[An empirical structural analysis of the IRES questionnaire version 2, dependent on indication, gender and age]

The patient questionnaire "Indicators of Reha Status" (IRES, Version 2) is used for assessing the need for rehabilitation and the success of rehabilitation. It is one of the most frequently used questionnaires in measuring subjective health conditions in medical rehabilitation in Germany. Based on the data of 8600 inpatient rehabilitees, the underlying structural model is examined by a confirmatory factor analysis. The model deviates in part from the original model of the questionnaire authors. The modified model was tested within 12 sub-groups. The sub-groups were divided depending on sex, age and indications (orthopaedic, cardiologic and psychosomatic) of the patients. Multi-group comparisons made between those 12 sub-groups showed specific structures within the groups of psychosomatic patients while no differences between female/male and younger/older patients were found. Furthermore, comparable structures of orthopaedic and cardiologic patients were found. Therefore the dimension values of the IRES patient questionnaire are not suited for a comparison between psychosomatic patients and patients from the somatic indications.