Estimation of Soluble Urokinase-type Plasminogen Activator Receptor in Septic Acute Kidney Injury Patients: A Prospective Observational Study from a Tertiary Care Center

BACKGROUND: Septic-acute kidney injury (SAKI) is one of the most common and most serious complications in critically ill patients, and conventional markers such as serum creatinine and urine output remain late and imperfect indicators of renal injury. Soluble urokinase plasminogen activator receptor (suPAR) has emerged as a biomarker of immune activation and systemic inflammation and may have diagnostic and prognostic relevance in septic AKI. METHODS: In this prospective observational study, 113 adults with sepsis, were enrolled over 1 year. A total 77 patients had S-AKI and 36 had sepsis without AKI. suPAR was measured by ELISA at admission, 24 h, and 48 h. AKI was classified according to Kidney Disease: Improving Global Outcomes (KDIGO) criteria. Group comparisons, correlation analyses, and receiver operating characteristic (ROC) analysis were performed. RESULTS: Admission suPAR was significantly higher in S-AKI than in septic non-AKI controls (29.0 [19.0-92.0] vs. 9.0 [6.0-16.0] ng/mL; P < 0.001). suPAR increased stepwise across KDIGO stages: 20.5 ng/mL in stage 1, 33.0 ng/mL in stage2, and 46.0 ng/mL in stage 3 (P < 0.001). Admission suPAR was higher in patients with partial renal recovery than in those with complete recovery at discharge [46.0 (23.0-88.0) vs. 19.5 (15.0-41.2) ng/mL; P = 0.005]. ROC analysis showed excellent diagnostic performance for S-AKI with an AUC of 0.906 (95% CI 0.84-0.96); the optimal cutoff was 16.0 ng/mL, with 77.9% sensitivity and 86.1% specificity. CONCLUSION: suPAR was significantly elevated in septic AKI, increased with increasing AKI severity, and predicted incomplete renal recovery. suPAR to be a promising diagnostic and prognostic biomarker in septic AKI.