Background
In sub-Saharan Africa (SSA), HIV-infected patients may under-report alcohol consumption. We compared self-reports of drinking to phosphatidylethanol (PEth), an alcohol biomarker. In particular, we assessed beverage-type adjusted fractional graduated frequency (FGF) and quantity frequency (QF) measures of grams of alcohol, novel non-volume measures, and the Alcohol Use Disorders Identification Test – Consumption (AUDIT-C).
Methods
We analyzed cohort-entry data from the Biomarker Research of Ethanol in Those with HIV cohort study (2011-2013). Participants were HIV-infected past year drinkers, newly enrolled into care. Self-report measures included FGF and QF grams of alcohol, the AUDIT-C, number of drinking days, and novel adaptations of FGF and QF methods to expenditures on alcohol, time spent drinking, and symptoms of intoxication. PEth levels were measured from dried blood spots. We calculated Spearman’s rank correlation coefficients of self-reports with PEth and bias-corrected bootstrap 95% confidence intervals (CI) for pairwise differences between coefficients.
Results
A total of 209 subjects (57% male) were included. Median age was 30; inter-quartile range (IQR) 25-38. FGF grams of alcohol over the past 90 days (median 592, IQR 43 to 2137) were higher than QF grams (375, IQR 33 to 1776), p<0.001. However, both measures were moderately correlated with PEth; rho = 0.58, 95% CI 0.47 to 0.66 for FGF grams and 0.54, 95% CI 0.43 to 0.63 for QF grams (95% CI for difference −0.017 to 0.099, not statistically significant). AUDIT-C, time drinking, and a scale of symptoms of intoxication were similarly correlated with PEth (rho = 0.35 to 0.57).
Conclusion
HIV-infected drinkers in SSA likely underreport both any alcohol consumption and amounts consumed, suggesting the need to use more objective measures like biomarkers when measuring drinking in this population. Although the FGF method may more accurately estimate drinking than QF methods, the AUDIT-C and other non-volume measures may provide simpler alternatives.