Table 2. Prodromal markers of PD in the prospective TREND study.
| Features | Visit 1 | Visit 2 | Visit 3 | Visit 4 | ||||
|---|---|---|---|---|---|---|---|---|
| Prodromal markers | Category | PD-free (n = 1178) | PD-free (n = 1170) | Incident PD (n = 6) | PD-free (n = 981) | Incident PD (n = 5) | PD-free (n = 880) | Incident PD (n = 5) |
| Hyposmia | Marker absent | 913 (78%) | 860 (80%) | 1 (17%) | 747 (76%) | 0 (0%) | 665 (76%) | 1 (20%) |
| Borderline | 244 (21%) | 186 (17%) | 4 (67%) | 194 (20%) | 5 (100%) | 164 (19%) | 4 (80%) | |
| Marker present | 17 (1%) | 4 (0.4%) | 0 (0%) | 24 (2%) | 0 (0%) | 42 (5%) | 0 (0%) | |
| Missing | 4 (0.3%) | 20 (2%) | 1 (17%) | 16 (2%) | 0 (0%) | 9 (1%) | 0 (0%) | |
| Constipation | Marker absent | 1015 (86%) | 891 (83%) | 4 (67%) | 810 (83%) | 2 (40%) | 758 (86%) | 5 (100%) |
| Borderline | 139 (12%) | 135 (13%) | 2 (33%) | 113 (12%) | 2 (40%) | 90 (10%) | 0 (0%) | |
| Marker present | 15 (1%) | 23 (2%) | 0 (0%) | 28 (3%) | 1 (20%) | 28 (3%) | 0 (0%) | |
| Missing | 9 (1%) | 21 (2%) | 0 (0%) | 16 (2%) | 0 (0%) | 4 (1%) | 0 (0%) | |
| Excessive Daytime Somnolence | No | 0 (0%) | 32 (3%) | 1 (17%) | 383 (39%) | 1 (20%) | 839 (95%) | 5 (100%) |
| Yes | 1178 (100%) | 1037 (97%) | 0 (0%) | 586 (60%) | 0 (0%) | 2 (0.2%) | 0 (0%) | |
| Missing | 0 (0%) | 10 (<1%) | 5 (83%) | 12 (1%) | 4 (80%) | 39 (4%) | 0 (0%) | |
| Symptomatic Hypotension | Marker absent | 918 (78%) | 793 (74%) | 5 (83%) | 746 (76%) | 5 (100%) | 738 (84%) | 3 (60%) |
| Borderline | 230 (20%) | 218 (20%) | 0 (0%) | 200 (20%) | 0 (0%) | 96 (11%) | 1 (20%) | |
| Marker present | 28 (2%) | 52 (5%) | 1 (17%) | 27 (3%) | 0 (0%) | 43 (5%) | 1 (20%) | |
| Missing | 2 (0.2%) | 7 (1%) | 0 (0%) | 6 (0.6%) | 0 (0%) | 3 (0.3%) | 0 (0%) | |
| Urinary Dysfunction | Marker absent | 733 (62%) | 691 (65%) | 4 (67%) | 637 (65%) | 2 (40%) | 631 (72%) | 3 (60%) |
| Borderline | 391 (33%) | 286 (27%) | 1 (17%) | 269 (27%) | 2 (40%) | 192 (22%) | 1 (20%) | |
| Marker present | 51 (4%) | 82 (8%) | 1 (17%) | 65 (7%) | 1 (20%) | 53 (6%) | 1 (20%) | |
| Missing | 3 (0.3%) | 11 (1%) | 0 (0%) | 10 (1%) | 0 (0%) | 4 (1%) | 0 (0%) | |
| pRBD | No | 1116 (95%) | 1041(97%) | 6 (100%) | 959 (98%) | 4 (80%) | 852 (97%) | 4 (80%) |
| Yes | 54 (5%) | 28 (3%) | 0 (0%) | 22 (2%) | 1 (20%) | 28 (3%) | 1 (20%) | |
| Missing | 8 (1%) | 1 (<0.1%) | 0 (0%) | 0 (0%) | 0 (0%) | 0 (0%) | 0 (0%) | |
| Subthreshold parkinsonism (MDS-UPDRS-III) | No motor deficit | 1006 (85%) | 980 (92%) | 0 (0%) | 913 (93%) | 1 (20%) | 784 (89%) | 1 (20%) |
| Borderline motor deficit | 120 (10%) | 66 (6%) | 1 (17%) | 39 (4%) | 2 (40%) | 63 (7%) | 0 (0%) | |
| Subthreshold parkinsonism | 52 (4%) | 24 (2%) | 5 (83%) | 29 (3%) | 2 (40%) | 33 (4%) | 4 (80%) | |
| Missing | 0 (0%) | 0 (0%) | 0 (0%) | 0 (0%) | 0 (0%) | 0 (0%) | 0 (0%) | |
| Depression | No | 830 (70%) | 735 (69%) | 3 (50%) | 666 (65%) | 4 (80%) | 599 (68%) | 4 (80%) |
| Yes | 348 (30%) | 335 (31%) | 3 (50%) | 315 (32%) | 1 (20%) | 281 (32%) | 1 (20%) | |
| Missing | 0 (0%) | 0 (0%) | 0 (0%) | 0 (0%) | 0 (0%) | 0 (0%) | 0 (0%) | |
| Global cognitive deficits | No | 971 (82%) | 911 (85%) | 6 (100%) | 856 (87%) | 4 (80%) | 788 (90%) | 4 (80%) |
| Yes | 194 (16%) | 142 (13%) | 0 (0%) | 111 (11%) | 1 (20%) | 81 (9%) | 1 (20) | |
| Missing | 13 (1%) | 17 (2%) | 0 (0%) | 14 (1%) | 0 (0%) | 11 (1%) | 0 (0%) | |
Summary statistics of prodromal markers of PD-free individuals and incident PD cases at different time points, absolute and relative (%) frequencies of marker presence or median (inter-quartile range in brackets) are given unless specified otherwise. Sample sizes per visit are indicated. Missingness of marker data within a given visit is indicated, i.e. not considering longitudinal study dropout. Percentage values indicate the relative frequency of marker presence/absence/borderline/missingness within PD-free and incident PD groups, respectively, and within each visit. MDS-UPDRS-III, MDS-sponsored Unified Parkinson’s Disease Rating Scale, motor part 3; PD, Parkinson’s disease, pRBD, possible REM sleep behavior disorder.