Organic colonic lesions in 3,332 patients with suspected irritable bowel syndrome and lacking warning signs, a retrospective case-control study

The diagnosis of irritable bowel syndrome is symptom based, and colonoscopy is the most direct way to rule out organic colonic diseases. It is controversial on the necessity of colonoscopy for patients with suspected irritable bowel syndrome and lacking alarm features. This study was designed to verify the organic lesions and discuss the value of colonoscopy in this type of patients. Colonoscopy of 3,332 patients with suspected irritable bowel syndrome and lacking warning signs from 2000 to 2009 were reviewed. One thousand five hundred eighty-eight patients under 50 years of age who underwent colonoscopy screening for health care in the same period were used as controls. The prevalence of different colonic organic lesions was compared between two groups. Organic colonic lesions were found in 30.3% of the patients with suspected irritable bowel syndrome (1,010/3,332) and 39.0% of the controls (619/1,588). Compared with controls, patients with suspected irritable bowel syndrome had higher prevalence of noninflammatory bowel disease and noninfectious colitis and terminal ileitis, however, had lower prevalence of diverticular disease, adenomatous polyps, and non-adenomatous polyps (all P < 0.001). The diagnostic sensitivity of symptom criteria on irritable bowel syndrome without colonoscopy is not more than 69.7% in patients with suspected irritable bowel syndrome lacking warning signs. Though the method of colonoscopy is hard to screen tumor in this type of patients, it is beneficial to uncover some other relevant organic lesions such as terminal ileitis. Colonoscopy should not be refused to suspected irritable bowel syndrome patients without warning signs.