Table 1.
Cohort demographics at baseline
| Demographics at baseline | Tracking Parkinson’s | Oxford Discovery | PPMI | ALL |
|---|---|---|---|---|
|
| ||||
| Number of PD patients | 1966 | 985 | 413 | 3364 |
| Total number of visits analyzed | 5936 | 3142 | 3066 | 12.144 |
| Mean length of follow-up (years) | 3.8 (1.4) | 4.3 (1.7) | 5.4 (1.2) | 4.2 (1.5) |
| Male (%) | 65.2% | 64.2% | 65.4% | 65.0% |
| Age at onset (years) | 64.4 (9.8) | 64.5 (9.8) | 59.5 (10.0) | 63.9 (10.0) |
| Age at diagnosis (years) | 66.3 (9.3) | 66.1 (9.6) | 61.0(9.7) | 65.6 (9.6) |
| Age at study entry (years) | 67.6 (9.3) | 67.4 (9.6) | 61.5(9.8) | 66.8 (9.7) |
| Disease duration — time from symptom onset to assessment (years) | 3.2 (3.0) | 2.9 (1.9) | 2.0 (2.0) | 2.9 (2.6) |
| Time from diagnosis to assessment (years) | 1.3 (0.9) | 1.3 (0.9) | 0.5 (0.5) | 1.2 (0.9) |
| MDS-UPDRS part III | 22.9 (12.3) | 26.8 (11.1) | 20.7 (8.8) | 23.8 (11.7) |
| MDS-UPDRS part III annual changea | 1.9 (3.7) | 2.1 (3.5) | 1.8 (2.2) | 2.1 (6.2) |
| MDS-UPDRS part II | 9.9 (6.6) | 8.9 (6.2) | 5.8 (4.1) | 9.0 (6.3) |
| MDS-UPDRS part II annual changea | 1.3 (1.6) | 1.3 (1.6) | 0.9 (1.1) | 1.3 (2.8) |
| Hoehn and Yahr stage meanb | 1.8 (0.6) | 1.9 (0.6) | 1.6 (0.5) | 1.8 (0.6) |
| Hoehn and Yahr stage annual change | 0.1 (0.2) | 0.06 (0.1) | 0.08 (0.1) | 0.06 (0.3) |
| Hoehn and Yahr stage 0 to 1.5 (%) | 48.1% | 23.2% | 44.8% | 40.4% |
| Hoehn and Yahr stage 2 to 2.5 (%) | 45.1% | 68.8% | 54.7% | 53.2% |
| Hoehn and Yahr stage 3c (%) | 6.8% | 8.1% | 0.5% | 6.4% |
| MoCA total (adjusted for education) | 24.9 (3.6) | 24.5 (3.5) | 27.1 (2.3) | 25.0 (3.6) |
| MoCA total annual change | −0.1 (0.9) | −0.1 (0.8) | −0.2 (0.6) | −0.1 (1.5) |
| Semantic fluencyc | 21.8 (6.9) | 34.7 (9.0) | 21.0 (5.4) | 25.5 (9.5) |
| Semantic fluency annual change | −0.2 (1.5) | −0.5 (2.0) | −0.1 (0.9) | −0.5 (3.0) |
| MDS-UPDRS part I.1 | 0.5 (0.7) | 0.5 (0.6) | 0.3 (0.5) | 0.5 (0.7) |
| MDS-UPDRS part I.1 annual change | 0.07 (0.2) | 0.05 (0.2) | 0.07 (0.1) | 0.05 (0.3) |
SD, standard deviation; PPMI, Parkinson’s Progression Markers Initiative; PD, Parkinson’s disease: MDS-UPDRS, Movement Disorder Society Unified Parkinson’s Disease Rating Scale; MoCA, Montreal Cognitive Assessment. Mean (SD) shown unless otherwise indicated.
Annual change score derived from a mixed-effects model of the raw scores as a function of years from onset, with subject random effects to account for individual heterogeneity in the intercept (baseline values) and slope (rate of progression). No other covariates were included in the model within each cohort. For the overall value, we adjusted for cohort and the interaction between cohort and years from onset.
Tracking Parkinson’s used the modified Hoehn and Yahr stage scale, whereas Oxford Discovery and PPMI used the original scale. Hoehn and Yahr stage proportions are shown as a total of the number of people with nonmissing Hoehn and Yahr ratings at baseline.
Instructions and timing for the semantic fluency task were slightly different between cohorts (completed within 60 or 90 seconds). To account for these differences, we standardized all scales within each cohort separately (see Methods section).