Vesicoureteral Reflux in Transplanted Kidney Among Children With Congenital Anomalies of Kidney and Urinary Tract: Case-Control Study Assessing Impact on Renal Function and Graft Survival

Background: Congenital anomalies of the kidney and urinary tract (CAKUT) are a common cause of kidney failure in childhood. Renal transplantation is the modality of treatment used for kidney failure that promotes improved quality of life for pediatric patients. It is believed that patients with CAKUT are more predisposed to developing graft reflux in the post-transplant period, but its influence on graft survival is poorly understood. A comparative analysis between patients with and without VUR in the graft was made to determine the impact of reflux on graft function and survival in pediatric CAKUT patients.

Methods: A retrospective case-control study of patients undergoing first renal transplantation between April 2008 and October 2021 was done. The study included CAKUT individuals who underwent voiding cystourethrogram after transplantation. Patients were stratified into a group without reflux in the transplanted kidney (controls) and a group with reflux (cases). Six-year graft and patient survivals were calculated and compared using Kaplan-Meier curves and the log-rank test.

Results: A total of 257 CAKUT patients were studied. Of this group, 63 (24%) underwent voiding cystourethrogram after transplantation, and 48 (76%) had reflux in the transplanted kidney. Estimated six-year survival of the graft was 72% in the control group versus 96% in the case group (log-rank 0.889). The median follow-up time after transplantation in years was 7.6 in controls and 6.6 in cases (p = 0.383).

Conclusions: Pediatric patients with CAKUT who presented reflux in transplanted kidneys had similar graft and patient survivals compared to patients without reflux.