Introduction and Objectives: Pre-emptive kidney transplantation (PKT) has recently become more common, particularly in living-donor kidney transplantation (LDKT), as a treatment option for end-stage chronic kidney disease (CKD). The rate of PKT in total LDKT cases has been increasing and comprises approximately 25% of LDKT in Japan. Although PKT offers numerous advantages, it has been observed that in a few patients who are originally selected to undergo PKT, progression of kidney disease necessitates the institution of dialysis prior to undergoing LDKT. We aimed to determine the optimal timing at which a patient should be referred to a transplant center during the course of end-stage CKD to undergo a successful living-donor PKT.
Methods: Between 2006 and 2016, 61 end-stage CKD patients were referred to our department prior to institution of renal replacement therapy (RRT) and eventually underwent LDKT. We divided them into 2 groups-patients who successfully underwent PKT (PKT group) and those who required dialysis prior to LDKT (Non-PKT group). We compared the groups in terms of estimated glomerular filtration rate (eGFR) calculated using the Japanese formula at the first visit as well as in the interval between the first visit and the induction of RRT-either dialysis or a KT (Time to RRT). Eventually, we determined the cut-off value of eGFR and Time to RRT using the receiver operating characteristic curve (ROC) analysis to determine an optimal timing to refer end-stage CKD patients intending to undergo PKT to a transplant center.
Results: The PKT group comprised 49 patients, and the non-PKT group comprised 12. Median eGFR at the first visit in the PKT and non-PKT group was 10.9 mL/min/1.73m² (4.4-27.3) and 6.7 mL/min.73m² (4.3-16.9) and showed a significant difference between the groups (p < 0.01). ROC analysis determined that an eGFR level > 8.1 mL/min/1.73m² at the first visit was a cutoff value to predict successful PKT, and area under the curve was 0.865. Time to RRT was significantly shorter in the non-PKT (median 75 days, 2-379) than in the PKT group (median 205 days, 55-1350). A cutoff point determined using ROC analysis was 116 days, and area under the curve was 0.745.
Conclusion: This study demonstrates that PKT from a living donor may be successfully performed if CKD patients are referred to a transplant center before their eGFR declines to < 8.7 mL/min/1.73m². We propose that pre-transplant clinical examination of both the donor and the recipient be completed within 116 days.