Co-occurring amphetamine use and associated medical and psychiatric comorbidity among opioid-dependent adults: results from the clinical Trials Network

Figures & data

Table 1 Demographic and substance use characteristics of opioid-dependent adults according to amphetamine use status (n = 1257)

Proportion, %	Nonamphetamine users	Current amphetamine injectorsa	Current amphetamine noninjectorsa	Former amphetamine injectorsa	Former amphetamine noninjectorsa
Sample size	n = 977	n = 35	n = 78	n = 50	n = 117
Age in years, mean (SD)b	36.4 (0.34)	34.4 (1.50)	36.1 (1.17)	38.2 (1.38)	36.5 (0.89)
Gender
Male	69.9	57.1	50.0**	70.0	59.0*
Female	30.1	42.9	50.0	30.0	41.0
Race/ethnicity
Nonwhite	43.5	25.7*	18.0**	20.0**	17.1**
White	56.5	74.3	82.0	80.0	82.9
Education, years
0–12	56.4	54.3	50.0	64.0	50.4
13+	43.6	45.7	50.0	36.0	49.6
Marital status
Married	27.4	34.3	35.9	24.0	33.3
Separated/divorced/widowed	25.6	14.3	25.6	32.0	26.5
Never married	47.0	51.4	38.5	44.0	40.2
Employment, past month
Not employed	50.0	60.0	61.5*	52.0	51.3
Employed	50.1	40.0	38.5	48.0	48.7
Randomization
No	31.5	34.3	32.1	34.0	36.8
Yes	68.5	65.7	68.0	66.0	63.3
Number of other substances used regularly, lifetime, mean (SD)	3.00 (1.42)	3.91 (1.27)**	3.41 (1.42)*	4.34 (1.33)**	4.10 (1.44)**

Notes:

a Each amphetamine use group was compared with nonamphetamine users;

b t-tests for age were not significant.

* P ≤ 0.05;

** P ≤ 0.01.

Abbreviation: SD, standard deviation.

Table 2 Prevalence of specific medical conditions by amphetamine use status among opioid-dependent adults aged 18 years or older (n = 1257)

Proportion of medical illness, %	Nonamphetamine users	Current amphetamine injectorsb	Current amphetamine noninjectorsb	Former amphetamine injectorsb	Former amphetamine noninjectorsb
Sample size	n = 977	n = 35	n = 78	n = 50	n = 117
Current chronic medical problems that continue to interfere with life	25.4	37.1	30.8	44.0**	34.2*
Dermatological illnessa	22.8	60.0**	38.5**	60.0**	37.6**
Psychiatric illnessa	27.9	51.4**	42.3**	42.0*	41.9**
Hepatitisa	22.3	48.6**	35.9**	54.0**	17.1
Allergiesa	21.9	31.4	34.6**	34.0*	29.1‡
Respiratory illnessa	17.0	31.4*	29.5**	28.0*	19.7
Seizurea	3.8	14.3**	7.7‡	12.0**	7.7*
Gastrointestinal illnessa	19.2	22.9	29.5*	24.0	25.6
Cardiovascular illnessa	17.7	14.3	23.1‡	26.0	20.5
Genitourinary illnessa	12.5	20.0	20.5*	22.0*	18.0‡
Neurological illnessa	11.0	14.3	14.1	32.0**	8.5
Musculoskeletal illnessa	28.9	34.3	34.6	34.0	32.5
Eye, ear, nose, or throat illnessa	13.1	17.1	20.5	14.0	10.3
Tuberculosisa	8.7	5.7	6.4	10.0	4.3
Endocrine illnessa	4.0	0	1.3	8.0	6.8

Notes:

a Lifetime status;

b each amphetamine use group was compared with nonamphetamine users. Chi-square test:

‡ P < 0.10;

* P ≤ 0.05;

** P ≤ 0.01.

Table 3 Adjusted odds ratios of specific medical conditions in relation to amphetamine use status among opioid-dependent adults aged 18 years or older (n = 1257)

