Palacio-Vieira et al. BMC Public Health (2021) 21:1596 https://doi.org/10.1186/s12889-021-11613-y RESEARCH ARTICLE Open Access Strategies to reengage patients lost to follow up in HIV care in high income countries, a scoping review Jorge Palacio-Vieira1,2,3* , Juliana Maria Reyes-Urueña1,2,4, Arkaitz Imaz5, Andreu Bruguera1,4, Luis Force6, Amat Orti Llaveria7, Josep M. Llibre8, Ingrid Vilaró9, Francesc Homar Borràs10, Vicenç Falcó11, Melchor Riera12, Pere Domingo13, Elisa de Lazzari14, Josep M. Miró14, Jordi Casabona1,2,3 and PICIS study group Abstract Background: Despite remarkable achievements in antiretroviral therapy (ART), losses to follow-up (LTFU) might prevent the long-term success of HIV treatment and might delay the achievement of the 90–90-90 objectives. This scoping review is aimed at the description and analysis of the strategies used in high-income countries to reengage LTFU in HIV care, their implementation and impact. Methods: A scoping review was done following Arksey & O′Malley’s methodological framework and recommendations from Joanna Briggs Institute. Peer reviewed articles were searched for in Pubmed, Scopus and Web of Science; and grey literature was searched for in Google and other sources of information. Documents were charted according to the information presented on LTFU, the reengagement procedures used in HIV units in high-income countries, published during the last 15 years. In addition, bibliographies of chosen articles were reviewed for additional articles. Results: Twenty-eight documents were finally included, over 80% of them published in the United States later than 2015. Database searches, phone calls and/or mail contacts were the most common strategies used to locate and track LTFU, while motivational interviews and strengths-based techniques were used most often during reengagement visits. Outcomes like tracing activities efficacy, rates of reengagement and viral load reduction were reported as outcome measures. Conclusions: This review shows a recent and growing trend in developing and implementing patient reengagement strategies in HIV care. However, most of these strategies have been implemented in the United States and little information is available for other high-income countries. The procedures used to trace and contact LTFU are similar across reviewed studies, but their impact and sustainability are widely different depending on the country studied. Keywords: Cohort studies, HIV, Lost to follow-up, Reengagement, Linkage * Correspondence: jpalacio@ceeiscat.cat 1 Centre for Epidemiological Studies on Sexually Transmitted Infections and HIV/AIDS of Catalonia (CEEISCAT), Badalona, Spain 2 CIBER Epidemiologia y Salud Pública (CIBERESP), Barcelona, Spain Full list of author information is available at the end of the article © The Author(s). 2021 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data. Palacio-Vieira et al. BMC Public Health (2021) 21:1596 Page 2 of 11 Background In a step forward, USAID extended their target strat- Effective HIV antiretroviral therapy (ART) controls viral egy to 95–95-95 by 2030 [16], which implies not only a replication, enhances or maintains immune function and need to increase retention in care, improve ART adher- decreases morbidity and mortality, allowing people living ence and VS but also proactively reengage lost patients with HIV (PLWH) to have a life expectancy comparable by hiring case managers to locate and give these patients to general population and helps prevent new infections the support they need to attend their clinical visits [17]. [1–3]. Several studies have demonstrated the effect of However, previous studies aimed at identifying the best antiretroviral drugs in preventing HIV transmission by measures to increase linkage, retention and reengagement suppressing HIV RNA replication in people living with to HIV care found no evidence-based interventions ad- HIV (PLWH) to undetectable levels (treatment as pre- dressing reengagement [18] and described as major diffi- vention [TasP]), a strategy which has led to the ‘Un- culties LTFU tracing, updating whereabouts data, lack of detectable equals Untransmittable’ (or ‘U=U’) campaign clinical records and time-gaps between HIV laboratory aimed at advocating for early access to HIV testing and testing and initiating treatment [19]. The description and treatment and motivate patients in the need to become analysis of previous experiences will allow us to design, virally suppressed through constant follow-up care [4]. prepare and deploy a new evidence-based reengagement Since it has been demonstrated that sexual transmission strategy directed at LTFU HIV positive patients in Catalo- of HIV does not occur if undetectable blood plasma HIV nia and Balearic Islands, nested and piloted within a RNA is maintained [5, 6], treatment for HIV also pre- population-based cohort (PISCIS cohort), in order to help sents a great opportunity to reduce stigma and trans- reduce the risk of untreated and