Homelessness linked to 44% lower odds of progressing through HIV care cascade


Fifteen years of data from a cohort of people living with HIV who use drugs in Vancouver, Canada shows that periods of homelessness are associated with a 44% decrease in the odds of overall progression through the HIV care cascade. Specific impacts were recorded for being on HIV treatment, adhering to it and being virally suppressed.

The study shows the impact of homelessness, even in a setting where HIV treatment and care are free of charge, and which offers support services for this vulnerable population. This means that outcomes are almost certainly worse in places with higher barriers to getting medical care and support.

Researchers at the University of British Columbia published the longitudinal prospective study in the journal AIDS. Data come from 947 people who took part in ACCESS between 2005 and 2019. This is a cohort of people living with HIV who use illicit drugs, mostly in Vancouver’s Downtown Eastside neighbourhood. Every six months, participants were interviewed, provided blood samples, and they gave permission for linkage to their medical records.


care cascade

A model that outlines the steps of medical care that people living with HIV go through from initial diagnosis to achieving viral suppression, and shows the proportion of individuals living with HIV who are engaged at each stage. 

prospective study

A type of longitudinal study in which people join the study and information is then collected on them for several weeks, months or years. 

odds ratio (OR)

Comparing one group with another, expresses differences in the odds of something happening. An odds ratio above 1 means something is more likely to happen in the group of interest; an odds ratio below 1 means it is less likely to happen. Similar to ‘relative risk’. 

longitudinal study

A study in which information is collected on people over several weeks, months or years. People may be followed forward in time (a prospective study), or information may be collected on past events (a retrospective study).


In HIV, usually refers to legal jurisdictions which prosecute people living with HIV who have – or are believed to have – put others at risk of acquiring HIV (exposure to HIV). Other jurisdictions criminalise people who do not disclose their HIV status to sexual partners as well as actual cases of HIV transmission. 

Most participants were in their late thirties or forties, two-thirds were male and just over half were White. In the six months before the first interview, just under a third had been homeless (living on the street), less than one in five had any employment, and just under a third had been injecting drugs daily.

The researchers were interested in progression through the HIV care cascade. This was defined as being linked to an HIV care provider, taking HIV treatment, being adherent to HIV treatment (measured by the number of days medication that was picked up) and having an undetectable viral load. They could not look at the first stage of the care cascade – knowing your HIV status – as the cohort is only open to people who have already been diagnosed with HIV.

Homelessness was associated with a 44% lower odds of progression through the care cascade (adjusted odds ratio 0.56). Specifically, it was also linked to 42% lower odds of being on HIV treatment, 54% lower odds of being adherent, and 41% lower odds of being undetectable.

Importantly, these figures are after statistical adjustment for other factors that influence the results. Progression through the care cascade was also slower for people who were younger, used drugs daily, injected drugs daily, drank heavily or sold sex. However, the quoted figures reflect the independent effect of homelessness.

Dr Hudson Reddon and colleagues say their results might be explained by various mechanisms. The daily challenges of securing basic survival needs may take precedence over healthcare. Lack of food and safe places to store medication make adherence more challenging. People who are homeless tend to have more mental health problems and more intense drug and alcohol use, which can both limit engagement with health services. Finally, people who are homeless may sell sex or drugs in order to survive, and the criminalisation and stigmatisation of these behaviours creates additional barriers to accessing healthcare.

“These findings support calls for the integration of services to address intersecting challenges of HIV, substance use and homelessness among marginalized populations such as people who use drugs,” they say.


Reddon H et al. Experiencing homelessness and progression through the HIV cascade of care among people who use drugs. AIDS 37: 1431-1440, 2023.

DOI: 10.1097/QAD.0000000000003570