Evaluating strategies to improve HIV care outcomes in Kenya: a modelling study

Abstract

Background: With expanded access to antiretroviral therapy (ART) in sub-Saharan Africa, HIV mortality has decreased, yet life-years are still lost to AIDS. Strengthening of treatment programmes is a priority. We examined the state of an HIV care programme in Kenya and assessed interventions to improve the impact of ART programmes on population health.

Methods: We created an individual-based mathematical model to describe the HIV epidemic and the experiences of care among adults infected with HIV in Kenya. We calibrated the model to a longitudinal dataset from the Academic Model Providing Access To Healthcare (known as AMPATH) programme describing the routes into care, losses from care, and clinical outcomes. We simulated the cost and effect of interventions at different stages of HIV care, including improvements to diagnosis, linkage to care, retention and adherence of ART, immediate ART eligibility, and a universal test-and-treat strategy.

Findings: We estimate that, of people dying from AIDS between 2010 and 2030, most will have initiated treatment (61%), but many will never have been diagnosed (25%) or will have been diagnosed but never started ART (14%). Many interventions targeting a single stage of the health-care cascade were likely to be cost-effective, but any individual intervention averted only a small percentage of deaths because the effect is attenuated by other weaknesses in care. However, a combination of five interventions (including improved linkage, point-of-care CD4 testing, voluntary counselling and testing with point-of-care CD4, and outreach to improve retention in pre-ART care and on-ART) would have a much larger impact, averting 1·10 million disability-adjusted life-years (DALYs) and 25% of expected new infections and would probably be cost-effective (US$571 per DALY averted). This strategy would improve health more efficiently than a universal test-and-treat intervention if there were no accompanying improvements to care ($1760 per DALY averted).

Interpretation: When resources are limited, combinations of interventions to improve care should be prioritised over high-cost strategies such as universal test-and-treat strategy, especially if this is not accompanied by improvements to the care cascade. International guidance on ART should reflect alternative routes to programme strengthening and encourage country programmes to evaluate the costs and population-health impact in addition to the clinical benefits of immediate initiation.

Funding: Bill & Melinda Gates Foundation, United States Agency for International Development, National Institutes of Health.

Figure 1

Operational steps involved in navigating an ART programme Blue arrows show linkage step in which patients were seen by a clinician and had blood taken for a CD4 test. Grey arrows show the shortcut to immediate ART initiation taken by individuals presenting with WHO stage 3 or 4 symptoms. Dashed arrow shows ART reinitiation after loss from ART care (does not occur in the baseline programme). ART=antiretroviral therapy.

Figure 2

Distribution of care experience of patients who died from HIV ART=antiretroviral therapy. Late initiation is defined as a person with a CD4 count of less than 200 cells per μL.

Figure 3

Disability-adjusted life-years averted and additional cost of care (based on 2013 US$) for interventions acting on the cascade between 2010 and 2030 Optimal combination of interventions includes facilitated linkage, on-ART outreach, VCT point-of-care CD4, pre-ART outreach, and point-of-care CD4. ART=antiretroviral therapy. HBCT=home-based counselling and testing. VCT=voluntary counselling and testing.