We used the Center for Disease Control and Prevention (CDC)’s HIV/AIDS Prevention Research Synthesis (PRS) (http://www.cdc.gov/hiv/topics/research/prs) project’s cumulative HIV/AIDS/STI prevention database [36] to identify relevant citations. Two subject-experienced librarians annually update the PRS database with automated and manual searches. The automated search was conducted in October, 2011 and then updated in May, 2012 for capturing those citations due to publication gaps. It consisted of searching in MEDLINE, EMBASE, CINHAL, and PsycINFO by cross-referencing multiple search terms (i.e. index terms, keywords, and proximity terms) in three areas: HIV-positive persons; prevention/intervention/evaluation; and health care utilization descriptors (e.g., health care access, case management, health services, linkage, retention) for citations available in these electronic databases between January 1996 and December 2011. The on-going manual search consisted of checking reference lists of pertinent articles, examining HIV/AIDS Internet listservs (i.e., adherence@ghdonline.org; www.RobertMalow.org) and other government funded projects and programs such as those located on the Health Resources and Services Administration (HRSA) website devoted to Special Projects of National Significance (SPNS) (http://hab.hrsa.gov/abouthab/special/spnsproducts.html). Additionally, we hand-searched 2010–2012 conference abstracts presented at the International Conference on HIV Treatment and Prevention Adherence (herein referred to as “Treatment and Adherence Conference”) and at the Conference on Retroviruses and Opportunistic Infections (CROI).

Studies were included in this review if they met all of the following criteria: (1) U.S.-based studies of interventions designed exclusively to improve retention or interventions that included retention as part of a broader intervention focusing on HIV-diagnosed persons; (2) studies that included tests of statistical significance of the intervention effect or provided descriptive data (without statistical tests) that could be used to interpret whether the intervention improved retention; and (3) measured retention in care which was operationally defined as having multiple HIV medical care visits within specified time intervals. The number of visits and the time intervals could vary across studies [15, 37, 38]. Studies were excluded if they focused only on initial entry into HIV care or if they focused on medical care other than care for HIV infection.

Due to the heterogeneity among studies in target population, study design, measurement, and analysis, we conducted a qualitative review instead of a meta-analysis. We extracted information on study characteristics such as study dates, location, and target sample. We treated reports that provided data from the same project (e.g., HRSA SPNS outreach project) as independent studies even though some may have used pooled data from different sites. We also extracted information on study characteristics such as analytic sample size, data collection method, measures used, study design, and findings. We described how studies measured the outcome (e.g., self-report, medical records), the type of retention in care outcome that was used (e.g., multiple visits over time, gaps in care), and the study design. The studies had a variety of designs including randomized controlled trials (RCTs), comparisons to a historical control group, 1-group pre-post designs, and 1-group post-only designs that collected retention data after implementation of the intervention but not before the intervention started. For these 1-group post-only studies, we compared the post-intervention data to findings from a recent meta-analysis [15]that found an aggregated retention rate of 54% for 2 or more visits in a 12-month period. We assessed the strength of intervention findings based on study design (e.g., RCTs offer the strongest evidence).

We also extracted information on select intervention characteristics (e.g., goals, settings, deliverers, duration, and strategies). For intervention duration, we abstracted the number of sessions and the length of the intervention. Intervention strategies were classified into 10 categories: (1) ancillary services other than case management (e.g., child care, emergency financial assistance, housing, drug treatment, and mental health services) (2) appointment accompaniment (i.e., taking the client to the medical provider and in some cases being with the client during the medical exam), (3) appointment coordination (e.g., making or helping clients make medical care appointments), (4) case management or making referrals to case management or helping access and coordinate social services, (5) cognitive-behavioral strategies (e.g., establishing rapport, counseling, motivational interviewing, social support), (6) co-location of services (e.g., having medical care and social services in the same agency), (7) home visits or home-based services, (8) media (e.g., brochures and posters in exam rooms), (9) outreach, and (10) transportation services (e.g., providing transport to medical appointments).

Studies in this review reported similar intervention goals but reported different intervention settings, deliverers, durations, and strategies to help keep HIV-diagnosed persons in care (see Table 2). Eleven (85%) studies reported retention in care as a primary intervention goal and 1 of these studies focused primarily on initial entry into care but also assessed whether the intervention improved clinic attendance after the initial linkage [39]. The remaining two studies [48, 49] reported a broader intervention focus such as reducing HIV transmission or stabilizing housing but also included retention in care as an outcome. Interventions were conducted in various settings; the most common setting was medical clinics (n=10, 77%), followed by community-based organizations (CBOs; n=5, 33%), patient residences (n=2, 15%), research offices (n=2, 15%) and community outreach (n=1, 8%), not mutually exclusive. Studies also reported diverse intervention deliverers including case managers (n=5, 38%), peers (n=4, 31%), and health care providers (e.g., nurses, physicians) (n=4, 31%). For intervention duration, studies reported a range from 2 to 30 intervention sessions. A couple of studies reported offering services on an “as needed” basis such as providing transportation [33]. The most common length for an intervention was 12 months (n=6; 46%). The majority of studies (n=10, 77%) used multiple intervention strategies to facilitate retention in care. The most common intervention strategies were cognitive-behavioral approaches (n=10, 77%), case management (n=10, 77%), co-location of services (n=3, 23%), and appointment accompaniment (n=3, 23%). Less common strategies included appointment coordination, transportation services, home-based services, providing ancillary services, outreach, and media.

