People who use illicit opiates such as heroin or opioid drugs can develop opioid depencence. Opioid maintenance treatment (OMT) with buprenorphine or methadone is a comprehensive treatment option for opioid dependence. The current evidence base shows that OMT patients stay in treatment longer and use less heroin than patients who receive no drug therapies. We cannot rule out that new studies could have an impact on this conclusion.
The objective of this systematic review was to update the evidence base for effects of OMT compared to no drug therapy.
- We did not identify any recent relevant systematic reviews or randomised controlled trials.
- We found and included five relevant cohort studies with 34,651 participants in total.
- The results indicated that:
- OMT patients had higher retention rates and lower overdose mortality than patients with no drug therapies.
- There were no differences between the two treatment options with regard to illicit opioid use and suicide attempts.
Our confidence in these results is very low. We are uncertain whether there are any differences in treatment effects between OMT and no drug therapy, and in what direction any differences would point.
The findings of this systematic review cannot add to the current evidence base for effects of OMT versus no drug therapies.
Opioid maintenance treatment (OMT) is an intervention for people with opioid dependence (ICD-10 code F11.2) from illegal opiate use or licit/illicit use of opioid drugs. Long-acting buprenorphine and methadone are main components of OMT. In 2018, 7,762 persons received OMT in Norway. Patients were on average 46 years-of‑age, and 71 per cent were male.
No drug therapy may consist of a variety of psychological or psychosocial measures, provided as in-patient or out-patient treatment. The overall aim of opioid dependence treatment is to reduce patients’ drug use, to mitigate associated health problems, and to help them access medical and social services, including residence, education and work.
According to Norwegian legislation, OMT should generally not be the first choice of treatment for opioid dependence. In contrast to Norway, health authorities in countries like Canada, Sweden, the United Kingdom and the United States of America do recommend OMT as first-line treatment. These recommendations are based on research syntheses that show well-documented effects of OMT compared to no drug therapy. OMT patients stay in treatment longer and use less heroin and other non-prescribed opioids than patients in no drug therapies. We cannot rule out that new studies could have an impact on these conclusions.
The objective of this systematic review was to update the current evidence base on the effects of OMT versus no drug therapy for opioid dependence.
We developed search strategies for systematic reviews, randomized controlled trials (RCTs) and observational studies. Firstly, we searched the following databases in September 2019 for systematic reviews published in 2014 or later: Cochrane Database of Systematic Reviews, Epistemonikos, MEDLINE (Ovid), Embase (Ovid) and PsycINFO (Ovid). We were unable to obtain any relevant systematic reviews and extended our searches to include RCTs published in 2005 or later, in the Cochrane Controlled Register of Trials (CENTRAL), Embase, MEDLINE and PsycINFO. We did not identify any relevant RCTs. We then searched in November 2019 for observational studies published within the same period and in the same databases as for RCTs.
We included studies that compared the effects of OMT with buprenorphine or methadone and no drug therapies in patients diagnosed with opioid dependence. Eligible studies included one or several of the following outcomes: retention, opioid use, mortality, quality of life, and side effects/adverse events.
We screened all results based on titles and abstracts, then read the full texts of all studies that appeared to meet our inclusion criteria. From the final selection of studies that met our criteria, we extracted data and carried out risk of bias assessments. At least two team members carried out each of these steps independently.
We pooled the effect estimates for each outcome using meta-analyses, if possible. Two authors independently graded our confidence in the effect estimates using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) tool.
Our literature searches for systematic reviews, RCTs and observational studies returned 2,444, 1,694 and 5,870 unique search hits, respectively. Of these, only five observational studies met our selection criteria.
The five included studies were cohort studies with control groups (four prospective and one retrospective study) conducted between 1998 and 2012 in Australia, India, Iran, Italy and the United Kingdom, respectively. In total, the studies included 34,651 persons with opioid dependence. OMT drugs were either buprenorphine or methadone (two studies), only methadone (one study) or only buprenorphine (one study). No drug therapies included counselling services and cognitive-behavioral therapy, administered either individually or in groups in outpatient or inpatient settings. We assessed the overall methodological quality of all five cohort studies as low.
The overall effect estimates indicated that patients in OMT (72 %) remained longer in treatment than patients who received no drug therapy (57 %). OMT patients had lower overdose mortality (3 % vs 15 %). There was no difference between the treatment groups in non-prescribed opioid use (42 % vs 35 %). Patients in both groups reported having used non-prescribed opioids in 7 out of the last 28 days. The only adverse event reported was suicide attempts, for which the researchers found no difference between the groups (approximately 1 % of patients in each group had attempted suicide during the last month of treatment). However, we have very low confidence in these results. It is unclear if there is any difference in effect between OMT and no drug therapy, and in what direction any differences would point.
No relevant systematic reviews have been published during the last five years, and no RCTs have been published over the last fifteen years.
The findings from five relatively recent observational studies are too uncertain to add anything to the existing evidence base. The current evidence base appears sufficiently solid to inform treatment recommendations.