Unstable housing associated with low CD4 cell count and detectable viral load for HIV-positive women in US

Unstable housing is associated with an increased risk of a detectable viral load and low CD4 cell count among HIV-positive women, according to US research published in Social Science & Medicine. Women with unstable housing were around 50% more likely to have adverse HIV treatment outcomes than women living in more secure accommodation. Reasons for the poorer outcomes observed in women with unstable housing included poorer continuity of health care.

“We find that unstable housing drastically reduces both HIV suppression and CD4 T-cells for PLHIV [people living with HIV]; thus worsening clinical outcomes and further exacerbating health disparities,” write the investigators. “We show specific pathways for the effects, including use of any mental health/counselling, any healthcare, and continuity of care.”

Understanding the impact of socio-economic factors, including housing, on health is a research priority. Previous research has shown that PLHIV are at increased risk of experiencing unstable housing. However, the impact of homelessness on key HIV outcomes including viral load and CD4 cell count is unclear.

Investigators from the US therefore used data obtained from the large Women’s Interagency HIV Study (WIHS) and funding data from the Housing Opportunities for People with AIDS (HOPWA) programme to determine the relationship between unstable housing, a detectable viral load (above 200 copies/ml) and low CD4 cell count (below 350 cells/mm³).

The study population consisted of 3082 WIHS participants who received care between 1995 and 2015 at sites in the Bronx, Brooklyn, Chicago, Washington DC, Los Angeles and San Francisco. Unstable housing was defined as living in the previous 12 months on the street, beach, a shelter, a welfare hostel, a jail or correctional facility, or in a halfway house.

About a third of participants were high school graduates, 57% were African American and 23% Hispanic, 33% were married or living with a partner, 30% had ever injected drugs and three-quarters reported using recreational drugs.

The availability of resources to address housing instability among people living with HIV was estimated with funding allocations to Housing Opportunities for Persons with AIDS (HOPWA). This is a federal programme which provides housing and supportive services (such as substance abuse treatment, job training and assistance with daily living) to people living with HIV who have a low income.

For each location and each year, the researchers calculated HOPWA funding per 1000 people newly diagnosed with HIV. There was considerable variability in HOPWA funding between study sites.

The investigators’ model examined the impact of unstable housing on the two key HIV treatment outcomes after taking into account HOPWA funding allocations.

The study participants attended 57,323 follow-up appointments. Unstable housing was reported at 4.8% of these visits. Viral load was suppressed at 48% of visits, with CD4 cell count was above 350 cells/mm³ at 56% of visits.

The probability of unstable housing fell with increasing HOPWA funding. Lower HOPWA funding allocations were strongly associated with an increased likelihood of unstable housing, a relationship that remained robust after taking into account covariates such as age, education, relationship status and drug use.

The investigators' calculations showed that unstable housing had a negative impact on health, decreasing the probability of viral suppression and of an adequate CD4 cell count, both by 8%. When HOPWA allocations were included as the key variable, unstable housing reduced viral suppression by 51% and it decreased the likelihood of having a CD4 cell count above 350 cells/mm³ by 53%.

The authors also examined the potential pathways between unstable housing and adverse viral load and CD4 cell outcomes. Unstable housing was shown to affect use of healthcare resources and continuity of care. It was associated with 25% less use of counselling and mental health services, 37% less use of any healthcare services and a 76% reduction in the probability of seeing the same provider.

“This paper shows a strong negative effect on viral suppression and adequate CD4 cell count, and it elucidates specific channels by which unstable housing can affect these HIV treatment outcomes,” conclude the researchers. “These findings suggest that increasing efforts to improve housing assistance, including HOPWA allocations, and other interventions to make housing more affordable for low-income populations, and HIV-positive populations in particular, may be warranted not only for the benefits of stable housing, but also to improve HIV-related biomarkers.”