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Abstract: High levels of missing outcome data for biologically confirmed substance use (BCSU) threaten the validity of substance use disorder (SUD) clinical trials. Underlying attributes of clinical trials could explain BCSU missingness and identify targets for improved trial design. We reviewed 21 clinical trials funded by the NIDA National Drug Abuse Treatment Clinical Trials Network (CTN) and published from 2005 to 2018 that examined pharmacologic and psychosocial interventions for SUD. We used configurational analysis-a Boolean algebra approach that identifies an attribute or combination of attributes predictive of an outcome-to identify trial design features and participant characteristics associated with high levels of BCSU missingness. Associations were identified by configuration complexity, consistency, coverage, and robustness. We limited results using a consistency threshold of 0.75 and summarized model fit using the product of consistency and coverage. For trial design features, the final solution consisted of two pathways: psychosocial treatment as a trial intervention OR larger trial arm size (complexity=2, consistency=0.79, coverage=0.93, robustness score=0.71). For participant characteristics, the final solution consisted of two pathways: interventions targeting individuals with poly- or nonspecific substance use OR younger age (complexity=2, consistency=0.75, coverage=0.86, robustness score=1.00). Conclusions: Psychosocial treatments, larger trial arm size, interventions targeting individuals with poly- or nonspecific substance use, and younger age among trial participants were predictive of missing BCSU data in SUD clinical trials. Interventions to mitigate missing data that focus on these attributes may reduce threats to validity and improve utility of SUD clinical trials. Related protocols: CTN-0002, CTN-0003, CTN-0004, CTN-0006, CTN-0007, CTN-0009. CTN-0013, CTN-0014, CTN-0015, CTN-0017, CTN-0021, CTN-0029, CTN-0030, CTN-0031, CTN-0037, CTN-0044, CTN-0046, CTN-0048, CTN-0051, CTN-0053

Abstract:

The selection of appropriate efficacy endpoints in clinical trials has been a long-standing challenge for the substance use disorder field. Using data from a large, multi-site National Drug Abuse Treatment Clinical Trials Network trial (CTN-0044; n=474), this secondary data analysis aimed to explore whether specific proximal (during-treatment) substance use outcome measures predict longer-term improvements in psychosocial functioning and post-treatment abstinence, and whether predictions vary depending on the specific substance (cannabis, cocaine/stimulants, opioids, and alcohol).

Generalized linear mixed models examined associations between six during-treatment substance use outcome measures and social functioning impairment (Social Adjustment Scale Self-Report) and severity of psychiatric symptoms (Brief Symptom Inventory-18) at end-of-treatment, and 3- and 6-months after treatment as well as post-treatment abstinence.

Maximum days of consecutive abstinence, proportion of days abstinent, 3 weeks of continuous abstinence, and the proportion of urine specimens negative for the primary substance were associated with post-treatment psychiatric and social functioning improvement and abstinence. However, only the effects of abstinence during the last 4 weeks of the treatment period on all three post-treatment outcomes was stable over time and did not differ between primary substance groups. In contrast, complete abstinence during the 12-week treatment period was not consistently associated with functioning improvements.

Conclusions: Substance use outcome measures capturing the duration of primary substance abstinence during treatment are suitable predictors of post-treatment abstinence and longer-term psychosocial functioning improvement. Binary outcomes, such as end-of-treatment abstinence, may be particularly stable predictors and attractive given their ease of computation and straightforward clinical interpretability.

Related protocols: CTN-0044

Abstract:

Traditional treatments for substance use disorders (SUDs) rely heavily on face-to-face interactions, which pose substantial limitations for patients. A clinical trial of a digital therapeutic (DT) delivering behavioral therapy demonstrated safety and efficacy in a population including patients with opioid use disorder (OUD) not treatment with buprenorphine, which is not a guideline-recommended approach. This study re-analyzed the data excluding patients with OUD to more closely approximate real-world patient populations.

The study was a secondary analysis of data from CTN-0044 (“Web-Delivery of Evidence-Based, Psychosocial Treatment for Substance Use Disorders;” n=399 after patients with OUD were excluded). Patients received 12 weeks of outpatient treatment-as-usual (TAU; n=193) or TAU with reduced counseling plus a digital therapeutic (DT; n=206) providing computerized cognitive behavioral therapy and contingency management (the reSET, a commercial version of the Therapeutic Education System (TES)). Primary outcomes were abstinence in weeks 9-12 and retention in treatment.

