Predictive value of NGAL for use of renal replacement therapy in patients with severe sepsis

Background The predictive value of plasma and urine neutrophil gelatinase‐associated lipocalin (NGAL) for use of renal replacement therapy (RRT) and acute kidney injury (AKI) is not established in patients with severe sepsis. Methods This was a prospective observational study in three general intensive care units (ICUs) in adult ICU patients with severe sepsis needing fluid resuscitation and a sub‐study of the 6S trial. Plasma and urine were sampled at baseline and NGAL was measured using particle‐enhanced turbidimetric immunoassay (The NGAL Test). Outcome measures were use of RRT in ICU, development of AKI according to the Kidney Disease: Improving Global Outcomes plasma creatinine criteria within 48 h and 90‐day mortality. Results Two‐hundred‐ twenty‐two patients had samples taken (211 had plasma and 162 urine sampled); simplified acute physiology score II was 54 (39–66). Forty patients (18%) had RRT in the ICU, 91 patients had AKI at enrolment; of the remaining 131 patients 24% developed AKI during the first 48 h, and 55% had died at 90 days. Areas under receiver‐operating characteristics curve (AuROC) for predicting use of RRT in ICU were 0.70 (95% confidence interval 0.61–0.78) and 0.62 (0.51–0.73) for plasma and urine NGAL, respectively. AuROC of plasma and urine NGAL for AKI were 0.66 (0.54–0.77) and 0.71 (0.59–0.82), respectively, and for 90‐day mortality 0.55 (0.47–0.63) and 0.61 (0.53–0.70), respectively. Combining NGAL values with plasma creatinine did not improve AuROCs. Conclusion In ICU patients with severe sepsis, plasma and urine NGAL had low predictive power for use of RRT, AKI and 90‐day mortality. These results were supported by sensitivity and exploratory analyses.