Measurement properties of the German Unité Rhumatologique des Affections de la Main (URAM) scale in patients treated for Dupuytren's disease

Abstract

We sought to investigate the reliability, validity, responsiveness, and interpretability of the German version of the Unité Rhumatologique des Affections de la Main (URAM) scale in patients with Dupuytren's disease. Patients with Dupuytren's disease were evaluated before receiving an injection of collagenase Clostridium histolyticum or undergoing surgical treatment and again 1 year later. Patients completed the URAM, the brief Michigan Hand Outcomes Questionnaire (brief MHQ), and the 5-level EuroQol version (EQ-5D-5L). Flexion contracture was measured. Internal consistency (Cronbach's alpha), construct validity (Spearman's correlation coefficient, r), responsiveness (effect size), and the minimally important change (MIC) and minimally important difference (MID) were determined. Confirmatory factor analysis was used to test the structural validity of the questionnaire. We included 231 patients (273 cases) with a mean age of 67 (SD, 9) years. Cronbach's alpha was 0.91. Correlations between the URAM and the brief MHQ, EQ-5D-5L and flexion contracture were r=−0.76, r=−0.46 and r=0.53, respectively. The URAM effect size was 0.96 and the MIC and MID were 6 and 7 points, respectively. The factor analysis revealed unidimensionality but indicated that one item (pick up small objects) could be removed. The German URAM has high reliability, good construct validity and excellent responsiveness. However, the questionnaire could be shortened by one item to increase its structural validity. We recommend using the URAM as a specific tool for evaluating the treatment effect in patients with Dupuytren's disease in daily practice and for research purposes.