[The Indicators of Rehab Status questionnaire version 3 (IRES-3) in 1818 rehabilitees with musculoskeletal Diseases]

The revised version 3 of the questionnaire "Indicators of Reha Status" (IRES-3) was recently tested and introduced to the scientific community. The IRES-3 differs considerably from the previous version. It now comprises 16 multi-item scales that are combined to 6 dimensions and 3 single items that are combined to a 7th dimension. The aim of the study was to receive a further impression of the psychometric properties of the IRES-3 in a clinical population.

1818 patients with musculoskeletal diseases from 10 rehabilitation hospitals completed the questionnaire at admission and at discharge. In addition to descriptive statistics (scale properties, internal consistency, sensitivity to change) logistic regression models were used to analyse the characteristics of patients in comparison to a random sample drawn from the general population.

From a psychometric point of view the scale properties are sound. The internal consistency of the multi-item scales ranges from Cronbach's alpha = 0.77 to 0.93. The sensitivity to change ranges from SRM = 0.03 to 1.00. All scales of the IRES-3 are able to discriminate between the clinical and the general population. In all scales the clinical population demonstrated a higher level of burden than the general population.

In our clinical population we were able to reproduce the measurement properties as reported by the authors of the IRES-3. The scales of the IRES-3 demonstrate good internal consistency and respond to change. A high discriminative validity of the instrument could be demonstrated. To further test the instrument the formation of dimensions by the authors of the IRES-3 has to be awaited.