Designing an optimal HIV programme for South Africa: Does the optimal package change when diminishing returns are considered?. (December 2017)

• Record Type: Journal Article
• Authors: Chiu, Calvin; Johnson, Leigh; Jamieson, Lise; Larson, Bruce; Meyer-Rath, Gesine
• Is Part Of: BMC public health. Volume 17:Number 1(2017)
• Page Start: 1
• Page End: 9
• Publication Date: 2017-12
• Subjects: HIV -- Modelling -- Optimisation -- Cost-effectiveness analysis -- South Africa -- Health economics; Public health -- Periodicals; 362.105
• DOI: 10.1186/s12889-017-4023-3
• Languages: English
• ISSNs: 1471-2458

Abstract

Abstract Background South Africa has a large domestically funded HIV programme with highly saturated coverage levels for most prevention and treatment interventions. To further optimise its allocative efficiency, we designed a novel optimisation method and examined whether the optimal package of interventions changes when interaction and non-linear scale-up effects are incorporated into cost-effectiveness analysis. Methods The conventional league table method in cost-effectiveness analysis relies on the assumption of independence between interventions. We added methodology that allowed the simultaneous consideration of a large number of HIV interventions and their potentially diminishing marginal returns to scale. We analysed the incremental cost effectiveness ratio (ICER) of 16 HIV interventions based on a well-calibrated epidemiological model that accounted for interaction and non-linear scale-up effects, a custom cost model, and an optimisation routine that iteratively added the most cost-effective intervention onto a rolling baseline before evaluating all remaining options. We compared our results with those based on a league table. Results The rank order of interventions did not differ substantially between the two methods- in each, increasing condom availability and male medical circumcision were found to be most cost-effective, followed by anti-retroviral therapy at current guidelines. However, interventions were less cost-effective throughout when evaluated under the optimisation method, indicating substantial diminishing marginal returns, with ICERs being on average 437% higher under our optimisation routine. Conclusions Conventional league tables may exaggerate the cost-effectiveness of interventions when programmes are implemented at scale. Accounting for interaction and non-linear scale-up effects provides more realistic estimates in highly saturated real-world settings.