Meta-analysis shows that alcohol consumption has negative impact on antiretroviral adherence

HIV-positive individuals who drink alcohol are approximately 50% less likely to be adherent to their antiretroviral therapy than those who abstain from alcohol, according to a meta-analysis published in the online edition of the Journal of Acquired Immune Deficiency Syndromes. The investigators also found that the volume of drinking also affected adherence, with those defined as “problem drinkers” being 60% less likely to adhere to their treatment.

Drinking alcohol has been associated with reduced adherence to HIV treatment in a number of individual studies. However, the nature, strength and consistency of this association are unclear. Therefore US investigators conducted a meta-analysis of all published, peer-reviewed studies examining the association between alcohol and adherence to antiretroviral therapy that were published between 1996 and 2007.

A total of 40 studies were included in the analysis. These had different methodology and definitions of adherence (90% - 100% of doses). However, when combined the studies showed that individuals who drank alcohol were between 50% and 60% more likely to be classified as non-adherent as individuals who did not drink (odds ratio [OR] = 0.548; 95% CI, 0.490-0.612; p < 0.001).

Furthermore, the amount an individual drank was also associated with an increased risk of poor adherence. Patients who met established US criteria for problem drinking were approximately 60% more likely to be non-adherent than individuals who abstained from drinking or who drank moderately (OR = 0.474; 95% CI, 0.408 – 0.550; p < 0.001). Further analysis revealed that it was the volume of alcohol an individual drank, rather than the frequency of their drinking that contributed to non-adherence. The investigators write, “taken together, the available evidence suggests that drinking quantity is a more robust and important criteria of adherence than drinking frequency, a finding that seems consistent with dose-related alcohol effects on adherence.”

One of the factors associated with alcohol consumption and poor adherence was male sex. The investigators note that that this finding “is inconsistent with previous reports suggesting that alcohol’s effects on adherence are more prominent among women.”

The effect of alcohol on adherence was also more pronounced in studies that included a lower proportion of injecting drug users. “Given the established association of injecting drug use with lower adherence, it is possible that any effects of alcohol on adherence are obscured in the context of injecting drug use”, comment the investigators.

However, although the authors are confident of the “robust and replicable” association between alcohol and poor adherence, they are less clear about the reasons for this. They therefore suggest “future research should continue to evaluate potential moderators to clarify the conditions under which alcohol use is likely to influence adherence.”

Not only does consumption of alcohol affect adherence, but it has also been shown to have an impact on immune function. In the light of this research and their own meta-analysis, the researchers conclude, “successful alcohol interventions could potentially show salutary effects on disease progression and, theoretically, life expectancy.”