BACKGROUND:

The Veterans Aging Cohort Study (VACS) is a study of human immunodeficiency virus (HIV) infected and uninfected patients seen in infectious disease and general medical clinics. VACS includes the earlier 3 and 5 site studies (VACS 3 and VACS 5) as well as the ongoing 8 site study.

OBJECTIVES:

We sought to provide background and context for analyses based upon VACS data, including study design and rationale as well as its basic protocol and the baseline characteristics of the enrolled sample.

RESEARCH DESIGN:

We undertook a prospectively consented multisite observational study of veterans in care with and without HIV infection.

MEASURES:

Data were derived from patient and provider self report, telephone interviews, blood and DNA samples, focus groups, and full access to the national VA "paperless" electronic medical record system.

RESULTS:

More than 7200 veterans have been enrolled in at least one of the studies. The 8 site study (VACS) has enrolled 2979 HIV-infected and 3019 HIV-uninfected age-race-site matched comparators and has achieved stratified enrollment targets for race/ethnicity and age and 99% of its total target enrollment as of October 30, 2005. Participants in VACS are similar to other veterans receiving care within the VA. VACS participants are older and more predominantly black than those reported by the Centers for Disease Control.

CONCLUSIONS:

VACS has assembled a rich, in-depth, and representative sample of veterans in care with and without HIV infection to conduct longitudinal analyses of questions concerning the association between alcohol use and related comorbid and AIDS-defining conditions.