Malformative Uropathies and Kidney Transplantation

Renal Transplants Due to Congenital Anomalies of the Kidney and Urinary Tract (CAKUT) Have Better Graft Survival Than Non-CAKUT Controls: Analysis of Over 10,000 Patients

OBJECTIVE

To determine whether graft survival for patients with congenital anomalies of the kidney and urinary tract (CAKUT) is impaired compared to non-CAKUT counterparts.

METHODS

The United States Renal Data System (USRDS) is a national data system that has collected information about end stage renal disease (ESRD) and renal transplantation since 1995. We identified 10,635 first-time renal transplant patients with ESRD attributed to a CAKUT diagnosis transplanted between 1995 and 2018, with follow-up of 7.9 ± 5.8 years. We matched 1:1 with non-CAKUT transplant recipients, using age at transplant, sex, race, year of transplant, and donor-type. We compared renal transplant death-censored graft survival between CAKUT vs non-CAKUT controls, with further stratification for age at transplant and lower urinary tract malformations (LUTM) vs upper urinary tract malformations (UUTM).

RESULTS

Graft survival was better in CAKUT patients with a 5-year survival of 83.3% vs 79.3% (P< .001), and CAKUT status infers a hazard ratio of 0.878 for graft failure on multivariable analysis with Cox regression. Favorability of CAKUT status persisted when stratifying for both pediatric (80.3 vs 77.6% P< .001) and adult (84.5 vs 81.4% P< .001) age groups. Looking within the CAKUT population: comparison of LUTM to UUTM yielded no difference, implying that LUTM is not a risk factor for graft failure. Examining pediatric LUTM alone, graft survival was not better than matched non-CAKUT counterparts with 5-year graft survival of 69%-75% for LUTM adolescents.

CONCLUSION

Renal transplant graft survival is better overall in CAKUT patients as opposed to non-CAKUT counterparts. Pediatric LUTM patients have similar graft survival to controls.

Favorable Outcomes of Renal Transplant in Children With Abnormal Lower Urinary Tract

OBJECTIVES

Chronic kidney disease caused by lower urinary tract abnormalities is a significant complication in pediatric care. Although there are conflicting reports about clinical outcomes in the past, favorable outcomes have been reported in recent years. Despite this, many centers still refrain from performing renal transplant in these patients. Here, we compared clinical outcomes of renal transplant recipients with and without lower urinary tract abnormalities.

MATERIALS AND METHODS

Our study included 71 renal transplant recipients who were divided into 3 groups: 17 patients with abnormal lower urinary tracts having vesicoureteral reflux (group 1), 7 patients with abnormal lower urinary tracts having bladder dysfunction (group 2), and 47 patients with anatomically and functionally normal lower urinary tracts (group 3). We retrospectively compared demographic features, clinical course, graft survival, pre- and posttransplant incidence of urinary tract infections, and final graft function among the groups.

RESULTS

There were no statistically significant differences among groups regarding median age at time of transplant, graft survival, median creatinine level, and median glomerular filtration rate (P > .05). Significant differences were shown in incidence of urinary tract infections between patients in groups 1 and 2 (abnormal lower urinary tracts) and group 3 (normal lower urinary tracts) before transplant (P < .05). Although frequency of urinary tract infections in groups 1 and 2 were moderately higher than shown in group 3 after transplant, this difference was not statistically significant.

CONCLUSIONS

Although the children with abnormal lower urinary tracts had slightly higher incidence of urinary tract infections, there were no differences between patients with abnormal and normal lower urinary tracts regarding allograft survival and function. In addition, proper follow-up of patients before and after transplant, based on our experience, should include educating patients and their parents about potential complications after transplant for the best outcome of renal transplant.