Buprenorphine and methadone have similar efficacies in the management of opioid dependence.10
However, most clinical trials enrolled only heroin users, with protocolized treatment provided in rigid research protocols rather than in primary care settings. Flexible buprenorphine dose schedules have been tested in 6 trials (n
=411), with an overall retention rate of 52.7%.11–16
The duration of treatment is predictive of improved patient outcomes; however, none of these studies included an analysis of predictors of retention.3
The current study described our experience with 41 opioid-dependent patients in a primary care clinic treated according to the regulations of the Drug Addiction Treatment Act of 2000. At 24 weeks, 59% of patients remained in treatment. The cohort included active heroin users, persons dependent on oral opioids, and persons transferring care from methadone maintenance treatment programs, most often for convenience or insurance reasons. Our policy dictated that no one was to be discharged for continued drug use during the first 6 months (referrals for counseling increased, as did frequency of clinical visits), and no one was discharged for either behavioral or financial (unable to afford medication) reasons. Our ability to confer with physicians nationally who had more experience with buprenorphine/naloxone provided an important support network during the care of our earliest patients, and underlines the benefits of mentorship.
Most treatment dropout occurred during the first month of care. Indeed, continued opiate use during the first week of buprenorphine/naloxone treatment, as documented by a week 1 urine toxicologic analysis, was predictive of treatment dropout. This early drug use may signal low motivation for treatment or perhaps inadequate dosing, although all patients were receiving at least 12 mg of buprenorphine daily during the first week of care.
Employment, full- or part-time, protected against treatment dropout. Keeping one's job (even if it means temporarily taking time off to attend medical appointments) is likely to be a strong motivation for continuing care. Because many of our patients relied on employer-based health insurance to pay for the buprenorphine/naloxone, continued employment would also seem essential to medication adherence, consistent with previous treatment research.17
No other baseline variables were significantly associated with treatment dropout, but addiction counseling during treatment was protective against dropout and should be strongly encouraged.
Limitations of the study include explicit exclusion of heavy alcohol or cocaine users, patients with uncontrolled psychiatric problems, and those without means to pay for the medication. This situation reflects real-world practice in the United States, where the 30-person limit and lack of universal health insurance create strong incentives to limit access for severely addicted, dual diagnosis, and uninsured patients to office-based buprenorphine programs. The small sample size and observational nature of the study were also limitations.
We conclude that retention rates in a primary care buprenorphine maintenance practice reflects those reported in clinical trials. Abstinence during the first week of treatment and psychosocial counseling are critical to patient retention.