Phosphatidylethanol versus clinical criteria to diagnose alcohol use relapse after liver transplantation: a...

Alcohol-associated liver disease (ALD) with concomitant alcohol use disorder (AUD) is a leading indication for liver transplantation (LT). Return to alcohol use after LT (RAULT) affects a considerable proportion of recipients but lacks an objective diagnostic standard. We evaluated blood phosphatidylethanol (PEth) as a direct biomarker of RAULT and compared it with conventional clinical criteria (ClinC).

We prospectively studied adult patients who underwent LT for ALD between 2008 and 2023. Since 2020, RAULT has been assessed quarterly using both ClinC and PEth (cut-off > 0.05 µg/L). Discordant results were interpreted using PEth as a biochemical comparator, given its higher objectivity and specificity compared with ClinC, although it was not considered a definitive diagnostic standard.

Among 143 patients (median age 56 years; 29% female; median post-LT follow-up 72 months), during a 3-year comparative study interval, RAULT was identified in 46 patients (32.2%) by PEth and in 69 patients (48.3%) by ClinC. Concordance between the two methods was observed in 98 cases (68.5%): in 63 cases (44.0%) for absence of RAULT and in 35 cases (24.5%) for presence of RAULT. Discordance occurred in 45 cases (31.5%), including 34 ClinC-positive/PEth-negative cases (23.8%) and 11 ClinC-negative/PEth-positive cases (7.7%). Quarterly and semi-annual PEth testing yielded comparable overall RAULT detection rates; however, quarterly testing identified a higher proportion of severe RAULT (16.1% vs. 12.6%). Time since LT independently predicted RAULT according to PEth (OR = 1.17; 95% CI 1.08-1.27; p = 0.0002).

Clinical criteria may overestimate the occurrence of RAULT after liver transplantation. Quarterly or semi-annual PEth testing provides additional objective insight into post-transplant alcohol use dynamics and may enhance monitoring of patients with AUD following LT.