Background
For persons with HIV, the ability to remain retained in care plays a critical role in achieving good health outcomes and in preventing HIV transmission to others. In a general sense, retention in care is defined as a patient’s regular engagement with medical care at a health care facility after initial entry into HIV clinical care. Despite tremendous advances in HIV treatment, a significant proportion of persons with HIV do not consistently receive antiretroviral therapy, often due to decreased engagement in long-term clinical care. Recent work has shown that lower retention rates in HIV medical care correlate with worse outcomes and increased transmission of HIV.[1,2,3,4] In contrast, higher retention rates in care correlate strongly with suppression of HIV RNA levels, improved health outcomes, and lower risk of transmitting HIV.[5,6,7,8] The National HIV/AIDS Strategy: Updated to 2020 set a goal that at least 90% of persons with diagnosed HIV in the United States are retained in HIV medical care.[9] In addition, improving screening, linkage, and retention in HIV care is clearly one of the key priorities in the bold new initiative—Ending the HIV Epidemic: A Plan for America.[10] More formal definitions and measurements have utilized required follow-up at certain intervals to define retention in care; these definitions have typically conceptualized retention in care based on appointments missed or medical visits attended at regularly defined intervals.[11]
HRSA and HIV Care Continuum
The discussion of retention in care for people with HIV should be in the context of the overall HIV Care Continuum. The concept and foundation of the HIV Care Continuum were initially introduced by the Health Resources and Services Administration (HRSA) as the Continuum of Engagement in HIV Care—a model that described the spectrum of engagement in HIV clinical care, spanning from persons unaware of their HIV status to those fully engaged in HIV care.[12] The Engagement in HIV Care model was modified and adapted by HRSA and now is prominently known as the HIV Care Continuum, a model that outlines the sequential steps or stages of HIV medical care that persons with HIV go through, beginning with initial diagnosis to achieving consistent suppression of plasma HIV RNA levels (Figure 1).[13,14] Using this model, clinics, health officials, and policymakers can determine the proportion of individuals with HIV at each one of the stages in the HIV Care Continuum, and this process can help to identify where problems may exist in the overall care of persons with HIV. Each stage included in the HIV Care Continuum serves as a key benchmark indicators in the National HIV/AIDS Strategy for the United States. The following summarizes current estimates for the HIV Care Continuum in the United States.
CDC and Prevalence-Based HIV Care Continuum
The Centers for Disease Control and Prevention (CDC) provides prevalence-based HIV care continuum data based on persons living with HIV (diagnosed or undiagnosed) (Figure 2).[15] The HIV prevalence used as the starting point for this model includes an estimate of all people living with HIV in the United States during the year of reporting, irrespective of when they acquired HIV and regardless of whether or not they have received an HIV diagnosis. These data are from 48 states and the District of Columbia.[15]