[Sensitivity and Specificity of the Reizdarm-Fragebogen]

The Reizdarm-Fragebogen (RDF) is the first German questionnaire to assess subjectively perceived symptom severity of irritable bowel syndrome (IBS). Thus far, this was only possible in the context of a medical examination by a practitioner. The goal of the current study was to assess differences in RDF scores among IBS patients and other clinical and non-clinical populations. Further, the study aimed to define a cut-off score for the presence of IBS and thereby, to evaluate the RDF as screening instrument in IBS diagnosis.

The study sample consisted of 372 individuals (62.6% male, mean age=41±17 years). 17.5% (of the sample) were IBS patients, 9.9% received treatment for chronic inflammatory bowel disease, 12.1% of the participants were recruited from a psychosomatic clinic, and 50.5% belonged to a control group. All participants filled out the 13 item RDF.

The IBS patients' RDF scores differed significantly from those of other clinical and non-clinical subsamples [t(98.82)=13.61, p<0.001]. Except for the subscale "bloating" this difference was consistently found for all RDF subscales ("diarrhea", "constipation", and "pain and feeling of tension"). With respect to the identification of a cut-off for IBS diagnosis, a score of 32 showed both good sensitivity (90.80%) and specificity (75.56%).

The RDF is an efficient instrument for the assessment of subjectively perceived symptom severity in IBS. Based on the current findings and its good psychometric properties it can be used as a screening instrument for IBS in both clinical practice and research.