An economic evaluation of contingency management for completion of hepatitis B vaccination in those on treatment for opiate dependence.

AIMS: To determine whether the provision of contingency management using financial incentives to improve hepatitis B vaccine completion in people who inject drugs entering community treatment represents a cost-effective use of healthcare resources. DESIGN: A probabilistic cost-effectiveness analysis was conducted, using a decision-tree to estimate the short-term clinical and healthcare cost impact of the vaccination strategies, followed by a Markov process to evaluate the long-term clinical consequences and costs associated with hepatitis B infection. SETTINGS AND PARTICIPANTS: Data on attendance to vaccination from a UK cluster randomised trial. INTERVENTION: Two contingency management options were examined in the trial: fixed vs. escalating schedule financial incentives. MEASUREMENT: Lifetime healthcare costs and quality-adjusted life years discounted at 3.5% annually; incremental cost-effectiveness ratios. FINDINGS: The resulting estimate for the incremental lifetime healthcare cost of the contingency management strategy versus usual care was £22 (95% CI: -£12 to £40) per person offered the incentive. For 1,000 people offered the incentive, the incremental reduction in numbers of hepatitis B infections avoided over their lifetime was estimated at 19 (95% CI: 8 to 30). The probabilistic incremental cost per quality adjusted life year gained of the contingency management programme was estimated to be £6,738 (95% CI: £6,297 to £7,172), with an 89% probability of being considered cost-effective at a threshold of £20,000 per quality-adjusted life years gained (98% at £30,000). CONCLUSIONS: Using financial incentives to increase hepatitis B vaccination completion in people who inject drugs could be a cost-effective use of healthcare resources in the UK as long as the incidence remains above 1.2%.