The 399 patients in the analysis (206 in the DT group and 193 in the TAU group) reported substance use disorders related to alcohol, cannabis, cocaine, or other stimulants (e.g. methamphetamine). Demographic and baseline characteristics including age, sex, race, education, and reported primary substance use disorder were balanced between treatment groups. Abstinence was significantly higher in the DT group compared to the TAU group (40.3 vs. 17.6%), as was retention in therapy (76.2 vs. 63.2%).

Conclusions: These results demonstrate that use of a digital therapeutic safely increased abstinence (reduced substance use) and retention in treatment among patients with substance use disorders related to alcohol, cannabis, cocaine, or other stimulants (including methamphetamines).

Related protocols: CTN-0044

Abstract:

Patient engagement may play a key role in the success or failure of treatments for substance use disorder (SUD). This exploratory analysis of data from a large, multisite effectiveness trial (CTN-0044) sought to determine how patient engagement with a digital therapeutic for SUD delivered at clinics was associated with abstinence outcomes.

The study evaluated engagement for 206 participants enrolled in a treatment program for SUDs related to cocaine, alcohol, cannabis, or other stimulants who were randomized to receive treatment as usual (TAU) or reduced TAU plus the digital Therapeutic Education System (TES) for 12 weeks. Participants were eligible for contingency management incentives for module completion (modules cover Community Reinforcement Approach topic areas) and negative urine drug screens. Analyses examined the association of module completion with end-of-treatment abstinence.

Participants completed a mean of 38.8 (range 0–72) TES modules over 12 weeks of treatment. Study completers (n = 157) completed a mean of 45.5 (range 9–72) TES modules, whereas study noncompleters (n = 49) completed a mean of 17.4 (range 0–45) TES modules. The study observed a strong positive correlation between TES engagement (i.e., total number of modules completed) and the probability of abstinence during weeks 9–12 of treatment among 157 study completers. Each module completed increased the odds of abstinence during weeks 9–12 by approximately 11% for study completers and 9% for the full sample. The study observed a similar, but weaker, association between engagement and abstinence among 49 patients who did not complete the study.

Conclusions: Greater engagement with a digital therapeutic for patients with SUD (i.e., number of modules completed over time) was strongly associated with the probability of abstinence in the last four weeks of treatment among those who completed the recommended 12-week treatment.

Related protocols: CTN-0044

Abstract:

The application of digital technologies to better assess, understand, and treat substance use disorders (SUDs) is a particularly promising and vibrant area of scientific research. The National Drug Abuse Treatment Clinical Trials Network (CTN), launched in 1999 by the U.S. National Institute on Drug Abuse, has supported a growing line of research that leverages digital technologies to glean new insights into SUDs and provide science-based therapeutic tools to a diverse array of persons with SUDs.

This article provides an overview of the breadth and impact of research conducted in the realm of digital health within the CTN. This work has included the CTN’s efforts to systematically embed digital screeners for SUDs into general medical settings to impact care models across the nation. This work has also included a pivotal multi-site clinical trial conducted on the CTN platform, whose data led to the very first “prescription digital therapeutic” authorized by the U.S. Food and Drug Administration (FDA) for the treatment of SUDs. Further CTN research includes the study of telehealth to increase capacity for science-based SUD treatment in rural and under-resourced communities. In addition, the CTN has supported an assessment of the feasibility of detecting cocaine-taking behavior via smartwatch sensing. And, the CTN has supported the conduct of clinical trials entirely online (including the recruitment of national and hard-to-reach/under-served participant samples online, with remote intervention delivery and data collection). Further, the CTN is supporting innovative work focused on the use of digital health technologies and data analytics to identify digital biomarkers and understand the clinical trajectories of individuals receiving medications for opioid use disorder (OUD).

This paper concludes by outlining the many potential future opportunities to leverage the unique national CTN research network to scale-up the science on digital health to examine optimal strategies to increase the reach of science-based SUD service delivery models both within and outside of healthcare.

Related protocols: CTN-0044, CTN-0059, CTN-0073-Ot, CTN-0076, CTN-0083, CTN-0084-A-2, CTN-0090, CTN-0095, CTN-0101, CTN-0102

Abstract:

Significant fixed effects of site (main effects of site and/or site by treatment interactions) on primary outcome have been identified in the majority of studies performed by NIDA’s National Drug Abuse Treatment Clinical Trials Network. While rarely explored, identifying patient- and site-level variables that are associated with site effects can provide information about the context in which outcome is optimized.

