Bottom-Up Project

Launched in 2019, the Bottom-Up Project is a multi-organizational initiative focused on leveraging health information exchange (HIE) data and peer navigation to identify people with HIV who are lost to follow-up. Using real-time clinical data, in combination with linkage to HIV care and social services, the Bottom-Up Project locates and reengages people with HIV who are not currently in medical care and are not virally suppressed. This project is a collaboration involving the New York-Presbyterian (NYP) HIV Center of Excellence, Alliance for Positive Change, Healthix (a New York State HIE), Housing Works, and New York City’s HIV AIDS Service Administration (HASA). Through this collaboration, over half of patients on the lost-to-follow-up list were found and invited to enroll in the linkage to care/reengagement program.


Implementation Guide
Emerging Intervention
Emerging Intervention
Icon for Intervention Type
Data utilization approach; Outreach and reengagement activities
Icon for HIV Care Continuum
Retention in HIV medical care
Icon for Focus Population
People with HIV who are not in care
Icon for Priority Funding
Non-RWHAP; City funding
Icon for Setting
Hospital or hospital-based clinic
Need Addressed

Sustained engagement in HIV care promotes optimal health outcomes and reduces HIV transmission. Yet, there are various reasons why people stop treatment, including having more than one health condition, or psychosocial and structural barriers, such as lack of family support or income. Reengagement interventions can help people facing such barriers to become virally suppressed. A meta-analysis found that reengagement programs were able to find 39% of all people characterized as lost to follow-up and to reengage 58% of them in care.1 HIEs present an opportunity to find people who are not in HIV care while using other health services through real-time surveillance and clinical data. Studies show that HIE-informed interventions have been successful in identifying and linking people back into care.2

Core Elements
Monthly lost-to-follow-up list

NYP generates a list of people with HIV who appear to be lost to follow-up, defined as no HIV-related medical visits for more than nine months. First, clients with HIV are identified through lab results, ICD-10 diagnostic codes, and medication fill patterns. Then NYP reviews encounter data and medication refills from its electronic health record (EHR) system to narrow the list to those who are lost to follow-up. This list, generated monthly and reviewed to ensure accuracy, contains client contact information, demographics, and medical information.

Using HIE data to locate clients from the lost-to-follow-up list

The list is then compared to the HASA Healthix database to determine whether clients are using services in the area. HASA Healthix aggregates over 20 million client records from thousands of contributing organizations, including hospital systems, nursing facilities, behavioral health facilities, community-based organizations, home health agencies, emergency medical services, and insurance plans. Any clinical registration event for people on the lost-to-follow-up list creates an alert for the involvement of peer navigators.

Peer navigators reaching lost-to-follow-up clients

Alliance for Positive Change, a key partner in the Bottom-Up Project, employs peer navigators to connect people to HIV care. Navigators use the information shared through HIE alerts to locate lost-to-follow-up clients and enroll them in a reengagement program that includes linkage to medical care and ongoing care coordination. Peer navigators share lived experiences with clients, and the program builds trust by matching peers and clients by demographic characteristics and by prioritizing confidentiality. Meeting clients where they are and using motivational interviewing have also facilitated successful outreach.

Addressing social determinants of health

Lost-to-follow-up clients often have multiple health conditions—such as behavioral and mental health needs and substance use disorders—that require enhanced support. Peer navigators routinely connect clients to mental health and substance use disorder services, along with food and housing resources.

“They don’t overwhelm you. They meet you where you are. They taught me to build with stones and metal, so my foundation is going to stick and I don’t have to worry about my house caving.” – Client


Over the course of 11 months (July 2021 to May 2022), Alliance for Positive Change conducted outreach and linkage-to-care services for 221 NYP lost-to-follow-up clients. Eligibility criteria included: no medical visit at NYP in nine to 18 months; not virally suppressed; no recent medication refill; and no evidence for care transfer, incarceration, or death. CUNY Institute for Implementation Science in Population Health (CUNY ISPH) evaluated outcomes for these 221 clients, and found that about half were successfully contacted; 13 were reengaged in care.

Category Information
Evaluation data

Data were collected through the Alliance for Positive Change and included case notes, medical data client observation, surveys, and interviews with clients.


Of the NYP clients identified as lost to follow-up:

  • Number who were found/contacted
  • Number who were enrolled in the peer navigation program
  • Number who were reengaged in medical care

Of the 221 clients identified as lost to follow-up:

  • 116 were found (52%) 
  • 24 were enrolled (21% of those who were found) 
  • 13 were reengaged in medical care (54% of those enrolled)

Source: NRWC 2022 Presentation: Leveraging Health Information Exchanges to Reengage Hardest-to-reach People with HIV

Planning & Implementation

  • Partnerships.The Bottom-Up Project involves formal partnerships across NYP, Alliance for Positive Change, HASA Healthix, and CUNY ISPH with each organization playing a unique and crucial role. NYP, a large health care delivery system, supplies the list of lost-to-follow-up clients, while Alliance for Positive Change leverages its decades of experience as an AIDS service organization to reengage clients in care. HASA Healthix provides up-to-date information on client care, aggregated across hundreds of organizations; and CUNY ISPH serves as the evaluator.

  • Staffing. The project team consists of a program manager, supervisors at NYP and Alliance for Positive Change, and two peer navigators. Peer navigators have similar backgrounds and lived experiences as their clients, which strengthens reengagement efforts.

  • Training. Peer navigators were trained to become certified health workers.


This project is funded by the NYC City Council to support program staff, including a program manager, supervisors at NYP and Alliance for Positive Change, and two peer navigators. The Einstein-Rockefeller-CUNY Center for AIDS Research supported the evaluation.

Lessons Learned
  • The Bottom-Up Project has experienced implementation issues that stemmed from operating within a large complex institution with competing priorities. NYP has two major academic medical centers, seven hospital sites, 13 community ambulatory sites, and seven school-based clinics. The project also coordinates complex program governance within its multiple partners. Consistent communication and project champions continue to help all partners stay engaged.
  • Outreach to clients on the lost-to-follow has proven to be difficult due to the lack of accurate, up-to-date contact information, though the availability of HIE data has mitigated this challenge. Lost-to-follow-up clients can appear to be completely disconnected from care, so attempts to locate and engage people are labor-intensive.
  • Due to the complexities of relying on multiple EHRs to find clients and conduct outreach, it is crucial to utilize standard, commercially available IT analytic and visualization tools for data aggregation, analysis, display, and reporting.
New York Presbyterian’s HIV Center of Excellence
Peter Gordon, MD
Medical Director

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