FAR values based on time windows.

PurposeSepsis-associated acute kidney injury (SA-AKI) is a critical complication associated with negative outcomes. However, the effective prevention of SA-AKI is limited. This retrospective cohort study, which used the MIMIC-IV database, investigated the association between fibrinogen-to-albumin ratio (FAR) and SA-AKI.Materials and methodsThe retrospective cohort study involved 1,771 sepsis patients in MIMIC-IV database. Multivariable logistic and Cox regression models were used to estimate ORs/HRs with 95% CIs for incident SA-AKI. Sensitivity analyses, including stratified analyses and RCS curve, assessed the strength of the association. The predictive performance was compared to other marker using ROC curves and AUCs.ResultsAn elevated FAR level (≥110.74) was found to be associated with an elevated risk of SA-AKI (adjusted OR 1.55, 95%CI 1.11–2.18, P = 0.011), but the association was timing, it reached statistical significance only when SA-AKI occurred after ICU day 3 (adjusted HR 5.17, 95%CI 1.81–14.72, P = 0.002). Subgroup analyses indicated that chronic obstructive pulmonary disease (COPD) and hypertension interacted in this association. In sepsis patients without COPD and hypertension, high FAR (≥110.74) was linked to SA-AKI (adjusted OR 2.31, 95%CI 1.40–3.82, P = 0.001), with statistical significance also occurring 3 days after ICU admission (adjusted HR 8.57, 95%CI 1.88–38.94, P = 0.005). The RCS curve showed a linear relationship between FAR and SA-AKI (P for non-linearity: 0.415). ROC analyses showed that FAR combined with SOFA slightly outperformed SOFA alone (AUC 0.697 vs. 0.678, P = 0.004).ConclusionsAn elevated FAR level was associated with an increased incidence of SA-AKI in patients without COPD and hypertension. However, this association reached statistical significance only when SA-AKI occurred after ICU day 3. Further research is needed to investigate this association.