Although there are a growing number of studies about the adoption of buprenorphine, this is the first study to examine the pattern of adoption, discontinuation, and sustainability of this pharmacotherapy over a 2-year period. Previous studies used either a cross-sectional design (Ducharme &Abraham, 2008
; Koch et al., 2006
) or a time frame of a year or less without controlling for baseline adoption (Ducharme et al., 2007
; Knudsen et al., 2006
). This examination of buprenorphine adoption over a 2-year period within the CTN revealed accelerating adoption over time. The percentage of CTPs using buprenorphine doubled over this 2-year period. Among CTPs using buprenorphine at the 24-month follow-up, about one third of these CTPs were early adopters, and two thirds were later adopters. This increase in adoption is consistent with Rogers (2003)
concept of the S-shaped curve of innovation adoption. This type of pattern was similar to a previous study of naltrexone adoption in private sector programs (Oser & Roman, 2007
This study points to an ongoing benefit of research involvement in promoting the transfer of buprenorphine into practice. The advantage of involvement in a buprenorphine protocol persisted at the 2-year follow-up, even after controlling for whether CTPs had already adopted buprenorphine as of the baseline interview. This association is consistent with the argument made by Rogers (2003)
about the importance of trialability of innovations, in terms of whether organizations can gain experience with an innovation on a limited basis. Clinical trials offer such experience, where an organization does not have to commit to long-term adoption but can try an innovation for a limited period with a specified number of clients. Consistent with the broader literature on research networks (Fennell & Warnecke, 1988
; Laliberte, Fennell, & Papandonatos, 2005
), this finding suggests that the value of conducting clinical research in real-world settings extends beyond the substantive findings of clinical trials. In the case of buprenorphine, such research has had a measurable impact on adoption behavior. However, it should also be noted that the selection of CTPs for protocol involvement was not a random process. There was some variability in the criteria used to select CTPs across the different buprenorphine protocols, but CTPs did need to demonstrate the capacity to serve as research sites.
Although protocol involvement offered an advantage in terms of sustainability across the 2-year period, much of the later adoption over the 24-month follow-up period occurred within the CTPs that reported no experience with a CTN buprenorphine protocol. This pattern is consistent with Rogers’ (2003)
concept of “observability,” in which innovations are more likely to be adopted when the results of their use can be seen by others. The use of buprenorphine in several trials has meant that the clinical outcomes associated with its use has been a topic of significant discourse within the CTN, as findings have been presented to its members and disseminated via publications and NIDA’s Blending Products (http://www.nattc.org/aboutUs/blendingInitiative/products2.htm
These panel longitudinal data also revealed discontinuation by a small subset of CTPs, which had reported using buprenorphine at the baseline interview. There have been no previous studies of buprenorphine that have measured the phenomenon of discontinuation. On the one hand, the number of “discontinuers” was relatively low in terms of the overall sample. However, these discontinuers represent about one third of the 36 CTPs that had adopted buprenorphine at baseline. About half of the CTPs that discontinued using buprenorphine by the follow-up interview had been in a buprenorphine protocol at baseline. It may be that use reported at baseline represented protocol involvement rather than an organizational decision to use buprenorphine as part of its treatment as usual. The number of discontinuers was too low to estimate statistical models to understand organizational characteristics associated with this pattern, but it does suggest that future research might consider why some treatment programs initially adopt a medication and then discontinue its use.
It is important to note that the CTPs within the CTN are not representative of the American treatment system as a whole (Ducharme et al., 2007
; Ducharme Roman, in press; McCarty et al., 2008
). However, the organizational characteristics associated with buprenorphine adoption at the 24-month follow-up interview are consistent with prior studies. The greater likelihood of adoption in for-profit programs and those facilities with inpatient detoxification services has been reported in studies using data from the National Survey of Substance Abuse Treatment Services (N-SSATS; Ducharme & Abraham, 2008
; Koch et al., 2006
) and nationally representative samples of the private and public treatment sectors (Knudsen et al., 2006
). The greater adoption by for-profit programs may be reflective of environmental changes related to payment sources for buprenorphine services, such as private insurance coverage and the addition of buprenorphine on some state Medicaid formularies (Ducharme Abraham, 2008
). We were unable to examine changes in the funding environment, but this represents an important avenue for future research.
Access to physicians is a necessary condition for the adoption of pharmacotherapies. Nearly three quarters of CTPs had at least one physician employed or on contract, which was an important variable in baseline adoption of buprenorphine. In a supplemental analysis (not shown), we examined the small subset of CTPs that did not have physician resources at the baseline interview to see whether gaining access to physicians by the follow-up interview was associated with buprenorphine adoption. Although we did not have enough cases to estimate multivariate models, there was a significant bivariate association between gaining access to a physician and buprenorphine adoption at follow-up. Although some of the organizational characteristics are structural and less amenable to change, system-level efforts to improve access to physicians through employment or contracts may promote the transfer of pharmacotherapies into routine practice.
One interesting finding is related to whether programs with methadone services are more likely to adopt buprenorphine. These data from programs affiliated with the CTN indicated that at baseline, the odds of buprenorphine adoption were significantly greater in programs offering methadone. Similar results were reported by Koch et al. (2006)
using the 2003 N-SSATS data, which roughly parallel the time frame of our baseline data collection. However, we found that at the 24-month follow-up interview, the availability of methadone was no longer associated with buprenorphine adoption.
Several limitations about this research should be noted. The participating CTPs do not constitute a random sample, so it is unclear the extent to which these findings would generalize to other organizations. However, several of the findings are consistent with other national studies, suggesting that despite differences in CTP’s organizational characteristics relative to the national system, the patterns of explanatory relationships show signs of consistency. An additional limitation was the relatively small number of organizational characteristics considered as predictors. In part, there was a need to restrict the number of predictors due to the limited number of occurrences of the dependent variable (Cepeda, Boston, Farrar, Strom, 2003
; Peduzzi, Concato, Kemper, Holford, Feinstein, 1996
). Additional variables would likely explain portions of the variance in buprenorphine adoption. Another limitation is the reliance on self-report data for all measures. It is possible that administrators may err in their descriptions of their programs, although our reliance on self-reports is similar to the federal N-SSATS methodology. Finally, it should be noted that this research does not address the issue of implementation of buprenorphine, particularly in terms of how routinely it is used by CTPs and whether patient characteristics are associated with receiving this medication. These are important directions for future research.
This research contributes to the growing body of literature about the adoption of buprenorphine in CTPs by considering both adoption and discontinuation over a 2-year period. Data from programs affiliated with the National Drug Abuse Treatment CTN suggest that the availability of buprenorphine expanded over this period, although a small percentage of programs discontinued using this medication. These findings point to the dynamic nature of service delivery within treatment programs and the continued need for longitudinal research on how and why programs change over time.