Improving Social Determinants of Health Significantly Reduce AIDS Incidence: A Modeling Study of 1.17 Million Individuals in Brazil

Abstract

Despite progress in addressing HIV/AIDS, the burden remains uneven, especially in low- and middle-income countries (LMICs). Social determinants of health (SDH) significantly influence HIV/AIDS. We studied the impact of SDH inequalities on AIDS incidence in Brazil, a large and diverse LMIC. We used an agent-based model (ABM) to introduce the SDH inequalities of income, education, sex, and race in an HIV/AIDS model of 1,172,721 residents in ten Brazilian state capitals. We simulated the poorest half of the population using the CadastroÚnico database and calibrated our baseline models for each city with AIDS incidence from 2012 to 2019. We compared them with alternative scenario where the effect of inequalities in SDH was removed. The difference between scenarios and by sub-populations were measured in terms of cumulative rate-ratios (RR), and avoidable cases over the study period. If there was no inequality in income, education, sex, and race, there would be 38.8% lower AIDS incidence (95%CI: 33.0%- 44.4%) compared with the baseline scenario. Furthermore, AIDS incidence was lower among individuals with low-income (44.9%, 95%CI: 34.7%-61.0%), lower education (39.8%, 95%CI: 34.6%-46.5%), and people of Brown or Black race (39.3%, 95%CI: 33.5%-47.3%), in the alternative scenario compared with the baseline scenario. Furthermore, addressing inequality in the selected SDH had a positive spillover effect in reducing AIDS incidence in high-income (31.0%,95%CI: 23.3%-48.8%), high-educated (13.7%, 95%CI: 8.4%-27.8%), and White or Asian (35.4%, 95%CI: 27.5%-46.6%) populations, indicating a strong benefit to the whole of society. Our results suggest that addressing social inequalities in key SDH could reduce the number of AIDS cases among Brazil's poorest population by at least a third from 2012-2019. This effect is particularly significant in sub-populations with higher vulnerabilities. Implementing social protection policies to tackle these inequalities has the potential to help control the HIV/AIDS epidemic and advance the AIDS-related Social Development Goals (SDG).

JEL Classification: I15