Logistic regression	Model controlled for age, gender, race/ethnicity, education, and employment status				Model controlled for age, gender, race/ethnicity, education, employment status, and lifetime number of other substances used
AOR, 95% CI	Current amphetamine injectorsb	Current amphetamine noninjectorsb	Former amphetamine injectorsb	Former amphetamine noninjectorsb	Current amphetamine injectorsb	Current amphetamine noninjectorsb	Former amphetamine injectorsb	Former amphetamine noninjectorsb
Chronic medical problems	1.9,0.9–3.8	1.2,0.7–2.1	2.3, 1.2–4.1*	1.5, 1.0–2.3	1.9,0.9–3.9	1.2,0.7–2.1	2.3, 1.2–4.2*	1.5, 1.0–2.3
Dermatologicala	5.0,2.5–10.1*	1.9, 1.2–3.2*	5.3, 2.9–9.3*	1.9, 1.3–2.9*	4.7, 2.3–9.5*	1.9, 1.2–3.1*	4.7, 2.6–8.6*	1.9, 1.2–2.9*
Psychiatrica	2.5, 1.2–5.0*	1.6, 1.0–2.6	2.0, 1.1–3.5*	1.6, 1.1–2.4*	2.2, 1.1–4.5*	1.5, 0.9–2.4	1.6,0.9–3.0	1.4,0.9–2.1
Hepatitisa	4.1,2.0–8.5*	2.1, 1.23–3.5*	4.3, 2.3–8.0*	0.7,0.4–1.2	3.8, 1.8–7.8*	2.0, 1.2–3.4*	3.9, 1.1–7.3*	0.6,0.4–1.1
Allergiesa	1.5,0.7–3.2	1.7, 1.1–2.9*	1.9, 1.1–3.5*	1.4,0.9–2.1	1.5,0.7–3.3	1.7, 1.1–2.9*	1.9, 1.1–3.5*	1.4, 0.9–2.2
Respiratorya	2.2, 1.0–4.5*	2.0, 1.2–3.3*	2.0, 1.1–3.8*	1.2, 0.7–2.0	2.0,0.9–4.1	1.9, 1.1–3.2*	1.6,0.8–3.2	1.1,0.6–1.8
Seizurea	3.9, 1.4–10.9*	1.7, 0.7–4.3	3.2, 1.3–8.3*	2.0, 0.9–4.3	3.3, 1.2–9.5*	1.6,0.6–4.1	2.4, 0.9–6.7	1.7,0.7–3.7
Gastrointestinala	1.2, 0.5–2.8	1.7, 1.0–2.9*	1.3, 1.7–2.6	1.4, 0.9–2.2	1.2, 0.5–2.7	1.7, 1.0–2.83	1.2,0.6–2.5	1.4, 0.9–2.2
Cardiovasculara	1.7, 0.7–4.2	1.8, 1.0–3.3	1.0,0.4–2.3	0.8,0.4–1.5	1.9, 0.7–4.9	1.9, 1.0–3.5*	1.2,0.5–2.8	0.9,0.5–1.7
Genitourinarya	1.6,0.6–3.9	1.4, 0.8–2.7	2.1, 1.0–4.4	1.4, 0.8–2.3	1.6,0.6–3.8	1.4, 0.8–2.7	2.0, 0.9–4.4	1.3, 0.8–2.3
Neurologicala	1.3,0.5–3.4	1.2, 0.6–2.4	4.1, 2.2–7.9*	0.7,0.4–1.4	1.2,0.4–3.1	1.2, 0.6–2.3	3.6, 1.8–7.0*	0.6,0.3–1.3

Notes:

a A lifetime status of illnesses;

b results were based on separate logistic regression analyses of each medical condition; the reference group was nonamphetamine users.

* P ≤ 0.05.

Abbreviations: AOR, adjusted odds ratio; CI, confidence interval.

Table 4 Lifetime number of medical conditions and hospitalizations in relation to amphetamine use status among opioid-dependent adults aged 18 years or older (n = 1257)

Mean (SD)	Nonamphetamine users	Current amphetamine injectorsb	Current amphetamine noninjectorsb	Former amphetamine injectorsb	Former amphetamine noninjectorsb
Sample size	n = 977	n = 35	n = 78	n = 50	n = 117
Number of medical illnesses in the lifetimea	2.2 (2.02)	3.3 (2.41)**	3.2 (2.34)**	3.4 (2.63)**	2.5 (1.96)
Number of hospitalizations in the lifetime	1.7 (2.60)	3.3 (3.06)**	2.2 (2.91)	3.0 (3.21)**	2.1 (2.42)

Notes:

a The number of medical conditions in the lifetime included the 14 categories of illness listed in Table 2 except for current chronic health problems;

b each amphetamine use group was compared with nonamphetamine users. t-test:

** P < 0.01.

Abbreviation: SD, standard deviation.

