Table 2.
Independent Effect of Primary Care Availability in the Substance Abuse Treatment Program on Patients' Addiction Severity at 12-month Follow-up
| Explanatory Variables | Regression Coefficients (95% CI)* |
|---|---|
| Fixed effects | |
| Program-level | |
| Primary medical care availability | |
| On-site care available | −25.88 (−43.24 to −8.52)† |
| Only off-site care available | −9.01 (−26.49 to 8.47) |
| No primary care available through the program | Referent |
| Treatment modality | |
| Short-term residential | 3.67 (−18.89 to 26.23) |
| Long-term residential | 7.22 (−8.09 to 22.53) |
| Outpatient drug-free | Referent |
| Geographic region | |
| Northeast | −13.62 (−31.40 to 4.17) |
| South | 9.01 (−11.65 to 29.69) |
| Central | −7.55 (−26.71 to 11.60) |
| West | Referent |
| Patient-level | |
| Addiction severity at intake | 0.236 (0.196 to 0.276)‡ |
| Depressive symptoms | |
| Suicidal thoughts/behavior | 35.08 (23.17 to 47.00)‡ |
| Depressive symptoms only | 8.94 (0.94 to 16.93)§ |
| No depressive symptoms | Referent |
| Drug injection in the past 12 mo | 33.21 (22.71 to 43.70)‡ |
| Treatment duration, per mo in treatment | −2.31 (−3.21 to −1.41)‡ |
| Methadone status at 12-mo follow-up | |
| Methadone maintenance | 64.38 (40.48 to 88.28)‡ |
| Withdrawn from methadone | 76.78 (53.58 to 99.98)‡ |
| Treatment other than methadone | Referent |
| Ethnicity/race | |
| Non-Hispanic black | 15.94 (3.68 to 28.19)§ |
| Non-Hispanic white | 2.05 (−9.93 to 14.02) |
| Other | Referent |
| Age category, in years | |
| ≤20 | 19.27 (3.28 to 35.26)§ |
| 21 to 30 | Referent |
| 31 to 40 | −1.07 (−7.79 to 9.94) |
| ≥41 | −1.28 (−13.30 to 10.75) |
| Marital status | |
| Currently married | −12.95 (−22.42 to −3.47)† |
| Past married | −1.22 (−12.11 to 9.67) |
| Never married | Referent |
| Educational attainment | |
| At least high school graduate | −22.61 (−30.01 to −15.20)‡ |
| Did not graduate from high school | Referent |
| Constant | 87.07 (63.07 to 111.07)‡ |
| Random effects | |
| Program-level variance (SE) | 204.2 (97.5)§ |
| Patient-level variance (SE) | 7,664.4 (222.1)‡ |
| −2 Log-likelihood | 28,701.7 |
*
From multivariable mixed effects linear regression models controlling for the variables displayed, and adjusted for the clustering of patients within programs. Regression coefficients provide the adjusted mean difference in the addiction severity score between a particular category and the referent category.
†
P < .01.
‡
P < .001.
§
P < .05.