Using phosphatidylethanol as an adjunct to self-reported alcohol use improves identification of liver fibrosis risk

Introduction: Accurate assessment of alcohol use informs prevention and management of liver disease. We examined whether phosphatidylethanol (PEth, an alcohol metabolite) blood concentrations are associated with liver fibrosis risk independently of self-reported alcohol use, among persons with and without HIV. Methods: We pooled individual-level data from 12 studies from the United States, Russia, Uganda, and South Africa with PEth, AUDIT-C (Alcohol Use Disorders Identification Test-Consumption), and FIB-4 measurements. We conducted mixed-effects logistic regression of the relationship between PEth and AUDIT-C as continuous variables (after checking linearity), with high FIB-4 (≥2.67). We divided PEth (range 0-1000) by 83.3 to put it on the same scale as AUDIT-C (0-12) to directly compare odds ratios. Adjusted models included sex, race/ethnicity, age, body mass index, HIV and virologic suppression status. Results: Among 4,644 adults, the median age was 49 years (interquartile range [IQR]: 40-55), 998 (21%) were female, and 3,520 (76%) were living with HIV among whom 2,386 (68%) were virologically suppressed. Median PEth was 13 ng/mL (IQR: <8-132.0) and median AUDIT-C was 3 (IQR: 1-6); 554 (12%) had high FIB-4. The adjusted odds ratios per 83.3 ng/mL difference in PEth and one-unit difference in AUDIT-C with high FIB-4 were 1.15 (95%CI: 1.08-1.22) and 1.03 (95%CI: 1.00-1.07), respectively. Findings were similar when PEth and AUDIT-C were treated as categorical variables. Conclusions: PEth was independently associated with high FIB-4, with a larger odds ratio than that of the association of AUDIT-C. Use of PEth may improve identification of alcohol use and liver fibrosis prevention and management.