Neighbourhood-level material deprivation and response to combination antiretroviral therapy in the Canadian Observational Cohort (CANOC): a longitudinal cohort study.

Background: Socioeconomic status has been associated with higher viral loads and lower CD4 cell counts among people living with HIV. The objective of this study was to evaluate the relation between neighbourhood-level material deprivation and immunologic and virologic response to combination antiretroviral therapy (ART) among people living with HIV in Canada.

Methods: The Canadian Observational Cohort (CANOC) is a longitudinal cohort of people living with HIV, containing data from 2000-2016 from 5 Canadian provinces. We defined response to combination ART as positive if the CD4 cell count increased by 50 cells/mm (0.05 cells × 10/L) or more (CD4+) and viral load decreased to 50 copies/mL or less (VL+) within 6 months of treatment initiation. We further categorized response to therapy as concordant positive (CD4+/VL+), concordant negative (CD4-/VL-) or discordant (CD4+/VL- or CD4-/VL+). We used adjusted multinomial logistic regression to quantify the relation between neighbourhood-level material deprivation and immunologic and virologic response.

Results: This study included 8274 people living with HIV, of which 1754 (21.2%) lived in the most materially deprived neighbourhoods. Most individuals (62.2%) showed a concordant positive response to combination ART. After adjustment, living in the most materially deprived neighbourhoods was associated with a CD4-/VL+ discordant response (adjusted odds ratio [OR] 1.31, 95% confidence interval [CI] 1.06-1.62) and a concordant negative response (adjusted OR 1.45, 95% CI 1.13-1.86), using a concordant positive response as the reference. No other deprivation quartile was independently associated with a particular response.

Interpretation: People living with HIV from the most materially deprived neighbourhoods had increased odds of poor immunologic or virologic response to combination ART. These results motivate further study of the specific socioeconomic factors that potentially affect response to combination ART among people living with HIV in Canada.