Neutrophil gelatinase-associated lipocalin as a predictor of treatment outcomes in primary glomerulonephritis

Background/Aim. Biomarkers for predicting disease course could facilitate treatment selection in primary glomerulonephritis (PGN). Data on the role of neutrophil gelatinase-associated lipocalin (NGAL) in PGN are limited. The aim of this study was to evaluate the significance of NGAL in predicting treatment outcomes in PGN. Methods. The study included a total of 60 PGN patients followed between 2012 and 2024. At diagnosis, serum NGAL (sNGAL) and urinary NGAL (uNGAL) were measured. Renal function parameters (serum creatinine, proteinuria) and disease outcome-development of end-stage renal disease (ESRD)-were assessed at baseline, after 5 years, and at the end of the follow-up period. The association between NGAL and clinical outcomes was analyzed using appropriate statistical tests. Results. At baseline, median sNGAL and uNGAL levels were 154.71 ng/mL and 13.94 ng/mL, respectively. During a median follow-up of 112 months, 8.33% of patients were lost to follow-up, and 20% developed ESRD. Patients who developed ESRD had higher sNGAL levels (p = 0.027). Using sNGAL, ESRD was fairly predictive (AUC = 0.709; p = 0.036), and sNGAL was associated with time-to-ESRD (Kaplan-Meier analysis, p < 0.001). The group with the highest sNGAL showed the lowest 5-year renal survival. Patients with stable or improved estimated glomerular filtration rate (eGFR) had higher uNGAL/creatinine ratio values (p = 0.049). Changes in proteinuria correlated negatively with sNGAL (p < 0.001) and uNGAL (p = 0.005). Conclusion. In PGN, sNGAL could be a predictor of ESRD development, potentially reflecting its pro-fibrotic activity. In contrast, the correlation between NGAL levels and change in proteinuria, as well as the associations between higher uNGAL/creatinine ratios and improved eGFR, suggest a complex and potentially protective role of NGAL in disease progression.