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The National Drug Abuse Treatment Clinical Trials Network (CTN) has faced many challenges over its first eleven years. This review explores some of these challenges and the paths the CTN took to meet these challenges, including: designing clinical trials that reflect the CTN’s mission and changing public health needs, finding the synergies in the varied expertise of clinical treatment providers and academic researchers, promoting evidence-based practices, and expanding the Network into mainstream medical practices to reach a broader patient population. Included in this exploration are specific examples from CTN clinical trials.
CTN studies have shown that quality clinical trials can be successfully implemented into practice settings unfamiliar with research logistics by taking clinicians’ practical needs and research knowledge level into account. The challenges yet to be faced in the CTN’s efforts to expand opportunities to offer existing treatments to the segment of the drug-abusing population that utilizes mainstream health care seem large, but not as large as the potential for improvements in public health.
Related protocols: CTN-0001, CTN-0002, CTN-0003, CTN-0004, CTN-0005, CTN-0006, CTN-0007, CTN-0009, CTN-0010, CTN-0011, CTN-0013, CTN-0014, CTN-0015, CTN-0017, CTN-0018, CTN-0019, CTN-0020, CTN-0021, CTN-0027, CTN-0028, CTN-0029, CTN-0030, CTN-0031, CTN-0032, CTN-0037, CTCN-0044, CTN-0047, CTN-0048, CTN-0049
Participant retention is critically important for clinical research studies in the area of addictions. This study, using data from fifteen trials in the National Drug Abuse Treatment Clinical Trials Network, sought to examine predictors of retention in a series of treatment outcome studies. Studies were combined, defining retention through the final follow-up visit, and multivariate logistic regression models were used to assess predictors of study retention, focusing on age, gender, and ethnicity (non-Hispanic White, African American, and Hispanic/Other). Results found no clear pattern, however retention seemed higher in adult pharmacologic trials and lower in sexual risk reduction trials. Younger participants were more likely to drop out and, in comparison to African American participants, non-Hispanic Whites were more likely and Hispanic/Others less likely, to drop out. In terms of gender, no significant difference was found between the sexes, though a significant interaction was discovered between ethnicity and gender in relation to study retention. This interaction was largely driven by Hispanic/Other women (not in methadone treatment), who were approximately 40% less likely to be lost to follow-up than their African American counterparts. The results suggest that strategies focused on improving study retention in younger subjects, and in non-Hispanic females, may be particularly important for increasing participant retention and improving the validity of clinical trial data.
Related protocols: CTN-0001, CTN-0002, CTN-0003, CTN-0004, CTN-0005, CTN-0006, CTN-0007, CTN-0009, CTN-0010, CTN-0011, CTN-0013, CTN-0015, CTN-0018, CTN-0019, CTN-0021
Multisite effectiveness trials such as those carried out in the National Drug Abuse Treatment Clinical Trials Network (CTN) are a critical step in the development and dissemination of evidence-based treatments because they address how such treatments perform in real-world clinical settings. Several possible experimental designs may be chosen for such effectiveness trials. These include (a) a new treatment intervention (Tx) is compared to an existing mode of community based treatment as usual (TAU): Tx versus TAU; (b) a new intervention is added to TAU and compared to TAU alone: Tx + TAU versus TAU; or (c) a new intervention is added to TAU and compared to a control condition added to TAU: Tx + TAU versus control + TAU. Each of these designs addresses a different question and has different potential strengths and weaknesses. As of December 2009, the primary outcome paper had been published for 16 of the multisite randomized clinical trials conducted in the CTN, testing various treatments for drug abuse, HIV risk behavior, or related problems.
This paper systematically examines, for each of the completed trials, the experimental design type chosen and its original rationale, the main findings of the trial, and the strengths and weaknesses of the design in hindsight. Based on this review, recommendations are generated to inform the design of future effectiveness trials on treatments for substance abuse, HIV risk, and other behavioral health problems. Addressing the right questions, looking closely at effect size and power, as well as internal versus external validity, and more consideration for three-arm designs and cost-effectiveness will serve well the goals of effectiveness research.
