Disease Stage-Dependent Association Between Nephrotic-Range Proteinuria and Severe Acute Kidney Injury in Patients with Liver Cirrhosis

Background: Acute kidney injury (AKI) is a common and serious complication in patients with liver cirrhosis and is associated with poor outcomes. However, whether the association between nephrotic-range proteinuria (NRP) and severe AKI varies by liver disease severity remains unclear. Methods: This retrospective cohort study included 408 adult patients with cirrhosis stratified by Child–Pugh class (A, B, and C). Severe AKI was defined as Kidney Disease: Improving Global Outcomes stage 2–3. Multivariable logistic regression analyses were performed in the overall cohort and within each class, with the additional evaluation of interaction effects. Results: The incidence of severe AKI increased from 18.4% in class A to 38.8% in class C. In the extended multivariable model incorporating hemodynamic and inflammatory variables, nephrotic-range proteinuria was not significantly associated with severe AKI. In stratified analyses, a significant association was observed only in Child–Pugh class A. Additional analyses suggested that this relationship was attenuated after accounting for sepsis and systemic severity. Conclusions: Although NRP prevalence was similar across Child–Pugh classes, the association between NRP and severe AKI appeared to vary by disease stage, particularly before adjustment for systemic severity.