Validating Self‐Reported Unhealthy Alcohol Use With Phosphatidylethanol (PEth) Among Patients With HIV.

Background: We sought to compare self‐reported alcohol consumption using Timeline Followback (TLFB) to biomarker‐based evidence of significant alcohol use (phosphatidylethanol [PEth] > 20 ng/ml). Using data from patients with HIV (PWH) entering a clinical trial, we asked whether TLFB could predict PEth > 20 ng/ml and assessed the magnitude of association between TLFB and PEth level. Methods: We defined unhealthy alcohol use as any alcohol use in the presence of liver disease, at‐risk drinking, or alcohol use disorder. Self‐reported alcohol use obtained from TLFB interview was assessed as mean number of drinks/day and number of heavy drinking days over the past 21 days. Dried blood spot samples for PEth were collected at the interview. We used logistic regression to predict PEth > 20 ng/ml and Spearman correlation to quantify the association with PEth, both as a function of TLFB. Results: Among 282 individuals (99% men) in the analytic sample, approximately two‐thirds (69%) of individuals had PEth > 20 ng/ml. The proportion with PEth > 20 ng/ml increased with increasing levels of self‐reported alcohol use; of the 190 patients with either at‐risk drinking or alcohol use disorder based on self‐report, 82% had PEth > 20 ng/ml. Discrimination was better with number of drinks per day than heavy drinking days (AUC: 0.80 [95% CI: 0.74 to 0.85] vs. 0.74 [95% CI: 0.68 to 0.80]). The number of drinks per day and PEth were significantly and positively correlated across all levels of alcohol use (Spearman's R ranged from 0.29 to 0.56, all p values < 0.01). Conclusions: In this sample of PWH entering a clinical trial, mean numbers of drinks per day discriminated individuals with evidence of significant alcohol use by PEth. PEth complements self‐report to improve identification of self‐reported unhealthy alcohol use among PWH. [ABSTRACT FROM AUTHOR]