Related protocols: CTN-0001, CTN-0002, CTN-0003, CTN-0004, CTN-0005, CTN-0006, CTN-0007, CTN-0009, CTN-0010, CTN-0011, CTN-0013, CTN-0015, CTN-0017, CTN-0018, CTN-0019, CTN-0021
Differential attrition by minority populations can be as limiting to interpreting final results as poor initial recruitment of minority populations. This is especially important in drug abuse treatment studies, as minorities are over-represented in substance abuse clinical treatment programs. This ancillary investigation aimed to determine if there are differences in study retention rates by race/ethnicity and age, and to explore other client characteristics, as well as protocol and treatment program factors, that could account for differential retention rates. Analyzing data from six CTN trials (CTN-0001, -0002, -0005, -0006, -0007, and -0011), the researchers found that older African Americans and Caucasians had the greatest odds of retention and younger African Americans the lowest — only age was significantly related to study retention. Additionally, primary drug of abuse, having HIV risk screening as a program benefit, and lower percentages of female admissions were also significantly related to study retention.
In conclusion, efforts should be made to increase the study retention of younger participants to improve the validity and generalizability of drug abuse treatment study results.
Related protocols: CTN-0001, CTN-0002, CTN-0005, CTN-0006, CTN-0007, CTN-0011
Substance use relapse rates are often high in the first months after discharge from inpatient substance abuse treatment, and patient adherence to aftercare plans is often low. Four residential addiction treatment centers participated in a feasibility study designed to estimate the efficacy of a post-discharge telephone intervention intended to encourage compliance with aftercare (CTN-0011, “A Feasibility Study of a Telephone Enhancement Procedure (TELE) to Improve Participation in Continuing Care Activities “). A total of 282 participants (100 women, 182 men) with substance use disorders were included in this secondary analysis.
The findings revealed that women were more likely than men to attend aftercare. This “gender effect” persisted after adjustment for a number of potential mediators.
Related protocols: CTN-0011
The TELE study (protocol CTN-0011) examined the feasibility and potential efficacy of phone calls to patients after discharge from short-term inpatient and residential substance abuse treatment programs to encourage compliance with continuing care plans. After review of their continuing care plans, 339 patients from four programs were randomized either to receive calls or have no planned contact. Ninety-two percent of patients randomized to receive calls received at least one call. No difference was found between groups in self-reported attendance at one or more outpatient counseling sessions after discharge (p = .89). When program records of all participants were examined, those receiving calls had a greater likelihood of documented attendance (48%) than those not called (37%).
Results were not statistically significant (p < .003) because of the Hochberg correction for multiple tests. While the phone calls were feasible, the lack of clear evidence of efficacy of the calls suggests the need for further investigation of the role of telephone intervention to encourage compliance and improve outcomes.
Related protocols: CTN-0011
This secondary analysis of data from protocol CTN-0011, “Feasibility Study of a Telephone Enhancement Procedure (TELE) to Improve Participation in Continuing Care Activities,” examines the relationship of participant gender on aftercare attendance, and the moderating effects of a history of physical abuse. Four residential addiction treatment centers participated in CTN-0011, a feasibility study designed to estimate the efficacy of a post-discharge telephone intervention intended to encourage compliance with aftercare.
Participants were 282 outpatients (100 women, 182 men) with substance use disorders. The findings revealed that the odds of attending aftercare were 1.91 times higher in women than men. Women were also more likely to report higher rates of physical abuse (PA) and sexual abuse (SA). To determine whether prior PA or SA confounded the gender effect observed, separate logistic regression models were used to test each interaction. A significant gender-by-PA interaction was found, but there was no interaction between SA and gender. However, while the interaction between SA and gender was not significant, the gender effect persisted after adjustment for history of SA. For the PA-by-gender interaction, women without PA were more likely to return for aftercare when compared to men with PA or men without PA; however, the odds of aftercare for women with PA were one-tenth times that of females without PA. Women with PA were no more likely to attend aftercare than either males with or without PA. The findings suggest that women may be more influenced by the post-discharge telephone intervention than men, although it is not clear from the data whether this is a result of the women benefiting more from this particular intervention or the result of other unmeasured variables. Further studies are needed to better understand the observed gender effect.
Related protocols: CTN-0011
This brochure, intended for participants thinking about joining the CTN-0011 (A Feasibility Study of a Telephone Enhancement Procedure (TELE) to Improve Participation in Continuing Care Activities) study, provides an overview of telephone enhancement and answers questions participants might have.
Related protocols: CTN-0011
This brochure, intended for participants in the CTN-0011 (A Feasibility Study of a Telephone Enhancement Procedure (TELE) to Improve Participation in Continuing Care Activities) protocol, provides an overview of the project and answers any questions participants might have about being involved.
Related protocols: CTN-0011