Table 3.
Difference in substance use the last 3 months according to time and intervention
| βa | 95% CI | p-value | |
|---|---|---|---|
| Intervention compared with control at start of treatment |
1.88 |
−1.50 to 5.22 |
0.271 |
| Time 3 months compared with start of treatment b |
−4.13 |
−7.17 to −1.10 |
0.008 |
| Time 6 months compared with start of treatment b |
−3.24 |
−6.46 to −0.02 |
0.049 |
| Time 12 months compared with start of treatment b |
−3.59 |
−6.85 to −0.34 |
0.030 |
| Time 24 months compared with start of treatment b |
2.37 |
−1.54 to 6.28 |
0.235 |
| Time 3 months a Intervention c |
1.18 |
−3.00 to 5.35 |
0.580 |
| Time 6 months a Intervention c |
−1.28 |
−5.71 to 3.15 |
0.571 |
| Time 12 months a Intervention c |
−1.81 |
−6.27 to 2.65 |
0.425 |
| Time 24 months a Intervention c |
−7.26 |
−12.64 to −1.89 |
0.008 |
| Constant | 11.72 |
Estimated days per month with 95% confidence intervals, using a linear mixed model.
a Unstandardized regression coefficient.
b Estimate for the control group.
c Estimate for additional effect of time for the intervention group compared with the control group relative to start of treatment.