Early compensatory increase in single-kidney estimated GFR after unilateral nephrectomy is associated with a lower long-term risk of estimated GFR decline.

BACKGROUND AND HYPOTHESIS

A more pronounced short-term increase in single-kidney GFR (ΔskGFR) has been associated with better long-term kidney function in living kidney donors. Whether this also applies to non-donors is unknown. We evaluated whether ΔskGFR is associated with long-term risk of eGFR decline in individuals undergoing unilateral nephrectomy.

METHODS

This study included 1777 participants from the SCREAM cohort who underwent radical unilateral nephrectomy in Stockholm between 2006 and 2021. The ΔskGFR was calculated as the early (1-6 months) post-nephrectomy eGFR minus 50% of the pre-nephrectomy eGFR. Multivariable Cox regression was used to study the association between Δsk-GFR and the subsequent risk of progressive eGFR decline, defined as composite of an eGFR decline >30% compared to the early (6 months) post-nephrectomy eGFR or kidney failure.

RESULTS

Mean age at nephrectomy was 68 ± 11 years, 40% were female, 92% had kidney cancer, and median (IQR) pre-nephrectomy eGFR was 76 (61-89) ml/min/1.73 m2. Median Δsk-GFR was 11 (7-20) ml/min/1.73 m2. Pre-nephrectomy determinants of Δsk-GFR were age (inverse association) and pre-nephrectomy eGFR (positive association). During a median follow-up of 5 years (range 0.6-15 years), 178 participants developed progressive eGFR decline. Individuals with a Δsk-GFR above the median had a lower rate of progressive eGFR decline (adjusted HR: 0.58, 95% CI: 0.42-0.80), compared to those with a Δsk-GFR below the median, independent of baseline eGFR and age.

CONCLUSIONS

A stronger increase in single-kidney eGFR early after unilateral nephrectomy was associated with a lower long-term risk of progressive eGFR decline. Evaluation of Δsk-GFR could help identify patients at higher risk of progressive kidney function decline following unilateral nephrectomy.