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Abstract: TH-PO410

The Association Between Urinary Neutrophil Gelatinase-Associated Lipocalin and Renal Prognosis in Patients with CKD

Session Information

Category: CKD (Non-Dialysis)

  • 2101 CKD (Non-Dialysis): Epidemiology, Risk Factors, and Prevention

Author

  • Fujii, Naohiko, Hyogo Prefectural Nishinomiya Hospital, Nishinomiya, Japan
Background

Urinary neutrophil gelatinase-associated lipocalin (uNGAL) is a new biomarker for renal tubular damage. Significant associations between uNGAL and renal prognosis have been reported in many papers; however, it may often be affected by urinary tract infection (UTI), and its cut-off value in patients with chronic kidney disease (CKD) has not been well established. The aims of our study were to investigate the association between uNGAL and renal prognosis in CKD and to explore the cut-off value specific for patients with CKD.

Methods

This was a retrospective observational cohort study at a single hospital in Japan. We included adult patients with the estimated glomerular filtration rate (eGFR) of 10 to 70 mL/min/1.73m2 from Jan 2017, who had at least one measurement of uNGAL. We used baseline uNGAL adjusted for urinary creatinine (Cr) as an exposure variable and divided the patients into quartiles. The renal outcome was defined as a 30% increase in serum Cr from baseline values. UTI was determined by baseline urinalysis. We performed survival analyses for the renal outcome, by using the Cox proportional hazards model including restricted cubic spline (RCS) curves. We also performed longitudinal analyses for eGFR decline using the mixed effects model. All statistical analyses were done using STATA 13.1.

Results

In total, 195 patients with CKD were included. Mean age and eGFR at baseline were 70.6 years and 32.3 mL/min/1.73m2, respectively. The median [interquartile range (IQR)] of baseline uNGAL and urinary protein to Cr ratio (uPCR) were 71 [21 - 219] ug/gCr and 0.71 [0.18 - 2.53] g/gCr, respectively. Patients with UTI showed significantly higher uNGAL at baseline than those without (226 [90 - 429] vs. 42 [15 – 123]). During the mean follow up of 171 days, there were 59 renal events. The Kaplan-Meier curve indicated a gradual risk escalation towards the upper quartiles of uNGAL. The adjusted hazards ratios of uNGAL quartiles were 2.8 [0.8 - 10.2], 4.9 [1.3 - 18.7], and 4.2 [1.0 - 17.2] in Q2, Q3, and Q4, respectively. The RCS curves suggested a significantly higher risk at 73.6 ug/gCr or greater. The eGFR slope, however, was comparable among Q1-4, while proteinuria was significantly associated with a greater reduction in eGFR.

Conclusion

A single measurement of uNGAL greater than 73.6 was associated with poor renal outcome. UTI may partially explain its limited prognostic value in clinical practice.