Is increased hepatitis C virus case-finding combined with current or 8-week to 12-week direct-acting antiviral therapy cost-effective in UK prisons? A prevention benefit analysis

Abstract

Prisoners have a high prevalence of hepatitis C virus (HCV), but case-finding may not have been cost-effective because treatment often exceeded average prison stay combined with a lack of continuity of care. We assessed the cost-effectiveness of increased HCV case-finding and treatment in UK prisons using short-course therapies. A dynamic HCV transmission model assesses the cost-effectiveness of doubling HCV case-finding (achieved through introducing opt-out HCV testing in UK pilot prisons) and increasing treatment in UK prisons compared to status quo voluntary risk-based testing (6% prison entrants/year), using currently recommended therapies (8-24 weeks) or interferon (IFN)-free direct-acting antivirals (DAAs; 8-12 weeks, 95% sustained virological response, £3300/week). Costs (British pounds, £) and health utilities (quality-adjusted life years) were used to calculate mean incremental cost-effectiveness ratios (ICERs). We assumed 56% referral and 2.5%/25% of referred people who inject drugs (PWID)/ex-PWID treated within 2 months of diagnosis in prison. PWID and ex-PWID or non-PWID are in prison an average 4 and 8 months, respectively. Doubling prison testing rates with existing treatments produces a mean ICER of £19,850/quality-adjusted life years gained compared to current testing/treatment and is 45% likely to be cost-effective under a £20,000 willingness-to-pay threshold. Switching to 8-week to 12-week IFN-free DAAs in prisons could increase cost-effectiveness (ICER £15,090/quality-adjusted life years gained). Excluding prevention benefit decreases cost-effectiveness. If >10% referred PWID are treated in prison (2.5% base case), either treatment could be highly cost-effective (ICER<£13,000). HCV case-finding and IFN-free DAAs could be highly cost-effective if DAA cost is 10% lower or with 8 weeks' duration.

Conclusions: Increased HCV testing in UK prisons (such as through opt-out testing) is borderline cost-effective compared to status quo voluntary risk-based testing under a £20,000 willingness to pay with current treatments but likely to be cost-effective if short-course IFN-free DAAs are used and could be highly cost-effective if PWID treatment rates were increased. (Hepatology 2016;63:1796-1808).

Figure 1. Cost-effectiveness acceptability curves for doubled HCV case-finding in prison combined with (A) status quo treatments (B) 8–12 week IFN-free DAAs in prison

Incremental comparisons shown are: (A) Doubled HCV case-finding in prison combined with status quo treatments compared to status quo testing/treatment; (B) Doubled HCV case-finding combined with 8–12 week IFN-free DAAs in prison compared to doubled case-finding with status quo treatments.

Figure 2. Changes in mean ICER with increased PWID treatment rates in prison (2.5%-25% after referral)

Base-case analysis assumes a mean of 2.5% PWID treated after referral in prison. (a) Doubled testing with status quo treatments compared to status quo testing/treatment. (b) Double testing with 8–12 week IFN-free DAAs compared to doubled testing with status quo treatments.

Figure 3. One-way sensitivity analyses on mean ICERs

Black horizontal line denotes the base-case ICER. (a) Doubled testing with status quo treatments compared to status quo testing/treatment. (b) Double testing with 8–12 week IFN-free DAAs compared to doubled testing with status quo treatments.