Times from HIV diagnosis to starting antiretroviral therapy (ART) and to viral suppression both dwindled more than 40% from 2000 to 2013 in the HIV Outpatient Study (HOPS). But compared with whites, non-Hispanic blacks had significantly slower times to starting ART and to viral suppression.
The U.S. National HIV/AIDS Strategy emphasizes the importance of viral suppression to improve individual health and limit HIV transmission, but disparities persist in HIV diagnosis, ART uptake and viral suppression. To determine times from HIV diagnosis to first ART and to viral suppression (a viral load below 500 copies/mL) in a diverse U.S. population, HOPS investigators analyzed data on 1156 cohort members who entered care within six months of HIV diagnosis from January 2000 through June 2013 at one of nine HOPS clinics in six U.S. cities. No participants had taken antiretrovirals before enrolling in HOPS, and all completed at least two HOPS visits during the study period.
The 1156 study participants had a median age of 37 years, 75% were men, 43% were non-Hispanic black, 39% non-Hispanic white and 14% Hispanic. Just over half of study participants (52%) were men who have sex with men, and the same proportion had private health insurance.
Median CD4+ cell count at HIV diagnosis proved significantly lower in blacks (285 cells/mm3) and Hispanics (225 cells/mm3) than in whites (374 cells/mm3) (P < .01). For the entire study group, median CD4+ cell count when ART began rose over the observation period, from 207 cells/mm3 in 2000-2003, to 231 cells/mm3 in 2004-2007, to 317 cells/mm3 in 2008-2010 and 2011-2013. When ART began, whites had significantly higher CD4+ counts than blacks or Hispanics (P < 0.001).
Of the 1156 study participants, 926 (80%) started ART during the study period. Compared with those who did not start, those who did were older (median 38 versus 35 years), more often white than nonwhite (41% versus 31%) and less often injection drug users (IDUs) (3.8% versus 8.7%). Chances of starting ART did not differ by sex, HIV transmission group, insurance payor or HOPS clinic.
Cox proportional hazards models adjusting for age, race, CD4+ count and other variables determined that blacks were more likely to start ART later than whites (adjusted hazard ratio [aHR] 0.8, 95% confidence interval [CI] 0.7 to 0.9). In this analysis Hispanics did not differ from whites in time to starting ART, but IDUs started significantly later than non-IDUs (aHR 0.6, 95% CI 0.4 to 0.8). Compared with 2000-2003, likelihood of starting ART proved greater in each subsequent study period (aHR 1.3 for 2004-2007, 1.4 for 2008-2010 and 2.0 for 2011-2013).
Among 1156 cohort members included in the virologic suppression analysis, 916 (79%) reached a viral load below 500 copies/mL during the study period. Proportional hazards models adjusting for CD4+ count and other variables identified several factors independently associated with later viral suppression: black versus white race (aHR 0.8, 95% CI 0.7 to 1.0), age younger than 25 years versus 40 or older (aHR 0.8, 95% CI 0.6 to 1.0), age 25 to 29 versus 40 or older (aHR 0.8, 95% CI 0.6 to 1.0), care at a publicly funded center (aHR 0.8, 95% CI 0.7 to 1.0) and HIV diagnosis in 2000-2003 versus a later period. These variables remained independent predictors of time to achieve viral suppression in a multivariate analysis starting with the date when ART began rather than the date of HIV diagnosis.
The authors conclude that in this large and diverse cohort of HIV-positive people linked to care, time to starting ART improved significantly over the 13.5-year study period. And "as a result of earlier cART [combination antiretroviral therapy] initiation and likely improvements in potency and tolerability of cART over time, we observed more prompt [viral suppression] after HIV diagnosis across the study intervals."
The HOPS team stresses that non-Hispanic blacks lagged whites in time to starting ART and reaching an undetectable viral load, even though the analysis controlled for poverty surrogates such as public insurance and enrollment at a publicly funded site. The authors suggest this disparity "may stem from residual confounding by poverty, access to HIV care, or other structural or psychosocial factors that were not captured by our medical abstraction study." They note that other studies reflecting these findings identified several potential contributors to worse outcomes in blacks, including stigma, fear of HIV disclosure, distrust of the medical establishment or providers, low literacy, poor access to case management and racial/ethnic discrimination.
The investigators believe perhaps their most important finding is delayed virologic suppression in people younger than 25 years old -- the very group in which HIV incidence is growing fastest in the United States.
Mark Mascolini is a freelance writer focused on HIV infection.