This paper presents new information on baseline and during-treatment factors related to treatment success in this outpatient, community-based, multi-site trial of Bup/Nal treated opioid dependent adolescents and young adults.
Injection drug use (IDU) at baseline was a significant and independent predictor of lower rates of OPU at week 12. This finding is consistent with prior research that injection drug users had better Bup/Nal outcomes or were more likely to believe that it would be helpful15, 28–29
lending further support for the role of Bup/Nal as a potentially effective tool in reducing HIV and Hepatitis-C infections/risk28
. Having more active medical and/or psychiatric problems at treatment-entry also emerged as a significant independent predictor of lower rates of OPU. Higher mean baseline scores on self-reported internalizing problems, was associated with better opioid use outcomes (in bivariate analyses) but was not a significant independent predictor of lower rates of OPU. This finding is concordant with reports of adult patients treated with buprenorphine showing that higher levels of depression was associated with better opioid outcomes12–13, 15
. For youth, the association between IDU and high distress levels and better treatment outcome may be explained by their awareness of being in a downward spiral and being tired of devoting so much time and resources to obtaining and using drugs to the exclusion of prosocial activities. This could be a motivating factor for treatment..
The third significant finding was that Bup/Nal treatment led to similar rates of opioid abstinence regardless of the type of opioid they reported using (i.e. heroin, non-heroin prescription opioid analgesic or both), consistent with findings from another adolescent opioid treatment study17
. Also non-significant were baseline predictors such as race, education/employment status, and concomitant cocaine, tobacco or marijuana use with a trend towards significance for gender and elevated liver enzymes, in contrast to the results from adult treatment studies12–16
The during-treatment factors associated with treatment success spanned three areas: non-study medications and other non-study treatment services; early treatment phase opioid abstinence; and study treatment completion. The significance of receiving ancillary treatments and medications (to ease withdrawal symptoms, insomnia, pain and co-occurring psychiatric symptoms) to augment Bup/Nal interventions was not supported with adult patients15, 30
. It is likely that the improved outcomes for patients that received non-study medications and/or treatment reflect benefits of treating other medical/psychiatric disorders while in the study (as shown in studies with adults12
) and the important benefits of receiving additional treatment elsewhere for co-occurring problems even after dropping out of the study.
Achieving opioid abstinence during the early treatment phase may serve as an important marker of treatment success, as in a previous study with adults31
, and may have been driven by motivation to get well among those severely addicted resulting in adherence to medication and counseling. Similarly, it was no surprise that treatment completion was associated with better outcomes since longer periods of treatment participation have consistently been linked to better buprenorphine and other substance abuse treatment outcomes32–34
This study was not adequately powered to detect a clinically significant interaction with all the baseline and during-treatment factors examined. While the lack of statistical significance in the results may be a result of sample size, our analyses were meant to generate hypotheses for future study. Future, adequately powered studies are needed to replicate these findings, re-evaluate the non-significant findings from this study, evaluate specific co-occurring psychiatric disorders, consider study-endpoints/outcomes other than end-of-study urine results and include other predictors e.g. biological and genetic markers that were not examined in this study. Although we did not find that youth < 18 years (n=26, 18%) fared differently from those who were older, this finding may be an artifact of the small sample size. The low rates of study treatment completion/retention may have adversely affected the outcomes. Consistent with the primary study, we, conservatively, imputed positive results for missing urine results, which may have incorrectly estimated those who achieved recovery.
The primary study demonstrated the efficacy of 12 weeks of Bup/Nal in reducing opioid use and improving treatment retention among opioid dependent youth ages 15–21 years. The current study has contributed new and important clinical information on baseline and during-treatment factors that were linked to lower rates of OPU. Patients presenting with an advanced opioid use pattern (i.e. IDU and other health issues) were more likely to have lower rates of OPU at week-12, suggesting that they can respond well to outpatient Bup/Nal treatment. Those that were able to achieve early opioid abstinence, receive supplemental treatment services and medications outside of the study and remain in treatment for the entire 12 weeks of treatment were more likely to have better opioid outcomes. These new findings have the potential to facilitate tailored treatments for opioid dependent youth and inform the design of future treatment trials for this largely understudied population.