Table 1.
Baseline Characteristics of the Participants in the Intention-to-Treat Population.*
| Characteristic | All Participants | Stage 1 | Stage 2 | ||
|---|---|---|---|---|---|
| Total† (N = 403) | Naltrexone–Bupropion (N = 109) | Placebo (N = 294) | Naltrexone–Bupropion (N = 114) | Placebo (N = 111) | |
| Demographic characteristics | |||||
| Male — no. (%) | 277 (68.7) | 78 (71.6) | 199 (67.7) | 78 (68.4) | 79 (71.2) |
| Age — yr | 41.0±10.1 | 41.0±10.6 | 41.0±10.0 | 41.0±10.5 | 42.0±9.6 |
| Hispanic or Latino ethnic group — no. (%)‡ | 55 (13.6) | 13 (11.9) | 42 (14.3) | 20 (17.5) | 18 (16.2) |
| Race or ethnic group — no. (%)‡ | |||||
| White | 287 (71.2) | 82 (75.2) | 205 (69.7) | 84 (73.7) | 69 (62.2) |
| Black | 48 (11.9) | 10 (9.2) | 38 (12.9) | 8 (7.0) | 22 (19.8) |
| Other | 68 (16.9) | 17 (15.6) | 51 (17.3) | 22 (19.3) | 20 (18.0) |
| High school diploma, GED, or lower education level — no. (%) | 142 (35.2) | 39 (35.8) | 103 (35.0) | 36 (31.6) | 33 (29.7) |
| Marital status — no. (%) | |||||
| Married or living with partner | 93 (23.1) | 26 (23.9) | 67 (22.8) | 25 (21.9) | 25 (22.5) |
| Never married | 204 (50.6) | 49 (45.0) | 155 (52.7) | 60 (52.6) | 59 (53.2) |
| Divorced, separated, widowed, or unknown — no. (%) | 106 (26.3) | 34 (31.2) | 72 (24.5) | 29 (25.4) | 27 (24.3) |
| Employed — no. (%)§ | 156 (38.7) | 43 (39.4) | 113 (38.4) | 46 (40.4) | 44 (39.6) |
| Methamphetamine use | |||||
| No. of days that methamphetamine was used in the 30 days before consent¶ | 26.7±4.1 | 27.0±3.9 | 26.5±4.2 | 26.7±4.1 | 26.1±4.3 |
| Most frequent route of methamphetamine use — no. (%) | |||||
| Smoking | 293 (72.7) | 80 (73.4) | 213 (72.4) | 83 (72.8) | 79 (71.2) |
| Intravenous | 77 (19.1) | 23 (21.1) | 54 (18.4) | 21 (18.4) | 22 (19.8) |
| Nasal or oral | 33 (8.2) | 6 (5.5) | 27 (9.2) | 10 (8.8) | 10 (9.0) |
| Participants reporting intravenous methamphetamine use ≥1 days in the 30 days before consent — no. (%) | 135 (33.5) | 39 (35.8) | 96 (32.7) | 38 (33.3) | 36 (32.4) |
| Intensity of methamphetamine craving∥ | 66.1±22.3 | 65.7±22.2 | 65.8±21.6 | 66.7±21.3 | 63.7±21.9 |
| Age of first methamphetamine use — yr | 24.8±9.9 | 24.7±10.7 | 24.8±9.6 | 25.5±10.9 | 24.8±9.1 |
| Other characteristics | |||||
| Coexisting cocaine use disorder according to DSM-5 criteria — no./total no. (%) | 31/365 (8.5) | 9/97 (9.3) | 22/268 (8.2) | 9/104 (8.7) | 9/100 (9.0) |
| Coexisting opioid use disorder according to DSM-5 criteria — no./total no. (%) | 27/370 (7.3) | 7/93 (7.5) | 20/277 (7.2) | 7/109 (6.4) | 7/104 (6.7) |
| Coexisting alcohol use disorder according to DSM-5 criteria — no./total no. (%) | 94/293 (32.1) | 25/77 (32.5) | 69/216 (31.9) | 23/85 (27.1) | 27/75 (36.0) |
| Coexisting cannabis use disorder according to DSM-5 criteria — no./total no. (%) | 116/318 (36.5) | 29/89 (32.6) | 87/229 (38.0) | 33/86 (38.4) | 33/85 (38.8) |
| Daily nicotine cigarette use — no./total no. (%) | 238/337 (70.6) | 66/99 (66.7) | 172/238 (72.3) | 73/89 (82.0) | 56/89 (62.9) |
| Score on PHQ-9 depression scale** | 19.9±6.5 | 19.4±6.5 | 20.0±6.5 | 20.1±6.9 | 19.5±5.9 |
| Score on Treatment Effectiveness Assessment†† | 18.3±7.2 | 16.7±7.0 | 18.6±7.3 | 18.4±7.5 | 19.2±7.1 |
| HIV-positive status — no./total no. (%) | 90/356 (25.3) | 24/92 (26.1) | 66/264 (25.0) | 24/96 (25.0) | 33/105 (31.4) |
Plus–minus values are means ±SD. The intention-to-treat population included all participants who underwent randomization in stage 1 and the participants who underwent randomization again in stage 2. DSM-5 denotes Diagnostic and Statistical Manual of Mental Disorders, fifth edition, and GED General Educational Development diploma. Percentages may not total 100 because of rounding.
The total number reflects all participants who underwent randomization in stage 1.
Race and ethnic group were reported by the participants. The “other” category included American Indian or Alaska Native (6 participants), Asian (11 participants), Native Hawaiian or Pacific Islander (2 participants), other (20 participants), multiracial (16 participants), don’t know (10 participants), and declined to answer (3 participants).
The remaining participants were unemployed, disabled, or retired; were keeping house; were students; or had other status.
The number of days of methamphetamine use at baseline was assessed for the 30 days before informed consent. One participant had only 24 days of assessment. Eligibility required a minimum of 18 days of methamphetamine use at baseline.
Methamphetamine craving (the intensity of the worst craving over the previous week) was assessed at each screening or baseline visit on a visual analogue scale; ratings on the scale, which range from 0 to 100, were averaged to determine a baseline craving, with 0 indicating no craving at all and 100 indicating the most intense craving possible.
Depressive symptoms were assessed weekly with the use of the Patient Health Questionnaire 9 (PHQ-9); scores range from 0 to 27, with higher scores indicating greater depressive symptoms.
Life satisfaction was reported by the participants and was assessed with the use of the Treatment Effectiveness Assessment, which consists of four items; the scores for each item are summed, and total scores range from 4 to 40, with higher scores indicating greater satisfaction.