Cost-effectiveness of emergency department opt-out testing for HIV in England: a modelling study.

Abstract

In England, up to 5% of people living with HIV are undiagnosed and the proportion of late diagnoses remains high. Opt-out testing could help to identify people living with undiagnosed HIV who might not access testing in other settings. We aimed to evaluate the cost-effectiveness of the first phase of UK National Health Service (NHS)-funded opt-out testing for HIV in emergency departments, which scaled up from 2022. We adapted a previously developed deterministic model of HIV diagnosis, progression, and transmission to simulate the impact of the first 33 months of the opt-out testing intervention in improving HIV diagnosis, incorporating programme data on CD4 cell count at diagnosis. We conducted a bottom-up costing of the intervention in two sites, from an NHS perspective, and gathered costs of HIV care from the literature. In the base case we assumed 93% of new diagnoses would not have been diagnosed elsewhere during the programme as these individuals had never previously been tested for HIV. Cost-effectiveness is presented as incremental costs per quality-adjusted life-year (QALY) gained over 20 years compared with a £25 000-35 000 per QALY threshold. We explored scenario analyses to address the limitations of the model assumptions. The mean cost per HIV test was £6·31 (US$7·91). Under base case assumptions, emergency department opt-out testing is projected to avert 187 HIV-related deaths (95% credible interval 182-196) and 28 secondary acquisitions (26-52) over 20 years, costing £18 630 (17 413-23 119) per QALY gained. This result is robust (below £35 000 per QALY) to different assumptions about HIV-related quality of life and HIV care costs, HIV-related mortality, and the rate of diagnosis outside the programme. Under a lower test yield scenario of 0·20 new diagnoses per 1000 tests (compared with 0·29 in the base case), the intervention remains cost-effective at £25 000 per QALY. Emergency department opt-out testing for HIV in England was cost-effective due to averted HIV-related morbidity and mortality resulting from improving diagnosis and linkage to care for people who would otherwise not be tested, many of whom have already reached an advanced stage of HIV progression. Our findings provide evidence to support continuation of the opt-out testing programme as part of the HIV Action Plan for England. National Institute for Health and Care Research and NHS England.