|Title||RESPONSIVENESS OF THE PAIN DISABILITY INDEX IN PATIENTS UNDERGOING INTERDISCIPLINARY PAIN REHABILITATION|
|Language||English, Spanish, and French|
Background: For several widely-used patient-reported outcome measures (PROMs) in chronic musculoskeletal pain (CMSP) rehabilitation, it is still not known whether they are responsive to change, and what the smallest detectable change (SDC) and minimal clinically important change (MCIC) are. Knowledge of these values can be used to accurately interpret change scores in research and clinical practice. Methods: In this retrospectivecohort study, the responsiveness, the SDC, and MCIC of the Pain Disability Index (PDI) were investigated in CMSP patients. The responsiveness, the SDC, and MCIC were determined according to the COSMIN criteria and by using both anchor and distribution-based methods. Results: Therewas a progression from smallest to largest mean change scores between participants who did not perceive change and those who reported improvement after treatment. However, the correlations with the change scores and the general perceived eufb00ect (GPE) were low. Moreover, the SDC was larger than the MCIC, independent of the GPE used. Conclusions: For this population, the PDI was shown not to be responsive. Furthermore, the PDI appeared not to be able to distinguish clinically important change from measurement error in individual patients. Probably the outcomes would have been diufb00erent, if the GPEs were composed asking the patients to rate the change in experienced disability during physical activities. However, the ufb01nding of a large measurement error of a PROM is in line with previous research in pain rehabilitation. Using outcome measures to examine changes in disability due to a pain rehabilitation program is therefore highly questionable.