In a 10-site clinical trial that evaluated the effectiveness of a web-based psychosocial intervention compared to usual treatment of patients (N=507) with substance use disorders (CTN-0044), the primary outcome analysis revealed significant main effect of site, modeled as a fixed effect, on the outcome of abstinence. In the current analysis, researchers used a two-level, hierarchical generalized linear model (HGLM) to identify patient- and site-level variables associated with abstinence outcome, while modeling site as a random factor.

The site-specific percentage of patients abstinent in the last 4 weeks of the study varied from 6.1% to 40%. However, only 6.7% (p=0.08) of variability in end-of-study abstinence was accounted for by site, indicating a small-moderate effect. Among patient-level predictors, older age, abstinence at baseline, and among site-level predictors, higher annual clinic admissions, were significantly associated with increased likelihood of abstinence. When controlling for these three variables in a HGLM, only patient age and abstinence at baseline remained significant, and random factor site explained only 1.4% of variability in end-of-study abstinence, a 79% reduction in magnitude.

Conclusions: These findings suggest that only some amount of variability in abstinence outcomes among sites can be explained by a combination of patient- and site-level variables, supporting the case that variability between sites is a natural phenomenon. The methodological recommendation is that site be modeled as a random factor when analyzing multi-site clinical trials.

Related protocols: CTN-0044

Abstract:

The Community Reinforcement Approach (CRA) is an evidence-based practice for the treatment of substance use disorders (SUDs) and achieving and maintaining abstinence, but few studies have systematically explored the effect of CRA on secondary, yet also important, outcomes, such as social functioning.

This study was a secondary data analysis of CTN-0044, “Web Delivery of Evidence-Based, Psychosocial Treatment for Substance Use Disorders.” The purpose was to examine whether an internet-based version of CRA plus contingency management (Therapeutic Education System, TES) is associated with improved social functioning of individuals seeking substance use disorder treatment in a multi-site clinical effectiveness trial.

Social functioning was measured using the 54-item Social Adjustment Scale (SAS) assessing role performance in six domains (work, social and leisure activities, extended family relationships, marital relationship, parenting, and immediate family). Generalized linear mixed models tested the effects of treatment, time, sex, baseline abstinence, baseline social functioning and baseline psychological distress on overall social functioning and across social functioning subscales at the end of the 12-week treatment phase and three and six months post treatment.

Results showed no significant association between treatment and total social functioning score or any subscale scores. Being male, however, was significantly associated with better social functioning overall at the end of treatment (p=.024). Additionally, higher levels of psychological distress at baseline predicted significantly worse social functioning at the end of treatment overall (p=.037).

Conclusions: While TES was not associated with improvement in social functioning outcomes among participants when compared to TAU, male participants and those with less psychological distress at baseline experienced greater improvements in social functioning at the end of treatment. When integrating TES into community treatment programs, it may be important to have counselors involved to guide clients when choosing modules; completing home practice is also a critical factor in improving outcomes and should be monitored. In addition, improved measures of social functioning may be needed for studies involving patients with substance use disorders as more traditional secondary outcomes, such as social functioning and quality of life, should be more systematically studied in research involving treatment for substance use disorders.

Related protocols: CTN-0044

Abstract:

Substance use disorders are associated with lower cognitive functioning, and this impairment is associated with poorer outcomes. The Therapeutic Education System (TES) is an internet-based psychosocial intervention for substance use disorders that may provide enhanced treatment for individuals with cognitive deficits. This secondary analysis investigates the association between cognitive functioning and treatment outcomes in a large (N=507) randomized controlled effectiveness trial of TES compared to treatment-as-usual conducted within outpatient programs in the NIDA Clinical Trials Network (CTN-0044, “Web-Delivery of Evidence-Based, Psychosocial Treatment for Substance Use Disorders”).

Participants in the study completed a computer-based cognitive assessment (MicroCog (TM) short version) at baseline. Scores on subtests of attention, reasoning, and spatial perception were tested as moderators of the treatment effect on abstinence and retention at the end of the 12-week treatment phase using mixed effects logistic regression.

