A clinical predictive model of renal injury in children with congenital solitary functioning kidney.

BACKGROUND: Solitary functioning kidney (SFK) is an important condition in the spectrum of congenital anomalies of the kidney and urinary tract. The aim of this study was to describe the risk factors for renal injury in a cohort of patients with congenital SFK. METHODS: In this retrospective cohort study, 162 patients with SFK were systematically followed up (median, 8.5 years). The primary endpoint was time until the occurrence of a composite event of renal injury, which includes proteinuria, hypertension, and chronic kidney disease (CKD). A predictive model was developed using Cox proportional hazards model and evaluated by c statistics. RESULTS: Among 162 children with SFK included in the analysis, 132 (81.5%) presented multicystic dysplastic kidney, 20 (12.3%) renal hypodysplasia, and 10 (6.2%) unilateral renal agenesis. Of 162 patients included in the analysis, 10 (6.2%) presented persistent proteinuria, 11 (6.8%) had hypertension, 9 (5.6%) developed CKD stage ≥ 3, and 18 (11%) developed the composite outcome. After adjustment by the Cox model, three variables remained as independent predictors of the composite event: creatinine (HR, 3.93; P < 0.001), recurrent urinary tract infection (UTI) (HR, 5.05; P = 0.002), and contralateral renal length at admission (HR, 0.974; P = 0.002). The probability of the composite event at 10 years of age was estimated as 3%, 11%, and 56% for patients assigned to the low-risk, medium-risk, and high-risk groups, respectively (P < 0.001). CONCLUSION: Our findings have shown an overall low risk of renal injury for most of infants with congenital SFK. Nevertheless, our prediction model enabled the identification of a subgroup of patients with an increased risk of renal injury over time.

A predictive model of chronic kidney disease in patients with congenital anomalies of the kidney and urinary tract.

BACKGROUND: The antenatal detection of congenital anomalies of the kidney and urinary tract (CAKUT) has permitted early management of these conditions. The aim of this study was to identify predictive factors associated with chronic kidney disease (CKD) in CAKUT. We also propose a risk score of CKD. METHODS: In this cohort study, 822 patients with prenatally detected CAKUT were followed up for a median time of 43 months. The primary outcome was CKD stage III or higher. A predictive model was developed using the Cox proportional hazards model and evaluated by using c statistics. RESULTS: Chronic kidney disease occurred in 49 of the 822 (6 %) children with prenatally detected CAKUT. The most accurate model included bilateral hydronephrosis, oligohydramnios, estimated glomerular filtration rate and postnatal diagnosis. The accuracy of the score was 0.95 [95 % confidence interval (CI) 0.89-0.99] and 0.92 (95 % CI 0.86-0.95) after a follow-up of 2 and 10 years, respectively. Based on survival curves, we estimated that at 10 years of age, the probability of survival without CKD stage III was approximately 98 and 58 % for the patients assigned to the low-risk and high-risk groups, respectively (p < 0.001). CONCLUSIONS: Our predictive model of CKD may contribute to an early identification of a subgroup of patients at high risk for renal impairment. It should be pointed out, however, that this model requires external validation in a different cohort.