RESUMEN
PURPOSE: We evaluated the clinical course of patients prenatally diagnosed and enrolled early with congenital solitary functioning kidney, and identified the risk factors for renal injury. MATERIALS AND METHODS: We retrospectively evaluated 322 patients with congenital solitary functioning kidney according to the inclusion criteria of 1) prenatal diagnosis of solitary kidney; 2) first evaluation at 1 to 3 months of life with confirmation of congenital solitary functioning kidney, and evaluation of possible associated congenital anomalies of the kidney and urinary tract by abdominal ultrasound, renal scintigraphy and cystography; and 3) absence of any condition potentially affecting renal function in the neonatal period as well as absence of renal injury at enrollment (1 to 3 months of life) confirmed by a normal estimated glomerular filtration rate, lack of proteinuria and hypertension. Followup of 306 patients was evaluated. RESULTS: Median followup was 7.2 years (range 1 to 23) and 1 or more signs of renal injury were found in 12 of 306 patients (3.9%). Considering the entire population the cumulative proportion of patients free from renal injury at 17 years old was 93.7%, vs 81.3% and 95.9% for subjects with and those without congenital anomalies of the kidney and urinary tract of congenital solitary functioning kidney (p <0.001), respectively. Of congenital anomalies of the kidney and urinary tract, congenital solitary functioning kidney resulted in significant risk factors for renal injury (HR 8.75, 95% CI 2.77-27.65). CONCLUSIONS: In an evaluation of a large cohort of patients enrolled early with congenital solitary functioning kidney with a prenatal diagnosis, excluding those with neonatal onset of renal damage, the prevalence of renal damage was 3.9%. Among congenital anomalies of the kidney and urinary tract, congenital solitary functioning kidney represented the major risk factor.