Cognitive functioning was not found to be a moderator of treatment on abstinence or retention. Post-hoc analysis of the main effect of cognitive functioning on retention and abstinence found impaired reasoning and cognitive flexibility were associated with lower retention. There were no other main effects of cognitive functioning on retention or abstinence.

Conclusions: The benefit of internet-delivered treatment over standard care was unchanged across a range of cognitive functioning. Consistent with previous research, mild to moderate impairment in reasoning and cognitive flexibility were associated with lower retention across both treatment arms. TES appears to be equally effective across a spectrum of cognitive functioning among diverse patients. Further study is needed to determine mechanisms by which cognitive functioning influences retention in treatment and to optimize technology-based interventions for those with cognitive impairment.

Related protocols: CTN-0044

Abstract:

There is growing concern regarding the generalizability of findings from randomized controlled trials (RCTs) of interventions for substance use disorders (SUDs). This study used a selection model approach to assess and improve the generalizability of an evaluation for a web-based SUD intervention by making the trial sample resemble the target population.

The sample of the web-based SUD intervention (Therapeutic Education System vs. treatment-as-usual; n=507) was compared with the target population of SUD treatment-seeking individuals from the Treatment Episodes Data Set-Admissions (TEDS-A). Using weights based on the probabilities of RCT participation, weighted treatment effects on retention and abstinence were computed.

Substantial differences between the RCT sample and the target population were demonstrated in significant difference in the mean propensity scores (1.62 standard deviations at p<.001). The population effect on abstinence (12 weeks and 6 months) was statistically insignificant after weighting the data with the generalizability weight.

Conclusions: Findings from this study provide insights into the differences between RCT participants of a web-based SUD intervention and the target population from recent years. The results of this study also indicate how poor sample representativeness of the RCT compared with the target population impacted the observed findings of the web-based SUD intervention. Given the great potential for scalability of web-based SUD interventions, the representativeness of the sample with regard to the target population of potential users for the intervention should be carefully considered. Additionally, with a careful consideration of the treatment effect modifiers which are over- or under-representing in RCTs, application of generalizability weights could be a potentially useful tool for assessing and improving the generalizability of the findings from RCTs when the RCT sample does not well-represent the target population.

Related protocols: CTN-0044

Abstract:

This study is a secondary descriptive analysis that explores and compares the cognitive profiles of adults entering treatment at geographically diverse community-based substance use disorder treatment facilities. Performance on cognitive measures at baseline was compared across 5 primary substance subgroups of individuals (alcohol=104; cocaine=102; stimulants=69; opioids=108; marijuana=114) enrolled in a web-based psychosocial treatment study conducted within the NIDA Clinical Trials Network (protocol CTN-0044, “Web Delivery of Evidence-Based, Psychosocial Treatment for Substance Use Disorders”). Microcog subtests were used to assess cognitive domains of attention and mental control, reasoning and cognitive flexibility, and spatial processing.

The average age of onset for a substance use disorder was early to mid-20s, with marijuana users reporting the earliest age of onset (mean 19.9, SD 7.5) and stimulant users reporting the latest (mean 25.2, SD 9.9). Among the total sample, half (49.7%) demonstrated impairment in cognitive flexibility and reasoning, and over one-third (37.3%) had impairment in verbal learning and memory. Stimulant (37.68%) and cocaine (34.31%) users showed significantly greater clinical impairment in attention and mental control compared with alcohol users (17.31%) and opioid (21.3%) users (stimulant subgroup only). Cocaine users showed the greatest overall impairment across total and proficiency subtest scores, although these were not statistically different from other subgroups.

Conclusions: These findings confirmed previous studies, indicating a high prevalence of significant cognitive dysfunction across all substance use categories among treatment-seeking adults, and found that cocaine use appears to be associated with the most impairment. Increasing knowledge of similarities and differences between primary substance subgroups can help guide substance use disorder treatment planning.