Table 5 Current psychiatric statusa by amphetamine use status among opioid-dependent adults aged 18 years or older (n = 1257)

Psychiatric status, %	Nonamphetamine users	Current amphetamine injectorsb	Current amphetamine noninjectorsb	Former amphetamine injectorsb	Former amphetamine noninjectorsb
Sample size	n = 977	n = 35	n = 78	n = 50	n = 117
Anxiety	36.3	48.6	55.7**	47.1	44.4‡
Depression	28.9	40.0	38.0	31.4	38.5*
Cognitive impairment	24.3	25.7	38.0**	22.0	33.3*
Violent behaviors	6.2	17.1**	12.7*	7.8	10.3‡
Suicidal thoughts or attempts	3.5	11.4*	2.5	5.9	5.1
Hallucinations	2.0	5.7	6.3*	3.9	0.9
Psychotropic medication treatment	9.6	20.0*	17.7*	5.9	12.8

Notes:

a Past 30 days;

b each amphetamine use group was compared with nonamphetamine users. Chi-square test (df = 1):

‡ P < 0.10;

* P ≤ 0.05;

** P ≤ 0.01.

Table 6 Adjusted odds of current (past 30 days) psychiatric symptoms and of psychotropic medication treatment in relation to amphetamine use status among opioid-dependent adults aged 18 years or older (n = 1257)

Logistic regression	Model controlled for age, gender, race/ethnicity, education, and employment status				Model controlled for age, gender, race/ethnicity, education, employment status, and lifetime number of other substances used
AOR, 95% CI	Current amphetamine injectorsa	Current amphetamine noninjectorsa	Former amphetamine injectorsa	Former amphetamine noninjectorsa	Current amphetamine injectorsa	Current amphetamine noninjectorsa	Former amphetamine injectorsa	Former amphetamine noninjectorsa
Anxiety	1.5,0.8–3.1	2.0, 1.3–3.3*	1.6,0.9–2.8	1.4,0.9–2.0	1.4, 0.7–2.9	1.9, 1.2–3.1*	1.4, 0.8–2.5	1.3,0.9–1.9
Depression	1.6,0.8–3.2	1.5,0.9–2.4	1.2, 0.7–2.3	1.6, 1.1–2.4*	1.6,0.8–3.2	1.5, 0.9–2.4	1.1,0.6–2.1	1.6, 1.1–2.4*
Cognitive impairment	1.0, 0.5–2.2	1.7, 1.1–2.8*	0.9,0.5–1.8	1.5, 1.0–2.4*	0.9,0.4–1.3	1.6, 1.0–2.7*	0.7,0.4–1.5	1.4,0.9–2.1
Violent behaviors	2.9, 1.1–7.6*	2.2, 1.1–4.7*	1.1,0.3–3.6	2.0, 1.1–4.0*	2.6, 1.0–6.8	2.1, 1.0–4.5*	0.9, 0.2–3.0	1.7,0.8–3.4
Suicidal thoughts or attempts	3.2, 1.1–9.9*	0.6,0.1–2.7	1.9, 0.5–6.5	1.4,0.6–1.5	3.1, 1.0–9.8*	0.6,0.1–2.6	1.7, 0.5–6.0	1.3,0.5–3.3
Hallucinations	2.2,0.5–10.6	2.9, 1.1–8.2*	2.0, 0.4–9.2	0.4,0.1–3.2	2.3,0.5–11.2	2.8, 1.0–7.9	1.9, 0.4–9.1	0.4,0.1–3.0
Psychotropic medication	2.1,0.9–5.0	1.5, 0.8–2.9	0.6, 0.2–2.0	1.1,0.6–2.0	2.1,0.9–5.1	1.5,0.8–2.8	0.6,0.2–1.9	1.1,0.6–2.0

Notes:

a Results were based on separate logistic regression analyses of each psychiatric condition; the reference group comprised nonamphetamine users.

*P ≤ 0.05.

Abbreviation: AOR, adjusted odds ratio.