Introduction Functional dependency is a key outcome in Parkinson’s disease (PD). We created an algorithm to dichotomously assess dependency in PD patients, based on the Unified Parkinson’s disease rating scale (UPDRS) part 2, routinely collected in PD studies.

Methods We defined dependency from items of UPDRS Part 2 (i.e. hygiene, dressing, feeding, getting out of chair and walking). We validated this algorithm using dependency data from 1113 patients from 6 community-based incidence PD cohorts. We also validated against indirect measures relating to cognition, quality of life and motor impairment.

Results Our algorithm showed high specificity and sensitivity (specificity 94% and sensitivity 70% at baseline; 90% and 84% respectively at 5 years). We found evidence for construct validity with poorer MMSE and quality of life scores in dependent patients.

Discussion We have validated a algorithm to dichotomously assess dependency in PD patients, which can be widely used in research studies.