What is the cost utility of screening for hepatitis C virus (HCV) in intravenous drug users?

Objectives To model the likely cost utility of the prevalence round of a screening programme for hepatitis C (HCV) in intravenous drug users (IVDUs) in contact with services in the South and West health region of the UK.

Methods Information on the prevalence of HCV, performance of diagnostic tests, and effectiveness of interferon α (IFNα) for treatment of chronic hepatitis were brought together with estimates of the costs of service provision. A simple spreadsheet model was used to estimate cost utility (cost/quality adjusted life year (QALY)). Assumptions (including use of ribavirin plus IFNα combination therapy) were tested by a one way sensitivity analysis.

Results About 5600 IVDUs live in the region. A combination of enzyme linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR) testing has high sensitivity and specificity for detecting HCV. There is excellent evidence that IFNα is effective in producing sustained normalisation of liver function and, by inference, eradicating HCV. Evidence for long term benefits comes from modelling studies based on progression of HBV or non-A, non-B hepatitis and is considerably less robust. The cost of the prevalence round of screening in IVDUs would be about £700 000 and is likely to identify about 1400 people, of whom about 270 would be eligible for treatment and 20 would respond to IFNα. This gives a cost/QALY of £9300 for the screening programme. However, much uncertainty around the estimates used to inform the cost utility calculation limits confidence in the value of screening IVDUs for HCV. Sensitivity analysis shows a range of possible cost utility from £3333 to £81 438. Estimates are particularly sensitive to adherence to liver biopsy and treatment and to discounting of benefits.

Conclusions Although potentially cost effective, many important uncertainties surround the assumptions used to estimate the long term effectiveness of screening and treatment. There is insufficient evidence to inform policy development and further research is required in this rapidly changing field.