The Veterans Aging Cohort Study (VACS) Index is predictive of mortality and combines age, traditional HIV biomarkers (HIV-1 plasma RNA and current CD4 count), and non-HIV biomarkers (indicators of renal and liver function, anemia, and hepatitis C coinfection). We examined the association between the VACS Index and HIV-associated neurocognitive impairment (NCI).
Participants included 601 HIV-infected adults enrolled in cohort studies at the University of California, San Diego, HIV Neurobehavioral Research Program (ages: 18–76 years; 88% male; 63% white; median current CD4 = 364 cells/mm3; 63% on antiretroviral therapy; AIDS = 64%). Biomarkers used in calculating the VACS Index were measured in prospectively collected blood samples using conventional laboratory methods. NCI was defined using global and seven domain deficit scores.
Higher VACS Index scores were associated with concurrent risk for global NCI [P < 0.001; odds ratio = 1.21, confidence interval (CI): 1.12 to 1.32], even when adjusting for psychiatric comorbidities. This relation was statistically significant for most cognitive domains in adjusted models. Furthermore, the VACS Index predicted concurrent NCI beyond nadir CD4 and estimated duration of infection. Older age, lower hemoglobin, and lower CD4 counts were the VACS components most strongly linked to NCI.
The findings extend previous research on the potential usefulness of the VACS Index in predicting HIV-associated outcomes to include NCI. Although the effect size was relatively small, our findings suggest that demographic information, HIV-disease factors, and common comorbidities might each play important roles in the clinical manifestation of cognitive impairment among HIV-infected individuals. Additional research is needed to determine if a more sensitive and specific index can be developed.
Departments of *Psychiatry;
‡Neurosciences, University of California, San Diego, San Diego, CA.
Correspondence to: David J. Moore, PhD, Department of Psychiatry, HIV Neurobehavioral Research Program, University of California, San Diego, 220 Dickinson Street, Suite B (8231), San Diego, CA (e-mail: firstname.lastname@example.org).
Supported by NIH funding through the NIMH, NIDA, and NINDS institutes by the following grants: The HIV Neurobehavioral Research Center (HNRC), P30MH062512; California NeuroAIDS Tissue Network (CNTN), U24 MH100928, U01MH083506, and R24MH59745; National Institute on Drug Abuse Program Project Grant, P01-DA12065; and Training in Research on Addictions in Interdisciplinary NeuroAIDS (TRAIN), T32DA031098.
Presented partly at the Third International Workshop on HIV and Aging, November 5, 2012, Baltimore, MD.
The authors have no conflicts of interest to disclose.
The views expressed in this article are solely the responsibility of the authors and do not necessarily represent the official view of the NNTC, HNRC, NIH, Department of the Navy, Department of Defense, nor the United States Government.
Received June 06, 2013
Accepted September 10, 2013