Table 4.
Factors associated with greater changes in total InDUC scores by mixed effected model, multivariable analyses
| Unadjusted |
Completed only |
Regression based multiple imputations |
Propensity score based multiple imputations |
||
|---|---|---|---|---|---|
| β (95% CI) | β (95% CI) | β (95% CI) | β (95% CI) | ||
| Age (years) | −1.29 (−4.46, 1.89) | −3.41 (−7.19, 0.37) | 0.01 (−0.7, 0.72) | −0.17 (−1.21, 0.86) | |
| Years of formal education | |||||
| Less than 12 years | ref | ref | ref | ref | |
| Grade 12 | −5.54 (−8.71, −2.37) | −5.56 (−9.46, −1.67) | −0.36 (−1.36, 0.64) | −0.32 (−1.35, 0.70) | |
| More than 12 years | −3.83 (−6.83, −0.82) | −3.34 (−6.90, 0.23) | −0.37 (−1.37, 0.63) | −0.30 (−1.28, 0.68) | |
| Intervention needed at baseline | |||||
| Brief intervention | ref | ref | ref | ref | |
| Intensive intervention | 0.90 (−2.80, 4.61) | 4.80 (0.28, 9.33) | 0.16 (−0.66, 0.97) | −0.04 (−0.94, 0.85) | |
| Time effect | |||||
| 3 month follow-up | ref | ref | ref | ref | |
| 6 month follow-up | −3.68 (−8.61, 1.24) | −7.03 (−12.98, −1.07) | −0.24 (−1.6, 1.12) | −0.59 (−2.83, 1.65) | |
| 9 month follow-up | 3.49 (−2.07, 9.04) | 1.01 (−5.33, 7.35) | 0.21 (−1.26, 1.69) | 0.32 (−1.89, 2.53) | |
| 12 month follow-up | 1.58 (−4.13, 7.28) | −1.51 (−8.19, 5.17) | 0.10 (−1.40, 1.59) | −0.11 (−2.26, 2.03) | |
| Interaction Analysis* | |||||
| Study arm: 3 month follow-up | ref | ref | ref | ref | |
| Study arm: 6 month follow-up | 1.56 (−1.71, 4.83) | 0.13 (−3.57, 3.83) | −0.03 (−0.86, 0.79) | −0.09 (−1.32, 1.14) | |
| Study arm: 9 month follow-up | 2.13 (−1.18, 5.43) | 3.06 (−0.65, 6.77) | −0.09 (−0.93, 0.76) | −0.10 (−1.34, 1.14) | |
| Study arm: 12 month follow-up | 1.06 (−2.24, 4.36) | 2.14 (−1.57, 5.84) | −0.21 (−1.14, 0.73) | −0.29 (−1.65, 1.08) | |
| No drug use: 3 month follow-up | ref | ref | ref | ref | |
| No drug use: 6 month follow-up | −3.82 (−7.48, −0.16) | −2.36 (−6.65, 1.93) | −0.37 (−1.59, 0.86) | −0.02 (−1.35, 1.30) | |
| No drug use: 9 month follow-up | −3.30 (−7.39, 0.78) | −1.64 (−6.50, 3.22) | −0.31 (−1.48, 0.85) | 0.06 (−1.28, 1.41) | |
| No drug use: 12 month follow-up | −2.15 (−6.67, 2.36) | 1.80 (−3.61, 7.22) | −0.36 (−1.62, 0.89) | 0.11 (−1.28, 1.51) | |
| Drug treatment: 3 month follow-up | ref | ref | ref | ref | |
| Drug treatment: 6 month follow-up | 0.53 (−4.35, 5.40) | 0.80 (−1.97, 4.02) | 0.18 (−1.10, 1.46) | 0.38 (−1.56, 2.32) | |
| Drug treatment: 9 month follow-up | −7.04 (−12.78, −1.29) | 0.75 (−6.11, 7.61) | −0.48 (−2.18, 1.23) | −0.36 (−2.50, 1.79) | |
| Drug treatment: 12 month follow-up | −5.36 (−11.67, 0.94) | 4.44 (−3.58, 12.47) | −0.14 (−1.57, 1.29) | 0.32 (−1.78, 2.42) | |
| No drug use (past 90 days) | −5.25 (−8.01, −2.49) | −6.56 (−9.96, −3.15) | −0.11 (−0.8, 0.58) | −0.36 (−1.58, 0.86) | |
| Drug treatment (past 90 days) | −6.72 (−10.50, −2.93) | −10.24 (−14.89, −5.60) | −0.43 (−1.74, 0.88) | −1.05 (−3.69, 1.59) | |
| No drug use (accumulative) | −2.21 (−3.65, −0.77) | −2.79 (−4.36, −1.23) | −0.17 (−0.65, 0.30) | −0.21 (−0.80, 0.38) | |
| Drug treatment (accumulative) | 0.42 (−1.66, 2.51) | −2.00 (−4.42, 0.43) | −0.05 (−0.50, 0.40) | −0.14 (−0.78, 0.50) | |
| Baseline total InDUC score | 0.48 (0.44, 0.53) | 0.40 (0.34, 0.46) | 0.05 (−0.05, 0.15) | 0.03 (−0.03, 0.08) | |
*
n.b. Beta coefficients of each interaction terms were calculated separately
Key: InDUC=Inventory of drug use consequences; Ref=Reference; IQR=Interquartile range; β=Beta coefficients; 95% CI=95% confidence interval