Table 2 Summary of included studies
First author last name, year of publication | N cases/controls | % Male | Mean age (SD) | Ethnicity | Type of MOUD | Study design | Relevant outcomes measured |
|---|---|---|---|---|---|---|---|
Cox, 2020 [20] | 4049 | 63.45% | NA | African American = 1130, European = 2919 | Opioid Substitution Treatment (unspecified) | Prospective | Opioid cessation - USA sample: defined as self-reported abstinence from illicit opioids for > 1 year (ceased) or < 6 months (not ceased) before the interview date - Australia sample: self-reported last use of an opioid was at least one year before the age at the interview (ceased) or the age of last use of an opioid was the same as the age at the interview (not ceased) |
Nelson, 2016 [21] | 1167 cases, 161 controls | 60.1% | 36.9 (8.4) | European | Methadone or Buprenorphine Opioid Replacement Therapy (cases) | Case–control | Continued opioid use (ODE – self-reported daily heroin injection while on treatment) |
Smith, 2017 [22] | 1410 | 59.72% | AA: Males: 45.6 (8.4); Females: 43.0 (7.2) EA: Males: 37.2 (10.1); Females: 37.5 (9.8) | African American = 383, European American = 1027 | Methadone | Prospective | Usual daily methadone dose (self-reported) (mg) |
Wang, 2018 [23] | 344 | 81.68% | 38.17 (7.69) | Han Chinese (Taiwan) | Methadone | Cross-sectional | Methadone dose (obtained from participant medical record) (mg) |
Yang, 2016 [24] | 344 | 81.68% | Males: 39.31 (7.66); Females: 33.03 (5.45) | Han Chinese (Taiwan) | Methadone | Prospective | Plasma concentrations of methadone and its metabolite EDDP R- and S-enantiomers (measured using high-performance liquid chromatography) (ng/ml/mg/dose) |