. Author manuscript; available in PMC: 2021 Jan 1.

Published in final edited form as: J Atten Disord. 2019 Nov 3;24(2):205–214. doi: 10.1177/1087054719883008

Table 3:

Analyses^a of ZIP code tabulation area (ZCTA) level effects on prevalent and incident stimulant prescribing rates in California

Variable	All Prescriptions				Incident^b Prescriptions
Variable	RR	95% CI	RRC^c	95% CI	RR	95% CI	RRC^c	95% CI

Rural Classification^d
Metropolitan	Ref		1.030	[1.022, 1.038]	Ref		0.968	[0.958, 0.979]
Non-Metropolitan	0.81	[0.74, 0.88]	1.068	[1.064, 1.072]	0.88^**	[0.79, 0.97]	1.011	[1.006, 1.015]
SES^e
Very Low	Ref		1.068	[1.058, 1.079]	Ref		1.018^*	[1.004, 1.032]
Low	1.14	[1.06, 1.23]	1.069	[1.059, 1.078]	1.02^†	[0.94, 1.10]	1.017	[1.007, 1.027]
Medium	1.22	[1.12, 1.32]	1.071	[1.064, 1.079]	1.02^†	[0.94, 1.11]	1.013^**	[1.005, 1.022]
High	1.39	[1.28, 1.51]	1.068	[1.063, 1.074]	1.08^†	[0.99, 1.17]	1.004^†	[0.998, 1.011]
Very High	1.79	[1.64, 1.95]	1.060	[1.055, 1.065]	1.20	[1.10, 1.31]	0.994^*	[0.989, 0.999]
Proportion White^e
< 23.2%	Ref		1.095	[1.087, 1.104]	Ref		1.042	[1.033, 1.051]
23.2% – 45.3%	1.73	[1.62, 1.85]	1.067	[1.061, 1.073]	1.56	[1.46, 1.67]	1.008^*	[1.000, 1.016]
45.4% – 64.3%	2.39	[2.22, 2.56]	1.062	[1.057, 1.068]	1.94	[1.81, 2.08]	1.001^†	[0.995, 1.007]
64.4% – 80.0%	3.11	[2.87, 3.37]	1.055	[1.050, 1.060]	2.41	[2.23, 2.61]	0.987	[0.982, 0.992]
> 80.0%	3.86	[3.38, 4.42]	1.046	[1.040, 1.053]	2.81	[2.45, 3.22]	0.979	[0.972, 0.986]

Note. RR = rate ratio; CI = confidence interval; Ref = referent group; RRC = rate ratio change; SES = socioeconomic status

p < 0.001 unless otherwise indicated,

^†

p > 0.05.

0.01 < p < 0.05.

^**

0.001 < p < 0.01.

Poisson models utilizing general estimating equations; covariates included patient age, gender, year of data, and the three-way interaction of year, gender, and age.

No stimulant prescriptions in the preceding two years (730 days).

Annual prescribing rate change, adjusted for aforementioned covariates and expressed as rate ratios, from 2008 to 2017 (all prescriptions) or from 2010 to 2017 (incident prescriptions) across all ZCTAs in the named category.

Derived from 2010 Rural-Urban Commuting Area Codes.

Derived from 2013–2017 American Community Survey