Minimal Clinically Important Differences for the Experiences of Daily Living Parts of Movement Disorder Society-Sponsored Unified Parkinson's Disease Rating Scale

Background: The minimal clinically important difference is the smallest change of scores clinically meaningful to patients. Objectives: We aimed to calculate these threshold values in association with the International Parkinson and Movement Disorder Society UPDRS (MDS-UPDRS) Parts I and II and to evaluate the feasibility of the composite score of Part I and II (MDS-UPDRS I+II) as an outcome. Methods: Nine hundred eighty-five paired investigations of 365 patients were reviewed, implementing three different techniques simultaneously. Results: Based on the ordinal regression modeling, the MDS-UPDRS I+II score is an applicable outcome measure. Any improvement greater than 2.64 points or any worsening more than 2.45 points on MDS-UPDRS Part I represent a minimal, yet clinically meaningful change. In reference to Part II, the smallest changes considered clinically relevant were 3.05 and 2.51 points for improvement and deterioration, respectively. The thresholds for MDS-UPDRS I+II were 5.73 points for improvement and 4.70 points for worsening. Conclusions: Our minimal clinically important difference thresholds can be utilized in clinical practice in judging clinical relevance. (C) 2017 International Parkinson and Movement Disorder Society