Serum Neutrophil Gelatinase-associated Lipocalin: A Potential Marker of Impending Acute Kidney Injury in Sepsis

Abstract

Abstract Introduction: Kidney injury is an inherent component of sepsis. Serum creatinine (S. Cr) as a marker of kidney injury has certain pitfalls and may not rise until significant kidney function has been lost. This study evaluated neutrophil gelatinase-associated lipocalin (NGAL) as a marker of impending acute kidney injury (AKI) in sepsis. Materials and Methods: A hospital-based cross-sectional, observational analytic study was conducted during one calendar year among patients admitted to medicine wards/intensive care units of a tertiary care hospital in Western India. A total of 80 study participants of age above 18 years fulfilling the criteria of sepsis were recruited in the study according to the Sepsis-3 criteria. Patients below 18 years of age, pregnant women, patients with known kidney diseases, malignancies, autoimmune diseases, and exposure to nephrotoxic agents (i.e. aminoglycoside, angiotensin-converting-enzyme inhibitors, and contrast agents) within the past 2 months, and patients who failed to give consent were excluded from the study. Clinical and biochemical data were collected till Day 7. Sequential organ failure assessment (SOFA) scores were calculated on Day 1 and Day 3. NGAL levels were measured on Day 3. Results: The mean age was 48 ± 19 years, with a male preponderance (63.8%). The mean of SOFA score on Day 1 and Day 3 was 9.84 ± 3.19 and 13.75 ± 3.14, respectively. The mean serum NGAL levels on Day 3 were 436.78 ± 242.23 ng/ml. The mean serum urea on Day 7 (86.99 ± 22.88 mg/dL) was significantly higher than on Day 3 (38.64 ± 9.49 mg/dL) (P = 0.004). Similarly, the mean S. Cr on Day 7 (2.97 ± 1.45 mg/dL) was significantly higher than on Day 3 (0.82 ± 0.23 mg/dL) (P = 0.033). The estimated glomerular filtration rate (eGFR) on Day 7 (35.42 ± 18.99 mL/min/1.73 m2) was also significantly lower in comparison to Day 3 (117.67 ± 56.10 mL/min/1.73 m2) (P < 0.05). Serum NGAL showed a significant positive correlation with S. Cr on Day 3 (r = 0.3257, P = 0.003), Day 7 (r = 0.5944, P < 0.00001), and mean change in S. Cr (r = 0.5562, P < 0.00001). Serum NGAL showed a significant negative correlation with eGFR on Day 3 (r = −0.3061, P = 0.005), Day 7 (r = −0.4362, P = 0.00005), and mean change in eGFR (r = −0.1629, P < 0.0001). Receiver-operating curve analysis showed 90.9% sensitivity and 98.3% specificity of NGAL (cutoff value 152 ng/ml) to predict impending AKI. Conclusion: Traditional marker of renal dysfunction (S. Cr, eGFR) had a significant correlation with NGAL. NGAL can predict impending AKI in sepsis patients earlier than S. Cr or eGFR.