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Increase in HCV screening, treatment in UK prisons may be cost-effective

VIENNA — Increasing the screening and treatment of inmates may prove cost-effective in prisons in the United Kingdom, especially if there is a focus on persons who inject drugs, according to a study presented at the 2015 International Liver Congress.

“Providing 8 to 12 weeks of interferon-free treatments in prison substantially increases QALYs gained due to a high SVR and more treatment completions, but it is still borderline cost-effective unless the costs are reduced,” Natasha K. Martin, MD, associate professor from the University of California San Diego, said during her presentation. “If treatment is 8 weeks with the interferon-free [direct-acting antiviral] therapy is available, then increasing testing in prison is highly likely to be cost effective, primarily due to decreased drug costs.”

Martin explained that in 2014, several prisons in the U.K. implemented opt-out HCV testing, a plan that is expected to be implemented across the prison system this year.

Looking at three intervention scenarios, Martin and colleagues analyzed the cost-effectiveness of this strategy. The scenarios included: one, doubling HCV testing in prison with current treatment; two, doubling HCV testing in prison combined with 8 to 12 week interferon-free DAAs in prison; and, three, doubling HCV testing in prison combined with 8 week interferon-free DAAs.

Martin used a U.K. health care provider perspective, costs and quality-adjusted life years (QALYs) taken from previous literature, looking at a 100-year horizon and multivariate probabilistic uncertainty analysis as well as one-way sensitivity analysis. The research makes certain assumptions about genotype prevalence, persons who inject drugs (PWID), testing costs, sustained virologic response rates (95%) and drug cost (£3,300 per week). They also used a £20,000 to £30,000 willingness to pay threshold.

In scenario one, Martin predicted a mean incremental cost effectiveness ratio (ICER) of £19,286 per QALY gained compared to current status quo. It was 44% likely to be below the £20,000 threshold and 86% likely to be below the £30,000 threshold.

In scenario two, mean ICER was £18,389 per QALY gained and was 54% likely to be below the £20,000 threshold. This model, she said, shows the sensitivity of cost-effectiveness to drug costs.

“There was a substantial increase in QALYs gained and that was due both to an increase in sustained virologic response — we assumed a 95% SVR across the board — but also due to an increase in completion of therapy because of these shorter treatments. However, this was offset by the increase in costs incurred by providing DAA therapy to everyone,” Martin said. “If we assume that the interferon-free DAA cost was 20% lower at £2,600 per week instead of £3,300, then ICER drops to £13,000 per QALY gained compared to baseline.”

Lastly, scenario three, with limiting treatment to 8 weeks produced a mean ICER of £12,323 per QALY gained compared to baseline. It was also 83% likely to be below the £20,000 lower threshold and 97% likely to be below the upper threshold of £30,000.

“This lower cost effectiveness ratio was primarily actually because of the reduced costs of 8-week treatment vs. 12-week treatment at the same per-week cost,” Martin said.

In looking at the sensitivity analysis, Martin showed how a lower SVR rate, a drop in yield, a 50-year horizon and increased drug costs could all put ICER above the baseline, though they would still be below the willingness to pay threshold. Yet, if 25% of persons who inject drugs are treated after their prison referral, as opposed to the base case of 2.5%, mean ICER drops dramatically, she said.

“Scaling up treatment to persons who inject drugs could substantially increase cost-effectiveness due to potential prevention benefits,” Martin said. – by Katrina Altersitz

For More Information:

Martin NK. Abstract O124. Presented at: International Liver Congress; April 22-26, 2015; Vienna.

Disclosure: Martin reports receiving grants from Gilead.