disengaged HIV positive form PLWH’s sexual relationships [7]. However, despite patients. The objective of this scoping review is to evaluate ART’s success, patient attrition and loss to follow-up the current knowledge on LTFU patient reengagement, (LTFU) remain legitimate threats to the long-term suc- describe procedures used to re-link LTFU patients into cess of ART scale up. treatment, and determine which factors play a role in the The ambitious but achievable 90–90-90 UNAIDS tar- implementation of these strategies. get proposes that by 2020 90% of all PLWH know their HIV status, 90% of all people diagnosed HIV infection Methods receive sustained antiretroviral therapy, and 90% of all Following scoping review methods described by Arksey people on ART maintain viral suppression (VS )[8]. In H & O’Malley and the corresponding guidance devel- this sense, the main barriers in achieving this target in oped by Peters et al. and Joanna Briggs Institute [20], we high income countries are patients lost during any of divided our review strategy into the following steps [21]: these three steps. Results from a multicentre study ana- lysing 31 countries form Europe has shown that LTFU – Stage 1: identify the research question (defined as 12 months of HIV care disengagement) was 22%, and were mostly men, young, people who inject This review was guided by the question: “What is drugs and patients with high viral loads [9]. In another known about those interventions used to reengage pa- UK study, LTFU reached 28.1% of disengagement during tients in HIV treatment and reduce lost to follow-up?” nine consecutive months, and further analysis of these patients showed that 26% were found as transferred to – Stage 2: identify relevant studies clinics outside the UK [10]. In Spain, cohort studies re- ported 15% of LTFU (disengaged during a minimum of Two types of documents were searched for: peer-review 12 months) and was linked to intravenous drug use, un- articles and grey literature. In the first case, searches were employment, more sporadic sex partners, being born in performed through PubMed, Scopus, Web of Science, another country, and not having initiated ART [11]. In Cochrane, PsycInfo EBSCO (see Additional file 1 for the Catalonia and Balearic islands, the PISCIS cohort [12] search strategy). In the second case, grey literature was has shown that 85% of HIV-diagnosed patients were searched in Google. Initially, searches were performed retained (defined as 1 or more visits per year) [13] and a using the following keywords in titles and abstracts, “reen- more recent study estimated that 89% of the PLWH gagement/re-engagement”, “reengaged/re-engage”, “re- were diagnosed, of these 78% were under treatment and link/re-link”, “HIV”, and “AIDS”; and then the medical 73% are virally suppressed [14]. Also in Catalonia, men subject headings (MeSH) were also used. All searchers who have sex with men (MSM) with a migration back- where restricted to the last 15 years, (from January 2006 to ground experienced greater losses throughout the three May 2021) and were assessed by an independent librarian steps of the 90–90-90 cascade: retention in care (74% vs. who checked the sources of data and the strategy used. In 55%), antiretroviral treatment (70% vs. 50%) and virally addition, bibliographies of chosen articles were further suppressed (65% vs. 46%), respectively [15]. scanned for additional articles. Palacio-Vieira et al. BMC Public Health (2021) 21:1596 Page 3 of 11 – Stage 3: study selection encompassed within a broader project aimed at the study of LTFU in a cohort of PLWH in Spain. Studies were selected if they fulfilled the following cri- teria: 1) defined, analysed, developed, or used HIV patient care reengagement strategies, 2) provided details on the Results type of strategies used, 3) showed details on the outcomes A total of 282 documents were selected from both peer- of its implementation, and 4) were carried out in high- review articles and grey literature sources and 126 were income countries according to the classification of the selected for full text assessment after reviewing their title World Bank [22]. Documents not published in English and abstract. Twenty-eight documents fulfilled all the in- were excluded. Although, processes of search, selection clusion criteria. Figure 1 shows the review results and and data charting were performed only by one person, the number and characteristics of included and excluded one librarian specialist in health sciences research was articles. (Fig. 1, here). consulted to assist and approve all these strategies. – Stage 4: charting the data Studies characteristics Our review yielded 27 peer-reviewed articles and one ab- Documents that met the inclusion criteria were regis- stract presented in a virtual conference (Table 1). Most tered in an Excel file specifying its title, author, abstract, of the studies selected consisted in the use or test of an intervention developed/used to reengage