Cost-effectiveness of hepatitis C virus (HCV) elimination strategies among people who inject drugs (PWID) in Tijuana, Mexico

Abstract

Background and aims: In Latin America, Mexico was first to launch a hepatitis C virus (HCV) elimination strategy, where people who inject drugs (PWID) are a main risk group for transmission. In Tijuana, HCV seroprevalence among PWID is > 90%, with minimal harm reduction (HR). We evaluated cost-effectiveness of strategies to achieve the incidence elimination target among PWID in Tijuana.

Methods: Modeling study using a dynamic, cost-effectiveness model of HCV transmission and progression among active and former PWID in Tijuana, to assess the cost-effectiveness of incidence elimination strategies from a health-care provider perspective. The model incorporated PWID transitions between HR stages (no HR, only opioid agonist therapy, only high coverage needle-syringe programs, both). Four strategies that could achieve the incidence target (80% reduction by 2030) were compared with the status quo (no intervention). The strategies incorporated the number of direct-acting anti-viral (DAA) treatments required with: (1) no HR scale-up, (2) HR scale-up from 2019 to 20% coverage among PWID, (3) HR to 40% coverage and (4) HR to 50% coverage. Costs (2019 US$) and health outcomes [disability-adjusted life years (DALYs)] were discounted 3% per year. Mean incremental cost-effectiveness ratios (ICER, $/DALY averted) were compared with one-time per capita gross domestic product (GDP) ($9698 in 2019) and purchasing power parity-adjusted per capita GDP ($4842-13 557) willingness-to-pay (WTP) thresholds.

Results: DAAs alone were the least costly elimination strategy [$173 million, 95% confidence interval (CI) = 126-238 million], but accrued fewer health benefits compared with strategies with HR. DAAs + 50% HR coverage among PWID averted the most DALYs but cost $265 million, 95% CI = 210-335 million). The optimal strategy was DAAs + 50% HR (ICER $6743/DALY averted compared to DAAs only) under the one-time per-capita GDP WTP ($9698).

Conclusions: A combination of high-coverage harm reduction and hepatitis C virus treatment is the optimal cost-effective strategy to achieve the HCV incidence elimination goal in Mexico.

Keywords: Cost-effectiveness; HCV; harm reduction; modeling; people who inject drugs; prevention.

Figure 1.. Incremental costs and DALYs averted for various HCV elimination strategies to achieve 80% HCV incidence reduction by 2030 compared to status quo in Tijuana, Mexico.

Note that the DAAs+20%HR and DAAs+40% HR are weakly dominated by DAAs+ 50% HR. DAA: Direct-acting antiviral treatment. HR: Harm reduction includes (1) OAT: Opioid agonist therapy and (2) HCNSP: High coverage needle/syringe program (receiving ≥1 sterile syringes per injection).

Figure 2.. Cost-effectiveness acceptability curves for (a) DAAs only compared to status quo and (b) DAAs+50%HR compared to DAAs only.

Note that the DAAs + 20%HR and DAAs + 40% HR are weakly dominated by DAAs + 50% HR. DAA: Direct-acting antiviral treatment. HR: Harm reduction includes (1) OAT: Opioid agonist therapy and (2) HCNSP: High coverage needle/syringe program (receiving ≥1 sterile syringes per injection).

Figure 2.. Cost-effectiveness acceptability curves for (a) DAAs only compared to status quo and (b) DAAs+50%HR compared to DAAs only.

Note that the DAAs + 20%HR and DAAs + 40% HR are weakly dominated by DAAs + 50% HR. DAA: Direct-acting antiviral treatment. HR: Harm reduction includes (1) OAT: Opioid agonist therapy and (2) HCNSP: High coverage needle/syringe program (receiving ≥1 sterile syringes per injection).

Figure 3.. Incremental cost-effectiveness ratio (ICER) of DAAs only strategy compared to status quo, with varying proportions of HCV-infected accessing care in Tijuana, Mexico.

OAT: Opioid agonist therapy; HCNSP: High coverage needle/syringe program (receiving ≥1 sterile syringes per injection); DAA: Direct-acting antiviral treatment.