This study evaluated the effectiveness of two telephone-based, extended continuing care interventions, which were compared to what has become standard care for substance dependent patients with at least moderate severity who seek publicly funded treatment—intensive outpatient programs, or IOPs. One continuing care intervention provided standardized monitoring of current symptoms and status, feedback, CBT-based counseling linked to the monitoring results, and stepped care as needed. The second intervention provided monitoring and feedback only. The participants all were alcohol dependent and had achieved initial engagement in IOP, as evidenced by regular attendance for three weeks. In this paper, we examined substance use outcomes over the 18 months in which the continuing care interventions were provided.
The results indicated that the telephone intervention that included counseling (i.e., TMC) yielded better outcomes than standard care on each of the four alcohol use measures examined. On the frequency of alcohol use and heavy alcohol use measures, these differences were largest over the last six months of the follow-up (i.e., months 13–18), with effect sizes ranging from .46 to .65. These effects translated into a difference between TMC and TAU of 14 percentage points on alcohol use and 11 percentage points on heavy alcohol use outcomes at 18 months, with slightly larger differences at 12 or 15 month follow-ups. On the categorical measures of alcohol use, rates of any alcohol use and any heavy alcohol use at 18 months were 17 and 18 percentage points higher, respectively, in TAU than in TMC, again with somewhat larger differences at 12 or 15 month follow-ups. These differences clearly exceed the effect sizes that have been found to be clinically meaningful to therapists (Miller & Manuel, 2008
), although it should be acknowledged that these descriptive percentages are not standard effect size measures, which were presented earlier. There was considerably less evidence that the telephone intervention that consisted of monitoring and feedback only produced better outcomes than standard care. TM did not improve heavy alcohol use outcomes over what was obtained in TAU, and reductions in frequency of any alcohol use relative to TAU were observed at only two of six follow-ups.
Formal analyses of mediation effects have not been conducted, so any comments on potential mechanisms of action in TMC are necessarily speculative at this point. As noted earlier, mediation analyses in our prior study of telephone continuing care indicated that its effects were mediated by initial increases in self-help involvement, relative to standard care, followed by increases in self-efficacy and commitment to abstinence (Mensinger et al., 2007
). These factors may have at least partially accounted for the positive effect of TMC observed here.
The TMC intervention evaluated in the present study differed in several ways from the earlier telephone intervention. Specifically, TMC included the progress assessment and feedback process, and the results of the assessment were used to structure the rest of the session. The process of assessing current status, providing feedback, and utilizing the data to focus the content of the session is used in a number of effective behavioral treatments for substance use disorders, including Motivational Enhancement Therapy (MET) (Miller, Zweben, DiClemente, & Rychtarik, 1995
). In addition, the extended contact and support provided during the individual TMC sessions with counselors over as long as 18 months can be seen as examples of “general factors” that appear to account for much of the benefit of behavioral therapies (Morgenstern & McKay, 2007
; Wampold, 2001
The benefits of TMC appeared to be stronger between months 10 and 15 of the follow-up, with deterioration of effects over the final 3 months. It is possible that the smaller effects in the final 3 months were due to the fact that most participants in TMC were no longer receiving the intervention in the last six months of the follow-up. However, the data in – suggest that the reduction in effects was due to improvements in the TAU condition, not to deterioration in TMC. The follow-up rate in TAU was not lower than that in the other two conditions, so the improvement in TAU is not an artifact created by differential study dropout. Rather, it could reflect the cycling between periods of relatively light use and heavy use observed in similar populations over periods of several years (Dennis & Scott, 2007
) as well as regression to the mean.
The strong performance of TMC relative to standard care was particularly impressive given that participants in all three conditions averaged 36 IOP and OP treatment sessions over the first six months of the follow-up. This dose of treatment exceeds what most patients receive in publicly funded outpatient programs (SAMHSA, 2008
). Alcohol use in participants who received standard care only began to increase after either the three or the six month follow-up, depending on the outcome measure, whereas good alcohol use outcomes were sustained for 18 months in participants who received the TMC intervention. This suggests that even patients who receive a considerable amount of more intensive treatment initially can benefit from an extended telephone-based continuing care intervention.
Although the results consistently indicated that TMC was superior to standard care whereas TM was generally not, there was little evidence that TMC produced significantly better outcomes than TM. TMC did produce fewer days of alcohol use and fewer days of heavy alcohol use than TM during months 4–6 of the follow-up, and there was also a main effect trend favoring TMC over TM on the categorical measure of any heavy drinking (p= .06, OR=1.69). However, other differences between TMC and TM were small and did not approach statistical significance. It is possible that larger sample sizes are needed to find further evidence of reliable differences between TMC and TM.
