This study demonstrates that selected patients from a socioeconomically disadvantaged population of persons receiving long-term methadone treatment remained clinically stable and engaged in treatment in a far less intensive setting than traditional methadone maintenance.
Our MMM participants represent a distinct sample with respect to the general MMTP patient population from which they were drawn. MMM participants’ older age likely reflects their greater number of years receiving methadone maintenance treatment. Higher proportions of both men and Whites in our MMM sample may be due to the original admission requirement of employment, reflecting socioeconomic forces at play in the Bronx as in all U.S. cities. Alternatively, selection bias by MMTP staff may have contributed to observed demographic differences.
Methadone is most effective at relieving craving for opioids when properly dosed, often in the range of 80 to 120 mg daily (Dole & Nyswander 1965
; Donny, Brasser, Bigelow, Stitzer, & Walsh, 2005
; Faggiano, Vigna-Taglianti, Versino, & Lemma, 2003
; Strain, Bigelow, Liebson, & Stitzer, 1999
). It is interesting to note that the mean dose among all patients enrolled for more than 6 months in the traditional MMTPs was within this range, whereas the mean dose among MMM patients was significantly lower. Furthermore, methadone dose increased over the course of MMM treatment for 26% of the participants, suggesting that some patients may not have been optimally dosed prior to MMM entry. It is possible that some patients enrolled in MMM might have been reluctant to report symptoms of craving or withdrawal when they had been enrolled in the traditional MMTP, perhaps wishing to avoid appearing clinically “unstable.” In the MMM setting, patients may have felt more free to acknowledge and discuss such symptoms, resulting in dose increases. Enhanced patient understanding of the relative benefits of proper methadone dosing may have reflected the integral role the clinical pharmacist plays in our MMM program.
The relatively low rate of HIV infection among MMM participants may reflect the demonstrated protective effect of methadone maintenance against acquiring HIV infection by needle use (Novick et al., 1990
). It is also possible that patients with HIV infection were less likely to meet the original MMM eligibility requirement of employment. The high rate of hepatitis C infection among MMM participants is consistent with ready transmission of this virus early in the course of injection drug use (Garfein, Vlahov, Galai, Doherty, & Nelson, 1996
), resulting in injectors being infected with HCV before first entering methadone treatment.
MMM programs described in the literature vary considerably with respect to treatment setting, populations served, and duration of observation. All demonstrate alternative models for providing methadone maintenance to opioid-dependent persons. The robust treatment retention rate we report after 5 years of operation suggests that the program we describe successfully meets its patients’ needs. The MMM participants in our program are socioeconomically more diverse than those in other MMM programs. Patients’ income levels and categories of employment suggest that the group is composed principally of middle- and working-class persons; only 14% had a college or postgraduate education. The stability of this group is perhaps not surprising given their mean duration of methadone treatment of 18 years. Our program demonstrates that methadone treatment in a low-intensity setting can achieve positive outcomes in diverse patient populations. The high degree of success demonstrated here suggests that eligibility and referrals to this MMM program may have been more restrictive than necessary; however, logistical constraints have limited the number of patients that can be accommodated.
Our study has several limitations. The retrospective design limits data collection to variables recorded in patients’ clinical records. Inaccuracies and omissions in medical charts are possible. Although the low attrition rate suggests a high level of patient satisfaction, we do not have data directly addressing patients’ perceptions of the program. Enrollment criteria were relatively strict; hence, we could not address whether MMM would be equally effective if offered to a broader sample of patients enrolled in traditional MMTPs.
In the United States, only a fraction (approximately 20%) of opioid-dependent individuals receive pharmacotherapy for this chronic condition (Fiellin & O’Connor 2002
). Access to methadone maintenance therapy varies greatly by location, with limited availability of treatment slots resulting in waiting lists in many areas. Providing methadone to selected patients in physicians’ offices and other less regulated settings may be an effective means of expanding access to treatment (Fiellin & O’Connor, 2002
). Scarce addiction treatment resources could be allocated more effectively were it possible for more stable patients to migrate into less intensive opioid pharmacotherapy treatment settings. Buprenorphine, recently approved for out-patient treatment of opioid dependence, will enhance availability of such treatment options (Barnett, Rodgers, & Bloch, 2001
; O’Connor et al., 1996
; O’Connor et al., 1998
). Some stable patients may successfully transition from methadone to buprenorphine therapy (Whitley, Arnsten, & Gourevitch, 2004
); for others, methadone will remain the preferred treatment for their opioid dependence. The two randomized controlled trials to examine MMM (Fiellin et al., 2001
; King et al., 2002
) drew patients from populations similar to that treated in our program. The favorable outcomes they report complement our findings from a nonresearch setting, lending additional support to careful expansion of this model to more diverse populations with varying levels of clinical stability. Further research is needed to define long-term outcomes associated with more inclusive eligibility criteria for MMM and to assess the effectiveness of integrated and stand-alone MMM programs. More widespread adoption of the MMM model for eligible patients in traditional MMTPs is an important strategy for ensuring access to treatment and diminishing stigma for opioid-dependent persons.