Related protocols: CTN-0044

Abstract:

The Therapeutic Education System (TES), an Internet version of the Community Reinforcement Approach plus prize-based motivational incentives, is one of few empirically supported technology-based interventions. To date, however, there has not been a study exploring differences in substance use outcomes or acceptability of TES among racial/ethnic subgroups. This study uses data from a multisite (N=10) effectiveness study of TES to explore whether race/ethnicity subgroups (White [n=267], Black/African American [n=112], and Hispanic/Latino [n=55]) moderate the effect of TES. Generalized linear mixed models were used to test whether abstinence, retention, social functioning, coping, craving, or acceptability differed by racial/ethnic subgroup. Findings demonstrated that race/ethnicity did not moderate the effect of TES versus TAU on abstinence, retention, social functioning, or craving. A three-way interaction (treatment, race/ethnicity, and abstinence status at study entry) showed that TES was associated with greater coping scores among non-abstinent White participants (p=.008) and among abstinent Black participants (p<.001). Acceptability of the TES intervention, although high overall, was significantly different by race/ethnicity subgroup with white participants reporting lower acceptability of TES compared to Black (p=.006) and Hispanic/Latino (p=.008) participants.

Conclusions: Findings from this study lend additional support for the use of technology-based interventions in the treatment of substance use disorders. The acceptability of Internet-delivered interventions among racial/ethnic minority populations suggests promise for increasing access to services and reducing disparities in treatment outcomes. In this large multisite national study, racial/ethnic subgroups received similar benefit from Internet-based CRA/CM and reported high rates of acceptability, with Black participants reporting the highest rates of acceptability. TES should be considered as an additional tool to support usual care in outpatient treatment programs among diverse subgroups of patients.

Related protocols: CTN-0044

Abstract:

The acceptability, feasibility, and effectiveness of web-based interventions among criminal justice-involved populations are understudied. This study is a secondary analysis of baseline characteristics associated with criminal justice system (CJS) status as treatment outcome moderators among participants enrolling in a large randomized trial of a web-based psychosocial intervention (Therapeutic Education System [TES]) as part of outpatient addiction treatment.

Using data from CTN-0044 (Web Delivery of Evidence-Based, Psychosocial Treatment for Substance Use Disorders), the authors compared demographic and clinical characteristics, TES participation rates, and the trial’s two co-primary outcomes (end of treatment abstinence and treatment retention) by self-reported CJS status at baseline: 1) CJS-mandated to community treatment (CJS-mandated), 2) CJS-recommended to treatment (CJS-recommended), 3) no CJS treatment mandate (CJS-none).

Results found that CJS-mandated (n=107) and CJS-recommended (n=69) participants differed from CJS-none (n=331) at baseline: CJS-mandated were significantly more likely to be male, screen negative for depression, and score lower for psychological distress and higher on physical health status; CJS-recommended were younger, more likely single, less likely to report no regular Internet use, and to report cannabis as the primary drug problem. Both CJS-involved (CJS-recommended and -mandate) groups were more likely to have been recently incarcerated. Among participants randomized to the TES arm, module completion was similar across the CJS subgroups. A three-way interaction of treatment, baseline abstinence, and CJS status showed no associations with the study’s primary abstinence outcome.

Conclusions: Overall, CJS-involved participants in this study tended to be young, male, and in treatment for a primary cannabis problem. The feasibility and effectiveness of the web-based psychosocial intervention, TES, did not vary by CJS-mandated or CJS-recommended participants compared to CJS-none; CJS-involved participants appeared to experience the usual expected benefits in this large multisite randomized trial. These results should encourage treatment providers, policy makers, and CJS authorities to further consider online psychosocial interventions as viable and appropriate therapeutic approaches in CJS addiction treatment populations.

Related protocols: CTN-0044

Abstract:

This study aimed to examine prize-earning costs of contingency management (CM) incentives in relation to participants’ pre-study enrollment drug use status (baseline (BL) positive vs. BL negative) and relate these to previously reported patterns of intervention effectiveness. Participants were 255 substance users entering outpatient treatment who received the therapeutic education system (TES) in addiction to usual care counseling (as part of NIDA Clinical Trials Network protocol CTN-0044). TES included a CM component such that participants could earn up to $600 in prizes on average over 12-weeks for providing drug negative urines and completing web-based cognitive behavior therapy modules. This secondary analysis examined distribution of prize draws and value of prizes earned for subgroups that were abstinent (BL negative; N=136) or not (BL positive; N=119) at study entry based on urine toxicology and breath alcohol screen.

Results found that distribution of draws earned (median=119 vs. 17; p < .0001) and prizes redeemed (median=54 vs. 9; p < .001) for drug abstinence differed significantly for BL negative compared to BL positive participants. BL negative earned on average twice as much in prizes as BL positive participants ($245 vs. $125). Median value of prizes earned was 5.4 times greater for BL negative compared to BL positive participants ($237 vs. $44; p<.001).