In contrast to what was observed with the alcohol use outcomes, the continuing care conditions did not produce better cocaine use outcomes than standard care, as indicated by urine test results. These results therefore do not replicate our prior study, in which telephone continuing care produced lower rates of cocaine positive urines during follow-up than standard care (McKay et al., 2005
). The lack of better results with cocaine use may have been due to a number of factors, including the study’s focus on alcohol use and the limitations in the implementation of the telephone conditions, which are discussed below. In addition, the follow-up rates for the cocaine urine toxicology tests were lower than those for the self-report data, which may have affected the results of the analyses.
The study had a number of strengths, including documented adherence to the treatment manuals and clear differences between the two continuing care interventions (Carroll et al., 2000
), availability of some data to corroborate participant self-reports, six outcome assessments over an 18 month period, and a good follow-up rate. At the same time, the study had several limitations, which we discuss briefly here.
The two telephone continuing care interventions were designed to increase sustained treatment participation by providing a relatively low burden, “user friendly” approach to continuing care. Given these goals, the rates of continuing care participation we obtained in the study were somewhat disappointing. About 25% of the participants who were eligible for the interventions never initiated participation in them at any point in the 18 month window. In those who did initiate participation, the average number of sessions received was about 10 out of 36 possible. On the other hand, 38% of those who initiated participation in the protocol had at least one continuing care session in months 13–18. Therefore, significant numbers of participants continued active participation in the protocol into the second year, even if their contacts were at a lower frequency than was intended. It is notable that the TMC intervention achieved such good alcohol use outcomes relative to standard care, given the relatively small numbers of sessions delivered over the 18 month duration of the intervention.
Because the study was an evaluation of continuing care interventions, we only included those IOP participants who attended treatment regularly for three weeks. The study therefore followed a fairly traditional model of substance use disorder treatment in which continuing care is offered only to those patients who graduate from, or at least complete a significant part of, a more intensive, initial level of care. However, it actually might be more effective to enroll all patients who enter treatment into a continuing care protocol, because those individuals who drop out of treatment early may be the ones who are most in need of disease management. In this study, for example, about 27% of those screened dropped out of IOP prior to achieving the three week retention criterion for entrance into the study. It is possible that some of these early dropouts would have been open to receiving treatment via the telephone, and that the calls could have been used to provide support and encouragement for re-entry into clinic-based treatment.
Overall, only about 25% of participants screened for the study were ultimately enrolled in it. This raises questions about how representative the study sample was of typical patients in publicly funded IOPs. Unfortunately, data are not available to compare patients who were excluded from the study with those who were enrolled on factors other than those that were evaluated during the screening.
Another limitation was the lack of more complete data to corroborate the participants’ self-reports of alcohol use. Although the data that were available suggested that rates of patient underreporting of alcohol use were relatively low (around 16%), data from collaterals was available for only 32% of the participants who provided data at the 12 month follow-up. Given that participants with more intact social networks were more likely to have family members or friends who were able and willing to serve as collaterals, there were questions regarding to what extent the results of the analyses would generalize to the full sample. However, follow-up analyses indicted very little evidence of differences at baseline between participants with and without collaterals, and participants without collaterals did not report less drinking or have fewer cocaine positive urine samples during follow-up than those who did have a collateral. Moreover, a number of reviews have substantiated the validity of self-reports of alcohol use in treatment samples, particularly when the data are collected with calendar methods such as the TLFB in the context of research studies (Babor et al., 2000
The addition of extended telephone-based continuing care produced significantly better alcohol use outcomes than standard care in alcohol dependent patients receiving treatment in publicly funded intensive outpatient programs. The intervention reduced both the incidence and frequency of any alcohol use and heavy alcohol use, relative to standard care, with clinically significant effects still present at 18 months. Conversely, shorter telephone calls that provided monitoring and feedback but no counseling conferred little benefit with regard to frequency of alcohol use and no benefit with regard to incidence or frequency of heavy alcohol use. Neither intervention significantly reduced cocaine use in patients with co-occurring cocaine dependence. Most patients who were offered the intervention initiated participation, and a significant percentage continued with the intervention for 12 months or more.
However, utilization of the interventions was less than optimal, as patients who initiated the protocol received less than a third of the available sessions. Although protocols have been developed that increase participation in continuing care (Lash et al., 2007
; McKay, 2009a
), more work in this area is clearly needed. In related research, we have found that providing similar patients with low level incentives for participation (e.g., $10 gift coupons for each call completed) increases the percentage of patients who initiate the continuing care intervention and greatly increases the percentage of possible calls completed (McKay, Ivey, Lynch, Van Horn, & Oslin, 2009
It is also important to determine the costs and economic impact of the two telephone interventions. A key question is whether the improvements in alcohol use outcomes generate sufficient cost savings to pay for a significant portion of the added costs of the interventions. Future analyses will investigate the cost-effectiveness and cost-benefit of the two telephone interventions relative to standard care.