[Differences in definitions of irritable bowel syndrome]

Irritable bowel syndrome is inconsistently defined. The resulting difference in study populations may impede general application of results from one study to another. The aim of this study was to evaluate the consistency of various definitions. At a follow-up of a sex-and age-stratified randomly selected cohort, participants filled in a questionnaire about abdominal symptoms. Questions categorized the participants according to five different definitions of irritable bowel syndrome:1) two Manning criteria,2) Rome criteria,3) consensus report by Drossman,4) definition by Talley and 5) definition by Kay. The participation rate was 64.4%. Manning and Rome criteria were consistent with a kappa value of 0.72. Consistency was also present comparing definitions of Drossman. Tallay and Kay (kappa values of 0.60-0.66) All other comparisons had kappa values below 0.42. It is concluded that variations in study population selected by different definitions of Irritable Bowel Syndrome are so large that they impede general application of any results. There is a need for an international agreement on a definition of irritable bowel syndrome.