Heavy drinkers living with HIV have lower CD4 counts

HIV-positive people not taking antiretroviral treatment who are heavy drinkers have lower CD4 counts than moderate drinkers or those who never drink. However, the same difference isn’t true for people taking antiretrovirals, and alcohol consumption doesn’t affect viral load, researchers from Boston report in the Journal of Acquired Immune Deficiency Syndromes.

The difference, of around 50 cells/mm³, may place some heavy drinkers at earlier risk of developing opportunistic illnesses, but the study was not designed to assess how quickly people developed clinical illnesses related to HIV infection.

Nevertheless, the findings imply that someone who consistently drinks heavily would be quicker to reach the point at which treatment is recommended than someone who is teetotal.

The study reviewed CD4 cell counts and viral load in 595 people with HIV in Boston, USA, recruited into cohort studies on alcohol and HIV disease progression between 1997 and 2006. Participants were recruited through hospitals and the community (including a homeless shelter and a methadone clinic) and were predominantly non-white (66%) and injecting drug users (54%).

Fifty-nine per cent were abstinent from alcohol at study entry, but 30% were classified as heavy users, having reported consumption of either 14 or more drinks a week in the past month, or five or more drinks on a single occasion for men, and seven or more drinks in a week, or four or more drinks on a single occasion for women and men aged 66 and over.

Heavy drinkers averaged seven drinks per day, although the median number of drinks per day among heavy drinkers was 2.6, with an interquartile range of 0.8 – 6.8. This implies that the sample included a small number of very heavy drinkers, and a large number who regularly drank at least two drinks per day, or who binge-drank on several occasions each week.

Once recruited to the study participants had CD4 count and viral load assessments every six months, together with an assessment of recent alcohol consumption. Participants were followed for a median of approximately four and a half years.

The study found that after controlling for age, race, HIV risk behaviour, homelessness, depression, adherence and duration in the study, heavy drinkers not taking antiretroviral therapy had CD4 cell counts that were, on average, 48.6 cells/mm³ lower than those of untreated HIV-positive people who did not drink. Moderate drinkers did not show any significant difference from abstinent people. Viral load was not significantly affected by alcohol consumption.

In people taking antiretroviral treatment there was no significant difference in CD4 cell count according to alcohol consumption. However, heavy drinkers were more likely to be non-adherent at baseline.

When they looked at the CD4 cell percentage, researchers found no difference between heavy drinkers and abstinent individuals, implying that the effect of alcohol is not specific to the CD4 cell population but instead reduces the lymphocyte population across the board.

In settings where high alcohol consumption is common, such as Russia or South Africa, the researchers say that the findings could have major public health consequences.

The CD4 cell difference between heavy drinkers and teetotal people – around 50 cells – is the equivalent of one years-worth of CD4 cell loss, if compared with calculations of CD4 cell loss in asymptomatic people with HIV in the UK.

The findings imply that people with HIV with levels of alcohol consumption that may appear modest by the standards of some countries or communities may already be closer to the threshold for starting treatment by the time they are diagnosed with HIV, and that if alcohol consumption increases after diagnosis and stays high, it will moderately affect disease progression.