The Fibrosis-4 Index Predicts Ceftriaxone-Associated Gallstone Formation: Risk Stratification Using the Fibrosis-4 Index in a Clinical Cohort.

Background: Ceftriaxone is widely used because of its broad antimicrobial spectrum and convenient dosing; however, high biliary excretion can lead to calcium-ceftriaxone precipitation and gallstone-like formations. Although exposure-related risk factors have been described, the effect of hepatic fibrosis on ceftriaxone-associated gallstone formations remains unclear. Aims: To clarify the role of hepatic fibrosis in ceftriaxone-related gallstone formation. Methods: We conducted a retrospective study on adult patients who received intravenous ceftriaxone and underwent abdominal computed tomography at a tertiary hospital between October 2021 and July 2025. The primary outcome was newly detected gallstone formations during or after ceftriaxone therapy. Clinical variables, including treatment duration, cumulative dose, and fibrosis-4 index, were analyzed. Decision tree, Kaplan-Meier, Cox proportional hazards, and receiver operating characteristic analyses were performed. Results: Among the 320 eligible patients, 98 (30.6%) developed newly detected gallstones. Patients with gallstones had longer treatment duration (10 vs. 6 days, Conclusions: Elevated FIB-4 levels were independently associated with CRO-related gallstone formation. The FIB-4 index may facilitate risk stratification during CRO therapy, although the observed association should not be interpreted as direct evidence of hepatic fibrosis.