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Table 1 Model parameters and Sources

From: What is needed to achieve HCV microelimination among HIV-infected populations in Andalusia, Spain: a modeling analysis

Calibration Data
Calibrated parameter Value and Source
Number of diagnosed and in care HIV-infected and chronic HCV coinfected (HIV+/HCV+) in 2015 3075 as observed in the HERACLES cohort [17], with 2669 [range 2402–2936] with a history of PWID
HCV chronic prevalence among PWID injecting for < 10 years in 2010 45% [sampled uniformly from 40 to 50%]. Values from Folch et al. [29], adjusted for weighted spontaneous clearance given HIV coinfection prevalence and spontaneous clearance rates by HIV-status in the below table.
HCV chronic prevalence among PWID injecting for > 10 years in 2010 60% [sampled uniformly from 55 to 65%] Values taken from Folch et al. [29], adjusted for weighted spontaneous clearance given HIV coinfection prevalence and spontaneous clearance rates by HIV-status in the below table.
HIV prevalence among PWID injecting for <10 years, in 2010 20% [sampled uniformly from 10 to 30%] Values from Folch et al. [29]
HIV prevalence among PWID injecting for > 10 years in 2010 40% [sampled uniformly 30–50%]. Values from Folch et al. [29]
HCV chronic prevalence among HIV+ ever PWID in 2015 54% [sampled uniformly 50–58%] [18]
Proportion of HIV+/HCV+ diagnosed individuals who are current PWID in 2015 14% [sampled uniformly 10–18%] as observed in the HERACLES cohort [17]
Proportion HIV+/HCV+ diagnosed ever PWID who had previously failed HCV treatment in 2015 32% [sampled uniformly 30–34%] as observed in the HERACLES cohort [17]
General Parameters
Parameter Definition Symbol Sampled Value and 95% Interval Sampling Distribution Source
Sustained HCV viral response, monoinfected on DAAs 1- fmd 0.9   [2]
Sustained HCV viral response, coinfected on DAAs 1- fcd 0.948   HERACULES cohort
Sustained HCV viral response, monoinfected pre-DAAs 1- fmpd 0.52 (0.45–0.60) Uniform [0.45–0.60] Pooled SVR weighted by genotype and genotype distribution [30, 31].
Sustained HCV viral response, coinfected pre-DAAs 1- fcpd 0.30 (0.20.-0.39) Uniform [0.20–0.40] Pooled SVR weighted by genotype and genotype distribution [30, 32].
Excess death rate due to mono-infection with HIV untreated per year μuHIV 0.097 (0.09–0.10) Uniform [1/9.6–1/11.5] [33]
Decreased mortality hazard ratio for HIV on ART μHIV 0.26 (0.20–0.32) Uniform [1/5–1/3] [34, 35]
Excess death rate due to chronic HCV mono-infection per year μHCV 0.00169 (0.0016–0.00181) Uniform [0.00154–0.00183] [36]
Relative risk of death due to chronic HCV for HIV/HCV coinfection not on HIV treatment compared to HCV monoinfection RR_co_noART 2.58 (1.70–3.99) Lognormal, from distribution 2.5 (95%CI 1.8–3.4) [36, 37]
Excess death rate due to HCV for HIV-HCV co-infection with no HIV treatment per year μHCVuHIV 0.0042 (0.0039–0.0046) Uniform [0.0038–0.0046] [36, 37]
Relative risk of death due to chronic HCV for HIV/HCV coinfection on HIV treatment compared to HIV/HCV coinfection no HIV treatment RR_coART   0.68 [36, 37]
Excess death rate due to HIV for HIV-HCV co-infection with no HIV treatment per year μuHIVHCV 0.0005 (0.00041–0.00066) Uniform [0.0004–0.00069] [36]
PWID parameters
Inflow of new PWID per year θ    Deaths replaced, rate is halved in 2011. See text for discussion.
Population size of active PWID in 2010   7,500 (5,000-10,000) Uniform [5,000-10,000] 8.4 million Andalusia population in 2010, 92% > age 15, and a PWID prevalence among adults of 0.1% (national estimate) [38, 39],
HCV treatment rate among PWID who are HIV- or HIV+ and undiagnosed (%/year) r, rhu 0.99% (0.54–1.44%) Uniform
[0.5–1.5%]
Assumed similar to estimates worldwide [40]
HCV treatment rate among HIV+ diagnosed individuals prior to 2015 (%/year) rhd Calibrated   Calibrated to fit HERACLES data on proportion previously failed treatment in 2015
HCV treatment rate among HIV+ diagnosed individuals from 2015 to 2020 (%/year) rhd 33%   HERACLES cohort (unpublished data from 2015 to 2017)
Average duration of injecting until final cessation (years) 1/μcd 15.1 (6.8–24.4) Uniform
[5–25]
Uncertain, so vary widely [41, 42]
Background mortality rate per year among PWID μ 0.0179   Average life expectancy in Spain to 80.7 (WHO life table), and average age of injecting initiation age of 25 [43]
Overdose mortality rate among PWID per year μIDU 0.0062 (0.005–0.007) Uniform [0.0053–0.0070] [44]
Relative risk of HIV transmission through sex for those on ART RRHIVs 0.107 (0.03–0.198) Lognormal [95% CI 0.01–0.27] [45]
Relative risk of HIV transmission through injecting for those on ART RRHIVi 0.50 (0.27–0.72) Uniform
[0.25–0.75]
Limited data. One modeling study in Vancouver estimated 44% efficacy for preventing injecting transmission [5] but uncertainty was wide.
Relative risk of HCV transmission if HIV positive undiagnosed (off ART) compared to HIV negative RRHCV_ifHIVpos 2 (1.2–2.8) Uniform [1–3] [46, 47]
Annual probability of HIV transmission through sex during the latent untreated stage of infection βHIVs = 1/6* βHCV    [21]
Proportion spontaneous HCV clearance among HIV negatives n 0.25 (0.22–0.29) Uniform [0.22–0.29] [48]
Relative risk of spontaneous clearance among HIV positives compared to HIV negatives RRsponclearHIVpos 0.68 (0.39–0.90) Lognormal [0.46–1.0] [49]
MSM parameters
Number of HIV/HCV coinfected and diagnosed MSM in 2015   406   HERACLES cohort (unpublished)
Number of newly HIV/HCV coinfected and diagnosed MSM each year   Calculated   Based on multiplying the number of HIV-infected MSM in 2010 by the proportion of HIV+ MSM who are diagnosed, by the primary HCV incidence among HIV-infected MSM.
Number of HIV-infected MSM in 2010 θMSM 16,281 (9,018–23,526) Uniform
[8,646-23,913]
[50,51,52]
Based on multiplying the male population over 15 years of age by the prevalence of MSM, and the prevalence of HIV-infected MSM in 2010
Proportion of HIV+ MSM who are diagnosed   0.761 (0.751–0.771) Uniform
[0.75–0.772]
[53]
Primary HCV incidence among HIV-infected MSM (per 100 person-years)   1.17 (0.75–1.16) Uniform
[0.73–1.61]
[54]
See supplement for details.
HCV reinfection incidence among HIV+ MSM (per 100 person-years) Γ 7.07 (3.87–10.27) Uniform
[3.7–10.44]
[55]
Background (non HIV or HCV) mortality rate among HIV/HCV-diagnosed MSM (per year) μMSM 0.026   Average life expectancy in Spain of 80.7 [56], and average age at HIV/HCV diagnosis of 43 [57].