Secondary analyses of counts of ambulance and ED contacts, mean and SD, unadjusted (IRR) and adjusted incidence rate ratios (AIRR) and 95% CIs comparing use of emergency healthcare postrelease according to opioid agonist treatment (OAT) use in the first 3 months postrelease among a cohort of men who regularly injected drugs prior to imprisonment stratified by postrelease OAT exposure and frequency of opioid use
| Outcome | Count of contacts | Mean of contacts (SD) | IRR (95% CI) | P value | AIRR* (95% CI) | P value |
| Any postrelease opioid† use (n=203) | ||||||
| 1. Ambulance contacts | 61 | 0.30 (0.80) | ||||
| OAT: none | 35 | 0.37 (0.79) | 1.00 | 1.00 | ||
| OAT: partial | 11 | 0.32 (0.88) | 0.88 (0.39 to 1.96) | 0.751 | 0.57 (0.21 to 1.49) | 0.248 |
| OAT: retained | 15 | 0.20 (0.77) | 0.60 (0.30 to 1.19) | 0.146 | 0.34 (0.14 to 0.83) | 0.018 |
| 2. ED contacts | 104 | 0.51 (1.19) | ||||
| OAT: none | 62 | 0.66 (1.25) | 1.00 | 1.00 | ||
| OAT: partial | 14 | 0.41 (1.08) | 0.67 (0.33 to 1.37) | 0.273 | 0.45 (0.19 to 1.09) | 0.078 |
| OAT: retained | 28 | 0.37 (1.15) | 0.62 (0.36 to 1.08) | 0.092 | 0.37 (0.18 to 0.76) | 0.006 |
| 15 or more days of opioid† use in the 30 days before follow-up (n=139) | ||||||
| 1. Ambulance contacts | 44 | 0.32 (0.84) | ||||
| OAT: none | 18 | 0.50 (0.85) | 1.00 | 1.00 | ||
| OAT: partial | 11 | 0.39 (0.96) | 0.79 (0.32 to 1.99) | 0.621 | 0.81 (0.26 to 2.58) | 0.724 |
| OAT: retained | 15 | 0.20 (0.77) | 0.44 (0.20 to 0.98) | 0.045 | 0.34 (0.12 to 0.98) | 0.045 |
| 2. ED contacts‡ | 65 | 0.47 (1.13) | ||||
| OAT: none | 24 | 0.67 (1.07) | 1.00 | 1.00 | ||
| OAT: partial | 13 | 0.46 (1.17) | 0.73 (0.31 to 1.72) | 0.468 | 0.56 (0.19 to 1.67) | 0.300 |
| OAT: retained | 28 | 0.37 (1.15) | 0.59 (0.29 to 1.17) | 0.128 | 0.39 (0.16 to 0.92) | 0.032 |
| 25 or more days of opioid† use in the month before follow-up (n=129) | ||||||
| 1. Ambulance contacts | 39 | 0.30 (0.84) | ||||
| OAT: none | 11 | 0.44 (1.00) | 1.00 | 1.00 | ||
| OAT: partial | 11 | 0.44 (1.00) | 1.00 (0.37 to 2.68) | 0.995 | 1.34 (0.39 to 4.69) | 0.642 |
| OAT: retained | 15 | 0.20 (0.77) | 0.48 (0.20 to 1.16) | 0.102 | 0.41 (0.13 to 1.30) | 0.129 |
| 2. ED contacts‡ | 60 | 0.47 (1.17) | ||||
| OAT: none | 20 | 0.69 (1.17) | 1.00 | 1.00 | ||
| OAT: partial | 12 | 0.48 (1.23) | 0.73 (0.29 to 1.82) | 0.499 | 0.59 (0.18 to 1.93) | 0.383 |
| OAT: retained | 28 | 0.37 (1.15) | 0.56 (0.27 to 1.17) | 0.122 | 0.38 (0.15 to 0.95) | 0.039 |
*Adjusted for age at baseline, Aboriginal and/or Torres Strait Islander, historical psychiatric admission, self-reported fair or poor health, times moved accommodation, count of general practitioner consultations, psychiatric well-being (GHQ-12 score) and any IDU since baseline interview.
†Opioids include heroin as well as licit and illicit pharmaceutical opioids including methadone, buprenorphine, morphine and oxycodone.
‡Aboriginal and/or Torres Strait Islander omitted from analysis as no Aboriginal and/or Torres Strait Islander participant attended ED and used opioids at least 15 days in the month before follow-up interview.
GHQ-12, 12-item General Health Questionnaire; IDU, injecting drug use.