Hard-to-reach populations 45% less likely to achieve optimal HIV treatment adherence

18 July 2019

New study finds treatment adherence a major challenge for excluded and hard to reach populations living with HIV, exacerbating existing health inequalities.

People waiting for enter to the Bread Of Life Mission shelter house at Main street in Seattle
People waiting to enter the Bread Of Life Mission shelter house in Seattle, USA.

Hard-to-reach populations living with HIV are 45% less likely to achieve optimal antiretroviral treatment (ART) adherence when compared to the general population of people living with HIV, reveals a new study.

In a meta-analysis, researchers sought to understand the association between ART adherence and being part of a socially excluded population – known as ‘hard-to-reach’ in public health. The analysis also  quantifies the gap in ART adherence when compared to socially included populations.

Hard-to-reach populations and sub-populations are considered difficult to engage or interact with due to their behaviours, identities, or characteristics that are associated with stigmatisation and discrimination – often leading to social exclusion. For the purpose of this study, these included sex workers, homeless populations and people who use drugs, all of whom are generally ignored by the public.

Hard-to-reach populations are well known to experience exclusion from health services and severe health inequalities, exacerbated by certain behaviours that put them at greater risk of HIV, including substance abuse, sex without a condom, transactional sex, and multiple sexual partners. As such, HIV prevalence in these groups is much higher than the general population.

Some studies suggest the rate of ART adherence in these groups to be extremely low, in homeless people living with HIV ART adherences ranges from 51% to 89%. Among female sex workers living with HIV in low- and middle-income countries, ART adherence is 76%, and among people who use drugs living with HIV, overall adherence is 60%. But a pooled systematic review of the association between being hard-to-reach and ART adherence had not previously been undertaken.

This meta-analysis pulled an initial 593 global records for full-text review, with 29 studies eventually eligible for inclusion. These included 16 cohort studies and 13 cross-sectional studies performed between 1993 and 2017 and reporting data between 1999 and 2018.

Just over half (52%) of the studies were from the United States and a quarter (24%) originated in Canada, while most (90%) investigated the association between drug use and ART adherence. Most studies measured adherence using self-reported questionnaires (n = 21, 72%), seven studies used pharmacy refills, and only one study used the self-reporting plus pill count method.

While there was significant variation between the studies, they found a 45% lower likelihood of optimal adherence among hard-to-reach populations – equal to a pooled odds of 0.55 when compared to the general population of people living with HIV.

The investigators also ran a regression model and sensitivity analysis accounting for any bias of study design, adherence threshold/cut-off point, adherence measure, region/country, observational period, and quality assessment results. Despite numerous analyses, they found these factors did not impact the results in any way.  

While the study was not designed to investigate exactly why adherence is lower in hard-to-reach individuals, in their discussion they note the complications of service delivery for this group which is not the result of any single factor. Other research has suggested inconsistent and chaotic lifestyles affect drug-users consistent access to care, while sex workers and people who use drugs may also be challenged by criminalisation, stigma and unsupportive healthcare settings created by ignorance and prejudice, to name a few.     

Results from studies among homeless populations reveal that coexisting problems of limited access to healthcare, an elevated risk of mental health problems, and worse attitudes toward treatment are associated with an increased likelihood of worse adherence.

In their conclusion, the authors commented that suboptimal ART could lead to poorer health outcomes in this group who already face stark health outcomes, such as clinical failure, the emergence of viral resistance and, subsequently, the potential for on-going HIV transmissions and outbreaks.

“Our findings regarding ART adherence by hard-to-reach people who suffer from extreme health inequities have implications for public health and medical service provision. Developing strategies and policies to address these inequities is essential for providing sustainable assistance and support.”

Photo credit:
iStock/RUBEN RAMOS. Photos are used for illustrative purposes only, they do not imply the health status of any individual depicted.

Written by Caitlin Mahon

Content Specialist - HIV & Sexual Health