Figure 5

Cost-effectiveness evaluation of the pre-exposure prophylaxis (PrEP) program. The incremental cost per QALY gained (also known as incremental cost-effectiveness ratio [ICER]) in the 15 years since the introduction of the PrEP program with varied parameter values was calculated. Incremental cost varying each cost, QALYs, or transition parameter. The black solid vertical lines represent the cost-effectiveness threshold frequently referred to in Japan (5.0 million JPY, or 45,454.5 USD). The black dashed vertical lines represent the base case scenario (4.3 million JPY per QALY gained). Therefore, the values on the left of the base case scenario correspond to more favorable scenarios compared with baseline. Blue bars represent parameter values lower than baseline, and red bars represent parameter values higher than baseline. For example, when the cost of PrEP increased (red bar), the incremental cost also increased, which is not favorable. PrEP coverage was assumed to be 50%. (a) Cost parameters were varied: the cost of PrEP pills, cost of hospitalization due to AIDS, cost of ART for those infected by HIV, cost of screening for the HIV-positive population, and cost of screening for the HIV-negative population. (b) QALY parameters varied: QALYs for people with PrEP, people living with HIV, and AIDS. (c) The transition probabilities of the Markov model also varied. For the transition probability from PrEP to HIV, the PrEP efficacy was varied.