Table 2.

Univariate and multivariate cox proportional hazard regression analysis for predicting dementia conversion in PD subjects.

Covariates	Univariable analysis				Multivariable analysis
	HR	95% CI		p-value	HR	95% CI		p-value
		Lower	Upper			Lower	Upper
Age	1.067	1.026	1.110	<0.01
Weight (kg)	0.990	0.957	1.024	0.55
Sex
Male	Ref
Female	1.250	0.657	2.377	0.50
Type
TD	Ref
Intermediate	1.862	0.805	4.303	0.15
AR	3.066	1.442	6.520	<0.01
LEDD	1.003	1.001	1.005	<0.01	1.002	1.000	1.004	<0.05
UPRDS-III	1.095	1.057	1.133	<0.01	1.071	1.033	1.109	<0.01
K-MMSE	0.893	0.855	0.932	<0.01	0.921	0.65	0.980	<0.01
Fazekas scale	2.515	1.538	4.111	<0.01
Zinc (μg/dL)	0.972	0.936	1.009	0.14	0.953	0.919	0.988	<0.01
Copper (μg/dL)	0.997	0.983	1.010	0.62
Lead (μg/dL)	0.940	0.646	1.369	0.75
Mercury (μg/L)	0.919	0.777	1.089	0.33
Manganese (μg/L)	0.955	0.850	1.073	0.44

HR, Hazed Ratio; CI, Confidence Interval; UPDRS-III, United Parkinson’s Disease Rating Scale Part 3; LEDD, L-dopa equivalent daily dose; K-MMSE, Korean version of the mini mental state examination scale; TD, Tremor-dominant; AR, Akinetic-rigidity.