Underutilization of PETH testing among patients with MASLD – retrospective, single-center evaluation of the frequency and results of phosphatidylethanol testing among patients diagnosed with metabolic dysfunction-associated liver disease

Alcohol may confound or complicate diagnosis of Metabolic Dysfunction Associated Steatotic Liver Disease (MASLD). Though phosphatidylethanol (PETH) testing is widely available, its use among patients with MASLD has not been well established. This study set out to determine both the frequency of PETH testing and the rate of positive PETH tests among patients initially diagnosed with MASLD. We conducted a retrospective cohort study at a single institution of patients diagnosed with MASLD. Patient demographics, metabolic comorbidities, labs, and rate of PETH testing were collected. We compared characteristics of patients with and without PETH testing as well as those with positive results. LASSO regression was then used to identify predictive factors of a positive PETH test. We identified 10,208 patients who met the inclusion criteria; PETH testing was performed in only 700 patients (6.9%). Among those who underwent PETH testing, 275 patients (39.6%) had a positive PETH. Positive PETH results were associated with younger age, male sex, a lower BMI, the absence of diabetes, and elevated AST, ALT, and MCV values. However, using patient factors, the LASSO model demonstrated a poor ability to predict a positive PETH (AUC 0.64). Although PETH testing was only sent in a minority of patients diagnosed with MASLD, over a third were elevated. We found that patient and laboratory parameters were insufficient to predict potentially injurious alcohol use. These findings suggest that use of PETH testing may better inform care of patients with MASLD.