Conclusions: Two-thirds of expenditures in an abstinence incentive program were paid to BL negative participants. These individuals had high rates of drug abstinence during treatment and did not show improve abstinence outcomes with TES versus usual care. Effectiveness of the abstinence-focused CM intervention in TES may be enhanced by tailoring delivery based on patients’ drug use status at treatment entry.

Related protocols: CTN-0044

Abstract:

The purpose of this study was to estimate how results would have varied if a substance abuse clinical trial had been conducted with nationally representative adults with substance use and with representative adults receiving substance use treatment. Results were analyzed from NIDA Clinical Trials Network protocol CTN-0044, a multisite clinical trial comparing the effectiveness of the Therapeutic Education System to treatment as usual for outpatient addiction treatment (n = 507). Patients were recruited between June 2010 and August 2011. Abstinence was the primary outcome. The general population sample and general population-treated samples were derived from Wave 1 of the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC) (n = 43,093). Propensity scores provided a standardized measure of the difference between clinical trial participants and the 2 NESARC samples. The clinical trial was reanalyzed by reweighting the sample with propensity scores derived from the 2 samples to obtain generalizable estimates of treatment effects.

Before the clinical trial sample was reweighted, the odds ratio (OR) of response to Therapeutic Education System versus treatment as usual in the trial was 1.62 (95% CI, 1.12-2.35). After the sample was reweighted to be representative of the 2 NESARC groups, ORs were 1.33 (95% CI, 0.34-5.26) for the representative sample with any substance use and 1.64 (95% CI, 0.82-3.27) for the representative treated sample. The effect size of the original study was statistically significant; the estimate effect size for the nationally representative sample was not. This does not necessarily mean that the Therapeutic Education System is not efficacious for the treatment of substance use disorders. Instead, the width of the confidence intervals reflects increased uncertainty associated with extrapolating the results of the clinical trial sample to broader populations.

Conclusions: Applying propensity score weighting to clinical trial results provides a method for estimating the population generalizability of clinical trial findings that relies on effect moderators observed in the study sample and population. Broader confidence intervals in the reweighted samples do not necessarily indicate lack of efficacy of the Therapeutic Education System but rather greater uncertainty concerning effectiveness in general population samples.

Related protocols: CTN-0044

Abstract:

The acceptability and clinical impact of a web-based intervention among patients entering addiction treatment who lack recent internet access are unclear. This secondary analysis of a national multisite treatment study (CTN-0044) assessed for acceptability and clinical impact of a web-based psychosocial intervention among participants enrolling in community-based, outpatient addiction treatment programs. Participants were randomly assigned to 12 weeks of a web-based therapeutic education system (TES) based on the community reinforcement approach plus contingency management versus treatment as usual (TAU).

Demographic and clinical characteristics and treatment outcomes were compared among participants with recent internet access in the 90 days preceding enrollment (N=374) and without internet access (N=133). Primary outcome variables included (1) acceptability of TES (i.e., module completion, acceptability of web-based intervention) and (2) clinical impact (i.e., self-reported abstinence confirmed by urine drug/breath alcohol tests, retention measured as time to dropout).

Internet use was common (74%) and was more likely among younger (18-49 year old) participants and those who completed high school (p<.001). Participants randomized to TES (n=255) without baseline internet access rated the acceptability of TES modules significantly higher than those with internet access (t=2.49, df=218, p=.01). There was a near significant interaction between treatment, baseline abstinence, and internet access on time to dropout. TES was associated with better retention among participants not abstinent at baseline who had internet access.

Conclusions: This study explores the association between internet access and demographic and clinical outcomes among a national multi-site sample of patients entering community-based, outpatient addiction treatment. Overall, the data are encouraging for the potential to use technology-based interventions among diverse outpatient addiction treatment populations. Rates of internet access (in the 90 days prior to enrollment) (74%) were similar to the general population (79%). Further, there was high acceptability of the web-based intervention, especially among participants reporting no recent internet access. Findings also suggest that a lack of recent internet access was not associated with abstinence or retention outcomes. Expanding the capacity of publicly funded community-based addiction treatment programs with acceptable evidence-based health information technologies is imperative. The suitability of providing access and training to web-based interventions within clinics may mitigate barriers to access among vulnerable populations lacking remote internet access.

Related protocols: CTN-0044