Association of MASLD with Baseline and New-Onset Liver Function Test Elevation in Medical ICU Patients

<i>Background and Objectives</i>: Metabolic dysfunction-associated steatotic liver disease (MASLD) is highly prevalent and may influence the outcome of critical illness. Although abnormal liver function tests (LFTs) are frequent in the intensive care unit (ICU), the contribution of MASLD to organ-specific hepatic vulnerability and mortality remains unclear. This study aimed to evaluate whether pre-existing metabolic dysfunction-associated steatotic liver disease (MASLD) is associated with baseline and new-onset liver function test (LFT) abnormalities and with intensive care unit (ICU) outcomes in non-cirrhotic medical ICU patients. <i>Materials and Methods</i>: We conducted a retrospective cohort study of adult non-cirrhotic patients admitted to a tertiary medical ICU between December 2020 and December 2023, who underwent hepatobiliary ultrasonography within six months before admission. MASLD was defined as hepatic steatosis with ≥1 cardiometabolic risk factor. The baseline and 72 h LFTs, injury patterns, and ICU outcomes were compared between MASLD and non-MASLD patients. Logistic regression was used to identify the independent predictors of new-onset LFT elevation and ICU mortality. <i>Results</i>: Among 609 patients, MASLD was diagnosed in 240 (39.4%). LFT elevation at admission was more frequent in patients with MASLD (52% vs. 39%, <i>p</i> = 0.03), driven mainly by higher alkaline phosphatase (ALP). At 72 h, ALP (96 [67-146] vs. 85 [60-137]) and gamma-glutamyl transferase (GGT) (50 [27-123] vs. 42 [20-100]) levels remained higher in patients with MASLD (<i>p</i> < 0.01), although rates of new-onset LFT elevation were similar (<i>p</i> > 0.05). Compared to non-MASLD patients, those with MASLD more often required invasive mechanical ventilation (IMV) (64% vs. 33%), central venous catheterization (70% vs. 44%), CRRT (28% vs. 10%), blood product replacement (50% vs. 28%), and developed nosocomial infections (44% vs. 29%) (<i>p</i> < 0.05 for all); however, MASLD was not an independent predictor of mortality. The independent risk factors for mortality were IMV, shock, and higher APACHE II scores. <i>Conclusions</i>: common among medical ICU patients and is associated with a cholestatic biochemical profile and poor ICU outcomes. However, early hepatic injury and ICU mortality are primarily determined by systemic severity and organ support requirements, not the MASLD itself.