Data source
We analyzed patient-level data from a de novo cohort of the
Parkinson’s Progression Markers Initiative (PPMI) study - an ongoing
multi-cohort observational study to identify biomarkers of Parkinson’s
disease progression. The study design and its inclusion and exclusion
criteria can be found at
http://www.ppmi-info.org/wp-content/uploads/2017/02/PPMI-Am11-Protocol.pdf.
In brief, patients in this cohort were enrolled within two years of
positive diagnosis. They had not taken PD medications for more than 60
days prior to the baseline and were not expected to require PD
medications for at least six months from baseline. The MDS-UPDRS
observations were collected every 3 months up to 12 months and
thereafter every 6 months. We used data that were available as of
January 2020.
Symptomatic treatments were allowed at any time during the study. For
treated subjects, both Off-Med) and On-Med MDS-UPDRS observations on the
same day were recorded. To minimize the symptomatic impact of PD
medications and anticipate the intended analysis in the eventual drug
trials, this analysis used the Off-Med observations. The MDS-UPDRS Part
III assessment included 33 items.