LTFU, type of existing or slightly modified intervention (n = 16). The study or design used, outcomes used to analyse the impact United States of America was the country of origin of 24 of the strategy, and key findings (see Additional file 2 for documents (86%) while Australia, Ireland, Trinidad the final documents included in the review). Once chosen Tobago and Canada presented 1 document each. Most and entered into the study database, publications were re- documents were published in 2015 or after, while only vised again to confirm that they met inclusion criteria and 7% were published before. Exclusions were decided be- complete missing information. In addition, the Preferred cause published documents included data from middle- Reporting Items for Systematic Reviews - extension check- or low-income countries like Argentina, Puerto Rico, list for Scoping Reviews (PRISMA-ScR) was used (20] (see Kenya; other reported data on reengagement patients in Additional file 3). Although the implementation protocol care but did not show details of what kind of strategy for this review was not registered, its objectives are they used or their efficacy or effectiveness. Fig. 1 Flow diagram of data selection Palacio-Vieira et al. BMC Public Health (2021) 21:1596 Page 4 of 11 Table 1 Characteristics of the documents included Topic n (%) References Type of publication Peer-reviewed article 27 (96) [23–49] Conference presentation 1 (4) [50] Design/type of study Retrospective patient tracing program 1 (4) [30] Registry-based analysis/prospective reengagement 1 (4) [32] Qualitative 1 (4) [37] Randomized controlled trial 2 (7) [38, 41] Comparative/case-control/assessment study 7 (25) [25, 28, 33, 40, 42, 43, 49] Using or testing an existing or slightly modified intervention 16 (56) [23, 24, 26, 27, 29, 31, 34–36, 39, 44–48, 50] Country Australia 1 (4) [36] Ireland 1 (4) [42] Trinidad and Tobago 1 (4) [30] Canada 1 (4) [50] United States of America 24 (86) [23–29, 31–35, 37–41, 43–49] Publication date Before 2015 2 (7) [32, 44] 2015 or later 26 (93) [23–31, 33–43, 45–50] Definitions of LTFU, professionals involved and contact cities or deceased) [23–26, 28, 30, 32, 34, 36, 37, 44]; or methods b) lost to follow-up or out of any HIV care or clinical In order to consider patients as LTFU (some articles follow-up. Three main types of interventions were then used the term “out-of-care patients” [23–28] to referred described: a) those that consisted solely on phone calls, patients disengaged from care but are pending to be letters/mails, text messages or home visits [23–25, 30, confirmed as lost) different time periods were reported 43], b) others that started by establishing initial contact in the reviewed literature, including at least six [23, 29], and were later complemented by a face-to-face interven- nine [28, 30–38], 12 [24–27, 39–45] and even 14 or 15 tion in the HIV clinic guided by a trained professional months since the last appointment to HIV care, CD4 cell [26, 28, 29, 32–35, 41, 43] and c) a few opportunistic in- count or viral load test [46, 47]. Different strategies to terventions addressed to out-of-care patients who were find LTFU patients were reported and, in most articles, found in other medical units or contacted their health they were used simultaneously. Depending on the com- providers for different reasons not pertaining to HIV plexity of LTFU patients, some were reengaged into HIV care [38, 40]. care was by means of a simple intervention, while others Phone calls were used to contact the patient in almost needed other more specialized services, like the referral all reviewed articles [23–38, 40–43, 46, 48–50], with to drug addiction units or the support of social, mental some studies specifying the number of calls made (for or prevention services [27–30, 38, 39, 45, 46]. Although instance, a maximum of three calls) and the use of pre- diverse professionals were involved in the tracing and designed, tested scripts [25, 30, 33, 36]. When phone contact procedures, the most common categories were calls were not successful, other contact methods were counsellors/patient navigators, while nurses and social reported, including mailing notifications (email or pos- workers were less common (Table 2). tal) to the last known address [23–26, 28, 31, 34, 35, 40, Tracing and confirming the patient’s status was the 41, 43, 48, 49], home visits [23–26, 28, 31–33, 48], initial way to determine if the patient is LTFU and ac- searching for the patient in other public or external da- cording to the literature reviewed this was mainly tabases [25–28, 32, 33, 41, 45, 47–49] and contacting a achieved through the medical records [23–28, 30–36, close relative or their emergency contact [24, 25, 30]. 