Relationship between the MDS-UPDRS domains and the health-related quality of life of Parkinson's disease patients

Background and purpose The Movement Disorder Society sponsored version of the Unified Parkinson's Disease Rating Scale (MDS‐UPDRS) is a comprehensive instrument for assessing Parkinson's disease (PD). The present study was aimed at determining the relationships between MDS‐UPDRS components and health‐related quality of life (HRQoL) evaluations in PD patients. Methods An international, multicenter, cross‐sectional study was carried out of 435 PD patients assessed with the MDS‐UPDRS, Hoehn and Yahr (HY), Clinical Impression Severity for PD, EQ‐5D and PD Questionnaire − eight items (PDQ‐8). Spearman's rank correlation coefficients, exploratory factor analysis and multiple linear regression models (dependent variables EQ‐5D and PDQ‐8) were performed. Results The participants’ age was 66.71 ± 10.32 years (51.5% men). PD duration was 8.52 ± 6.14, and median HY was 2 (range 1–5). The correlation between the EQ‐5D index and the MDS‐UPDRS ranged from −0.46 (Part IV) to −0.72 (Part II) and for the PDQ‐8 index from 0.47 (Part III) to 0.74 (Part II). In multiple regression models with the MDS‐UPDRS domains as independent variables, the main determinant for both the EQ‐5D index and the PDQ‐8 was Part II followed by Part I. After factorial grouping of the cardinal PD manifestations embedded in the MDS‐UPDRS Parts III and IV for inclusion into multiple regression models, a factor formed by M‐EDL, nM‐EDL and fluctuations was the main determinant for both the EQ‐5D and PDQ‐8 indexes. Conclusions The MDS‐UPDRS component most tightly related with the HRQoL measures was a combination of motor and non‐motor experiences of daily living.