression analysis was performed to identify variables independently associated with the presence of isolated significant proximal disease.
Results: Young patients had a higher percentage of normal examinations than did older patients. The incidence of diverticular disease, small polyps, large polyps, and cancer rose with increasing age. No patient aged <40 yr had an isolated proximal cancer, but 7% had other significant isolated proximal disease. There was no overall association between age and significant proximal disease in the absence of significant distal disease (p = 0.66). The only variable associated with isolated proximal disease was anemia (odds ratio = 1.81; 95% CI = 1.11-2.93; p = 0.02).
Conclusion: The yield of colonoscopy (beyond the range of sigmoidoscopy) for neoplasia is low in patients aged <40 yr, but other significant disease may be missed if age is the only criterion determining colonoscopy use.