Validity and Reliability of the Turkish Version of the DASH-TR Questionnaire in Rheumatoid Arthritis Patients, Based on Rasch Analysis

Aim This study aimed to examine the validity and reliability of the Turkish version of the Disabilities of the Arm, Shoulder and Hand Problems (DASH-TR) questionnaire in rheumatoid arthritis (RA) using the Rasch analysis. Method A total 97 individuals (13 men, 84 women; mean age:51.99 +/- 11.12 years, range: 20-65 years) diagnosed as having RA according to the criteria of the American College of Rheumatology were included. The functional status of the upper extremities was evaluated with the DASH-TR questionnaire, patient global health with a visual analog scale (VAS), disease activity with Disease Activity Score 28-C-reactive protein (DAS28-CRP), and disability with Health Assessment Questionnaire (HAQ). DASH-TR was applied to the patients with RA who did not receive any treatment for test-retest at 1-week intervals. DASH-TR results were analyzed using the Rasch analysis. Results In the sample of patients with RA, it was determined that the DASH-TR scale did not provide a unidimensional structure and the items were collected in two dimensions. The first 20 items and the last nine items were differentiated in the two-dimensional structure, and the factor load of m21 was low. Person separation index was obtained as 0.948. Internal consistency reliability was quite high. A significant positive correlation was found between the DASH-TR and VAS, DAS28 and HAQ. There was excellent test-retest reliability according to the intra-class correlation coefficient (0.921, 95% CI 0.882-0.947; P < 0.001). Conclusion The DASH-TR is a reliable and valid questionnaire and can be used for measurement of functional status of the upper extremities in RA.