Fibrinogen-to-albumin ratio is associated with the prognosis of patients with septic acute kidney injury.

Abstract

Background: The fibrinogen-to-albumin ratio (FAR), a novel inflammatory biomarker, is strongly associated with the incidence of sepsis. Nonetheless, there is a lack of research regarding the FAR and prognosis in individuals with septic acute kidney injury (SAKI). The aim of this study was to assess the correlation between the FAR upon intensive care unit (ICU) admission and overall mortality in patients with SAKI.

Methods: All patient information was retrieved from the Medical Information Mart for Intensive Care-IV (MIMIC-IV) database. All patients were divided into four distinct categories according to the FAR. The primary endpoints for this study were the 30-day and 365-day all-cause death rates, whereas the secondary endpoints were the 60-day, 90-day and 180-day all-cause death rates. The FAR was quartile, and the Kaplan-Meier curve was used to evaluate the outcomes across the groups. To evaluate the correlation between the FAR and outcomes, we used a Cox proportional hazards regression model and restricted cubic splines (RCSs).

Results: Among the 6208 participants, the average age was 65 years, with 3659 (58.94%) identified as male. Patients exhibiting elevated FAR values demonstrated an increased risk of all-cause mortality at 30, 60, 90, 180 and 365 days, as evidenced by the Kaplan-Meier curves (log-rank P < .001). SAKI patients with elevated FAR values had a greater risk of all-cause mortality at 30, 60, 90, 180 and 365 days than did those with lower FAR values, as demonstrated by Cox proportional hazards regression analysis. With inflection points at 35.14 for 30-day mortality and 34.8 for 365-day mortality, the RCS analysis revealed that the FAR and all-cause mortality were related in an inverted N-type pattern. In instances where FAR levels were below 35.14 mg/g, a reduction of 1 unit in the FAR correlated with a 6.5% increase in the risk of 30-day all-cause mortality [hazard ratio (HR) 0.935; 95% confidence interval (CI) 0.923, 0.948]. In instances where FAR levels were below 34.8 mg/g, a reduction of 1 unit in the FAR correlated with a 6.2% increase in the risk of 365-day all-cause mortality (HR 0.938; 95% CI 0.927, 0.949).

Conclusion: In severely ill patients with SAKI, elevated FAR levels are strongly correlated with an increased risk of all-cause mortality at 30, 60, 90, 180 and 365 days. FAR may serve as a reliable metric for assessing and managing patients with SAKI in the ICU.