A snapshot of the current national HIV/AIDS epidemic in the United States indicates that only an estimated 19% of the 1.1 million persons living with HIV/AIDS (PLWHA) have achieved the guidelines-recommended treatment goals by suppressing their HIV plasma viral load to an undetectable level (< 50 copies/mL),^[1-3] whereas 4 out of 5 have failed to successfully navigate the treatment cascade.^[1] Loss to care can occur at any one of the steps across a continuum of care that begins with serostatus awareness through HIV testing and is followed by engagement in HIV medical care, antiretroviral therapy (ART) initiation, and persistence and adherence to treatment to ultimately achieve viral load suppression (Figure).^[4,5] Beyond the vital implications to individual health outcomes, failure to achieve virologic suppression has critical public health implications. Patients with unsuppressed HIV infection contribute to high HIV community viral load,^[6,7] allowing for secondary HIV transmission and propagating the continued spread of the domestic epidemic with an estimated 56,000 new cases annually.^[8] The recently released study findings of HPTN 052 demonstrated a 96% reduction in HIV transmission among serodiscordant couples attributable to viral load suppression in response to immediate vs deferred ART^[9] and generated considerable excitement among the scientific and lay communities. These findings have bolstered enthusiasm and contributed additional evidence support for the treatment as prevention paradigm, with recent initiatives focusing on "test and treat^[10]" or test, link-to-care plus (TLC+)^[11] strategies. However, the current national landscape indicates that considerable work lies ahead if we are to achieve the promise of treatment as prevention and successfully translate research findings to a population level and meaningfully affect HIV transmission dynamics, thereby reducing incident HIV infections.

Figure. The spectrum of engagement in HIV care in the United States spanning from HIV acquisition to full engagement in care, receipt of antiretroviral therapy, and achievement of complete viral suppression. Only an estimated 19% of HIV-infected individuals in the United States have an undetectable HIV viral load.
From Gardner EM, et al. Clin Infect Dis. 2011;52:793-800.^[1]

HIV Care Continuum

Of those PLWHA who reach the ART step in the HIV treatment cascade (Figure), an overwhelming majority are able to achieve virologic suppression.^[1] However, the formidable barriers faced at the earlier steps of the cascade in identifying the estimated 21% of HIV-infected Americans unaware of their serostatus^[12] and promoting linkage to and retention in HIV medical care limit the benefits of sustained ART. A recent meta-analysis indicated that only 72% (95% confidence interval [CI], 67%-77%) of individuals newly diagnosed with HIV infection in the United States entered medical care within 4 months of diagnosis.^[13] Moreover, entry into medical care with advanced HIV infection as measured by a low CD4 count (below 200 or 350 cells/µL) and/or an AIDS-defining condition is common.^[14] Such late presentation for HIV medical care results in considerable morbidity and mortality, with a 9- to 14-fold increased 1-year mortality observed among patients with initial CD4 counts < 200 cells/µL^[15] and persistently elevated mortality rates up to 4 years after entry into care.^[16] Promoting timely HIV diagnosis and linkage to HIV medical care is of vital importance.

The US Centers for Disease Control and Prevention (CDC) HIV prevention strategic plan has long included a goal of linking at least 80% of individuals to medical care within 3 months of an incident diagnosis.^[17] The US National HIV/AIDS Strategy released in July 2010 raised the stakes by setting a goal of 85% linkage to care within 3 months of diagnosis by 2015.^[18] The critical question then is this: How can providers better identify patients who are less likely to be linked to care? Moreover, how can they use this information to design and implement better programs and interventions that will increase linkage to and retention in care? This article reviews the literature in regard to patient- and system-level factors that influence the timing of linkage to medical care following an HIV diagnosis, ie, predictors of late entry into care, and further describes best evidence and model programs to promote timely linkage to and engagement in HIV medical care.

Barriers to Initial Linkage to Care

Engagement in HIV care begins at testing, and recent studies highlight the incredible importance of HIV counseling, testing, and referral (CTR) experience as it relates to subsequent linkage to medical care. In a study carried out by the CDC in 3 US cities, the investigators conducted qualitative and structured interviews with 42 individuals diagnosed with HIV infection for 5-19 months who had not yet sought care.^[19] Dissatisfaction with the CTR experience was a salient theme among participants; a negative experience with the tester or counselor and/or provision of inadequate information or misinformation at the time of testing served as deterrents to seeking medical care. Participants also voiced concerns in regard to gaps in follow-up services and referrals following the CTR experience, most of which were for case management services and limited to one-time interactions. At an individual level, fear of disclosure, privacy considerations, distrust of medical providers, feelings of shame, and lack of motivation were identified as barriers to seeking medical care. System-level barriers were also cited, with challenges related to navigating the healthcare and criminal justice systems and lack of financial means or health insurance most often identified as the primary reason(s) for not connecting to medical care. Perhaps the most striking study finding related to the importance of active rather than passive referral for follow-up case management and/or medical services. Participants reported limited effectiveness of written pamphlets, brochures, and other materials providing basic information about HIV infection and local treatment resources. Rather, active referral, whereby the tester made the appointment and/or accompanied the participant to the appointment had a positive influence on the CTR experience. These findings were validated by findings from the Health Resources and Services Administration (HRSA) Special Projects of National Significance (SPNS) initiative,^[20] which found that active referral to care and, more specifically, the tester arranging the medical appointment were significantly (P = .009) associated with early linkage to care among young men of color who have sex with men. These studies highlight the importance of the counseling component of the HIV CTR encounter and active referral for longitudinal case management or medical services as critical elements to promote timely linkage to care following a positive HIV test.

