Frailty-Related and Hepatic Prognostic Markers in Acute Biliary Tract Infections: A Diagnosis-Stratified Retrospective Cohort Study

Background: Acute biliary tract infections (BTIs), including acute cholecystitis and acute cholangitis, show substantial clinical heterogeneity and variable short-term outcomes. Prognostic markers reflecting frailty, nutritional reserve and hepatic dysfunction may improve early risk stratification. In this context, the present study aimed to evaluate the prognostic value of computed tomography (CT)–derived psoas muscle area (PMA), FIB-4 score, prognostic nutritional index (PNI) and systemic inflammatory indices in predicting intensive care unit (ICU) admission, 30-day mortality and length of hospital stay (LOS) in patients hospitalized with acute BTIs. Methods: We retrospectively analyzed 94 adults hospitalized with acute biliary tract infections between 2022 and 2023. Analyses were performed in a diagnosis-stratified manner (acute cholecystitis vs acute cholangitis). Psoas muscle area (PMA) was measured on admission CT at the L3 level, while FIB-4, prognostic nutritional index (PNI) and systemic inflammatory ratios were calculated from admission laboratory data. Outcomes included ICU admission, 30-day all-cause mortality and length of hospital stay. Logistic regression and linear regression analyses were used to identify prognostic factors and receiver operating characteristic (ROC) curves were applied to assess model discrimination. Results: Patients with acute cholangitis exhibited substantially higher 30-day mortality than those with acute cholecystitis (30.0% vs 4.1%), along with lower PNI, higher FIB-4 values, lower albumin and hemoglobin levels and a higher prevalence of low PMA. Age was associated with lower PMA and PNI and higher FIB-4 scores. In parsimonious multivariable logistic regression analysis, a diagnosis of acute cholangitis emerged as the strongest predictor of 30-day mortality. Although age and psoas muscle area (PMA) demonstrated directionally consistent associations with mortality, these did not reach statistical significance, likely owing to the limited number of outcome events. The resulting model showed good discriminatory performance for 30-day mortality (AUC ≈ 0.84). Conclusions: Frailty-related parameters, particularly impaired nutritional status and reduced muscle mass, cluster in patients with acute cholangitis and are associated with worse short-term outcomes. CT-based PMA assessment, together with nutritional and hepatic indices, may support early risk stratification in acute biliary tract infections.