Table 2:
Existing evidence for impacts* of opioid agonist treatment with methadone or buprenorphine
| Effect | Level of evidence | Sources | ||
|---|---|---|---|---|
| OAT vs. no treatment in the community | ||||
| Opioid use | ↓ | RR 0.48 (0.41, 0.55) SYNTH | A | 106 |
| Injecting frequency | ↓ | SMD −0.59 (−0.91, −0.26) SYNTH | A | 106 |
| Injecting risk (sharing needles/syringes) | ↓ | RR 0.53 (0.4, 0.7) SYNTH | A | 106 |
| HIV linkage to care and treatment | ↑ | HR 1.87 (1.50, 2.33) | C | 109 |
| HIV treatment adherence | ↑ | OR 2.14 (1.41, 3.26) | C | 109 |
| HIV treatment attrition/discontinuation | ↓ | OR 0.77 (0.63, 0.95) | C | 109 |
| HIV viral suppression | ↑ | OR 1.45 (1.21, 1.73) | C | 109 |
| HIV incidence | ↓ | RR 0.46 (0.32, 0.67) | C | 107 |
| HCV testing | ↑ | OR 1.73 (1.19, 2.51) | C | 169 |
| HCV linkage to care and treatment | ↑ | OR 1.40 (0.90, 2.17) | C | 169 |
| HCV treatment sustained virological response | × | OR 0.75 (0.45, 1.25) | C | 169 |
| HCV incidence | ↓ | RR 0.50 (0.40, 0.63) | C | 108 |
| Skin and soft tissue infections | ? | NE | D | 86 |
| Mental health problems | ↓ | SMD 0.49 (0.35, 0.63) | C | 170 |
| Quality of life (social – WHOQOL-BREF) | ↑ | SMD 0.29 (0.16, 0.42) | C | 170 |
| Criminal activity | ↓ | SMD −0.57 (−1.00, −0.13) | 110 | |
| Contact with the criminal justice system | × | RR 0.75 (0.46, 1.23) | C | 171 |
| Overdose mortality | ↓ | RaRa 0.25 (0.18, 0.36) SYNTH | C | 111 |
| Suicide mortality | ↓ | RaRa 0.48 (0.39, 0.59) | E | 112 |
| Other injury mortality | ↓ | RaRa 0.40 (0.34, 0.46) | E | 112 |
| All-cause mortality | ↓ | RaRa 0.33 (0.28, 0.39) SYNTH | C | 111 |
| OAT vs. no treatment in prison | ||||
| Unsanctioned opioid use | ↓ | NE | B | 172 |
| Injecting frequency | ↓ | NE | B | 172 |
| Injecting risk behaviour | ↓ | NE | B | 172 |
| HIV incidence | ? | NE | B | 172 |
| HCV incidence | ? | NE | B | 172 |
| Prison infractions | ↓ | NE | E | 172 |
| Criminal activity (post-release) | ? | NE | B | 172 |
| Reincarceration | ? | NE | C | 172 |
| OAT engagement (post-release) | ↑ | NE | B | 173,174 |
| HIV treatment adherence (post-release) | NR | |||
| HIV viral suppression (post-release) | NR | |||
| Overdose/suicide/injury mortality (in prison) | ↓ | aHR 0.13 (0.05, 0.35) | E | 175 |
| All-cause mortality (in prison) | ↓ | aHR 0.26 (0.13, 0.50) | E | 175 |
| All-cause mortality (4 weeks post-release) | ↓ | aHR 0.25 (0.14, 0.45) | E | 114,115 |
| Buprenorphine vs. methadone (ref) | ||||
| Retention in treatment | ↓ | RR 0.83 (0.72, 0.95) | A | 117 |
| Mortality during induction (4 weeks) | ↓ | RaRa 0.28 (0.08, 0.95) SYNTH | C | 111,118 |
| Mortality remainder in treatment | ND | RaRa 0.68 (0.44, 1.04) SYNTH | C | 111,118 |
| Mortality following cessation (4 weeks) | ND | RaRa 0.62 (0.16, 2.42) SYNTH | C | 111,118 |
| Neonatal outcomes… | ||||
| …Head circumference | ↑ | RCT WMD 0.91cm (0.14 1.66) | B | 119 |
| …Low birth weight | ↓ | RCT WMD 324g (32, 617) | B | 119 |
| …Preterm birth | ↓ | RR 0.40 (0.18, 0.91) | B | 119 |
For details of the search strategies used please see Appendix J.
Please note that the comparator groups used vary across outcomes; they can include a placebo or active control or an out-of-treatment comparator.
SYNTH – we pooled estimates for this review. NR – no quantification located. NE – no quantitative synthesis reported. ND – no difference between methadone and buprenorphine detected. RR – relative risk. RaRa – rate ratio. RCT – randomised controlled trial. WMD – weighted mean difference. SMD – standardised mean difference. HR – hazard ratio. OR – odds ratio.
Presence or absence of effect
OAT does not appear to have a significant effect upon the outcome
This outcome may be increased by OAT
This outcome is decreased by OAT
Unclear if OAT has an impact on this outcome
Level of evidence
Consistent conclusions across meta-analyses, high quality systematic reviews, or multiple RCTs
Evidence from one or two randomised controlled trials only
High quality systematic reviews of cohort, case-control or cross-sectional studies
Systematic reviews with inconsistent conclusions from authors; OR multiple consistent ecological studies
Cross-sectional association, case series suggesting outcome, single cohort study