Table 1 Descriptive Characteristics of Study Sample

Sociodemographic factors:

Age [M (SD)]

44.1 (11.5)

44.0 (10.9)

44.3 (12.5)

0.761

Gender

0.290

 Female

131 (26.6%)

90 (26.9%)

41 (25.9%)

 Male

357 (72.4%)

240 (71.6%)

117 (74.1%)

 Transgender/Gender Nonconforming

5 (1.0%)

5 (1.5%)

0 (0.0%)

Race

0.889

 White/Caucasian

302 (63.6%)

209 (64.3%)

93 (62.0%)

 Black/African American

70 (14.7%)

47 (14.5%)

23 (15.3%)

 Other

103 (21.7%)

69 (21.2%)

34 (22.7%)

Latino/Hispanic Ethnicity

0.961

 No

380 (77.1%)

258 (77.0%)

122 (77.2%)

 Yes

113 (22.9%)

77 (23.0%)

36 (22.8%)

Marital/cohabitation Status

0.699

 Single/Separated/Divorced/Widowed

430 (87.4%)

289 (86.5%)

141 (89.2%)

 Married/living together as married

57 (11.6%)

41 (12.3%)

16 (10.1%)

 Other

5 (1.0%)

4 (1.2%)

1 (0.6%)

Education

0.299

 Less than High school

117 (23.8%)

81 (24.3%)

36 (22.8%)

 High school diploma or GED

187 (38.0%)

133 (39.8%)

54 (34.2%)

 Some college or more

188 (38.2%)

120 (35.9%)

68 (43.0%)

Living stability^a

0.190

 Stable housing

256 (52.0%)

167 (50.0%)

89 (56.3%)

 Unstable housing

236 (48.0%)

167 (50.0%)

69 (43.7%)

Availability of transportation

0.667

 Yes

207 (42.2%)

136 (40.8%)

71 (44.9%)

 Maybe, if I can get a ride

26 (5.3%)

18 (5.4%)

8 (5.1%)

 Maybe, if public transportation is available

254 (51.7%)

177 (53.2%)

77 (48.7%)

 No

4 (0.8%)

2 (0.6%)

2 (1.3%)

Employed with a regular job or informal work

0.022

 Yes

173 (35.2%)

129 (38.6%)

44 (28.0%)

 No

318 (64.8%)

205 (61.4%)

113 (72.0%)

Clinical Characteristics:

Depressive symptoms (PHQ-9) [M (SD)]

9.9 (6.4)

9.6 (6.3)

10.6 (6.6)

0.170

Anxiety symptoms (GAD-7) [M (SD)]

8.4 (6.4)

8.3 (6.0)

8.6 (7.3)

0.941

HIV coinfection (positive)

0.706

 No

286 (80.1%)

196 (80.7%)

90 (78.9%)

 Yes

71 (19.9%)

47 (19.3%)

24 (21.1%)

Clinical setting type

0.216

 OTP

229 (46.5%)

162 (70.7%)

67 (29.3%)

 CHC

264 (53.5%)

173 (65.5%)

91 (34.5%)

Drug Use Characteristics:

Last drug injection (within 3 months of screening)

0.032

 0–4 weeks

366 (74.2%)

237 (70.7%)

129 (81.6%)

 5–8 weeks

84 (17.0%)

66 (19.7%)

18 (11.4%)

 9–12 weeks

43 (8.7%)

32 (9.6%)

11 (7.0%)

Number of days injected drugs in the past 3 months [M (SD)]

32.3 (30.4)

28.0 (28.7)

41.1 (32.0)

< 0.001

Times injecting drugs a day [M (SD)]

2.9 (2.7)

2.7 (2.7)

3.2 (2.6)

0.001

Substances injected in the past 3 months

 Mixture of cocaine and heroin

122 (26.1%)

80/314 (25.5%)

42/153 (27.5%)

0.649

 Mixture of methamphetamine and heroin

107 (22.9%)

70/314 (22.3%)

37/153 (24.2%)

0.648

 Heroin

376 (80.5%)

259/314 (82.5%)

117/153 (76.5%)

0.124

 Methamphetamine

173 (37.0%)

111/314 (35.4%)

62/153 (40.5%)

0.277

 Cocaine

136 (29.1%)

89/314 (28.3%)

47/153 (30.7%)

0.596

 Crack

68 (14.6%)

45/313 (14.4%)

23/153 (15.0%)

0.851

 Fentanyl

19 (42.2%)

13/34 (38.2%)

6/11 (54.5%)

0.341

 Poly-substances

275 (58.9%)

182/314 (58.0%)

93/153 (60.8%)

0.561

Urine drug screen positive results at baseline visit¹⁴

 Any drug

457 (96.8%)

311/321 (96.9%)

146/151 (96.7%)

0.910

 Amphetamine

131 (27.8%)

75/321 (23.4%)

56/151 (37.1%)

0.002

 Methamphetamine

148 (31.4%)

88/321 (27.4%)

60/151 (39.7%)

0.007

 Benzodiazepine

257 (54.4%)

178/321 (55.5%)

79/151 (52.3%)

0.524

 Cocaine

195 (41.3%)

131/321 (40.8%)

64/151 (42.4%)

0.746

 THC/Cannabis

236 (50.0%)

171/321 (53.3%)

65/151 (43.0%)

0.038

 Opiate

237 (50.2%)

153/321 (47.7%)

84/151 (55.6%)

0.106

 Oxycodone

127 (26.9%)

75/321 (23.4%)

52/151 (34.4%)

0.011