Frequent alcohol consumption is associated with faster HIV disease progression, US investigators report in the online edition of AIDS Research and Human Retroviruses.
The researchers found that individuals who consumed two or more alcoholic drinks a day had an increased risk of experiencing a fall in their CD4 cell count below 200 cells/mm3.
The investigators believe that this is due to the immunosuppressive effects of alcohol. In addition, this level of alcohol consumption by patients taking HIV treatment was associated with an increased risk of a detectable viral load, which the researchers attribute to poor adherence.
However, the robustness of the study’s findings are open to question. The sample size was small and, as all the individuals recruited to the study were drug users, the investigators acknowledge that their results cannot be generalised.
The study was undertaken because earlier research into the impact of alcohol on HIV disease progression has produced inconsistent results. Although some studies have found that alcohol use does not have an impact on CD4 cell count or risk of AIDS, research conducted in animals has shown that alcohol adversely affects CD4 and CD8 cell count and increases susceptibility to certain pathogens. Moreover, there is some evidence suggesting that alcohol use can lead to poorer adherence to antiretroviral therapy.
In order to gain a better understanding of this study, researchers in Florida undertook a prospective, longitudinal study involving 231 HIV-positive drug users. These individuals were recruited between 2002 and 2005 and followed for 30 months.
At baseline and at monthly follow-up appointments, the patients had their CD4 cell count and viral load monitored. The use of antiretroviral therapy was recorded, and the patients were asked to report their use of alcohol and drugs.
Individuals were classified as heavy drinkers if they consumed two or more alcoholic drinks a day. Moderate drinking was defined as one drink a day.
Most of the patients (77%) were black, 73% were men and the average age was 42 years,
Median CD4 cell count at baseline was 310 cells/mm3, with median viral load at this time being 11,911 copies/ml. HIV treatment was used by 63% of patients on entry to the study, and this did not increase significantly throughout the 30 months of the research.
Just over half (55%) of patients reported using alcohol, with beer consumption predominating.
Moderate alcohol use did not have any effect on HIV disease progression. Those consuming up to one drink a day were no more likely than those reporting abstinence from alcohol to experience a fall in their CD4 cell count below 200 cells/mm3.
However, even after controlling for baseline CD4 cell count and viral load and use of antiretroviral drugs, more frequent alcohol use nearly tripled the risk of a drop in CD4 cell count below this level (HR = 2.91; 95% CI, 1.23 to 6.85, p = 0.015).
Analysis restricted to patients who were not taking HIV treatment showed that, compared to those who abstained from alcohol, individuals who consumed two or more alcohol drinks a day were significantly more likely to experience a drop in their CD4 cell count below 200 cells/mm3 (HR = 7.76; 95% CI, 1.2 to 49.2, p = 0.03).
Heavy drinking in combination with the use of crack-cocaine also increased the risk of a drop in CD4 cell count (HR = 3.57; 95% CI, 1.24 to 10.31, p = 0.018).
The investigators then looked at the impact of alcohol on viral load.
Overall, viral load was 0.25 log10 copies/ml higher in heavy drinkers (p = 0.038).
However, the impact of alcohol on viral load was only found in individuals taking HIV therapy (p = 0.0457). The investigators believe that poor adherence explains this finding and that alcohol does not have an impact on HIV replication.
“Our main findings show that frequent alcohol consumption is a predictor of CD4 cell decline…in addition, frequent alcohol use increased plasma HIV viral load, although this relationship was statistically significant only in participants who were on antiretroviral therapy”, comment the investigators.
They therefore believe that “frequent alcohol consumption appears to affect HIV disease progression by accelerating the decline of CD4 cell count and increasing viral load only in those receiving antiretroviral therapy.”
However, the investigators acknowledge that their research has a number of limitations. Only 27 individuals reported consuming two or more alcoholic drinks daily. Moreover, the study population consisted of drug users. The investigators therefore write that their findings can only be generalised to HIV-positive individuals reporting similar patterns of substance use.
Baum MK et al. Alcohol use accelerates HIV disease progression. AIDS Research and Human Retroviruses, online edition, DOI: 10. 1089/aid.2009.0211, 2010.