Table 1.
Summary of main prior parameter ranges and calibration data (most recent estimates)
| Parameter | Range | Source |
|---|---|---|
| Calibration data | ||
| PWID population size | 255,702–474,887 | [47] |
| HIV prevalence among PWID | 22.1–22.2% | 2017 APH IBBA |
| HCV antibody prevalence among PWID | 61.6–63.9% | 2017 APH IBBA |
| Proportion of PWID in contact with NGOs | 37.6–39.3% | 2017 APH IBBA |
| Odds ratio of being in contact with NGO if HIV positive (vs. HIV negative) | 2.00–2.23 | 2013/15/17 APH IBBA |
| Odds ratio of being in contact with NGO if <25 years old (vs. >=25 years old) | 0.42–0.48 | 2013/15/17 APH IBBA |
| Proportion of PWID currently on OAT | 4.4–5.3% | 2017 APH IBBA |
| Odds ratio of being on OAT if in contact with NGOs | 6.75–9.47 | 2015/17 APH IBBA |
| Proportion of HIV‐positive PWID on ART | 35.3–47.2% | 2017 APH IBBA |
| Odds ratio of being on ART if in contact with NGOs (vs. not in contact) | 2.72–3.39 | 2015/17 APH IBBA |
| Parameters | ||
| Average duration of injecting (years) | 7.5–50 | 2011/13/15/17 APH IBBAs |
| Non‐disease‐related death rate among PWID (per 100 py) | 1.99–7.14 | [48] |
| Average length of each incarceration episode (months) | 13–15 |
2011/13/15/17 APH IBBAs; EXMAT |
| Rate of loss to care from ART (per 100 py) | 10.9–15.8 | CPH HIV treatment database |
| Proportion of PWID on ART who are virally supressed | 49–77% | [49] |
| Relative injecting risk (frequency of injecting with used equipment) if an NGO client versus not | 0.55–0.97 | 2011/13/15/17 APH IBBAs |
| OR of using a condom if NGO client versus not | 1.24–1.43 | 2011/13/15/17 APH IBBAs |
| Rate of loss to care from OAT if on OAT for <2 years (per year) | 0.45–0.50 | Estimated using data from [50] |
| Rate of loss to care from OAT if on OAT for >=2 years (per year) | 0.1–0.15 | |
| Relative risk of starting ART if on OAT versus not on OAT | 1.50–2.33 | [13] |
| Odds ratio of being virally supressed among those on ART if on OAT versus not on OAT | 1.21–1.73 | [13] |
| Relative risk of ART loss to care if on OAT versus not on OAT | 0.63–0.95 | [13] |
| Relative risk of HCV transmission through injecting if on OAT versus not on OAT | 0.40–0.63 | [15] |
| Relative risk of HIV transmission through injecting if on OAT versus not on OAT | 0.32–0.67 | [16] |
| Relative risk of incarceration if on OAT versus not on OAT | 0.58–0.90 | [14, 51] |
| Relative risk of non‐disease‐related mortality if on OAT versus not on OAT | 0.28–0.39 | [36] |
| Relative risk of non‐disease‐related mortality in first 4 weeks after starting OAT versus rest of time on OAT | 0.94–4.10 | [12] |
| Relative risk of non‐disease‐related mortality in first 4 weeks after leaving OAT versus rest of time off OAT | 1.51–3.74 | [12] |
Note: Full details are in the Supplementary Materials.
Abbreviations: ART, antiretroviral therapy; NGOs, non‐governmental organizations; OAT, opioid agonist treatment; PWID, people who inject drugs.