Cost-effectiveness of integrating methadone maintenance and antiretroviral treatment for HIV-positive drug users in Vietnam's injection-driven HIV epidemics

Drug use negatively affects adherence to and outcomes of antiretroviral treatment (ART). This study evaluated the cost-effectiveness of integrating methadone maintenance treatment (MMT) with ART for HIV-positive drug users (DUs) in Vietnam. A decision analytical model was developed to compare the costs and consequences of 3 HIV/AIDS treatment strategies for DUs: (1) only ART, (2) providing ART and MMT in separated sites (ART-MMT), and (3) integrating ART and MMT with direct administration (DAART-MMT). The model was parameterized using empirical data of costs and outcomes extracted from the MMT and ART cohort studies in Vietnam, and international published sources. Probabilistic sensitivity analysis was conducted to examine the model's robustness. The base-case analysis showed that the cost-effectiveness ratio of ART, DAART-MMT, and ART-MMT strategies was USD 1358.9, 1118.0 and 1327.1 per 1 Quality-Adjusted Life Year (QALY), equivalent to 1.22, 1.00, and 1.19 times Gross Domestic Product per capita (GDPpc). The incremental cost-effectiveness ratio for DAART-MMT and ART-MMT versus ART strategy was 569.4 and 1227.8, approximately 0.51 and 1.10 times GDPpc/QALY. At the willingness to pay threshold of 3 times GDPpc, the probability of being cost-effective of DAART-MMT versus ART was 86.1%. These findings indicated that providing MMT along with ART for HIV-positive DUs is a cost-effective intervention in Vietnam. Integrating MMT and ART services could facilitate the use of directly observed therapy that supports treatment adherence and brings about clinically important improvements in health outcomes. This approach is also incrementally cost-effective in this large injection-driven HIV epidemic.