Studies have indicated that other HIV testing factors also have considerable influence over delayed entry to medical care (Table 1). Moreover, a study examining predictors of failure to establish HIV care (or initial clinic no-shows) identified female gender, racial/ethnic minority status, public health insurance or lack of insurance, and nonlocal residence as factors highly associated with delayed linkage to HIV care.^[21] In addition, data show that shortening the time period between an initial call and a scheduled HIV medical appointment was associated with a greater likelihood of expeditious linkage to medical care.^[21,22] Taken together, these studies highlight additional individual and system-level factors related to HIV testing and referral for follow-up services that have profound implications on delayed entry to care.

Table 1. Factors Associated With Delayed Entry Into HIV Care

CI = confidence interval; HR = hazard ratio; OR = odds ratio; STI = sexually transmitted infection; TB = tuberculosis
^aData from Reed JB, et al. AIDS Patient Care STDS. 2009;23:765-773.
^bData from Torian LV, et al. Arch Intern Med. 2008;168:1181-1187.

Barriers to Retention in HIV Care

Data have shown that a number of issues can affect continuity of HIV care even after the initial linkage occurs. A study by Tobias and colleagues of 978 patients living with HIV infection used multivariate logistic regression modeling to identify factors significantly associated with failure to receive care in the previous 6 months, including sociodemographic and structural barriers (Table 2).^[23] Additional risk factors for loss to follow-up after receiving initial care have also been described. For example, in a study conducted in Atlanta, Georgia, and Miami, Florida, 40% of patients (N = 1038) had not seen their HIV medical care provider in the preceding 6 months. Female gender, age < 40 years, heavy alcohol use in the preceding 6 months, and not currently taking antiretroviral medications were significantly associated with loss to follow-up in this patient population.^[24] Dissatisfaction with the HIV care provider or reception staff, transportation, hospital site, lack of high school education, higher CD4 counts, and financial issues were also cited as reasons for discontinuation of care.^[25,26] Thus, beyond striving to facilitate initial linkage to care, providers should be aware of the many barriers that can affect retention in care for their patients with HIV.

Table 2. Multivariate Logistic Regression Modeling of Factors Associated With Receipt of Care (N = 978)

Data from Tobias CR, et al.^[23]

Despite the importance and considerable challenges faced in linking newly diagnosed PLWHA to medical care, a paucity of interventions have been evaluated to promote timely care entry. In recent years, increased attention has focused on the importance of the earlier steps in the HIV treatment cascade (Figure), including linkage and retention in care, with a new recommendation from the HIV Medicine Association that the concept of adherence should be extended beyond ART medications and include adherence to care.^[27] These interventions include the CDC Antiretroviral Treatment Access Study (ARTAS)^[28] and The University of Alabama at Birmingham Project CONNECT (Client Oriented New patient Navigation to Encourage Connection to Treatment).^[5] These and other strategies to improve linkage to and retention in HIV care are described in detail in the second part of this CME activity.

Measuring Linkage to and Retention in HIV Care

Beyond describing the individual and system-level barriers and interventions to linkage to HIV medical care, it is important to discuss the challenges faced in measuring linkage to care as we look to the future and the need to evaluate progress toward achieving the goals set forth by the CDC and National HIV/AIDS Strategy.^[17,18] Two dates are required to measure the time from HIV diagnosis to linkage to medical care: (1) the date of HIV testing and patient notification and (2) the date of the initial primary HIV medical care visit. A recent study demonstrated considerable variability in documentation of the HIV testing date when comparing surveillance (CDC HARS) data with medical record data and patient self-report,^[29] raising the question of the "right" data source for the first required date. Similar challenges are faced when considering the data source for capturing the initial primary HIV medical care visit date. This information can be provided by clinics providing medical services, which may lack accurate information in regard to the HIV testing date, and thus are unable to independently calculate the time from HIV diagnosis to linkage to care without concern for misclassification. In recent years, expanded HIV surveillance data capture including mandatory reporting of CD4 and viral load tests have been increasingly used as a proxy to measure HIV medical care utilization.^[30-33] Public health departments have used surveillance data to record the 2 data elements needed to calculate time from diagnosis to entry to care^[31,33] with publicly reported CD4 counts and/or viral loads as a surrogate for an initial medical care visit. However, it remains to be evaluated how accurately publicly reported HIV biomarkers serve as a proxy for a primary HIV medical care visit because PLWHA can obtain these laboratory results in other settings including inpatient hospital services, emergency departments, and urgent care settings. Although definitive recommendations cannot be made at this time in regard to the optimal approach to measure timely linkage to HIV medical care, it is imperative that persons working in this area have an appreciation of the complexity and importance of accurately recording this step on the treatment cascade both at a local and national level.

In summary, as stated in the National HIV/AIDS Strategy, the United States "is at a crossroads " and is faced with considerable challenges to individual and population treatment success across the continuum of HIV care.^[1,4,17] However, with this challenge comes incredible opportunity. An overwhelming majority of PLWHA who are able to access ART successfully achieve viral load suppression. Unfortunately, a sizable proportion of PLWHA in the United States are not consistently accessing ART because of failures at earlier steps along the HIV treatment cascade (Figure).^[1] Both individual and system-level factors serve as impediments to timely linkage to HIV medical care following diagnosis but are amenable to interventions. Specifically, the importance of counseling and active referral along with effectiveness of brief case management, skills building, and clinic-based system navigation programs hold promise and provide building blocks to foster more expedient entry to care. As we await the results of ongoing intervention studies, it is clear that opportunities already exist to critically examine our approaches to HIV counseling, testing, referral, and linkage to care, and to integrate and enhance these activities to promote more timely access to care and ART for newly diagnosed PLWHA.

Supported by an independent educational grant from Bristol-Myers Squibb and Gilead.