Background:  There is growing international concern that food insecurity may negatively affect ART outcomes, but no studies have directly evaluated the effect of food insecurity on viral load suppression and ART adherence. We hypothesized that food insecurity would be associated with poor virologic response among patients on ART and that this association would be modified by adherence. 
Methods:  Participants were ART-treated homeless and marginally housed persons receiving adherence monitoring (unannounced pill counts at the person’s place of residence) in the Research on Access to Care in the Homeless (REACH) Cohort. Food insecurity was measured by the Household Food Insecurity Access Scale (HFIAS) developed by Food and Nutrition Technical Assistance based on validation studies in 8 countries. The primary study outcome was suppression of HIV viral RNA to <50 copies/mL. We used logistic regression to assess whether food insecurity was associated with vial load suppression, and also stratified analyses by level of adherence (>80% vs ≤80%) to determine whether adherence modified these associations.
Results:  Among 104 participants, the mean age was 46.5 years, 33% of participants were white, 64% were male, and 66% had completed high school; 51% were food secure, 24% were mildly or moderately food insecure, and 25% were severely food insecure. Severely food insecure participants were less likely to be adherent ≥80%. In adjusted analyses, severe food insecurity was associated with a 72% lower odds of viral suppression (95%CI 0.10 to 0.84, p = 0.02) when controlling for all other covariates excluding adherence. In analyses stratified by adherence level, severe food insecurity was associated with an 85% lower odds of viral suppression (95%CI 0.02 to 0.99, p <0.05) among those with ≤80% adherence and a 66% lower odds among those with >80% adherence (95%CI 0.06 to 1.81, p = 0.21).
Conclusions:  Food insecurity is associated with incomplete viral suppression in the urban poor of San Francisco, one of the best-resourced settings for HIV-positive individuals in the United States. This effect was most pronounced among non-adherent persons. These findings suggest that addressing fundamental human needs, such as access to food, should be an integral component of public health HIV programs serving impoverished populations in the United States.