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Validation of a UPDRS-/MDS-UPDRS-based definition of functional dependency for Parkinson’s disease

Lookup NU author(s): Dr Rachael LawsonORCiD, Professor Alison Yarnall



This is the authors' accepted manuscript of an article that has been published in its final definitive form by Elsevier Ltd, 2020.

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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 <0.001). Algorithm-defined dependency status also predicted mortality: HR for mortality in those dependent vs independent at baseline was 1.6 (95%CI 1.2-2.1) and in those dependent vs independent at five-years’ follow-up was 2.2 (1.6-3.0). Discussion: We have demonstrated the concurrent validity, convergent validity, and predictive validity of a UPDRS-/MDS-UPDRS-based algorithm to define functional dependency in PD. This can be used for studying dependency in any study where UPDRS or MDS-UPDRS part 2 data have been collected.

Publication metadata

Author(s): Ramsay N, Macleod AD, Alves G, Camacho M, Forsgren L, Lawson RA, Maple-Grødem J, Tysnes OB, Williams-Gray CH, Yarnall AJ, Counsell CE

Publication type: Article

Publication status: Published

Journal: Parkinsonism and Related Disorders

Year: 2020

Volume: 76

Pages: 49-53

Print publication date: 01/07/2020

Online publication date: 30/05/2020

Acceptance date: 26/05/2020

Date deposited: 04/06/2020

ISSN (print): 1353-8020

ISSN (electronic): 1873-5126

Publisher: Elsevier Ltd


DOI: 10.1016/j.parkreldis.2020.05.034


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Funder referenceFunder name
J-0802Parkinson`s UK (formerly Parkinson`s Disease Society)