Table 1.

Demographics and clinical variables at baseline

	Converters	Nonconverters	Healthy controls	P‐value
				A	B	C	D
Age (years)	63.12 ± 8.61	62.32 ± 8.58	59.92 ± 12.03	0.392a	‐	‐	‐
Gender (Male/Female)	16/8	43/27	14/18	0.156b	‐	‐	‐
Education (years)	14.04 ± 3.18	15.14 ± 2.91	15.22 ± 3.22	0.325b	‐	‐	‐
Scan interval (years)	2.61 ± 1.25	2.44 ± 1.40	2.17 ± 1.37	0.231b	‐	‐	‐
Duration (years)	0.92 ± 0.85	0.80 ± 0.73	‐	‐	0.907c	‐	‐
H‐Y stages	1.67 ± 0.48	1.68 ± 0.47	‐	‐	0.473d	‐	‐
MDS‐UPDRS III	23.50 ± 11.06	21.11 ± 9.34	‐	‐	0.001*,d	‐	‐
MoCA	26.04 ± 3.09	27.83 ± 1.74	28.50 ± 1.22	0.004*,b	0.015c, *	0.002c, *	0.099c
SBRs Caudate_R	1.74 ± 0.54	1.87 ± 0.59	2.77 ± 0.40	<0.001*,a	0.888	<0.001*,d	<0.001*,d
SBRs Caudate_L	1.75 ± 0.54	1.89 ± 0.62	2.87 ± 0.50	<0.001*,a	0.925	<0.001*,d	<0.001*,d
SBRs Putamen_R	0.73 ± 0.31	0.81 ± 0.30	2.11 ± 0.41	<0.001*,b	0.064	<0.001*,c	<0.001*,c
SBRs Putamen_L	0.76 ± 0.27	0.76 ± 0.35	2.03 ± 0.36	<0.001*,a	1.000	<0.001*,d	<0.001*,d
CSF α‐syn (pg/mL)	1687.86 ± 492.67	1709.45 ± 712.81	1892.34 ± 792.82	0.435a	‐	‐	‐
CSF Aβ42 (pg/mL)	357.53 ± 71.17	374.16 ± 102.16	376.31 ± 100.30	0.739a	‐	‐	‐
CSF p‐tau (pg/mL)	13.40 ± 6.04	18.19 ± 12.15	20.72 ± 14.09	0.487b	‐	‐	‐

A = Comparison among Converters, Nonconverters and Healthy controls; B = Converters vs Nonconverters; C = Converters vs Healthy controls; D = Nonconverters vs Healthy controls.

Abbreviations: CSF, cerebrospinal fluid; L, left; MDS‐UPDRS III, part III of the Movement Disorder Society Unified Parkinson's Disease Rating Scale; MoCA, Montreal Cognitive Assessment; R, right; SBRs, striatal binding ratios.

^aANOVA.

^bKruskal‐wallis test.

^cWilcoxon rank‐sum test.

^dIndependent sample T test.

^*Indicates a P‐value < 0.05.