Table 2.
Treatment delivery and follow-up features of cohort studies on mortality risk in people with opioid dependence during and after opioid substitution treatment*
| Study | No of cohort participants† | Average OST dose (mg/day) | Inpatient induction (%) | OST provider | Follow-up period | Average follow-up (years)‡ | Loss to follow-up (%)§ | Mortality outcome | Quality score¶ |
|---|---|---|---|---|---|---|---|---|---|
| Methadone | |||||||||
| Gearing, 197424 | 3000 | 100 | 17.6 | Specialist | 1965-72 | 5.2 | 4.0 | All causes, overdose | 9 |
| Cushman, 197725 | 547 | 100 | NA | Specialist | 1966-75 | 3.6 | 23.2 | All causes, overdose | 6 |
| Grönbladh, 199026 | 166 | 75 | 100.0 | Specialist | 1967-87 | 11.0 | 0.0 | All causes, overdose | 4 |
| Caplehorn, 1994,27 199628 | 305 | 116 | 32.3 | Specialist | 1970-90 | 13.9 | 14.4 | All causes,27 overdose28 | 6 |
| Fugelstad, 199529 | 135 | NA | 100.0 | Specialist | 1986-90 | 2.1 | 0.0 | All causes** | 6 |
| Fugelstad, 199830 | 56 | 80 | 100.0 | Specialist | 1986-93 | 4.2 | 0.0 | All causes** | 6 |
| Buster, 20027 | 5200 | 48 | 0.0 | Mixed | 1986-98 | 5.7 | 0.0 | Overdose | 8 |
| Scherbaum, 200231 | 244 | 47 | 0.0 | Specialist | 1988-96 | 5.3 | 15.6 | All causes, overdose | 7 |
| Davoli, 200732 | 5276 | NA | 0.0 | Specialist | 1998-2001 | 1.3 | 3.7 | Overdose | 11 |
| Fugelstad, 200733 | 679 | NA | 100.0 | Specialist | 1988-2000 | 6.9 | 6.2 | All causes** | 3 |
| Clausen, 200834 | 3229 | 112 | 0.0 | Mixed | 1997-2003 | 2.4 | 0.0 | All causes, overdose | 7 |
| Degenhardt, 20096 | 31 846 | 70 | 0.0 | Mixed | 1985-2000†† | 6.8 | 0.0 | All causes‡‡ | 12 |
| Cornish, 20108 | 4894 | 50 | 0.0 | GP | 1990-2005 | 1.9 | 17.5 | All causes | 9 |
| Peles, 201035 | 613 | 113 | 0.0 | Specialist | 1993-2008 | 7.7 | 0.8 | All causes, overdose | 9 |
| Evans, 20159 | 32 322 | NA | 0.0 | Specialist | 2006-10 | 2.3 | 5.0 | All causes‡‡ | 12 |
| Kimber, 201510 | 26 064 | 70 | 0.0 | Mixed | 2001-10 | 5.3 | 0.0 | All causes, overdose | 13 |
| Nosyk, 201536 | 1326 | NA | 0.0 | GP | 1996-2010 | 4.2 | 7.9 | All causes‡‡ | 13 |
| Cousins, 201637 | 6983 | 72 | 0.0 | GP | 2004-10 | 4.1 | 2.0 | All causes, overdose | 12 |
| Buprenorphine | |||||||||
| Cornish, 20108 | 1373 | 10 | 0.0 | GP | 1990-2005 | 1.1 | 10.3 | All causes | 9 |
| Reece, 201038 | 2518 | NA | 0.0 | GP | 2000-07 | 3.2 | 1.2 | All causes** | 5 |
| Kimber, 201510 | 11 940 | 12 | 0.0 | Mixed | 2001-10 | 4.5 | 0.0 | All causes, overdose | 13 |
NA=not available; OST=opioid substitution treatment.
*Opioid substitution treatment with either methadone or buprenorphine, except for Clausen et al34 in which about 93% of participants used methadone and only 7% used buprenorphine during study period.
†Participants receiving opioid substitution treatment at least once during study period. Untreated participants and those receiving other types of treatment for opioid dependence (methadone detoxification, opioid antagonist therapy, therapeutic community) excluded from meta-analysis.
‡Average follow-up from start of opioid substitution treatment combining subsequent periods in and out of treatment.
§Percentage loss to follow-up before end of study period or death. If not otherwise specified, complete case ascertainment assumed for studies based on population mortality registries.
¶Quality assessment score ranging from 0 (lowest quality) to 16 (highest quality).
**Overdose mortality reported but not included in meta-analysis as there were no overdose deaths while participants were in opioid substitution treatment.
††Follow-up restricted to 1985-2000 as subsequent 2001-06 follow-up period overlapped with Kimber et al.10
‡‡Overdose mortality reported only for combined treatments or included untreated participants and hence not included in meta-analysis.