A recently published study by BC-CfE researchers titled Neighbourhood-level material deprivation and response to combination antiretroviral therapy in the Canadian Observational Cohort (CANOC): a longitudinal cohort study examines the relationship between a neighbourhood’s socioeconomic status and how this affects the lives and health of Canadians living with HIV who are on combination antiretroviral therapy (ART).
Introduced to the world by the BC-CfE in the ‘90s, ART significantly reduces risks of HIV-related morbidity and death by reducing HIV viral load and increasing the number of CD4 T-lymphocyte cells (CD4). In fact, with successful ART usage, those living with HIV can achieve an undetectable viral load and are unable to transmit the virus.
We’ve known for some time that socioeconomic status was associated with higher viral loads and lower CD4 cell counts among people living with HIV. In general, individuals of lower socioeconomic status have been disproportionately affected by HIV, and indicators of low socioeconomic status have been associated with suboptimal HIV treatment-related outcomes, including higher viral load and lower CD4 counts.
For example, when comparing people living with HIV who are employed to those who are not, employment predicted significantly higher CD4 counts, and higher education has been associated with lower viral loads. Meanwhile, after adjustment for demographic characteristics and ART adherence, it has also been shown that either being unemployed or not having completed a university education was significantly associated with higher viral loads.
The objective of this study was to examine the relationship between neighbourhood-level material deprivation-an index which combines one’s postal code with information from the Canadian census- and immunologic and virologic response to combination ART among people living with HIV in Canada.
CANOC, is a longitudinal cohort study of 13,057 people living with HIV who have initiated ART. CANOC includes 11 sites spanning five provinces, (BC, Saskatchewan, Ontario, Quebec, Newfoundland and Labrador), and contains data from 2000 to 2016. This study’s population of 8,274 people living with HIV consisted mainly of male (86 per cent) residents of BC (~53 per cent) who reported no previous history of injecting drugs (~58 per cent). This demographic and clinical data was extracted from medical files at individual sites and combined at the BC-CfE.
Of the study’s population, just over 21 per cent lived in the most materially deprived neighbourhoods. Delving deeper into the data, BC-CfE researchers found the odds of having a negative response to ART in the first six months is 45 per cent higher for individuals in the most deprived category than those in the least deprived category. Similarly, the odds of having a lower CD4 count and higher viral load for individuals in the most deprived neighbourhoods is 31 per cent higher than those in the least deprived group. These associations were found after adjustment for sex, province of enrolment, history of ever injecting drugs, era of entry into cohort, and age.
The authors of the study note how it lacks individual-level data on employment, income and education, and say that using a neighbourhood-level material deprivation index requires making generalizations about an individual based on a larger group. Furthermore, the study relied on information from 2000 to 2016, which means these findings may not be generalizable to more recent circumstances like the COVID-19 pandemic.
However, with the data from CANOC, BC-CfE researchers can conclude that people living with HIV from the most materially deprived neighbourhoods had increased odds of poor immunologic or virologic response to combination ART in the Canadian context. The researchers say these results should motivate further study of the specific socioeconomic factors that potentially affect response to combination ART among people living with HIV in Canada.