Table 4. Multivariable Poisson regression analysis for predicting the total number of devices and functions used among caregivers (n=486).

Outcome and variables		ba (SE)		IRRb (95% CI)	P value
Number of devices
	Age	0.001 (0.002)		1.001 (0.997-1.005)	.67
	Female	0.035 (0.059)		1.036 (0.923-1.162)	.55
	Non-Hispanic White	−0.026 (0.054)		0.975 (0.877-1.083)	.63
	Household income less than US $50,000	−0.130 (0.053)		0.878 (0.791-0.975)	.02
	High school or lower educational attainment	−0.086 (0.066)		0.918 (0.806-1.045)	.20
	Rural residence	−0.079 (0.094)		0.924 (0.769-1.110)	.40
Number of functions
	Age	−0.008 (0.002)		0.992 (0.989-0.996)	<.001
	Female	−0.017 (0.053)		0.983 (0.886-1.090)	.74
	Non-Hispanic White	−0.046 (0.048)		0.955 (0.869-1.049)	.34
	Household income less than US $50,000	−0.097 (0.048)		0.908 (0.826-0.998)	.04
	High school or lower educational attainment	−0.188 (0.061)		0.829 (0.735-0.934)	.002
	Rural residence	−0.068 (0.085)		0.934 (0.792-1.103)	.42

^ab: regression coefficient.

^bIRR: incidence rate ratio.