#5661 EARLY COMPENSATORY INCREASE IN SINGLE-KIDNEY EGFR AFTER UNILATERAL NEPHRECTOMY IS ASSOCIATED WITH A LOWER LONG-TERM RISK OF EGFR DECLINE

Abstract

Abstract Background and Aims The healthy kidney has reserve capacity, allowing for an increase in single-kidney GFR (ΔskGFR) in the remaining kidney after nephrectomy. We evaluated whether higher ΔskGFR, as a reflection of renal resilience, is associated with a lower long-term risk of eGFR decline in individuals undergoing unilateral nephrectomy. Method We included 1777 participants from the observational SCREAM project who underwent radical unilateral nephrectomy in Stockholm during 2006–2021. We calculated the ΔskGFR using the eGFR (CKD-EPI 2009) at 3 months post-nephrectomy eGFR minus 50% of the pre-nephrectomy eGFR and evaluated its pre-nephrectomy determinants (age, sex, eGFR, comorbidities) with multivariable linear regression. Follow-up started at 3-months post-nephrectomy, and Cox regression was used to explore the association between Δsk-GFR and the subsequent risk of CKD progression (defined as composite of a decline >30% relative to three months post-nephrectomy eGFR or initiation of kidney replacement therapy), adjusting for age, sex and pre-nephrectomy eGFR. Results Mean (SD) age was 68 ± 11 years, 40% of patients were female, 92% had a kidney cancer diagnosis and mean (SD) pre-nephrectomy eGFR was 75 ± 19 mL/min/1.73m2. Median (IQR) Δsk-GFR was 11 (7–20) mL/min/1.73m2. Pre-nephrectomy determinants of Δsk-GFR were age (St.Β = −0.20, P≪0.001) and pre-nephrectomy eGFR (St.Β = 0.14, P<0.001). During a median follow-up of 4 years (maximum 15 years), 178 participants developed CKD progression. The group with a Δsk-GFR above the median value (11 mL/min/1.73m2) had a 42% lower risk of CKD progression (adjusted HR: 0.58, 95% CI: 0.42 – 0.80), compared to those with a lower Δsk-GFR (Figure). Conclusion A larger compensatory increase in single-kidney eGFR early after unilateral nephrectomy, suggesting better renal resilience, was associated with a lower risk of CKD progression during long-term follow-up. Evaluation of Δsk-GFR could help identify patients at higher risk of progressive kidney function decline.