Table 2.
Sample characteristics and bivariable analysis comparing dropout patients with those who completed treatment (N = 464).
| Variable |
Total (N = 464) |
Treatment dropout |
P value | Effect sizea | Mean difference (95% CI) | |||
|---|---|---|---|---|---|---|---|---|
| Yes (N = 132) |
No (N = 332) |
|||||||
| Categorical | N | No. (%) | No. (%) | |||||
| Gender | ||||||||
| Female | 126 | 40 (30) | 86 (26) | .322 | 0.04 | |||
| Male | 336 | 91 (70) | 245 (74) | |||||
| Missing data | 2 | 1 | 1 | |||||
| Age, y | .001 | |||||||
| <25 | 78 | 33 (25) | 45 (14) | .002 | 0.14 | |||
| 25-34 | 125 | 41 (31) | 84 (25) | .207 | 0.06 | |||
| 35-44 | 94 | 29 (22) | 65 (20) | .561 | 0.03 | |||
| >44 | 167 | 29 (22) | 138 (42) | .001 | 0.18 | |||
| Education | .001 | |||||||
| Primary | 146 | 59 (47) | 87 (27) | .001 | 0.19 | |||
| Middle level | 247 | 56 (44) | 191 (60) | .003 | 0.14 | |||
| High | 54 | 12 (9) | 42 (13) | .282 | 0.05 | |||
| Missing data | 17 | 5 | 12 | |||||
| Primary drug | ||||||||
| Alcohol | 219 | 51 (39) | 168 (51) | .020 | 0.11 | |||
| Cannabis | 83 | 27 (21) | 56 (11) | .347 | 0.04 | |||
| Amphetamines | 77 | 22 (17) | 55 (17) | .958 | 0.00 | |||
| Opioids | 40 | 16 (12) | 24 (7) | .086 | 0.08 | |||
| Nonprescribed benzodiazepines | 31 | 10 (8) | 21 (6) | .615 | 0.02 | |||
| Other drugsb | 9 | 4 (3) | 5 (2) | .278 | 0.05 | |||
| Missing data | 5 | 2 | 3 | |||||
| Ever injected | ||||||||
| Yes | 180 | 65 (49) | 115 (35 | .004 | 0.14 | |||
| No | 284 | 67 (51) | 217 (65) | |||||
| Polydrug use | ||||||||
| Yes | 220 | 76 (58) | 144 (43) | .005 | 0.13 | |||
| No | 244 | 56 (42) | 188 (57) | |||||
| SUD diagnosis | ||||||||
| Yes | 442 | 122 (92) | 320 (96) | .089 | 0.08 | |||
| No | 22 | 10 (8) | 12 (4) | |||||
| Mood disorder | ||||||||
| Yes | 52 | 11 (8) | 41 (12) | .214 | −0.06 | |||
| No | 412 | 121 (92) | 291 (88) | |||||
| Anxiety disorder | ||||||||
| Yes | 42 | 11 (8) | 31 (9) | .727 | −0.02 | |||
| No | 422 | 121 (92) | 301 (91) | |||||
| PTSD | ||||||||
| Yes | 35 | 16 (12) | 19 (6) | .018 | 0.11 | |||
| No | 429 | 116 (88) | 313 (94) | |||||
| Personality disorder | ||||||||
| Yes | 38 | 13 (10) | 25 (8) | .412 | 0.04 | |||
| No | 426 | 119 (90) | 307 (92) | |||||
| ADHD | ||||||||
| Yes | 51 | 26 (20) | 25 (8) | .001 | 0.18 | |||
| No | 413 | 106 (80) | 307 (93) | |||||
| Previous inpatient treatment | ||||||||
| Yes | 284 | 85 (64) | 199 (61) | .373 | 0.04 | |||
| No | 176 | 47 (36) | 129 (39) | |||||
| Missing data | 4 | 0 | 4 | |||||
| Continuousc | N | Mean (SD) | N | Mean (SD) | ||||
| Mental distress | 463 | 132 | 2.27 (0.69) | 331 | 2.11 (0.69) | .027 | 0.23 | −0.16 (−0.30 to −0.02) |
| Motivation | 463 | 132 | 4.11 (0.80) | 331 | 4.32 (0.70) | .006 | −0.28 | 0.21 (0.06 to 0.36) |
Abbreviations: ADHD, attention-deficit hyperactivity disorder; CI, confidence interval; PTSD, posttraumatic stress disorders; SUD, substance use disorder.
χ2 test for overall differences in categorical variables exceeding 2 categories. Pairwise differences calculated with proportion tests and independent samples t tests as appropriate for categorical and continuous variables.
Bold values indicate significant differences.
Effect size calculated with Cramer V and Cohen d. Negative numbers reflect retention (less dropout).
Included cocaine, GHB (γ-hydroxybutyrate), ecstasy.
Higher scores reflect greater mental distress (range: 1-4) and greater intrinsic motivation (range: 1-5).