Table 1.

Characteristics of responders and nonresponders (N=23,336).

Characteristics	Responders n=5370	Nonresponders n=17,966	P
Gender (female), n (%)	3318 (61.79)	11,231 (62.51)	.34
Age (years), mean (SD)	56.6 (14.0)	50.4 (15.4)	<.001
Race (white), n (%)	4874 (90.76)	15,530 (86.44)	<.001
Selected problems on problem list,a mean (SD)	2.1 (1.2)	2.0 (1.1)	<.001
Years with patient portal account, mean (SD)	3.5 (3.3)	2.8 (2.9)	<.001
Sessions with patient portal, mean (SD)	100.4 (173.5)	57.9 (109.6)	<.001
Messages sent via patient portal, mean (SD)	7.7 (20.1)	4.3 (13.8)	<.001

^a The selected problems included hypertension, hyperlipidemia, diabetes, cancer (any), coronary artery disease, congestive heart failure, asthma, osteoarthritis, rheumatoid arthritis, and depression.