Purpose: Questionnaires measuring patients' subjective health or health-related quality of life are indispensable tools for the evaluation of effects revealed by intervention studies in the field of medical rehabilitation. These patient-reported outcomes should appropriately reflect change over time. Unfortunately, "sensitivity to change" has so far not been adequately examined for German health-related quality of life questionnaires, especially not in a comparative way. Therefore, indices of sensitivity to change for three widespread generic assessment tools have been determined: IRES-3, SF-36, scales of the SCL-90-R.
Methods: A prospective comparative study was conducted in n = 1145 inpatients with orthopaedic/rheumatologic and cardiac diseases from 16 rehabilitation clinics. All patients received usual care. Their subjective health-status was assessed at two to four weeks before admission (t0), admission (t1), discharge (t2), and three months after discharge (t3). At each time point, they completed the IRES-3, SF-36, and relevant scales of the SCL-90-R. For the time interval t1-t2, Guyatt's responsiveness index (GRI) was calculated and compared across scales and instruments.
Results: Virtually all GRI coefficients for scales and aggregated scores, respectively, reached statistical significance. With respect to the GRI distributions of the diagnostic groups, most coefficients were located in a middle to upper range. While the results for the scales do not clearly indicate which assessment instrument should be preferred, GRI coefficients for higher aggregated scores suggest the IRES-3 to be most sensitive to change.
Conclusion: These results can be helpful in selecting a health-related quality of life instrument or certain subscales for evaluation studies in the field of medical rehabilitation.