Cost effectiveness of option B plus for prevention of mother-to-child transmission of HIV in resource-limited countries: evidence from Kumasi, Ghana

Abstract

Background: Achieving the goal of eliminating mother-to-child HIV transmission (MTCT) necessitates increased access to antiretroviral therapy (ART) for HIV-infected pregnant women. Option B provides ART through pregnancy and breastfeeding, whereas Option B+ recommends continuous ART regardless of CD4 count, thus potentially reducing MTCT during future pregnancies. Our objective was to compare maternal and pediatric health outcomes and cost-effectiveness of Option B+ versus Option B in Ghana.

Methods: A decision-analytic model was developed to simulate HIV progression in mothers and transmission (in utero, during birth, or through breastfeeding) to current and all future children. Clinical parameters, including antenatal care access and fertility rates, were estimated from a retrospective review of 817 medical records at two hospitals in Ghana. Additional parameters were obtained from published literature. Modeled outcomes include HIV infections averted among newborn children, quality-adjusted life-years (QALYs), and cost-effectiveness ratios.

Results: HIV-infected women in Ghana have a lifetime average of 2.3 children (SD 1.3). Projected maternal life expectancy under Option B+ is 16.1 years, versus 16.0 years with Option B, yielding a gain of 0.1 maternal QALYs and 3.2 additional QALYs per child. Despite higher initial ART costs, Option B+ costs $785/QALY gained, a value considered very cost-effective by World Health Organization benchmarks. Widespread implementation of Option B+ in Ghana could theoretically prevent up to 668 HIV infections among children annually. Cost-effectiveness estimates remained favorable over robust sensitivity analyses.

Conclusions: Although more expensive than Option B, Option B+ substantially reduces MTCT in future pregnancies, increases both maternal and pediatric QALYs, and is a cost-effective use of limited resources in Ghana.

Figure 1

State transition model overview. A schematic diagram for the state transition model is given. Each oval represents a health state in which a woman can exist. She remains in a state for the period of time indicated underneath each oval. Each arrow represents a transition to the next state, which occurs with the probability indicated below each arrow.

Figure 2

Probability distribution of time between 1 ^st and 2 ^nd pregnancy. The fraction of women (n = 817) who wait a given number of years between their first and second pregnancy is shown, with the number of years indicated on the x-axis and the proportion of women indicated on the y-axis. “0 years” indicates that the mother had only one child.

Figure 3

Sensitivity analysis of model variables. This tornado diagram represents the sensitivity of different variables included in the model. Each variable is listed, along with the associated incremental cost-effectiveness ratio (ICER). The horizontal width of each bar represents the change in cost-effectiveness of Option B+ versus Option B ($/QALY gained) as each model parameter is varied over the range given in parentheses. Variables are listed in descending sensitivity; those whose ICER values change most significantly are listed first. For reference, a vertical line indicating the Ghanaian GDP per capita is included on the graph, which demonstrates that Option B+ is a cost-effective alternative, even across a wide range of sensitivity analyses. The base case ICER value is $785/QALY gained.

Figure 4

One-way sensitivity analyses. Each graph indicates the change in the incremental cost-effectiveness ratio (ICER) between Option B and Option B+ when a single variable’s value is changed. The “base case” scenario is indicated with a circle. A downward-sloping line indicates Option B+ is becoming more cost-effective as the variable’s value is increased, while an upward-sloping line indicates Option B+ is becoming less cost-effective as the variable’s value is increased. The curve of each line indicates the specific rate at which the ICER changes as the variable’s value is altered.