Urine Epidermal Growth Factor as a Biomarker for Kidney Function Recovery and Prognosis in Glomerulonephritis with Severe Kidney Failure

Background: Prognostication in glomerulonephritis (GN) with severe kidney failure is critical to evaluate the benefit-to-risk ratio of immunosuppression. This study aimed to evaluate the role of urine epidermal growth factor (uEGF) levels as predictor of kidney function recovery. Methods: We included 82 subjects with GN and severe kidney failure defined as eGFR ≤30ml/min/1.73m2 at presentation. Fifty-eight had lupus nephritis (LN) and 24 ANCA-associated vasculitis (AAV). Thirty-five subjects had initial kidney replacement therapy (KRT) requirement. Urine EGF was measured by ELISA and corrected by urine creatinine. The outcomes included time to persistent recovery of eGFR≥30ml/min/1.73m2 and time to recovery of kidney function with dialysis independence in those with initial KRT. Results: Forty-four (54%) subjects recovered their eGFR ≥30ml/min/1.73m2 with 6-month recovery rates of 93%, 57%, and 0% for subjects in the highest, middle, and lowest uEGF tertile, respectively. Recovery of kidney function was faster and to a higher eGFR in the highest uEGF tertile. The area under the curve (AUC) of uEGF as predictor of recovery was 0.92 (95%CI 0.87-0.98) with a cutoff of 2.60ng/mg having 100% sensitivity to detect all subjects who recovered kidney function above 30ml/min. In the subgroup of subjects with initial KRT, admission uEGF had an AUC of 0.96 (95%CI 0.92-0.99) to detect all subjects who recovered from KRT by 6 months. A uEGF cut-off of 2.0 ng/mg demonstrated 100% sensitivity in detecting all subjects who recovered from KRT within this period. Conclusion: Urine EGF is a promising biomarker to aid in the prediction of recovery of kidney function in glomerulonephritis with severe kidney function. The addition of uEGF to clinical and histopathological variables may aid therapeutic decisions in these patients.