Irritable bowel syndrome: which definitions are consistent?

Irritable bowel syndrome is inconsistently defined in international literature. Consequently, the resulting differences in study populations may impede any general application of results from one study to another. The aim of this study was to evaluate the consistency of various definitions of irritable bowel syndrome.

By means of a questionnaire concerning abdominal symptoms, subjects were categorized as having IBS according to five definitions: (1) two positive Manning criteria; (2) the Rome criteria; (3) a consensus report by Drossman; (4) definition by Talley; and (5) a newly suggested definition by Kay.

The study was carried out as part of a cohort study of 4122 Danes at the Centre of Preventive Medicine (former the Glostrup Population Studies), Glostrup County Hospital, Denmark.

Kappa coefficients comparing the irritable bowel populations as defined by the above five definitions.

The participation rate was 64.4%. Manning and Rome criteria of irritable bowel syndrome were consistent with a Kappa value of 0.72. A substantial degree of consistency was also present comparing definitions of Drossman, Talley and Kay (kappa, 0.60-0.62). All other comparisons had kappa values below 0.42.

Variations in study populations selected by different definitions of irritable bowel syndrome are so large that they impede the general application of any results. There is a need for international agreement on consistent use of one definition of irritable bowel syndrome.