Evaluating the Population Impact on Racial/Ethnic Disparities in HIV in Adulthood of Intervening on Specific Targets: A Conceptual and Methodological Framework

Abstract

Reducing racial/ethnic disparities in human immunodeficiency virus (HIV) disease is a high priority. Reductions in HIV racial/ethnic disparities can potentially be achieved by intervening on important intermediate factors. The potential population impact of intervening on intermediates can be evaluated using observational data when certain conditions are met. However, using standard stratification-based approaches commonly employed in the observational HIV literature to estimate the potential population impact in this setting may yield results that do not accurately estimate quantities of interest. Here we describe a useful conceptual and methodological framework for using observational data to appropriately evaluate the impact on HIV racial/ethnic disparities of interventions. This framework reframes relevant scientific questions in terms of a controlled direct effect and estimates a corresponding proportion eliminated. We review methods and conditions sufficient for accurate estimation within the proposed framework. We use the framework to analyze data on 2,329 participants in the CFAR [Centers for AIDS Research] Network of Integrated Clinical Systems (2008-2014) to evaluate the potential impact of universal prescription of and ≥95% adherence to antiretroviral therapy on racial disparities in HIV virological suppression. We encourage the use of the described framework to appropriately evaluate the potential impact of targeted interventions in addressing HIV racial/ethnic disparities using observational data.

Keywords: HIV; health status disparities.

Figure 1.

Causal diagram depicting receipt of human immunodeficiency virus (HIV) medical care and use of antiretroviral therapy (ART) as the main mediators of the influence of race/ethnicity on HIV-related outcomes in adulthood. AIDS, acquired immunodeficiency syndrome.

Figure 2.

Causal diagram depicting the relationship between African-American race and virological suppression in the unweighted data among 2,329 human immunodeficiency virus–infected African-American and Caucasian adults, CFAR Network of Integrated Clinical Systems, 2008–2014. Unmeasured variables have been omitted for simplicity. A box appears around “Censored” because the analysis is restricted to those participants who remain not censored due to dropout or death. ART, antiretroviral therapy.

Figure 3.

Causal diagrams depicting the relationship between African-American (AA) race and virological suppression in the weighted data among 2,329 human immunodeficiency virus (HIV)–infected AA and Caucasian adults, CFAR Network of Integrated Clinical Systems, 2008–2014. In diagram A, potential selection bias because of censoring due to dropout or death related to certain measured covariates is accounted for. In diagram B, potential selection bias because of censoring due to dropout or death and potential confounding of the relationship between antiretroviral therapy (ART) prescription and adherence and virological suppression related to certain measured covariates is accounted for. Unmeasured variables have been omitted for simplicity. A box appears around “Censored” because the analysis is restricted to those participants who remain not censored due to dropout or death. The arrows from gender, year of birth, and AA race to “Censored” and “ART prescription and adherence” remain because gender, year of birth, and AA race were used to stabilize the weights.