Evaluation of the Unified Wilson's Disease Rating Scale (UWDRS) in German patients with treated Wilson's disease

Abstract

Wilson's disease (WD) is an inherited autosomal-recessive disorder of copper metabolism characterized by a wide variety of neurological, hepatic, and psychiatric symptoms. The aim of the present study was the development and evaluation of a clinical rating scale, termed Unified Wilson's Disease Rating Scale (UWDRS), to assess the whole spectrum of clinical symptoms in WD. Altogether 107 patients (mean age 37.6 +/- 11.9 years; 46 male, 61 female) with treated WD participated in the study. Cronbach's alpha as a measure of the internal consistency for the entire scale was 0.92, whereas the intraclass correlation coefficient (ICC) was 0.98 (confidence interval (CI(95%)) 0.97-0.99), indicating an excellent interrater reliability as determined in 32 patients. Besides the total score was significantly correlated with the earning capacity of the patients as indicated by an estimated Spearman's rho approximately 0.54 (CI(95%) 0.40-0.69, P < 0.001). In summary, the UWDRS appears to be a promising tool to assess the disease severity in WD. Its usefulness in clinical research and drug trials should be further addressed.