Of the 13 studies reviewed, 10 (77%) found evidence that interventions improved retention in care. Table 1 describes the findings and how this outcome was operationalized in the studies. The strongest evidence comes from the Antiretroviral Treatment and Access Study (ARTAS) intervention [39], an RCT that primarily focused on promoting initial entry into care, but also assessed retention in care for recently diagnosed persons. The intervention tested a strengths-based case management model compared to a passive referral to medical care. Findings from ARTAS indicated that 64% in the intervention group and 49% of the passive referral group had care visits in each of the two consecutive 6-month periods; adjusted relative risk = 1.41, p=0.006).

Significant intervention effects were seen in studies that used less rigorous designs. For example, young ethnic-minority MSM who received a comprehensive retention in care intervention (e.g., outreach, case management, appointment coordination, and co-locating medical and social services) reported a higher percent of having 3 or more visits within the first year of enrollment compared to a historical control group [42]. Another study found that ethnic-minority youth who received HIV care from adolescent-specialist care providers and received enhanced services such as youth-focused psychosocial and educational services (e.g., improving self-efficacy, teaching health care navigation skills) were significantly less likely to have gaps in HIV care compared to youth who received HIV care from adolescent specialists without enhanced services [46]. No significant differences were found, however, when retention in care was operationalized as visit constancy (e.g., having 3 or more quarters with at least 1 visit in a year) [46].

Intervention effectiveness was also seen in 1-group pre-post study designs. One study used patient navigators to accompany clients to appointments, guide clients through the complex health care system and teach skills in communicating with providers [41]. Participants having 2 or more primary HIV care visits significantly increased from 64% pre-intervention to 87% at 6 months and 79% at 12 months post-intervention. A recent study found that clinic-wide brief messages from physicians, brochures given to patients, and posters in clinic waiting rooms significantly improved appointment keeping for primary care compared with appointment keeping at the clinic during the 12 months preceding onset of the intervention [44]. Another study found that the number of annual HIV specialty clinic visits for Spanish-speaking patients significantly increased from 2.81 to 5.30 when a bilingual/bicultural health care team was added to a medical clinic [47]. Although no statistical tests were reported, the two studies that included providing transportation as a major intervention component showed considerable increases in the relative percentages of participants who did not miss any HIV medical appointments in the past 6 months [33]. In the transportation-only intervention, the relative percentage increases for the first and second 6-month periods were 63% and 66% respectively. For women with mental health and/or substance abuse problems who received transportation and case management, the relative percentage increases for the first and second 6-month periods were 80% and 83% respectively.

Studies with only post-intervention data also reported promising findings when compared to the aggregated retention rate of 54% for 2 or more medical visits over a 12-month period based on Marks et al’s [15] meta-analysis of observational studies. As one example, one study provided intensive outreach services (e.g., using a mobile van in the community to offer HIV education and help with accessing resources) and reported 81% of their sample had a medical appointment in both 6-month periods over a 1 year interval [40]. Another study implemented a youth-focused case management intervention and found 70% of young ethnic minority MSM had attended 2 or more HIV care appointments in the past 6 months [43].

Two studies did not find positive intervention effects. Both studies were RCTs. One study tested the impact of peer mentoring training on HIV care use and risk reduction with intravenous drug users (IDUs) and found no significant increases in use of HIV care compared to a video discussion control [48]. This study did not exclusively focus on retention in care but included it as one of the outcomes. Similarly, the other study assessed the effect of immediate housing rental assistance on multiple outcomes, including retention of unstably housed persons in HIV medical care. No significant effects were found for retention in HIV care [49].

The remaining study [45] was a RCT but did not test an intervention to decrease gaps in care against a control group. Instead, the researchers tested motivational interviewing delivered by peers versus professionals for reducing gaps in care for newly HIV-diagnosed persons. The findings indicated no significant differences between the groups, suggesting that both types of intervention deliverers did equally well on the outcome.

