HIV and risk of dementia in older veterans.

Abstract

People living with HIV (PLWH) may be at an increased risk for dementia as they age. Surprisingly, it remains unclear whether PLWH have a higher risk of developing dementia in late life than those without. We explored whether HIV-infection is associated with incident dementia diagnosis in older U.S. veterans accounting for potential confounders and competing risk of death. We included 1114 veterans diagnosed with HIV, ages at least 55 years (mean = 62 years, SD = 6), followed in the Veterans Health Administration healthcare system from 2004 to 2015, and a propensity-matched comparison group (n = 1114) without HIV. HIV and dementia diagnoses were determined using electronic medical records. Using Fine-Gray proportional hazards models, we examined whether HIV status was associated with a greater risk of incident dementia. During follow-up (mean = 7 years, SD = 4 from date of HIV diagnosis), 5% of veteran PLWH developed dementia compared with 3% without (P = 0.01). Accounting for the competing risk of death and adjusted for demographics, substance use, education and income, PLWH remained 50% more likely to receive a dementia diagnosis [adjusted hazard ratio (aHR) = 1.50, 95% confidence interval 0.96-2.35]. Although combination antiretroviral therapy (cART) exposure was associated with an increased risk of incident dementia, this was driven by differences in illness severity as captured by CD4 cell count. There was no evidence of a differential effect by cART class. In a cohort of older USA veterans, HIV infection increased risk of dementia by 50%, while exposure to cART did not offset this risk. It is critical to understand the mechanisms by which HIV increases risk for developing dementia in later life.