Responsiveness of two Persian-versions of shoulder outcome measures following physiotherapy intervention in patients with shoulder disorders

Purpose: To identify the ability of the Persian-version of the Shoulder Pain and Disability Index (SPADI) and the Disabilities of the Arm, Shoulder, and Hand (DASH) to detect changes in shoulder function following physiotherapy intervention (i.e. responsiveness) and to determine the change score that indicates a meaningful change in functional ability of the patient (i.e. Minimally Clinically Important Difference (MCID)).

Method: A convenient sample of 200 Persian-speaking patients with shoulder disorders completed the SPADI and the DASH at baseline and then again 4 weeks after physiotherapy intervention. Furthermore, patients were asked to rate their global rating of shoulder function at follow-up. The responsiveness was evaluated using two methods: the receiver operating characteristics (ROC) method and the correlation analysis. Two useful statistics extracted from the ROC method are the area under curve (AUC) and the optimal cutoff point called as MCID.

Results: Both the SPADI and the DASH showed the AUC of greater than 0.70 (AUC ranges = 0.77-0.82). The best cutoff points (or change scores) for the SPADI-total, SPADI-pain, SPADI-disability and the DASH were 14.88, 26.36, 23.86, and 25.41, respectively. Additionally, moderate to good correlations (Gamma = -0.51 to -0.58) were found between the changes in SPADI/DASH and changes in global rating scale.

Conclusions: The Persian SPADI and DASH have adequate responsiveness to clinical changes in patients with shoulder disorders. Moreover, the MCIDs obtained in this study will help the clinicians and researchers to determine if a Persian-speaking patient with shoulder disorder has experienced a true change following a physiotherapy intervention. Implications for Rehabilitation Responsiveness was evaluated using two methods; the receiver operating characteristics (ROC) method and the correlation analysis. The Persian SPADI and DASH can be used as two responsive instruments in both clinical practice and research settings. The MCIDs of 14.88 and 25.41 points obtained for the SPADI-total and DASH indicated that the change scores of at least 14.88 points on the SPADI-total and 25.41 points on the DASH is necessary to certain that a true change has occurred following a physiotherapy intervention.