A few papers presented at recent Treatment and Adherence Conferences (2011, 2012) focused on retention in care interventions. None were identified at CROI from 2010–2012. Zinski et al. (2011) presented a systematic review of peer interventions indicating that peers working independently or as part of a care team promoted access to and retention in HIV primary care [50]. Effective peer-related intervention strategies included frequent contact with the HIV-diagnosed person, life skills development, appointment accompaniment, counseling and education related to treatment, and comprehensive assessment and help with unmet needs. Konkle-Parker et al. (2012) reported on a test of a multi-dimensional intervention targeting both medication adherence and retention in care using HIV education, motivational interviewing, training on medication adherence strategies, and patient-provider communication versus a standard of care [51]. Using an analytic sample of patients who had less than 1 visit per quarter, the study found significantly more patients fully retained in care (at least 1 visit per quarter) if they had at least 3 contacts with an interventionist. Gardner et al.’s (2012) preliminary results of an RCT conducted at 6 U.S. HIV clinics indicated that patients who received enhanced contact across a period of 12 months (reminder calls, interim visit call, missed visit call) had significantly higher primary care appointment adherence (proportion of scheduled appointments kept) and visit constancy (care visit in each of three consecutive 4-month periods) compared with patients who received the clinic’s standard of care [52].

There is evidence that interventions can improve retention in care among HIV-diagnosed individuals. Interventions that focus specifically on engaging and retaining patients in care may produce more favorable outcomes than interventions that target multiple issues or include broader prevention goals such as risk reduction. Findings from this review also suggest that using multiple intervention strategies within a single study may be effective. Using multiple retention strategies appears to be necessary to effectively address the multiple barriers to accessing and consistently using HIV primary care. In terms of specific intervention strategies, case management approaches that utilize patients’ strengths and help patients navigate increasingly complex health care systems seem to be especially beneficial in retaining persons in care. These approaches tend to involve the HIV-diagnosed individual as a partner in his or her own health care. Other evidence-informed interventions reduce or remove barriers to health care access such as accompanying patients to medical appointments, providing transportation, co-locating services, conducting intensive outreach (e.g., using a mobile van to provide services in the community), and providing bilingual and culturally competent care. Although time and resource-intensive, these strategies may be necessary to engage persons who are multiply diagnosed (e.g., HIV-diagnosed and substance abuse problems) or who are often marginalized in the health care system. Practical strategies that help patients remember appointments or the importance of keeping appointments such as reminder calls and brochures/posters in clinic waiting rooms also facilitate retention in care. Strategic messaging via health care providers and printed materials may be useful in health care clinics with limited resources. Additionally, including peers as advocates, outreach workers, and navigators/case managers on the HIV-diagnosed person’s health care team may be a crucial component to increase retention in care. In particular, HIV-diagnosed youth may benefit from working with trained peer interventionists.

Our review also identified areas where intervention strategies for retaining persons in care could be improved. For example, most strategies were targeted at the individual. A few structural- or system-level interventions, such as co-locating services, adding a bilingual/bicultural health care team to a medical clinic, or displaying posters in waiting rooms were assessed, but these strategies were infrequently utilized. Intervention strategies that address structural- and system-level barriers such as appointment tracking systems, flexible clinic hours, using health department surveillance data to track persons missing in care, and reducing HIV-related stigma were given little attention. Our review also found that relatively few interventions were being implemented in non-medical settings such as CBOs. CBOs may be underutilized in efforts to promote retention in care. For example, CBOs may play a role in communicating messages about the importance of staying in care and provide or make referrals to medical care or to critical ancillary services that may enhance retention in care. Finally, we found a lack of intervention strategies that intervened with health care providers and significant others of the HIV-diagnosed individual (e.g., family, partners, friends). Intervening with health care providers and involving significant others to improve retention in HIV care remains largely understudied and may be a critical piece in keeping HIV-diagnosed persons in care.

There were several studies that did not use a comparison group to test the intervention. Although having a comparison group may not always be feasible in CBOs or smaller health care clinics, researchers should strive for including comparison groups in their study designs to advance the field. When RCTs cannot be feasibly implemented, study designs such as historical and pre-post designs offer alternative methods, especially when used to evaluate operational research and program implementation. Another methodological issue is that almost half of the studies relied on self-reported measures of retention in care which may be prone to recall and social desirability bias. Although medical records are not without error, these records may provide a more accurate assessment of retention, especially when the outcomes are being monitored across long periods of time. State surveillance systems of viral load and CD4 laboratory testing results are also becoming available and could be put to use by researchers, program evaluators, and public health personnel for monitoring retention in care and conducting re-engagement activities. An additional methodological issue was that the majority of the studies in this review relied on a single measure of retention. Recent research suggests using multiple measures of retention may be important [54]. For example, measuring visit constancy (e.g., number of consecutive quarters seen for primary care) captures something slightly different than appointment adherence (proportion of scheduled appointments kept). A patient can have perfect appointment adherence, but only be seen at a clinic once a year, which is not optimal. To help address methodological issues for retention in care interventions, the CDC’s Prevention Research Synthesis (PRS) team are developing criteria to evaluate linkage and retention in care interventions, strategies, and programs.