Participants for the study were recruited from HIV treatment settings in Philadelphia between 2003 and 2005. We studied subjects with a history of alcohol and substance abuse, and as a comparison group, also enrolled a sample of non-alcohol users. Inclusion criteria required that participants had a confirmed seropositive status, and were receiving HIV treatment at the time of interview. The trial was approved by the Committee on Human Subjects of the University of Pennsylvania Institutional Review Board.
Alcohol Use Data
All behavioral data were assessed through self-report. Participant alcohol use was collected using the Risk Assessment Battery (RAB). The RAB measure asked participants of their frequency of alcohol use in the past month with four response options: everyday, a few times a week, a few times a month, and not at all. Using this measure, we classified our sample into “daily drinkers”, “regular drinkers”, and “non-drinkers”. “Daily drinkers” used alcohol everyday, “regular drinkers” reported drinking a few times a week, and “non-drinkers” reported drinking a few times a month or not at all.
Self-reported adherence to HAART was measured using a four-point scale (always, usually, sometimes, never), all participants were asked the way in which they took their prescribed medication for HIV. Participants currently not on HAART were provided the choice not on HAART. Based on this adherence schema, we dichotomized HAART users in our sample into “adherers” (always taking their medication), and “non-adherers” (usually, sometimes, or never taking their medicine).
Our primary outcomes were HIV viral load and absolute CD4 count. Levels of HIV RNA in plasma were quantified by means of RT-PCR assay (Roche Molecular Systems, Branchburg, NJ) according to the manufacturer’s protocol. The minimal detectable level of HIV RNA was 50 copies/ml.
In order to investigate the adjusted association between viral load and alcohol use, we first used logistic regression to examine the relationship between detectable viral load and daily alcohol use, adjusted for adherence (for HAART users only) and age, race and gender. Linear regression was employed to study the association between CD4 count and daily alcohol use. Finally, we included “regular drinkers” in the alcohol users group, in addition to the “daily drinkers”, and reran the above analyses. All statistical analyses were carried out in R 2.9.1 (Free Software Foundation, Inc, Boston, MA, USA).