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. Author manuscript; available in PMC: 2012 Nov 1.
Published in final edited form as: Drug Alcohol Depend. 2011 Apr 9;118(2-3):152–157. doi: 10.1016/j.drugalcdep.2011.03.012

Table 3.

Relationship between number of service encounters and change in frequency of substance use within each service level.

Days of Illicit Drug Use Days of Alcohol Use Days of Alcohol Intoxication
Patients receiving BI only (n=855)
 Number of Service Sessions 0.953 (0.839 – 1.083) 1.106 (1.006 – 1.217)* 1.121 (1.035 – 1.214)**
 6 month follow-up (ref=baseline) 0.533 (0.363 – 0.783)** 0.805 (0.652 – 0.995)* 0.902 (0.695 – 1.171)
 Time x Service Sessions 0.916 (0.705 – 1.189) 0.840 (0.736 – 0.958)** 0.816 (0.694 – 0.961)*
Patients receiving BT/RT (n=353)
 Number of Service Sessions 0.909 (0.861 – 0.958)*** 0.957 (0.919 – 0.996)* 0.939 (0.899 – 0.982)**
 6 month follow-up (ref=baseline) 0.370 (0.249 – 0.549)*** 0.581 (0.435 – 0.776)*** 0.585 (0.428 – 0.800)***
 Time x Service Sessions 1.030 (0.932 – 1.138) 0.980 (0.918 – 1.047) 0.978 (0.908 – 1.053)
*

p<.05;

**

p<.01;

***

p<.001.

Note: Random-effects negative binomial regression used. Models are adjusted for gender, age, race, and Hispanic ethnicity. Adjusted Incidence Rate Ratios reported. 95% Confidence Intervals in parentheses.