Table 3.
Parameter estimates and data inputs for the hepatitis C model
| Variables | Range | Sources |
|---|---|---|
| Hepatitis C parameters | ||
| Spontaneous clearance | 26% | Micallef et al.32 |
| Duration of acute stage | 12 weeks | Mondelli et al.33 |
| Treatment effectiveness | 95% | Lawitz et al., Poorded et al., Gane et al. 3, 4, 5 |
| Annual transition probabilities | ||
| F0->F1 | 10.4-13.0% | Thein et al.34 In the model, rates are calibrated between bounds to fit the distribution of liver disease and mortality over time. |
| F1->F2 | 7.5-9.6% | |
| F2->F3 | 10.9-13.3% | |
| F3->F4 | 10.4-12.9% | |
| F4->DC | 3.0-9.2% | National Centre in HIV Epidemiology and Clinical Research.35 In the model, rates are calibrated between bounds to fit the distribution of liver disease and mortality over time. |
| F4->HCC | 0.9%-3.8% | |
| DC->HCC | 4.1-9.9% | |
| DC->death | 7.4-20.2% | |
| HCC->death | 54.5-67.6% | |
| F4->DC (post cure) | 74% reduced risk | Nahon et al.,36 hazard ratio = 0.26 (0.17-0.39) post cure. |
| DC->HCC (post cure) | 71% reduced risk | Nahon et al.,36 hazard ratio = 0.29 (0.13-0.43) post cure. |
| DC->death (post cure) | 73% reduced risk | Nahon et al.,36 hazard ratio = 0.27 (0.18-0.42) for overall mortality following cure for patents with cirrhosis. |
| HCC->death (post cure) | 73% reduced risk | |
| Direct costs parameters | ||
| Ab testing | ||
| Cost of test | A$15.65 | MBS item number 69405.18 |
| Staff cost | A$37.60 | General practitioner appointment, MBS item number 23.18 |
| Positivity rate | 4.1% | 4% based on Australian Collaboration for Coordinated Enhanced Sentinel Surveillance (ACCESS) (ACCESS) data.37 Assumed to decrease to 1% by 2030 |
| RNA testing | ||
| Cost of test | A$92.20 | MBS #69499.18 |
| Staff cost | A$37.60 | General practitioner appointment, MBS #23.18 |
| Positivity rate | 40% pre-2016, assumed to decrease linearly to 10% by 2030 in status-quo and elimination scenarios. | Australian Collaboration for Coordinated Enhanced Sentinel Surveillance (ACCESS) (ACCESS) data.37 Sensitivity analysis used to compare if the positivity rate for RNA tests remained at 40% up to 2030, or if it declined to 5% (instead of 10%). |
| Treatment | ||
| Drug cost | 2016-2020: A$13,190 per DAA course 2021-2025: A$12,500 2026-2030: A$5,000 |
For 2016-2020, cost per DAA course was estimated as the total A$1.2 billion divided by 90,980 treatments (70,980 from 2016-2018 and an estimated 20,000 from 2019 to 2020 based on current trends). For 2021-2025, assuming approximate current price is maintained. For 2026-2030, based on 100 times the cost of generics in low and middle-income countries. |
| Staff and other pathology costs | Time varying: A$1,846 per course in 2016 linearly decreasing to A$1,166 per course in 2021 |
In 2016 costs include A$462.10 for screening pathology + 38%*A$422.90 non-specialist care human resources + 62%*A$1615.90 specialist care human resources + A$221.24 pharmacy costs.24 Changes over time are based on the percentage of treatments delivered in non-specialist care increasing from 38% in 2016 to 63% in 2018,13 and continuing to increase linearly up to 95% in 2021 (maintained from 2021 onwards). |
| Disease management | ||
| F0-2 | A$447 | Scott et al..25 Average costs per person per year, including appointment costs and recommended tests. |
| F3 | A$691 | |
| F4 | A$935 | |
| DC | A$15,202 | |
| HCC | A$10,760 | |
| Discounting | 3.5% per annum | Applied to direct costs, productivity losses and quality-adjusted life years. |
| Health utilities | ||
| Acute infection | 0.751 (0.718-0.785) | Saeed et al. systematic review and meta analysis38 |
| F0-F2 | 0.751 (0.718-0.785) | |
| F3 | 0.751 (0.718-0.785) | |
| F4 | 0.671 (0.630-0.713) | |
| DC | 0.602 (0.551-0.653) | |
| HCC | 0.662 (0.595-0.730) | |
| Population and epidemiological parameters | ||
| 15-64 year old population size | 15,867,004 at start of 2016 | Australian Bureau of Statistics.39 |
| PWID population size | 2010: 75,830 2011: 76,140 2012: 76,420 2013: 76,670 2014: 76,890 2015: 77,090 2016: 77,270 |
Kwon et al.40 |
| Additional injecting-related mortality | 0.0235 per year | Mathers et al.41 |
| Hepatitis C antibody prevalence | ||
| PWID | 2015: 51% | Heard et al.42 |
| General population | 1.2% at start of 2016 | Hepatitis C Mapping Project National Report.43 |
| Total people with chronic hepatitis C (RNA+) | 2015: 188,690* 2016: 160,280* 2017: 143,580 2018: 129,640 |
Kirby Institute12 *Personal communication |
| Hepatitis C-related mortality | 2009: 460 2015: 740 2018: 410 |
|
| Incidence | 4,126 new infections in 2015 | Palmer et al.22 |
| Productivity loss parameters | ||
| Employment rate | ||
| General Population | 65% | Participation in workforce, averaged over 2015-2019, Australian Bureau of Statistics.39 |
| PWID | 14% | Reported employment status averaged over 2015-2019, Illicit Drug Reporting System (IDRS).29 |
| Lost productivity attributable to hepatitis C | ||
| Absenteeism | 1.85% | Dibonaventura et al.27 US study (Australian study not available). People with hepatitis C had 4.88% absenteeism versus 3.03% for people without hepatitis C. |
| Presenteeism | 3.19% | Dibonaventura et al.27 US study. People with hepatitis C had 16.69% presenteeism versus 13.50% for people without hepatitis C. |
| Additional productivity losses for people with cirrhosis | ||
| Absenteeism | 2.79 times | Younossi et al.28 European study (Australian study not available). |
| Presenteeism | 1.54 times | |
| Relative reduction in absenteeism following hepatitis C cure | ||
| Cirrhotic | 44% | Younossi et al.28 |
| Non-cirrhotic | 0% | |
| Relative reduction in presenteeism following hepatitis C cure | ||
| Cirrhotic | 11% | Younossi et al.28 |
| Non-cirrhotic | 20% | |
| Per capita gross domestic product | A$53,663 | Organisation for Economic Co-operation and Development (OECD) data for Australia.44 |
| Percentage of hepatitis C-related deaths occurring at different age brackets | WHO cause-specific disease burden estimates, 2016.45 | |
| 15-29 years | 0.2% | |
| 30-49 years | 7.5% | |
| 50-59 years | 16.4% | |
| 60+ years | 75.8% | |