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The CHAIN Study

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The Community Health Advisory & Information Network (CHAIN) is an ongoing prospective study of representative samples of persons living with HIV/AIDS in New York City (NYC) and the Tri-County region of Westchester, Rockland and Putnam Counties. As part of the evaluation activities supporting local Ryan White Part A services planning and quality improvement, the mission of CHAIN is to supply systematic data from the perspective of persons living with HIV about their needs for health and human services, their encounters with the full continuum of HIV services, and their physical, mental and social wellbeing.

CHAIN is conducted by the Mailman School of Public Health at Columbia University in collaboration with the NYC Department of Health and Mental Hygiene (DOHMH), Public Health Solutions, Inc., the Westchester County Department of Health, the HIV Health and Human Services Planning Council of New York (HIV Planning Council), and the New York State Department of Health. A Technical Review Team (TRT), with representation from each of the collaborating institutions, oversees the work of CHAIN. With input from the Planning Council and its committees, the TRT selects topics for investigation, provides feedback on study plans and reviews reports for dissemination.

CHAIN collects data through in-person interviews that are designed to capture the diverse views and experiences of people living with HIV. They are conducted by trained community interviewers who are matched to respondents as much as possible with respect to gender and race/ethnicity. Approximately 10% of interviews are conducted in Spanish. Major interview topics include: (1) quality of life with respect to health, physical, psychological and social wellbeing, (2) need for health and social services, (3) health and social services access, utilization and satisfaction; (4) socio-demographic characteristics; (5) housing and other aspects of living situation; (6) sex and drug use behaviors; and (7) informal caregiving from friends, family and volunteers. A number of topics have been added or updated over the years, including revisions to account for advances in antiretroviral therapies, evolving models of care coordination, and use of the internet and social media.

Since its initiation in 1994, CHAIN has engaged three separate cohorts of NYC residents living with HIV/AIDS. The first NYC cohort was recruited during 1994 and 1995. It remained active through 2001. The second NYC cohort was recruited during 2002 and 2003. Recruitment of a third NYC cohort started in October 2015 and is planned for completion during the fall of 2018. For all three cohorts, a two-stage sampling method was followed to ensure that participants would be representative of adults (age 20+ years) who were aware of their HIV-positive status. For the first stage, a large number of medical care and social service agencies with HIV caseloads of 20 or more were randomly selected from across all five boroughs, and invited to participate as recruitment sites. HIV-positive clients were then recruited either through random selection from a client list prepared by agency staff or through onsite, sequential enrollment.

For the 1994 NYC cohort, 648 HIV-positive individuals were recruited from 43 sampled agencies. An additional 52 HIV-positive individuals unconnected to any HIV medical care and case management services at the time of the interview were also recruited to supplement the agency-based sampling strategy. These "unconnected" individuals were contacted at outreach sites and through acquaintance sampling from among previously recruited CHAIN participants. To offset gradual attrition from the 1994 cohort, in 1998 an additional 286 HIV-positive individuals were recruited from 22 of the 1994 recruitment sites. Baseline and up to seven follow-up interviews were completed with the 1994 cohort through June 2002. Following the same methodology used for the 1994 CHAIN cohort, a second NYC CHAIN cohort was recruited between July 2002 and December 2003. A total of 684 HIV-positive individuals were recruited from 36 randomly sampled agencies, along with nine persons living with HIV but unconnected to care. To offset gradual attrition from the 2002 cohort, an additional 319 HIV-positive individuals were recruited from 20 agencies during 2008 and 2009. Through March 2015, a baseline and up to seven follow-up interviews were completed with the 2002 NYC cohort.

In May 2015, a third NYC CHAIN cohort was initiated. It combines 266 continuing members who were recruited during 2008 and 2009 with a planned recruitment of 450 HIV-positive individuals under the age of 40. A first round of 526 interviews with the newly constituted 2015 NYC cohort was conducted between May 2015 and February 2018: 207 among the continuing cohort members and 319 among newly recruited individuals under 40. A second round of interviews began in February 2018.

Starting in 2001, CHAIN was extended to the Tri-County region. A methodology similar to that for the NYC cohorts was used to recruit a Tri-County CHAIN cohort of 398 HIV-positive adults from 22 agencies during 2001 and 84 additional members between 2004 and 2006. Four rounds of interviews were completed through 2007. Starting in 2008, a repeated cross-sectional design was instituted, in which Tri-County study participants are recruited and interviewed over two-year cycles. Up to eighteen Tri-County agencies participate as recruitment sites. In this repeated cross-sectional approach, 100 to 150 HIV-positive Tri-County residents are interviewed each year. Four two-year interview cycles have been completed. A fifth cycle commenced during the spring of 2018. Aside from death, sample attrition in the CHAIN cohorts has remained at low levels. Among CHAIN participants not known to be deceased or living outside NYC, survey completion rates have remained in excess of 80% and exceeded 90% for some rounds of interviews. Individuals lost to follow-up over the course of the study showed few differences on baseline demographic, clinical and psychosocial characteristics, when compared with those who continued to participate.

Since its inception, the CHAIN project has been supported under grants to the NYC DOHMH from the Ryan White HIV Treatment Extension (formerly CARE) Act. In addition to work on behalf of the HIV Planning Council and local health departments, the CHAIN team has conducted special studies funded by the Ryan White SPNS program of the Health Resources and Services Administration (HRSA) HIV/AIDS Bureau, the Centers for Disease Control and Prevention, and most recently the MAC AIDS Foundation.

The CHAIN team disseminates findings through written reports and presentations that respond to the questions, interests, and priorities of the HIV Planning Council, its committees, and the TRT. CHAIN reports range from documents of 30 or more pages that summarize results of complex statistical analyses to brief reports under 10 pages that address a narrowly defined policy or program question. Since 1994, close to 200 reports have been written examining a range of topics, with continuing attention to unmet health and social service needs, trends in service utilization, and various health and psychosocial outcomes.

Below is a complete list of CHAIN reports available for downloading. Senior CHAIN investigators are available to present results from CHAIN studies to interested professional and community groups. For more information about the Mailman School of Public Health at Columbia University, click here.

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