#812 Long-term changes in kidney function following living donor nephrectomy: a retrospective cohort study

Abstract Background and Aims Living kidney donation offers superior outcomes, including better graft and patient survival, compared to deceased donor transplantation. However, despite its benefits, it remains ethically, morally, and medically complex, relying on the expectation that donor risks are outweighed by the psychological benefits of altruism and improved recipient health. Kidney donation inevitably reduces functional kidney parenchyma, determining a reduction of kidney function. Therefore, the aim of this study was to evaluate changes in kidney function (eGFR) over time in living kidney donors following nephrectomy. Method This was a retrospective cohort study. Between 1999 and 2024, 163 living donor nephrectomies were performed at Vilnius University Hospital Santaros Klinikos, Lithuania. Exclusion criteria included incomplete data at the time of donation or loss to follow-up. We analyzed clinical and laboratory data from 105 donors. Using the CKD-EPI formula, we calculated the estimated glomerular filtration rate (eGFR) before nephrectomy and at 6 months, 1 year, 5 years, and 10 years after donation. Categorical variables were summarized as frequencies and percentages, while continuous variables were presented as means with standard deviations (SD) for normally distributed data or medians with interquartile ranges (IQR) for non-normally distributed data. A linear mixed model was used to assess changes in eGFR over time following nephrectomy. Statistical significance was set at P < 0.05. Data analysis was conducted using IBM SPSS Statistics Version 30.0. Results The mean (SD) age of donors was 52.8 (9.0) years. Female donors accounted for 62.9% (n = 66) of all donors, and all donors were related to the recipients. Only one donor died from causes unrelated to the donation. The median eGFR (IQR) for donors before nephrectomy was 93.3 (79.0–102.4) ml/min/1.73 m². The analysis of kidney function (eGFR) over time following nephrectomy revealed a significant decline in eGFR (F = 36.23, P < 0.001). The most pronounced decline occurred within the first 6 months post-nephrectomy (B = 57.37, P = 0.006). The median eGFR (IQR) after 6 months was 65.9 ml/min/1.73 m² (82.7–55.9). Beyond this point, changes at 1 and 5 years were not statistically significant. Age had a significant main effect (F = 2.17, P = 0.002) on eGFR, while sex alone was not a significant predictor (F = 0.32, P = 0.574). However, the interaction between time and sex was significant (F = 2.639, P = 0.039), indicating that the pattern of eGFR change over time differs between males and females. Conclusion Our findings suggest that the most critical period for monitoring kidney function is within the first 6 months post-nephrectomy, and individualized follow-up strategies may be required based on sex-specific patterns of kidney function change.