Table 1.
Descriptive characteristics of included articles.
| Author, year, and study design | Recruitment country | PD sample size and gender (n, % Male) | Diagnosis | Recruitment setting | Age, years (Mean, [SD])a | Disease duration, years (Mean, [SD])a | Disease stage, original H&Y Scale (n, [%])a | MDS-UPDRS motor examination score (Mean, [SD])a | LEDD, mg/day (Mean, [SD])a |
|---|---|---|---|---|---|---|---|---|---|
| Alwardat et al. (2019) 73 /Cross-sectional | ITA | 128 (60) | IPD | Hospital-based neurology unit | 61.98 (7.95) | 4.99 (4.05) | NR | 25.21 (10.49)o | 493.14 (309.39) |
| Amara et al. (2019) 47 /Longitudinal case–control | USA, EUR | 380 (65.5) | IPD | NR | 63.55 (9.8) | 2.6 (0.56) | 0 (n = 2 [0.71]) 1 (n = 71 [25.09]) 2 (n = 197 [69.61]) 3–5 (n = 13 [4.59]) |
27.16 (11.3) | 389.06 (302.5) |
| Cerff et al. (2017) 74 /Cross-sectional | DEU | PD-NC: 17 (59) PD-MCI: 22 (77) PDD: 9 (100) |
IPD | Community | PD-NC: 71 (44/80)f PD-MCI: 68 (57/78)f PDD: 72 (67/75)f |
PD-NC: 6 (1/13)f PD-MCI: 6 (1/20)f PDD: 6 (5/18)f |
PD-NC: 1 (n = 6 [35]) 2 (n = 10 [59]) 3 (n = 1 [6]) PD-MCI: 1 (n = 3 [14]) 2 (n = 13 [59]) 3 (n = 4 [18]) 4 (n = 2 [9]) PDD: 2 (n = 3 [33]) 3 (n = 3 [33]) 4 (n = 2 [22]) 5 (n = 1 [11]) |
PD-NC: 20 (11/58)fo PD-MCI: 24 (10/62)fo PDD: 36 (14/ 56)fo |
PD-NC: 620 (160/2420)f PD-MCI: 763 (210/2378)f PDD: 496 (100/1139)f |
| Donahue et al. (2022) 75 /Cross-sectional | USA | 96 (57.3%) | IPD | NR | 66.76 (8.60) | 4.72 (4.81) | NR | 23.99 (10.33) | 568.51 (383.41) |
| Dontje et al. (2013) 76 /Cross-sectional | NLD | 467 (66) | IPD | Hospital-based neurology unit | 65.7 (7.4) | 5.15 (4.38) | 1 (n = 8 [2])m 1.5 (n = 14 [3])m 2 (n = 350 [75])m 2.5 (n = 69 [15])m 3 (n = 26 [6])m |
32.9 (10.5) | 480.0 (389.7) |
| Duvdevani et al. (2024) 77 /Cross-sectional | ISR | 88 (65.9) | IPD | Movement Disorder Institute, Neurology Department, Health Care Campus | 66.84 (8.8) | NR | 1 (n = 4 [4.6]) 2 (n = 52 [59.8]) 3 (n = 18 [20.7]) 4 (n = 13 [14.9]) 5 (n = 0 [0]) |
31 (1–94)f | 763.86 (573.01) |
| Ellingson et al. (2017)78,79/Cross-sectional | USA | 52 (56) | IPD | Community | 67.8 (7.9) | 10.0 (6.7) | NR | 57.4 (19.4) | NR |
| Leavy et al. (2021) 80 /Cross-sectional | SWE | 89 (54) | IPD | Community and research database | 71.0 (6.0) | 6.0 (4.3) | NR | NR | 580 (291) |
| Loprinzi et al. (2018) 81 /Cross-sectional | USA | 23 (57) | IPD | Community | 68.7 (NR) | NR | 2.2 (NR)b | NR | NR |
| Ng et al. (2021) 82 /Longitudinal cohort | Singapore | 121 (61.2) | IPD | Movement disorder clinics | 64.5 (8.2) | NR | NR | 22.33 (8.71) | 186.96 (143.42) |
| Nguy et al. (2020) 83 /Cross-sectional | AUS | 52 (69) | IPD | Community, research clinic and database | 67.8 (7.8) | 7.8 (6.5) | NR | 33.7 (12.8) | NR |
| Oguh et al. (2014) 84 /Longitudinal cohort | NLD, N. Amer, IL | 4866 (63) | IPD | Research database | 67.0 (9.8) | 5.5 (2.0–10.0)c | ≥3 (n = 1699 [37.4]) m | NR | NR |
| Santos et al. (2018) 72 /Longitudinal cohort | USA | 130 (49) | MPS | Community | 78.45 (7.06) | NR | NR | NR | NR |
| Shih et al. (2019) 85 /Cross-sectional | USA | 174 (68) | IPD | Community | 65.79 (9.48) | 5.59 (0.54) | 1.96 (0.39)b | 29.94 (11.13) | NR |
Abbreviations: n, number; SD, standard deviation; NR, not reported; PD, Parkinson's disease; H&Y, Hoehn and Yahr Scale; MDS-UPDRS, International Parkinson and Movement Disorder Society — Unified Parkinson's Disease Rating Scale; LEDD, Levodopa equivalent daily dosage; IPD, Idiopathic Parkinson's disease; MPS, Mild Parkinsonian Signs; PD-NC, Parkinson's disease — non-cognitively impaired; PD-MCI, Parkinson's disease — mild cognitive impairment; PDD, Parkinson's disease dementia; ITA, Italy; USA, United States of America; EUR, Europe; DNK, Denmark; DEU, Germany; NLD, Netherlands; ISR, Israel; SWE, Sweden; AUS = Australia; N. Amer, North America; IL, Israel.
Except where indicated; bMean (SD); cMean (range); dn,(%); eMedian (IQR), fMedian (min/max); mModified Hoehn and Yahr Scale with stages 1–5; oOriginal UPDRS motor examination.