Delta index of the estimated glomerular filtration rate to amend the overestimated Neutrophil Gelatinase-Associated Lipocalin (NGAL) level in systemic inflammatory response syndrome

This study aimed to investigate a delta index of the estimated glomerular filtration rate (δeGFR-index) to amend an overestimated neutrophil gelatinase-associated lipocalin (NGAL) level in systemic inflammatory response syndrome (SIRS). A δeGFR-index was computed, and the NGAL/δeGFR-index was determined. Patients with SIRS exhibited significantly higher levels in NGAL, the δeGFR-index, and high sensitivity C-reactive protein (hsCRP) than non-SIRS inflammatory patients (216 ng/ml, 1.32, and 5.64 mg/dl vs. 153 ng/ml, 1.18, and 2.92 mg/dl, respectively, p < 0.05). After adjusting for potential confounders, the NGAL/δeGFR-index was closely associated with serum hsCRP concentrations (standard β = 0.552, p < 0.001). In a receiver operating characteristic curve, the diagnostic ability of the NGAL/δeGFR-index to identify SIRS in inflammatory diseases was superior to that of the NGAL [0.712 (95% CI, 0.638-0.786) vs. 0.646 (95% CI, 0.567-0.726), p < 0.001]. The area under the curve of the NGAL/δeGFR-index was significantly larger than that of NGAL for detecting hsCRP >3.80 mg/dl in SIRS [0.761 (95% CI, 0.660-0.862) vs. 0.728 (95% CI, 0.625-0.831), p = 0.019]. In short, the NGAL/δeGFR-index more correctly represents the disease activity in SIRS than the level of plasma NGAL. A measure of the NGAL/δeGFR-index may be of additional help when monitoring patients with SIRS, particularly in conjunction with concurrent renal dysfunction.