Diagnosis of functional constipation: agreement between Rome III and Rome II criteria and evaluation for the practicality.

Objective: To investigate the agreement between Rome III and Rome II criteria for diagnosing functional constipation (FC) and to evaluate the accuracy of each constipation symptom for FC diagnosis.

Methods: Patients with chronic constipation underwent rigorous biochemical and endoscopic/imaging tests to exclude organic and metabolic diseases. The questionnaires including general information, constipation symptoms, and the most troublesome constipation symptoms were completed in a face-to-face survey. The accuracy of constipation symptoms for FC diagnosis was examined using the likelihood ratio.

Results: Among 184 patients (43 males and 141 females) with chronic constipation, 166 (90.2%) met Rome II criteria and 174 (94.6%) met Rome III criteria for FC, while 166 met both criteria. There was a good diagnostic agreement between the two sets of criteria, with a kappa value of 0.69 and the overall agreement rate was 95.7% (P < 0.001). Based on Rome III criteria, the most accurate symptom for FC diagnosis was sensation of anorectal blockage, followed by straining during defecation and infrequent bowel movements. The most troublesome symptoms reported by patients were lumpy or hard stools, straining during defecation, sensation of incomplete evacuation. More patients indicated that 'the symptoms in the past 3 months' was better than 'those within the past one year' to reflect their constipation (36.7% vs 6.0%, P < 0.001).

Conclusions: There is good agreement between Rome III and Rome II criteria for FC diagnosis. Rome III criteria are more practical than Rome II criteria for Chinese patients.