Operationalizing treatment as prevention in Los Angeles County: antiretroviral therapy use and factors associated with unsuppressed viral load in the Ryan White system of care.

Despite extensive prevention efforts, an estimated 21% of individuals with HIV/AIDS in the United States are unaware of their status, placing them at greater risk for spreading the virus to others. HIV treatment as prevention (TasP) is rapidly becoming an important public health strategy to reduce HIV transmission at the population level. Data for this study were collected on a sample of 11,397 HIV-positive individuals in the Ryan White system, a publicly funded system of care for HIV-positive individuals in Los Angeles County who are uninsured, in 2009 to examine two components of TasP: baseline rates and factors associated with antiretroviral therapy (ART) use and viral load (VL) suppression in a publicly funded system of care. ART coverage among our sample was 90%. In multivariate analyses, those with a higher odds of having unsuppressed VL included: females compared to males (adjusted odds ratio [AOR]=1.25; 95% confidence interval [CI]=1.06, 1.47); African Americans compared to whites (AOR=1.42; 95% CI=1.24, 1.62); men who have sex with men compared to heterosexuals (AOR=1.15; 95% CI=1.00, 1.32); recent substance abusers compared to nonsubstance abusers (AOR=1.35; 95% CI=1.17, 1.55); those recently incarcerated or ever incarcerated compared to those never incarcerated (AOR=1.37; 95% CI=1.15, 1.63; and AOR=1.28; 95% CI=1.09, 1.50); and those retained in care compared to those not retained in care (AOR=1.98; 95% CI=1.76, 2.22). Understanding the key sociodemographic, geographic and behavioral factors associated with ART use as well as HIV VL suppression will be useful for informing the development and deployment of targeted programming and policies that may further enhance the implementation of the TasP approach in communities across the United States.