39–42, 45–50]. Patients were most classified as: a) pa- In all interventions, professionals offered different pro- tients in care (transferred to other HIV clinics, with up- cedures in order to reengage LTFU patients, such as iden- coming appointments, incarcerated, moved to other tifying possible barriers/reasons for missed appointments Palacio-Vieira et al. BMC Public Health (2021) 21:1596 Page 5 of 11 Table 2 Methods and professionals involved in the LTFU patients’ reengagement Intervention/Professional Description (reference) n (%) Identification of LTFU and - Distribution of flyers/brochures distributed to participants (29,38,44) 3 (10) contacting method - Coordination with other services (i.e. jails, pharmacies, hospitalization units) [25, 27, 28, 37, 38, 49] 6 (21) - Sending messages and contacting close relatives [24, 25, 30] 3 (11) - Home/field visit to the last known address [23–26, 28, 31–33, 48] 9 (32) - Internet searches and/or secondary database searches [25–28, 32, 33, 41, 45, 47–49] 11 (39) - Listing patients who meet LTFU criteria [23, 27, 30, 32, 34–37, 40, 41, 47, 50] 12 (43) - Post-mail letter/email [23–26, 28, 31, 34, 35, 40, 41, 43, 48, 49] 13 (46) - Use of electronic databases to confirm status [23–28, 30–36, 39–42, 45–50] 23 (82) - Calling patients by phone [23–38, 40–43, 46, 48–50] 23 (82) Professionals involved (as reported - Nurses [50] 1 (4) in the records found) - Social workers [30, 46] 2 (7) - Outreach coordinator [24, 43] 2 (8) - Peer mentor/partner advocates [29, 38, 48] 3 (8) - Disease intervention/linkage specialist [25, 28, 31, 41, 51]* 5 (21) - Not specified [35, 36, 40, 42, 44, 49] 6 (21) - Counsellors/patients navigators/field workers [23, 26, 27, 32–34, 37, 43, 47] 9 (24) * In some cases, reengagement activities were shared among DIS and other professionals like Social Workers and offering alternative solutions to facilitate reengage- to five [26, 27] or six sessions (1 per week, during 6 ment and overcome those barriers [25, 26, 28, 30, 32, 33, weeks) with a booster session 6 weeks later [29]. 36, 39, 41, 42], rescheduling appointments [25, 26, 31–34, 42, 45] and giving further information on medication and alternatives to access treatment [25, 27, 29, 30, 38, 45, 46]. Efficacy of the strategies analysed Other important strategy found were building report with Several outcomes were used to measure the reengage- the patient and enhancing patient empowerment [26, 29, ment activities (Table 4). First outcome, although it is 40, 41] by promoting the patient-centred care and setting not specifically related to the reengagement process, goals for both patients and clinicians [27, 29, 31, 38] was the proportion of patients found to be in care in (Table 3). other centres. Between 2 and 46% of the patients who During reengagement visits, interventions were fo- were initially considered as LTFU but were found to cused on encouraging active self-management and self- be transferred to other HIV care [24, 30, 34, 36, 40, determination by means of the use of a conversational 41, 48, 49]. Second, the proportion of patients that tone and often assisted by standard printed brochures. were successfully in contacted varied widely, ranging Patient-centred and tailored behavioural models like so- between 19 and 98% [25, 28, 30, 32, 33, 42, 46–50]. cial cognitive theory and wellness motivation theory [30, Thirdly, the percentage of successful interventions, 38, 46–48, 50], strengths-based case management/coun- considered those that made LTFU patients return to selling and motivational interview and behavioural skills regular care and restart ART. Relinkage to care or [26–28, 33, 37, 47] were some of the tools used during restarting treatment ranged between 7 and 86% [23– reengagement visits. According to the literature 26, 28–36, 39–50]. Finally, some publications reported reviewed, the number of reengagement activities and long-term outcomes, such as Viral Suppression (VS) amount of time invested on them is diverse (Table 3). at 6 months (34–90%) [29, 34, 41, 46] and 12 months While the majority of the articles used phone calls to (30–67%) [23, 29, 33, 34, 39, 40, 47] since the inter- trace LTFU, most did not specify details on the number vention. Other middle-long-term outcomes consisted of calls. A few cases consisted in three phone calls [25, in analysing retention after 1 to 6 months after the 30, 33, 49], followed by sending one contact email, an at- intervention [26, 30, 39]. Qualitative studies showed tempt to reach patients through other databases, and fi- that PLWH described the work of navigators as sup- nally reaching out to their designated emergency contact portive and helpful to find alternatives of care and [25]. The number of reengagement visits with patients these professionals described their work with clients and their duration were also diverse, with reports ran- as important to identify individual needs and behav- ging between two sessions of 20 to 60 min [38, 42], up iours that could improve PLWH care [37]. Palacio-Vieira et al. BMC Public Health (2021) 21:1596 Page 6 of 11 Table 3 Interventions’ characteristics addressed to reengage patients to HIV care Characteristic Description (reference) Details of the