Colonoscopy as an adjunctive method for the diagnosis of irritable bowel syndrome: focus on pain perception

Visceral hypersensitivity is an important component of the pathophysiology of irritable bowel syndrome (IBS). In the present study, we investigated differences in pain perception during colonoscopy between IBS patients and non-IBS patients. We further assessed the sensitivity, specificity, and predictive values of pain scores to diagnose IBS.

Patients who underwent colonoscopy for the evaluation of gastrointestinal symptoms or for screening purposes were included. All patients completed Rome III criteria questionnaires and reported pain scores on 0-100-mm visual analog scales after colonoscopy. The patients were divided into three groups: (i) IBS; (ii) other functional gastrointestinal disorders (FGID), including functional bloating, functional diarrhea, and functional constipation; and (iii) healthy controls.

A total of 217 patients were included. The pain scores (median, interquartile range) of IBS patients (52, 34-71) were higher than those of the healthy controls (22, 12-35) or other FGID patients (18, 10-29) (P < 0.001). Upper gastrointestinal symptoms were observed more often in the IBS group than in the non-IBS group (83.2% vs 34.5%, P < 0.001). At the pain score level of 31, the sensitivity, specificity, positive predictive value, and negative predictive value for IBS diagnosis were 86.1%, 75.9%, 75.7%, and 86.3%, respectively.

The degree of pain perception during colonoscopy was higher in IBS patients than in non-IBS patients. We concluded that colonoscopy can be useful in identifying IBS patients, with the additional benefit of excluding organic disorders of the lower gastrointestinal tract.