The interpretation of change score depends on PDI baseline score.

The PDI is responsive in patients with CMP at discharge of vocational rehabilitation. A PDI change score of 13 points (MIC 12.5) can be considered as a real change in pain-related disability for the total study sample, and a PDI change score of 7-20 points can be considered as a real change in pain-related disability for PDI lowest and highest baseline quartile scores.

The PDI showed responsive to detect clinically relevant changes in pain-related disability at discharge of vocational rehabilitation (AUC 0.79). A receiver operating characteristic curve was performed, including Area Under the Curve (AUC) and Minimal Important Change (MIC). The anchor-based method was used to assess the responsiveness of the total sample and of PDI baseline quartile groups. Retrospective data of patients with CMP who attended vocational rehabilitation between 20 was used. The aim of this study was to assess the responsiveness and interpretation of change score of the PDI in patients with chronic musculoskeletal pain (CMP) at discharge of vocational rehabilitation. The Pain Disability Index (PDI) is a widely-used instrument to measure pain-related disability.

6 Department of Rehabilitation Medicine, Center for Rehabilitation, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.

5 Amsterdam UMC, University of Amsterdam, Coronel Institute of Occupational Health, Amsterdam Public Health research institute, Amsterdam, The Netherlands.

4 Department of Research and Development, Heliomare Rehabilitation Center, Wijk aan Zee, The Netherlands. 3 Amsterdam UMC, University of Amsterdam, Coronel Institute of Occupational Health, Amsterdam Public Health research institute, Amsterdam, The Netherlands. 2 Department of Research and Development, Heliomare Rehabilitation Center, Wijk aan Zee, The Netherlands.

1 Department of Rehabilitation Medicine, Center for Rehabilitation, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.

Pdi p56784