Table 4.
Baseline characteristics of IRBD patients stratified according to clinical follow-up in non-converters, PD converters, and DLB converters
| Non-converters | Converted to PD | Converted to DLB | P value | |
|---|---|---|---|---|
| N | 100 | 24 | 23 | |
| Female, n (%) | 22 (22.0) | 7 (29.2) | 6 (26.1) | 0.731 |
| Age at LP, yrs | 67.7 ± 10.6 | 71.7 ± 6.1 | 73.5 ± 5.8 | 0.0104a |
| Age at IRBD diagnosis, yrs | 65.3 ± 10.1 | 68.6 ± 5.5 | 68.9 ± 7.2 | 0.126 |
| Time from IRBD diagnosis to LP, yrs | 1.4 (0.4–3.6) | 1.9 (0.5–4.5) | 4.3 (0.5–6.5) | 0.0218a |
| Prodromal PD rate at LP, % | 76.2 ± 31.5 | 92.7 ± 16.6 | 95.7 ± 10.5 | 0.0005b,c |
| DAT-SPECT abnormal/tested, n (%) | 48/97 (49.5) | 20/24 (83.3) | 15/23 (65.2) | 0.0079c |
| UPSIT-40 score | 21.0 (15.5–27.0) | 19.0 (14.5–22.5) | 15.0 (12.3–17.8) | 0.0139a |
| Mild cognitive impairment at LP, n (%) | 12 (12.0) | 6 (25.0) | 15 (65.2) | <0.0001d,e |
| AS positivity, n (%) | 68 (68.0) | 20 (86.9) | 21 (95.5) | 0.0095b |
| A+T+N+, n (%) | 8 (8.4) | 2 (8.7) | 3 (13.0) | 0.786 |
| A+T+, n (%) | 10 (10.6) | 3 (13.0) | 3 (13.0) | 0.907 |
| A+T-, n (%) | 18 (18.9) | 6 (26.1) | 8 (34.6) | 0.224 |
| Aβ42/Aβ40 | 0.8 (0.7–0.9) | 0.8 (0.7–0.9) | 0.7 (0.5–0.8) | 0.055 |
| p-tau, pg/mL | 37 (28–47) | 35 (26–50) | 41 (34–51) | 0.212 |
| p-tau/Aβ42 | 0.6 (0.4–0.9) | 0.6 (0.6–0.9) | 0.8 (0.6–1.5) | 0.0008e |
| t-tau, pg/mL | 292 (219–376) | 236 (182–329) | 285 (247–363) | 0.112 |
| NfL, pg/mL | 542 (412–751) | 540 (339–751) | 606 (507–794) | 0.489 |
Follow-up information was available in 147 patients, CSF AD core biomarkers in 95 non-converters, 23 PD converters, and 23 DLB converters; CSF NfL in 98 non-converters, 22 PD converters, and 22 DLB converters.
p values indicating statistically significant differences between groups are highlighted in bold.
LP lumbar puncture, IRBD isolated REM sleep behavior disorder, PD Parkinson disease, DLB dementia with Lewy bodies, AS misfolded α-synuclein, Aβ42 42 amino acid isoform of amyloid-beta, Aβ40 amino acid isoform of amyloid-beta, p-tau phosphorylated tau protein, A amyloid-beta, T tau, NfL neurofilament light chain, t-tau total tau protein.
aDLB converters vs non-converters, p < 0.05.
bDLB converters vs non-converters, p < 0.01.
cPD converters vs non-converters, p < 0.01.
dDLB converters vs non-converters, p < 0.0001.
eDLB converters vs PD converters, p < 0.001.