Persistent Severe Acute Kidney Injury Among Critically Ill Patients: Outcomes and Predictive Markers-A Single-Center...

Area of Science:

• Nephrology
• Critical Care Medicine
• Inflammation Biology

Background:

• Persistent severe acute kidney injury (PS-AKI), defined by Kidney Disease: Improving Global Outcomes (KDIGO) Stage 3 criteria persisting ≥72 hours or requiring renal replacement therapy/death, is a critical trajectory-based phenotype.
• Limited evidence exists on PS-AKI in contemporary intensive care unit (ICU) cohorts.
• Understanding PS-AKI is crucial for improving patient outcomes in critical care settings.

Purpose of the Study:

• To investigate the incidence and outcomes of PS-AKI in a tertiary ICU cohort.
• To identify predictors of PS-AKI, focusing on inflammatory and hematologic markers.
• To evaluate the utility of trajectory-based AKI phenotypes in predicting patient outcomes.

Main Methods:

• Retrospective study of 106 adult ICU patients with acute kidney injury (AKI) between January 2024 and June 2025.
• AKI staging followed KDIGO 2012 guidelines; trajectories classified as Stage 1 AKI, transient AKI, persistent mild-moderate AKI, or PS-AKI.
• Logistic regression and gradient boosting with SHAP attribution were used to identify PS-AKI predictors.

Main Results:

• PS-AKI occurred in 23% of the cohort, predominantly community-acquired.
• PS-AKI was associated with significantly higher in-hospital mortality (54%) and lower renal recovery (17%) compared to non-PS trajectories.
• Higher neutrophil-to-lymphocyte ratio (NLR) and C-reactive protein (CRP), and lower platelets were observed in PS-AKI patients. The NLR-to-platelet ratio (NLR/PLT) was independently associated with PS-AKI (aOR 2.51 per doubling).

Conclusions:

• PS-AKI is a frequent and severe complication in ICU patients, strongly linked to adverse in-hospital outcomes.
• The NLR/PLT ratio, reflecting inflammation and thrombocytopenia, shows promise as an early risk assessment tool for PS-AKI.
• Further research into trajectory-based AKI phenotypes and inflammatory markers is warranted for improved prediction and management.