intervention - Addressing patients with mental health, social needs or prevention services [27–30, 38, 39, 45, 46] - Comprehensive picture of the patient’s complete health/needs [26, 33, 36, 41, 48] - Promoting self-determination and self-care [27, 29] - Providing information on medication, access to care and treatment rights [25, 27, 29, 30, 38, 45, 46] - Building the staff-patient relationship and enhancing strengths [26, 29] - Knowledge and skills building [29, 38] - Schedule, change and complete a medical appointment [25, 26, 31–34, 42, 45] - Patient-centred care, setting objectives for patients and clinicians [27, 29, 31, 38] - Offering alternatives to complete appointments [23–26, 28, 31, 32, 36] - Identify and offering and solutions to the barriers to care [25, 26, 28, 30, 32, 33, 36, 39, 41, 42] Theoretical background - Social cognitive and wellness motivation theory [29] - Strengths-based case management/counselling [26–28, 33, 37, 47] - Motivational interview and behavioural skills [30, 38, 46–48, 50] Length and time needed - Three – ten phone calls [25, 30, 33, 49] - Two sessions of 20 to 44 min. Each followed by 5 phone calls during 10 weeks [38] - Six sessions (1 per week, during 6 weeks) + 1 booster session 6 weeks later [29] - One face-to-face interview of 45 min approximately [44, 46] - Two to ten sessions depending on the patients’ needs [26, 27] - Three field visits [33] Table 4 Assessment methods and results of the activities reported to reengage patients to HIV care Reengagement activities and outcomes Measurement (median) Reference Patients’ tracing activities and status confirmation In HIV care/misclassified as LTFU 11–61% (33%) [23, 25, 26, 28, 31, 32, 34, 36, 46–48, 50] Transferred to another clinic/care 2–46% (12%) [24, 30, 34, 36, 40, 41, 48, 49] Deceased 0.6–13% (6%) [23, 24, 26, 28, 30, 31, 34, 36, 40, 41, 48–50] Migrated/changed city 5–51% (12%) [25, 26, 30, 31, 40, 41, 48, 49] Incarcerated/other outcomes 1–9% (4,5%) [24, 30, 32, 40] Not located/unreached/not contacted 3–81% (29%) [24–26, 28, 31, 32, 34, 36, 40–42, 47–49] Contacted 19–98% (47%) [25, 28, 30, 32, 33, 42, 46–50] Reengagement outcomes Returned/linked to care/restarted treatment 7–86% (56%) [23–26, 28–36, 39–50] Refused linkage to care 3–58% (12%) [26, 30–32, 36, 41, 47–50] Follow-up outcomes Viral suppression at 6 months 34–90% (66%) [29, 34, 41, 46] Viral suppression at 12 months or more 30–67% (58%) [23, 29, 33, 34, 39, 40, 47] Retained within 1–6 months 28–82% (55%) [26, 30, 39] Retained within 1 a year 50–90% (56%) [23, 24, 39, 43, 47] 2 visits/laboratory tests 22–72% (50%) [38, 49] Palacio-Vieira et al. BMC Public Health (2021) 21:1596 Page 7 of 11 Determinants of the intervention and LTFU’ these patients, combined with mailed letters, emails, characteristics home visits. The reengagement process itself is per- Different variables are seen to be associated with suc- formed mainly by finding and reducing the barriers that cessful interventions. In the United States, patients with make patients disengage and enhancing their motivation Asiatic background were more likely to be reengaged to return to HIV care, while preventing new losses. than blacks [30, 33, 43]. Age and gender are also associ- Most of the selected studies were published in the ated with successful reengagement and retention, with United States and only one study was European some studies showing that younger patients are less (Ireland), evidencing a lack of knowledge in this field in reengaged than those over 40 years of age [23, 25, 33] different contexts. Analysing reengagement strategies and males reengaged less than women [24, 44]. Steady under different HIV-care, social, and economic factors is income, the ability to meet basic needs (food and hous- still pending, and this would imply adapting the different ing), having a reliable cell-phone, and accurate contact strategies to local circumstances, testing which of them information (as these programs rely on making direct would work well, and measuring their impact on the re- contacts) are related with better outcomes in retention engagement of LTFU patients. Additionally, the fact that after the implementation of reengagement strategies [25, most of the studies were published after the year 2015 42]. On the contrary, barriers such as the lack of trans- shows a growing need in reaching this group of PLWH, portation, unstable housing, the lack of financial or ma- that despite their particular circumstances, could easily terial resources, mental health, and substance abuse return to treatment and improve their health, with a issues [28, 44], scheduling issues, and feeling stigmatized relatively low effort and few resources invested. The were associated with no reengagement [30]. Compared dynamism of the HIV epidemic and the increased inter- to MSM, other key populations are less likely to achieve est in LTFU patient reengagement are aligned with the VS after reengagement, especially people who inject