Patients', doctors', and caregivers' assessment of disability using the UPDRS-ADL section: are these ratings interchangeable?

This multicenter study sought to analyze the validity and reliability of the Unified Parkinson's Disease Rating Scale (UPDRS)-section 2 (Activities of Daily Living, ADL) as applied by patients and caregivers. Sixty pairs of PD patients-caregivers were enrolled for study purposes. Neurologists used a set of scales to determine disease severity and patients' functional state. Patients and caregivers used adapted versions of the UPDRS-section 2 in tandem with other measures. Wilcoxon and Mann-Whitney tests, weighted kappa, intraclass and Spearman's correlation coefficients, as well as multivariate linear regression models were applied. On the whole, PD patient self-assessment and caregiver evaluation of patients' disability showed close concordance with neurologists' ratings. Correlation between caregiver ratings and clinical evaluation tended to be slightly lower than that for patient-based self-assessment. Depression showed a positive correlation with disability and had a nonsystematic influence on UPDRS-section 2 (ADL) scores. As expected, there was a significant correlation between perceived disability and health-related quality of life measures. Caregiver burden did not reduce the level of agreement with neurologists as to the overall rating of any given patient's disability. In PD, UPDRS-section 2-based assessment of disability by patients themselves and caregivers is a valid and reliable outcome.