Patterns and predictors of racial/ethnic disparities in HIV care continuum in the Southern USA: protocol for a population-based cohort study

Introduction Health disparities exist at every step of the HIV care continuum (HCC) among racial/ethnic minority population. Such racial/ethnic disparities may have significantly delayed the progress in HCC in the Southern US states that are strongly represented among geographic focus areas in the 2019 federal initiative titled 'Ending the HIV Epidemic: A Plan for America'. However, limited efforts have been made to quantify the long-term spatiotemporal variations of HCC disparities and their contributing factors over time, particularly in the context of COVID-19 pandemic. This project aims to identify the spatiotemporal patterns of racial disparities of each HCC outcome and then determine the contribution of contextual features for temporal change of disparities in HCC. Methods and analysis This cohort study will use statewide HIV cohort data in South Carolina, including all people living with HIV (PLWH) who were diagnosed with HIV in 2005-2020. The healthcare encounter data will be extracted from longitudinal EHR from six state agencies and then linked to aggregated county-level community and social structural-level data (eg, structural racism, COVID-19 pandemic) from multiple publicly available data sources. The South Carolina Revenue of Fiscal and Affairs will serve as the honest broker to link the patient-level and county-level information. We will first quantify the HCC-related disparities by creating a county-level racial/ethnic disparity index (RDI) for each key HCC outcomes (eg, HIV testing, timely diagnosis), examine the temporal patterns of each RDI over time and then using geographical weighted lasso model examine which contextual factors have significant impacts on the change of county-level RDI from 2005 to 2020. Ethics and dissemination The study was approved by the Institutional Review Board at the University of South Carolina (Pro00121718) as a Non-Human Subject study. The study's findings will be published in peer-reviewed journals and disseminated at national and international conferences and through social media.