Timing and outcome of renal replacement therapy in patients with congenital malformations of the kidney and urinary tract

Abstract

Background and objectives: Congenital anomalies of the kidney and urinary tract (CAKUT) are the leading cause of ESRD in children, but the proportion of patients with individual CAKUT entities progressing to ESRD during adulthood and their long-term clinical outcomes are unknown. This study assessed the age at onset of renal replacement therapy (RRT) and patient and renal graft survival in patients with CAKUT across the entire age range.

Design, setting, participants, & measurements: Patients with CAKUT were compared with age-matched patients who were undergoing RRT for other renal disorders on the basis of data from the European Renal Association-European Dialysis and Transplant Association Registry. Competing risk and Cox regression analyses were conducted.

Results: Of 212,930 patients commencing RRT from 1990 to 2009, 4765 (2.2%) had renal diagnoses consistent with CAKUT. The proportion of incident RRT patients with CAKUT decreased from infancy to childhood and then increased until age 15-19 years, followed by a gradual decline throughout adulthood. Median age at RRT start was 31 years in the CAKUT cohort and 61 years in the non-CAKUT cohort (P<0.001). RRT was started earlier (median, 16 years) in patients with isolated renal dysplasia than in those with renal hypoplasia and associated urinary tract disorders (median, 29.5-39.5 years). Patients with CAKUT survived longer than age- and sex-matched non-CAKUT controls because of lower cardiovascular mortality (10-year survival rate, 76.4% versus 70.7%; P<0.001).

Conclusions: CAKUT leads to ESRD more often at adult than pediatric age. Treatment outcomes differ from those of acquired kidney diseases and vary within CAKUT subcategories.

Figure 1.

Age distribution at onset of renal replacement therapy (RRT). Percentage of patients with congenital anomalies of the kidney and urinary tract (CAKUT) (closed bars) starting RRT at a given age compared with groups with non-CAKUT primary renal disease (hatched bars) in the European Renal Association-European Dialysis and Transplant Association registry.

Figure 2.

Incidence and cumulative percentage of patients starting renal replacement therapy (RRT) by subcategory of congenital anomalies of the kidney and urinary tract (CAKUT). (A) Incidence per million age-related population. (B) Cumulative percentage.

Figure 3.

Patient survival during renal replacement therapy in patients with congenital anomalies of the kidney and urinary tract (CAKUT) from the European Renal Association-European Dialysis and Transplant Association Registry. Findings are shown by CAKUT category and for all patients without CAKUT.

Figure 4.

Outcome of patients receiving renal replacement therapy. Competing risk analysis for patient survival and kidney transplantation during dialysis, comparing (A) patients with other primary renal diseases matched for age, sex, country, year of start of renal replacement therapy, and treatment modality at start with (B) all patients with congenital anomalies of the kidney and urinary tract (CAKUT) and (C) patients with neurogenic pyelonephritis from the European Renal Association-European Dialysis and Transplant Association Registry.

Figure 5.

Competing risk analysis for survival. (A) Graft survival. (B) Patient survival. Analysis compares patients who have congenital anomalies of the kidney and urinary tract (CAKUT) with those who do not have CAKUT (matched for age, sex, country, year of start of renal replacement therapy, and treatment modality at start) from the European Renal Association-European Dialysis and Transplant Association Registry.