Methods and Applications: Exploration for the Priority of HIV Intervention: Modelling Health Impact and Cost-Effectiveness — Six Cities, Eastern China, 2019–2028

Five cities in eastern China, namely Foshan, Ningbo, Shijiazhuang, Wuxi, and Yantai, were chosen based on the following criteria: each city had a total population exceeding three million and reported over 200 new cases of HIV infection annually. To simultaneously assess the cost-effectiveness discrepancies between two cities within the same province and provide insights for subsequent spatiotemporal distribution studies, Zhenjiang — an additional city in Jiangsu Province like Wuxi, boasting a population of three million and approximately 50 newly reported HIV cases each year — was included in the analysis (5).

A standardized data collection tool was developed following the Spectrum framework to calculate costs and model healthcare payer perspectives. Data from public and service sectors in six cities between 2015 and 2019 were collected. This study investigates the cost-effectiveness of 10 key HIV interventions (Table 1) and presents the HIV intervention priorities across sampled cities for the period 2019–2028.

Three scenarios were simulated to project the outcomes of scaling up interventions in each city, under the assumption of an unlimited budget.

In the Base scenario, from 2020 to 2028, all interventions maintain the same coverage as in 2019.

Enhance the scope of specific interventions by double up to 99.90% by 2028, with the exception of oral pre-exposure prophylaxis (PrEP) for high-risk heterosexual (HRH) individuals and men who have sex with men (MSM) due to the absence of prior testing and coverage in the studied cities. Simultaneously, escalate the coverage of oral PrEP for HRH and MSM from 0% in the starting year to 5% by 2028. Linear interpolation was utilized to project the coverage rates between 2020 and 2027, while the coverage for other interventions remained constant from 2019.

In this case, it was assumed that the coverage rate of the 10 chosen interventions would reach 99.90%. Linear interpolation was used to simulate the coverage rates for the years 2020–2027. The coverage rates of the remaining interventions were held constant at 2019 levels.

Definitions of the 10 selected intervention coverage and the remaining interventions’s coverage all displayed in the Supplementary Table S1. The Coverage assumptions for 10 selected HIV interventions in the target year 2028 were displayed in Supplementary Table S2. Unit costs for each intervention were based on local data from six cities in 2019 and kept constant in the model, as outlined in Supplementary Table S3.

Initially, the model simultaneously expanded the coverage of ten selected interventions to determine the total infections and deaths prevented, as well as the costs for each scenario in each city. Subsequently, each intervention was individually scaled up per scenario in every city to analyze the outcomes of each intervention.

The number of infections and deaths prevented by scaling up interventions from the Base scenario to the Achievable or Idealized scenarios was directly derived from the model calculations. Costs for each scenario, presented in 2019 Chinese Yuan (CNY) with a 3% annual discount rate and an exchange rate of 1 USD=6.90 CNY (6), were calculated. Incremental cost was manually determined by comparing intervention costs under the Achievable or Idealized scenarios with those under the Base scenario. The incremental cost-effectiveness ratio (ICER) was calculated as the ratio of incremental costs to infections averted. To account for economic variations across cities, cost-effective interventions in each city were classified as those with an ICER below the 2019 per capita GDP (Supplementary Table S4) for that city per infection averted.

A one-way sensitivity analysis was performed by adjusting the unit cost of selected interventions by +/- 50% of the original values to assess the model's stability.

Table 2 illustrates the comprehensive costs and cost-effectiveness of two distinct scenarios across six cities from 2019 to 2028. During this period, under the Achievable scenario with Shijiazhuang reaching optimal impact, a total of 1,580 HIV infections and 550 deaths were prevented. In contrast, the Idealized scenario showed even greater impact, with 2,608 HIV infections and 796 deaths averted. The least impact was noted in Foshan and Ningbo. As anticipated, the costs per infection and death averted in the Idealized scenario were considerably higher compared to those in the Achievable scenario across all six cities. In municipalities with high initial antiretroviral therapy (ART) coverage, like Foshan and Ningbo, the ICERs were significant, yielding 0.47 million yuan per infection averted in the Achievable scenario and exceeding 100 million yuan in the Idealized scenario, indicating poor cost-effectiveness when scaling up interventions. Conversely, in the other four cities with lower initial ART coverage, such as Shijiazhuang and Yantai, escalating current intervention coverage proved to be highly cost-effective, adhering to the cost-effectiveness thresholds established for these cities within the Achievable scenario.

Figure 1 and Table 3 display the cost-effectiveness of HIV interventions in six cities under Achievable and Idealized scenarios. In cities like Shijiazhuang, Wuxi, Yantai, and Zhenjiang, ART, especially for males, showed high effectiveness in averting infections. The most impactful strategy was ART for males in Shijiazhuang, projected to prevent 1,367 infections from 2019 to 2028. The majority of prevented deaths were attributed to ART based on the Spectrum framework (Supplementary Table S5). In Foshan and Ningbo, with high ART coverage, oral PrEP for MSM in the Idealized scenario demonstrated significant effectiveness.

Figure 1. 

Total HIV infections averted by 10 selected HIV interventions in Achievable and Idealized Scenarios in six cities from 2019 to 2028.

