DURBAN, SOUTH AFRICA – A large, longitudinal study of alcohol consumption patterns among HIV-infected U.S. military veterans indicates that only the highest level of persistent heavy drinking is associated with more advanced HIV disease severity over time.
In this study of 3,539 veterans receiving care for HIV infection for 15,354 person-years of follow-up at 8 VA centers, only those scoring in the top 8% on a validated measure of unhealthy drinking showed significant worsening of HIV disease over the 8-year study period, Brandon D.L. Marshall, PhD, reported at the 21st International AIDS Conference.
“The relationship between persistent unhealthy alcohol use and greater HIV disease severity is perhaps not as strong as we would have hypothesized. This suggests that, given the relatively small number of people reporting consistent unhealthy alcohol use, targeted risk reduction and treatment strategies are needed only in those consistent unhealthy drinkers,” said Dr. Marshall, an epidemiologist at Brown University in Providence, R.I.
The subjects’ median age was 49 years; 98% were men, and 68% were African American.
Alcohol use patterns were evaluated annually using the Alcohol Use Disorders Identification Test (AUDIT-C), a validated 3-question screening tool measuring self-reported frequency, quantity, and binge alcohol use. Alcohol use trajectories were linear and relatively stable over time. Eight percent of subjects were classified as high-risk drinkers on the basis of an AUDIT-C score of 8-12; 24% were deemed at moderate risk, with a score of 6-7; the 44% with a score of 4-5 were categorized as lower risk; and 24% of participants were abstainers. The abstainers fell into two distinct groups: sick quitters with worsening HIV disease and healthy abstainers.
Of note, this was the first large study to utilize an objective biomarker in order to validate long-term self-reported alcohol use patterns as assessed by the AUDIT-C test. Nearly 1,500 subjects had a blood test for phosphatidylethanol, a reliable indicator of exposure to alcohol within the previous 21 days. The biomarker has high specificity for alcohol abstinence and showed good correlation with AUDIT-C results across the board, according to Dr. Marshall.
Subjects’ HIV disease severity trajectory was determined annually using the Veterans Aging Cohort Study (VACS) Index, a weighted score that estimates an individual’s risk of all-cause mortality based upon age, HIV RNA viral load, CD4 count, and general indicators of organ system injury including hemoglobin, platelets, glomerular filtration rate, and hepatitis C infection. As was the case for AUDIT-C scores, VACS scores remained relatively stable over 8 years of follow-up. The HIV disease trajectory was categorized as low risk in 2% of subjects, moderate in 46%, high risk in 36%, and extreme in 16%.
To plot the joint trajectories of alcohol use and HIV disease severity, the investigators employed a statistical technique called group-based finite mixture modeling and performed a multivariate logistic regression analysis in which the moderate-risk drinkers and moderate VACS subgroups served as reference standards. Only two significant associations emerged: the highest-risk subgroup of drinkers were at 1.83-fold increased risk of extremely poor VACS trajectory, and the abstainers were at 1.9-fold increased risk for both the most favorable VACS trajectory and an extremely-high-mortality VACS trajectory, reflecting the split in prognosis between the healthy abstainer and sick quitter subgroups. No high-risk drinkers were in the low VACS group.
Unhealthy alcohol use is hypothesized to accelerate HIV disease progression through two mechanisms: Heavy drinkers are less likely to adhere to antiretroviral therapy and remain in care, and the heavy drinking itself has direct negative immunologic effects, Dr. Marshall said.
He reported having no financial conflicts of interest regarding his study, funded by the National Institute on Alcohol Abuse and Alcoholism and the National Institute of Allergy and Infectious Diseases.