Table 1.

Sample characteristics stratified by witnessing an overdose among substance users in Baltimore, Maryland, USA (n=450)

	In the past six months		Over six months ago		Never
	N = 88		N = 250		N = 112
	n	%	n	%	n	%
Gender
Male	53	60.2	150	60.0	58	51.8

Age
< 44 years	45	51.1	110	44.0	51	45.5

Education
Grade 11 or less	52	59.1	131	52.4	52	46.4

Slept on the street ^a
Yes	37	42.0	58	23.2	24	21.4
No	51	58.0	192	76.8	88	78.6
Needle exchange use ^a
Yes	35	39.8	74	29.6	17	15.2
No	53	60.2	176	70.4	95	84.8
History of drug overdose
Never	35	39.8	150	60.0	96	85.7
Over six months ago	39	44.3	92	36.8	13	11.6
In the past six months	14	15.9	8	3.2	3	2.7
Sold drugs ^b
Yes	18	20.5	34	13.6	7	6.3
No	70	79.5	216	86.4	105	93.8
Bought drugs in own neighborhood ^a
Never	24	27.3	70	28.0	39	34.8
Sometimes	24	27.3	69	27.6	40	35.7
Often	16	18.2	54	21.6	18	16.1
Always	24	27.3	57	22.8	15	13.4
Number of drug use settings ^a,c
0	7	8.0	33	13.2	23	20.5
1	13	14.8	63	25.2	36	32.1
2	13	14.8	47	18.8	27	24.1
3	18	20.5	41	16.4	13	11.6
4	12	13.6	20	8.0	8	7.1
5	17	19.3	23	9.2	4	3.6
6	8	9.1	23	9.2	1	0.9
Heroin and speedball (injecting)^d
Never injected either heroin or speedball	18	20.5	99	39.6	78	69.6
Injected one form of heroin over six months ago	2	2.3	5	2.0	5	4.5
Either injected both forms over six months ago or one form within the prior six months	18	20.5	38	15.2	9	8.0
Injected one form in the last six months over six months ago	5	5.7	13	5.2	5	4.5
Injected both forms of heroin in the past six months	45	51.1	95	38.0	15	13.4
Heroin (snorting)
Never	12	13.6	33	13.2	27	24.1
Over six months ago	20	22.7	59	23.6	19	17.0
In the past six months	56	63.6	158	63.2	66	58.9
Prescription opiates
Never	48	54.5	153	61.2	85	75.9
Over six months ago	10	11.4	26	10.4	8	7.1
In the past six months (	30	34.1	71	28.4	19	17.0

past six months

past 30 days.

The six drug uses settings in the past six months included: a friend’s place, shooting gallery, crack house, abandoned building, outside, and public bathroom

Injecting heroin was constructed from added the two variables of recency injecting cocaine and heroin (speedball) and recency of injecting heroin. The categories were “never”, “over six months ago” and “within the past six months.”