Relationship between the MDS-UPDRS and Quality of Life : a large international multicenter study of 3206 patients

250 words, limit 250) Background The relationship between Health-Related Quality of Life (HRQoL) and MDS-UPDRS has not been fully studied so far. The aim of this study was to evaluate the relationship between all MDS-UPDRS components and HRQoL in a representative international cohort of PD patients. Methods We collected demographic and disease-related data as well as MDS-UPDRS and PDQ8 scales. Data were analyzed using two hierarchical multiple regressions, first between the MDS-UPDRS Parts scores and PDQ8 and second between individual items from those Parts demonstrating significant relationship to PDQ8 in the first regression. LASSO regression analyses were performed to evaluate the relationship between PDQ8 and all individual MDS-UPDRS items. Results A total of 3206 PD patients were included in the study. In the first regression analysis PDQ8 was significantly related to MDS-UPDRS parts I and II, but not III and IV. In the second regression model significant contributions to PDQ8 were found for Part I items Fatigue, Pain, Depressed mood, Apathy; and Part II items Dressing, Doing hobbies, Freezing, Speech and Tremor. In the LASSO analysis, five Part I, six Part II, three Part III and one Part IV items contributed to PDQ8 scores. Five items most significantly related to the model were Depressed mood, Dressing, Apathy, Pain and Fatigue. Conclusions This is so far the largest study related to HRQoL issues in PD. Restrictions in activities of daily living and non-motor symptoms significantly contribute to QoL in PD.