In a 15-year study, risk for ischemic stroke was 40% higher among individuals with HIV, but having a high CD4 count or low HIV RNA appeared to attenuate this risk, according to researchers.
Michael J. Silverberg, PhD, MPH, of the Kaiser Permanente Division of Research in Oakland, California and colleagues sought to identify the association between HIV infection and the incidence for ischemic stroke in 24,768 HIV-positive and 257,600 HIV-negative patients included in the Kaiser Permanente Northern and Southern California system for the years 1996 to 2011.
The ischemic stroke rate per 100,000 person-years was 125 (n=151 events) for HIV-positive adults, and 74 (n=1,128 events) for HIV-negative adults (adjusted rate ratio 1.4; 95% CI: 1.2-1.7), the researchers reported in AIDS.
However, the risk for ischemic stroke was not elevated among patients with HIV who had a recent CD4+ count of at least 500 cells/mL (rate ratio: 1.0; 95% CI 0.8–1.4) or recent HIV RNA less than 500 copies/mL (rate ratio 1.1; 95% CI: 0.9–1.4) compared with those without HIV.
Recent CD4+ cell count less than 200 cells/mL (rate ratio=2.5; 95% CI, 1.3-4.6) was the only independent risk factor for ischemic stroke after the researchers adjusted for recent HIV RNA and nadir CD4 count.
The study supports the idea that immunodeficiency may play a role in ischemic stroke risk. It also suggests CD4 cell count may be useful beyond it’s function as a way to monitor HIV and may have additional utility in those with sustained virologic suppression.