Phosphatidylethanol and self-reported alcohol consumption among people living with HIV in Thai Nguyen, Vietnam

Background: Phosphatidylethanol (PEth) is a biomarker for recent alcohol consumption that would ideally validate self-reported alcohol consumption behaviors. We assessed the relationship between PEth and several self-reported alcohol consumption metrics among hazardous alcohol users living with HIV in Vietnam. Methods: Participants in a three-arm randomized controlled trial assessing two alcohol interventions reported recent alcohol consumption on a 30-day timeline follow-back interview and had a PEth assessment at enrollment, 3 months, and 12 months of the study follow-up. We examined the relationship between self-reported alcohol consumption and quantitative PEth results using Spearman rank correlation and receiver-operating characteristic (ROC) curves to calculate the area under the curve (AUC). We assessed associations between categorical PEth results and self-reported drinking behaviors using prevalence ratios calculated with regression models and generalized estimating equations. Results: Among 1221 study visits (n = 439 participants; 425 (97%) men), the median PEth result was 71 ng/mL (Interquartile range (IQR): 20, 212), and participants reported a median of 11 (IQR: 4, 24) drinking days and 25 (IQR: 8, 71) standard drinks in the previous 28 days. Quantitative PEth results were moderately correlated with drinking days (rho = 0.26-0.35) and standard drinks consumed (rho = 0.23-0.38) in the same period. AUCs ranged from 0.54 (any binge drinking in the past 28 days) to 0.82 (any alcohol consumed in the past 21 days). Positive PEth results (>= 50 ng/mL) were 2.24 (95% Confidence Interval [CI]: 1.49, 3.35) times as prevalent among participants who reported drinking in the previous 28 days compared with those who did not. Conclusions: Although PEth values and self-reported alcohol use were correlated, the observed associations were modest. Additional research into the dynamics of PEth production and elimination is warranted across diverse populations to better understand how PEth assessments can best be integrated into research and clinical care.