treatment and care objectives (90–90-90 and 95–95-95), drugs, heterosexuals, or those not in any of these key which not only focus in maintaining low viral loads and populations [23]. In comparison to those aged 18–29, well controlled patients, but also in reducing diagnostic PLWH who were 40–49 years showed an increased like- and treatment gaps. lihood of VS within two different periods of time since Defining who is a LTFU patient is crucial, and the the intervention, 180 days [34] and 1 year [33]. LTFU pa- most used classification found is having no contact with tients with higher viral loads and assigned to an inter- HIV care professionals for over 12 months. However, vention strategy were less likely to reengage in care why this is or other time-periods were chosen is only de- within 180 days and to achieve VS within 1 year of the scribed in one of the reviewed articles, referring to spe- intervention, compared to patients who were not cific clinical guidelines [36]. Selecting 12 months or assigned to the intervention [28]. In other studies re- longer periods was described as more challenging due to engagement was associated with having reached viral the difficulties in acquiring patients’ contact information suppression by the time of the inclusion in the imple- the longer they’ve been out-of-care [37]. Shorter periods, mentation strategy [39]. It is important to mention that such as 6 months, were selected due to clinical reasons one of the articles reviewed, consisted in a cluster ran- [34], because patients that were out-of-care during this domized evaluation of a intervention designed to In- period of time showed reduced chances of reengage- crease reengagement did not showed differences ment, which according to the authors may be explained between the patient subgroups assessed [41]. by treatment regimen fatigue, and decreased motivation and adhere to medication as prescribed [23]. In contrast, Discussion longer periods of time to be considered as out-of-care Retention in care and ART adherence constitute key were also reported, such as 14 months, because authors strategies in HIV management and are essential for tried to minimize the number of patients falsely identi- PLWH in order to stay healthy, live longer and prevent fied as being out of care due to delays in data reporting, HIV transmission to others. Although few publications maximizing the specificity of the classification strategy fulfilled the inclusion criteria for this scoping review, the [46]. Standard definitions of retention in care in the selected studies provide useful and well organized infor- United States are two clinical visits separated by ≥90 mation on how to identify LTFU patients, how to imple- days during a 12-months measurement period or at least ment successful strategies to motivate and reengage 1 visit in each 6-months period during a 24-months patients into HIV care, and how to determine the impact measurement period, with ≥60-d between visits in adja- of such strategies. During the identification of LTFU pa- cent 6-mo periods [52]. This might have implications for tients, electronic databases and other data sources are the organization, provision of HIV care and the need to useful to obtain information on probable patients, and follow patients frequently and avoiding losing them for phone calls were the most used strategy in contacting even 6 months. Palacio-Vieira et al. BMC Public Health (2021) 21:1596 Page 8 of 11 The most common way to find LTFU patients was to registries, allowing at the same time the proper follow- look for them in the clinical records, with some authors up of patients [25]. In addition, the proper use and shar- reporting the use of multiple data bases, as well as using ing clinical records might help avoid extra work in find- external or secondary sources of information. As the ing presumably lost patients, when they might have majority of the studies were published with data from simply transferred to other clinics, which according to United States, where patients can be registered with dif- the reviewed literature, can be as much as 50% of all ferent healthcare or buy-in providers [23], combining LTFU. The implementation of field/outreach programs different sources of information was common in order aimed at identifying, tracing, following-up on, and reen- to locate patients. However, in certain European coun- gaging LTFU patients can complement other clinic tries, where healthcare systems have less access barriers staff’s efforts to locate patients who are hard to reach or by having integrated and connected health records, those whose present access and adherence to care bar- tracking LTFU patients and reengaging them into HIV riers such as lack of transportation, unstable housing, care could take less time and resources. poverty, mental health, substance use disorders, among Tracking activities consisted mainly in making phone others [24, 28]. calls and sending letters/emails, with some publications