Is Rome III Criteria for Irritable Bowel Syndrome More Useful Than Rome II Criteria in Korea?: Author's Reply.

TO THE EDITOR: We appreciate the comments from Park. Irritable bowel syndrome (IBS) is one of the most frequent diseases in gastroenterologist practice. Although IBS is perceived as a relatively benign disorder which is not connected to actual overall survival (hazard ratio = 1.06),1 its negative impacts on the quality of life, productivity and healthcare resources2 bring about its importance in real practice. The prevalence of IBS varies depending on the diagnostic criteria, the country and the methodology.3,4 We are eager to know the 'true' prevalence of IBS which is the aim of our study.5-7

In comparison to our study with good agreement between Rome III and Rome II criteria (9.0% vs 8.0%, respectively),7 Sperber's study4 reported much higher prevalence of IBS by Rome III criteria compared with Rome II (11.4% vs 2.9%). Although the methodology of Sperber's study was similar to those of our studies, several factors contributed on generating a huge gap in the prevalence of IBS between the 2 diagnostic criteria in Israeli subjects.

First, the average age of subjects with IBS by Rome II in our study was younger than that of Israeli's (35.8 vs 44.5 years, respectively). Our previous study presented that IBS was more common among people in their 20s.6 Moreover, strict adherence and extended time frame of Rome II criteria make recall difficult for the olds particularly. Second, Sperber's study reanalyzed the data from Rome II questionnaires to approximate the actual prevalence of Rome III criteria and facilitated a retrospective comparison of the 2 criteria. Third, one of the other potential factors was the racial difference in the study population. Existing studies reported that the prevalence of IBS by Rome II was 6.6%-8.6% in Asian countries.6,7 Likewise, a similar rate of IBS by Rome II criteria (8.0%) was found in a study conducted by us.

We presented subgroups according to the Rome criteria to understand IBS subjects diagnosed by Rome II and Rome III. However our study design did not include questionnaires about psychological information. Our study was performed by survey through the phone which was rather time consuming, therefore psychiatric evaluation was not done.

Sperber et al4 presented that subjects with IBS by Rome II had more severe symptoms and more consultation rates. In other words, these findings suggest that diagnosing with Rome III criteria appears to reflect average IBS patients in clinical practice, more accurately. Most important thing is to figure out the 'true' prevalence of IBS and this will be the aim of the further studies from our group.