Table 1.

Factors associated with drug-poisoning mortality in the USA, 2012–2017

	IRR	95% CI	P value
Year
2012	Ref.
2013	1.05	1.04, 1.05	<0.001
2014	1.11	1.10, 1.12	<0.001
2015	1.23	1.22, 1.25	<0.001
2016	1.45	1.43, 1.48	<0.001
2017	1.59	1.56, 1.62	<0.001
ADI, quintile
1	Ref.
2	1.10	1.04, 1.16	<0.001
3	1.20	1.14, 1.26	<0.001
4	1.28	1.22, 1.35	<0.001
5	1.36	1.28, 1.44	<0.001
Sex, %
Male	0.97	0.96, 0.97	<0.001
Race/ethnicity, *%
White	1.05	1.04, 1.07	<0.001
Age, %
18–44 years	1.03	1.02, 1.03	<0.001
45–64 years	1.06	1.05, 1.07	<0.001
≥65 years	1.01	1.00, 1.01	0.04

Negative binomial regression analysis examined the risk of higher rates of drug-poisoning mortality in 3133 of 3142 US counties with available mortality data. Independent variables included year, ADI quintile, per cent male, per cent white and age.

*Percent white variable was scaled by 10 in the model (ie, per 10% change).

ADI, Area Deprivation Index; IRR, Incidence Risk Ratio.