Validation of a UPDRS-/MDS-UPDRS-based definition of functional dependency for Parkinson's disease.
Ramsay N., Macleod AD., Alves G., Camacho M., Forsgren L., Lawson RA., Maple-Grødem J., Tysnes O-B., Williams-Gray CH., Yarnall AJ., Counsell CE., Parkinson's Incidence Cohorts Collaboration None., PINE Study None., CamPaIGN study None., PICNICS study None., NYPUM Study None., ParkWest Study: ParkWest Principal investigators None., Study personnel None., ICICLE-PD Study None.
INTRODUCTION: Functional dependency in basic activities of daily living (ADLs) is a key outcome in Parkinson's disease (PD). We aimed to define dependency in PD, using the original and MDS versions of the Unified Parkinson's Disease Rating Scale (UPDRS). METHODS: We developed two algorithms to define dependency from items of UPDRS Part 2 and MDS-UPDRS Part 2 relating to basic ADLs (feeding, dressing, hygiene and walking, and getting out of a chair). We validated both algorithms using data from 1110 patients from six community-based PD incidence cohorts, testing concurrent validity, convergent validity, and predictive validity. RESULTS: Our optimal algorithm showed high specificity and moderate to high sensitivity versus Schwab & England <80% (specificity 95% [95% confidence interval (CI) 93-97] and sensitivity 65% [95% CI 55-73] at baseline; 88% [95% CI 85-91] and 85% [95% CI 79-97] respectively at five-years follow-up). Convergent validity was demonstrated by strong associations between dependency defined by the algorithm and cognition (MMSE), quality of life (PDQ39), and impairment (UPDRS part 3) (all p