Factors associated with renal function compensation after donor nephrectomy

Introduction: Kidney transplant donors lose 50% of their renal mass after nephrectomy. The remaining kidney compensates for this loss and it is estimated that 70% of the baseline renal function prior to donation is recovered. Factors associated with post-donation renal compensation are not well understood. Methods: Retrospective study of 66 consecutive kidney donors (mean age 48.8 years, 74.2% women). We analysed the potential factors associated with the compensatory mechanisms of the remaining kidney by comparing donors according to their renal compensation rate (RCR) (Group A, infra-compensation [<70%]; Group B, normal compensation [> 70%]). Results: We compared Group A (n= 38) and group B (n=28). Predictors for RCR > 70% were higher baseline creatinine (A vs B: 0.73 +/- 0.14 vs 0.82 +/- 0.11; P =.03) and a lower baseline glomerular filtration rate (GFR), estimated both by MDRD-4 (A vs B: 97.7 +/- 18.8 vs 78.6 +/- 9.6 ml/min; P < .001) and CKD-EPI (A vs B: 101.7 +/- 15 vs. 88.3 +/- 11.7 ml/min; P < .001). Age, gender, smoking, hypertension and GFR measured by Tc-DTPA did not show any conelation with the RCR. The multivariate analysis confirmed baseline estimated glomerular filtration rate (eGFR) to be a predictor of compensation: the higher the baseline eGFR, the lower the likelihood of > 70% compensation (MDRD-4, OR = 0.94 [95% CI 0.8-0.9], P = .01). The compensation rate decreased by 0.4% (P <.001) and 0.3% (P = .006) for every ml/min increase in baseline eGFR estimated by MDRD-4 and CKD-EPI, respectively. Conclusions: One year after living donor nephrectomy, the remaining kidney partially compensates baseline renal function. In our experience, baseline eGFR is inversely proportional to the one-year renal compensation rate. (C) 2018 Sociedad Espanola de Nefrologia. Published by Elsevier Espana, S.L.U.