There is evidence on how some determinants interfere also referring home visits to the patient’s last known ad- in the likelihood of being successfully reengaged in HIV dress, but few details on how confidentiality was ensured care. The provision of evidence-based training to health during home visits was described. Phone calls were re- professionals and the improvement of the communica- ported to be successful in reengaging patients, even tion skills would enhance the chance of reengagement, when used alone, and authors mentioned the potential reducing also the risk of stigma, time limitations and benefit of using this method in other countries/settings other difficulties [30, 41]. In addition, reengagement given its relatively low-cost and little time needed [24]. strategies should consider the fact that low socioeco- The type, quantity, and time spent in reengagement pro- nomic status plays an important role, making reengage cedures was also quite diverse among the reviewed lit- less likely [28] which in turn increases the need for so- erature, and there was no common trend since each cial workers to collaborate with HIV care and find better study presented specific circumstances. However, one ways to coordinate the units staff [24]. Clinical variables publication mentioned that the length of the interven- have also been associated with reengagement. High tion period was probably the reason of unsuccessful re- levels of CD4 cell counts and lower viral loads have been sults [38] and another study modified an intervention to reported as determinants of higher likelihood of reen- include more sessions and offered linkage to other gagement [24]. When patients have returned to care and healthcare services [26]. are followed over time (90 or 180 days), viral loads re- There was a considerable number of PLWH that, des- main lower compared to those not reengaged and pite multiple efforts, could not be reached and reen- retained [34]. Similarly, being diagnosed with either con- gaged. In the Irish study, where 81% of the contacts current or nonconcurrent AIDS increases the likelihood were reported to be unsuccessful, authors, along with of being retained in care after reengagement [23]. others, explained that out-of-service phone numbers Successful reengagement depends largely on the ability might explain for this high proportion and highlighted of the professional to involve and motivate patients to the need to maintain updated demographic and contact attend future appointments and working with them to information within each visit [30]. To do this, a strong solve the specific reasons why they may disengage. Add- and multidisciplinary work-team needs to be built within itionally, the number and length of these strategies, and each centre, or even between multiple centres, in order the efforts made to achieve success, might depend on to manage and update contact information and keep pa- the professionals’ ability to tailor and modify these strat- tients’ registries as accurate as possible, avoiding wrong egies according to each particular circumstance [26]. classifications of LTFU and optimizing the time needed Strength and motivational-based strategies are common to attend patients [25–27, 30, 33]. Updated clinical re- among the revised studies, and basically consist in find- cords is crucial, and some studies pointed out that at ing out and collaborating with the patient in order to least a third of the presumed LTFU patients might actu- find the best options in dealing with each particular en- ally be in care, reinforcing the importance of having a gagement barrier. The role of the healthcare profes- strong system that keeps these patients as well tracked sionals is very important, especially in motivating LTFU as possible [32, 37]. Moreover, integrating different re- patients, so professionals should be trained on increasing cords, for instance clinic-based and administrative re- their ability to meet the patients’ needs, listening and cords could avoid losses and ease the implementation of working together to find solutions and overcoming the reengagement activities [31]. In fact, these strategies has barriers that kept them out of care [41]. Although the been reported as an opportunity for improving clinical professionals’ work should be as holistic as possible, Palacio-Vieira et al. BMC Public Health (2021) 21:1596 Page 9 of 11 some LTFU patients could have needs which are difficult to Additional file 3. Preferred Reporting Items for Systematic reviews and meet. However, there is a basic group of LTFU needs that Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) Checklist. can ensure reengagement, which include: prioritization of urgent needs, dividing needs into short and long term, rely- Acknowledgements ing on partner organizations to provide support services, The authors would like to acknowledge and thank the support and inputs of Àngels Carles-Pomar, Librarian from the Universitat Autònoma de Barcelona