Explaining racial disparities in HIV incidence in black and white men who have sex with men in Atlanta, GA: a prospective observational cohort study

PurposeTo describe factors associated with racial disparities in HIV (human immunodeficiency virus) incidence among men who have sex with men (MSM) in the United States.MethodsIn a longitudinal cohort of black and white HIV-negative MSM in Atlanta, HIV incidence rates were compared by race. Incidence hazard ratios (HRs) between black and white MSM were estimated with an age-scaled Cox proportional hazards model. A change-in-estimate approach was used to understand mediating time-independent and -dependent factors that accounted for the elevated HR.ResultsThirty-two incident HIV infections occurred among 260 black and 302 white MSM during 843 person-years (PY) of follow-up. HIV incidence was higher among black MSM (6.5/100 PY; 95% confidence interval [CI]: 4.2–9.7) than white MSM (1.7/100 PY; CI: 0.7–3.3) and highest among young (18–24 years) black MSM (10.9/100 PY; CI: 6.2–17.6). The unadjusted hazard of HIV infection for black MSM was 2.9 (CI: 1.3–6.4) times that of white MSM; adjustment for health insurance status and partner race explained effectively all of the racial disparity.ConclusionsRelative to white MSM in Atlanta, black MSM, particularly young black MSM, experienced higher HIV incidence that was not attributable to individual risk behaviors. In a setting where partner pool risk is a driver of disparities, it is also important to maximize care and treatment for HIV-positive MSM.