Assisted partner notification services are cost-effective for decreasing HIV burden in western Kenya

Abstract

Background: Assisted partner services (aPS) or provider notification for sexual partners of persons diagnosed HIV positive can increase HIV testing and linkage in Sub-Saharan Africa and is a high yield strategy to identify HIV-positive persons. However, its cost-effectiveness is not well evaluated.

Methods: Using effectiveness and cost data from an aPS trial in Kenya, we parameterized an individual-based, dynamic HIV transmission model. We estimated costs for both a program scenario and a task-shifting scenario using community health workers to conduct the intervention. We simulated 200 cohorts of 500 000 individuals and projected the health and economic effects of scaling up aPS in a region of western Kenya (formerly Nyanza Province).

Findings: Over a 10-year time horizon with universal antiretroviral therapy (ART) initiation, implementing aPS in western Kenya was projected to reach 12.5% of the population and reduce incident HIV infections by 3.7%. In sexual partners receiving aPS, HIV-related deaths were reduced by 13.7%. The incremental cost-effectiveness ratio of aPS was $1094 (US dollars) (90% model variability $823-1619) and $833 (90% model variability $628-1224) per disability-adjusted life year averted under the program and task-shifting scenario, respectively. The incremental cost-effectiveness ratios for both scenarios fall below Kenya's gross domestic product per capita ($1358) and are therefore considered very cost-effective. Results were robust to varying healthcare costs, linkage to care rates, partner concurrency rates, and ART eligibility thresholds (≤350 cells/μl, ≤500 cells/μl, and universal ART).

Interpretation: APS is cost-effective for reducing HIV-related morbidity and mortality in western Kenya and similar settings. Task shifting can increase program affordability.

Figure 1

Simplified model schematic of HIV disease progression and the HIV care cascade among HIV-positive individuals. HIV-positive individuals progress through HIV disease stages and on to HIV-related death at rates σ (top to bottom); subscripts indicate the CD4 cell count category to which the rate applies. Infected individuals (and uninfected, not shown here) are tested at rate ρ, attend clinics for CD4 staging and other clinical tests at and initiate antiretroviral therapy at rate ε. Antiretroviral therapy dropout occurs at rate ψ irrespective of CD4 category at antiretroviral therapy initiation and individuals return to their previous CD4 count unlinked to care.

Figure 2

Health benefits and discounted costs associated with the aPS intervention under the base-case scenario (ART initiation for all HIV-positive persons). Ellipses encompass 90% model variability across 200 simulations. Health benefits shown are infections (A), HIV-related deaths (B), and disability adjusted life-years (DALYs) averted (C) for a population of 500, 000 persons at start of model projection.

Figure 3

Influence of varying healthcare costs on ICERs* *Base case scenario (universal ART initiation). Red lines represents Kenya’s GDP per capita, the threshold utilized for cost-effectiveness.