and having priority status to be included in programs like for her contributions to the selection of sources of information and the revi- addiction units or social work assistance [37]. sion of the strategies. We thank CERCA Programme / Generalitat de Catalu- A limitation of our review is the fact that only articles nya for institutional support. published in English were searched, missing possibly Authors’ contributions relevant information in other languages. In addition, al- JMRU and AI conceived the study and oversaw all aspects of the original though searches were performed to include different project. JMRU, AI and JPV had the original conception of the article. JPV types of documents, the vast majority of the results were conducted the literature search, analysed information, drafted and edited the manuscript. JMRU, AI and AB assisted the data collection and contributed to related to peer-reviewed articles and almost no reports the writing of the manuscript. LF, AOLL, JML, IV, FHB, VF, MR, PD, EL, JMM, JC, or conference proceedings were found. critically revised, read, commented, and approved the final manuscript. Funding Conclusions The project leading to these results (PISCIS Cohort) has received funding from The new targets related with the control of the HIV epi- “la Caixa” Banking Foundation under the project code LCF/PR/PR17/51120008. This work is supported by a grant from the Foundation Marató TV3 (project demic, consisting in reducing the gap of treatment adher- code 239/C/2018) aimed at the analysis of the LTFU patients of the PISCIS ence and retention in care, possess new challenges for Cohort. The funding bodies played no role in the design of the study and healthcare providers. If the new target 95–95-95 treatment collection, analysis, and interpretation of data and in writing the manuscript. challenges for HIV care are to be met, health care systems Availability of data and materials need to adapt themselves and proactively address LTFU The datasets supporting the conclusions of this article are included within patient reengagement and retention efforts. Although the the article. development of reengagement strategies is relatively new and there are certain tasks in common in the literature, Declaration there is still lack of information about how these strategies Ethics approval and consent to participate work in different contexts, for instance in Europe. Most of Not applicable. the evidences on the procedures, methods, and impact of Consent for publication reengagement strategies come from United States, where Not applicable. barriers and determinants could be different to other countries. This review shows that certain procedures, like Competing interests the definition of who is LUTF, the patient tracing in differ- JMM has received consulting honoraria and/or research grants from AbbVie, Angelini, Contrafect, Cubist, Genentech, Gilead Sciences, Jansen, Medtronic, ent databases and the use of different contact strategies MSD, Novartis, Pfizer, and ViiV Healthcare. might have a significant impact on the reengagement of LTFU, but they largely depend on the quality of the data Author details 1 Centre for Epidemiological Studies on Sexually Transmitted Infections and available of these patients. The results and lessons learned HIV/AIDS of Catalonia (CEEISCAT), Badalona, Spain. 2CIBER Epidemiologia y from this review have several implications on the Salud Pública (CIBERESP), Barcelona, Spain. 3Hospital Clinic-Institut provision and management of HIV care systems, these re- d’Investigacions Biomèdiques August Pi i Sunyer, University of Barcelona, Barcelona, Spain. 4Institute for Health Science Research Germans Trias i Pujol sults can serve as a guide to formulate future reengage- (IGTP), Badalona, Spain. 5HIV and STI Unit, Department of Infectious Diseases, ment strategies so as to reach HIV care goals adapted to Bellvitge University Hospital-IDIBELL, L’Hospitalet de Llobregat, Spain. 6 different contexts. Internal Medicine, Hospital de Mataró-Consorci Sanitari del Maresme, Mataró, Spain. 7Internal Medicine, Hospital Verge de la Cinta de Tortosa, Tortosa, Spain. 8Infectious Diseases and “Fight AIDS” Foundation, University Abbreviations Hospital Germans Trias i Pujol, Badalona, Spain. 9Hospital General de Vic, Vic, AIDS: Acquired immunodeficiency syndrome; ART: Antiretroviral therapy; Spain. 10Hospital Son Llàtzer, Palma de Mallorca, Spain. 11 Vall d’Hebron CD4: Cluster of differentiation 4; HIV: Human immunodeficiency virus; Hospital Universitari, Vall d’Hebron Institut de Recerca (VHIR), Universitat LTFU: Lost to follow-up; MSM: Men who have Sex with Men; PLWH: People Autònoma de Barcelona, Barcelona, Spain. 12Hospital Son Espases, Palma de living with HIV; USAID: United states agency for international development; Mallorca, Spain. 13Hospital de Sant Pau, Barcelona, Spain. 14HIV/AIDS Unit. VS: Viral suppression Hospital Clinic, Barcelona, Spain. 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