Purpose: To evaluate the cost-effectiveness of rapid Hepatitis C (HCV) and HIV tests to screen substance abuse treatment program clients and link them to appropriate care.
Methods: We used a decision analytic model to compare the cost-effectiveness of 3 testing strategies (offsite HCV testing referral, onsite rapid HCV testing, onsite rapid HCV&HIV testing) vs. no testing offer. Data were from a national randomized trial of HIV testing strategies in 12 substance abuse treatment programs and the literature. Base case prevalence included 11% undetected chronic HCV, 0.4% undetected HIV, and 35% HCV co-infection among HIV-infected. After screening positive, 53% linked to HCV care and 67% linked to HIV care. We assumed HIV co-infection would be detected in individuals tested for HCV alone if they were linked to HCV care. Quality-adjusted life expectancy and costs were from established disease progression and treatment models of HCV (HEP-CE) and HIV (CEPAC). Incremental cost-effectiveness ratios (ICERs) are in 2011 US dollars/QALY discounted at 3% annually.
Results: Offsite testing referral detected and linked 89 individuals with chronic HCV infection/10,000 test offers, and onsite rapid HCV testing detected and linked 440/10,000 offers; onsite rapid HCV testing and onsite rapid HCV&HIV testing detected and linked 6 HIV-infected (all HCV/HIV co-infected) and 22 HIV-infected (8 co-infected)/10,000 test offers, respectively. Compared to no testing, offsite referral was dominated by onsite HCV testing, which had an ICER of $18,500/QALY; the ICER of onsite HCV&HIV testing compared to onsite HCV testing alone was $66,100/QALY. The ICER of onsite HCV&HIV testing remained <$100,000/QALY over plausible ranges for linkage to care, HCV prevalence and test acceptance. In 2-way sensitivity analyses, onsite HCV testing alone was preferred to onsite HCV&HIV testing when HIV prevalence was <1/4 of the base case and the HCV/HIV co-infection proportion exceeded the base case (Figure).
Conclusions: Onsite rapid combined HCV and HIV testing in substance abuse treatment programs has an ICER <$100,000/QALY, even with current imperfect linkage to care, and should be implemented.
Sensitivity analysis varying HIV prevalence and HCV/HIV proportion ($100,000/QALY threshold)
