Table II.

Associations between clinical parameters and symptoms of insomnia or depression in linear regression analysis

	Insomnia Severity Index		Beck Depression Inventory
	Beta coefficient	P value	Beta coefficient	P value
Age	−0.06	.13	−0.05	.42
Duration	0.002	.20	0.002	.48
Visual analog scale	0.98	.0003	1.55	<.0001
Four-item itch questionnaire	0.65	<.0001	0.90	<.0001