Abbreviation: VCT=Voluntary counseling and testing for adult population; SSTT=Secondary students with teachers trained in AIDS; FSW=Female sex worker; MSM=Men who have sex with men; PrEP=Pre-exposure prophylaxis; HRH=High risk heterosexual; ART=Antiretroviral therapy; AS= Achievable Scenario; IS=Idealized Scenario.

* indicates that the impact of MSM receiving lubricants was modeled as 0 in six cities.

At the cost-effectiveness threshold of each city, interventions such as outreach to MSM, ART for males, and ART for females were found to be cost-effective across six cities in both scenarios. Among these, MSM outreach was identified as the most cost-effective, with a range between 0.39 to 42.48 thousand yuan per infection averted. However, the effectiveness of MSM outreach may plateau with expanded coverage, as depicted in Figure 1. For instance, in Zhenjiang and Wuxi, the number of HIV infections averted through MSM outreach increased significantly from Achievable to Idealized scenarios, while the impact in the other four cities did not show a further increase with scaled-up coverage.

The results indicate that the epidemiological efficacy of the intervention is influenced by the coverage levels in different scenarios. Supplementary Table S6 presents the cost per HIV infection averted based on varying unit costs of interventions. A direct correlation was observed between unit cost and cost per HIV infection averted; a 50% decrease in unit cost resulted in a similar decrease in the cost per HIV infection averted, and vice versa (Supplementary Table S7).

Our research conducted using the Spectrum model offers valuable insights for guiding resource allocation. Between 2019 and 2028, Shijiazhuang demonstrated the highest potential impact with the lowest ICER compared to other cities analyzed. Situated in Hebei province, Shijiazhuang stands out due to its large population of 11 million, low ART coverage, and limited HIV resources per capita. In contrast, Foshan had the lowest estimated potential impact, while Ningbo had the highest ICER. These cities, located in prosperous provinces like Guangdong and Zhejiang, exhibit high ART coverage and ample HIV resources. Therefore, prioritizing funding towards regions with growing economies, low treatment rates, and substantial populations is crucial in shaping the future of HIV intervention strategies (7).

The study showcased that transitioning from an Achievable to an Idealized scenario for a single intervention coverage results in a minor health impact change at a significantly higher cost. For instance, the ICER in the Idealized scenario is estimated to be approximately 4 times (in Foshan) to 45 times (in Zhenjiang) greater compared to the Achievable scenario. Thus, opting for an Achievable scenario is advisable for policymakers with constrained resources across the six cities.

The results guide the development of a ten-year priority intervention plan for six cities, including MSM outreach, ART for males, and ART for females. Prior research has shown that MSM outreach significantly enhances HIV testing rates (8) and encourages prompt treatment (9). However, there is limited data on the cost-effectiveness of MSM outreach (10). Our study indicated that the impact of MSM outreach on health outcomes plateaued at a baseline coverage of around 59.2% (in Ningbo). Beyond this threshold, supplementary interventions are necessary to address remaining gaps due to the saturation of MSM outreach.

ART has proven to be the most effective and economical approach for reducing HIV infections and mortalities in Shijiazhuang, Wuxi, Yantai, and Zhenjiang. In contrast, oral PrEP for MSM has emerged as the strategy of choice in Foshan and Ningbo, areas with high ART coverage, to meet the objectives of decreasing new HIV infections. These findings align with previous oral PrEP modeling studies (11–12). Nonetheless, the adoption of this strategy in Ningbo, where the ICER soared to 181.99 and 194.71 thousand yuan per infection averted, was deemed not cost-effective according to the city’s threshold of 146.12 thousand yuan per infection averted. While extensive ART coverage may significantly curb HIV transmission, rendering PrEP redundant and uneconomical in such cases (13), the indirect benefits of enhanced HIV testing and linkage to subsequent treatment attributable to PrEP cannot be overlooked (14). Given the substantial public health challenge posed by the prevalence of HIV among MSM in China, it is imperative that economically developed areas with high ART coverage continuously evaluate and expand oral PrEP for MSM, ensuring sufficient budgetary provisions. To achieve the ambitious aim of halting the HIV epidemic, strategies must be meticulously tailored and implemented at the local level.

Like all modeling studies, this study is subject to some limitations. First, due to insufficient regional data, we utilized some national-level indicators in the model, potentially impacting the accuracy of projections. Second, the lack of data on mobile populations could lead to underestimation of local epidemics. Third, our models did not consider the impacts of disruptions related to coronavirus disease 2019 (COVID-19) (15). While COVID-19 does not directly influence HIV transmission biologically, it does affect various factors such as awareness, behavior, and healthcare resource availability, as well as resource allocation in response to the sporadic nature of the epidemic.

In conclusion, this study by Spectrum delineated key actions for regions sampled from 2019 to 2028 to improve HIV response and achieve optimal health outcomes in AIDS control. The utilization of Spectrum is crucial for guiding prioritization in cities based on their unique epidemiological, economic, and HIV response characteristics.

No conflicts of interest.

Thank the staff from Jiangsu Provincial CDC, Guangdong Provincial CDC, Zhejiang Provincial CDC, Shandong Provincial CDC, Hebei Provincial CDC, Shijiazhuang CDC, Yantai CDC, Ningbo CDC, Zhenjiang CDC, Foshan CDC, and Wuxi CDC for their assistance in data collection and verification.