. 2018 Nov 7;20(11):e11350. doi: 10.2196/11350

Table 3.

My HealtheVet adoption and feature use with and without dual use (N=2,171,325).

My HealtheVet feature use	Dual users (n=32,723), n (%)^a	MHV^b only (n=449,445), n (%)^a	P^c value
Authenticated	23,573 (72.04)	347,610 (69.60)	<.001
Ever filled a prescription on the Web	20,589 (63.88)	293,409 (59.59)	<.001
Ever used secure messaging^d	3561 (10.88)	57,126 (11.44)	.002

^aThe total number of Veterans in each group and the percent of the overall study population.

^bMHV: My HealtheVet.

^cP value for chi-square.

^dOnly authenticated users who opt-in can secure message; however, the denominator for the percentage calculation is based on the total number of dual users or MHV only users to show the overall penetration of secure messaging activity among the entire population in each column.