#128 “ASK A FRIEND” IDENTIFYING THE HIDDEN POPULATION: FORMER INTRAVENOUS DRUG USERS WHO ARE NO LONGER IN CONTACT WITH SERVICES. A RESPONDENT DRIVEN SAMPLING PROTOCOL.


Author: Donaldson SR, Radley A, Dillon JF

Theme: Models of Care Year: 2019

Background: The group of people, who have previously used drugs but have changed their lifestyle,
leaving substance use behind them, represent a hidden population within our communities. Past
history of risk behavior may mean that they are infected with hepatitis C (HCV), but lack of contact
with drug services may mean that their infection remains undetected and they are unaware of their
status. Identifying this group is problematic, since normal routes of contact are not available;
however, they still may develop cirrhosis and carcinoma, arising from chronic infection.
Identifying and reaching this population requires a novel approach.
This study tests whether community based, peer-led invitation to be tested for HCV infection could
be a successful way to reach this population.
Description of model of care/intervention: We propose using the epidemiological technique of
respondent driven sampling, in a retrospective fashion. Social (former injecting) networks are selfmapped and individuals not currently in contact with services invited and encouraged to come
forward for testing by their peers. The study uses a lay-persons steering group to inform study
methodology and communication methods.
Effectiveness: The social network links of injecting partners will be visualized and described using an
egocentric mapping technique. The data obtained will inform estimates of the size of this hidden
population, but in a novel development it will be used in an unlimited fashion as a tool for diagnosis
and linkage to care. We will examine the effectiveness of peer-led invitation to identify and link with
HCV testing and treatment.
Conclusion and next steps: Understanding the size and distribution of this hidden population will
provide vital intelligence for the design and targeting of local services.
The views, perceptions and experiences of participants will be ascertained to provide feedback on
the implementation of the study methodology and to provide lessons for further work.
Disclosure of Interest Statement: This study is funded through a Gilead Fellowship.

Download abstract Download Poster