RESUMEN
Although anomalies in the urinary tract are the leading cause of chronic kidney disease (CKD) in the pediatric population, there are few studies focusing on etiological discrepancies between younger and older children. AIM: The aim of the study was to perform a comparative analysis of etiology of CKD in children hospitalized in the Department of Pediatric Nephrology at the Wroclaw Medical University, with reference to the patients' age and gender. MATERIALS AND METHODS: The retrospective analysis considered medical records of 174 patients aged 0-18 years, diagnosed with CKD, hospitalized in our Department in the years 2011-2017. The analyzed population was divided regarding the patients' age. Group A contained children up to 2 years of age (45 patients), group B - children aged 2-18 years (129 patients). RESULTS: In younger children, boys prevailed, in older children gender distribution was equal. The most common causative factors of CKD in group A were: urinary tract anomalies (66,7%), perinatal acute kidney injury (17,8%) and hereditary renal disorders (8,9%). In children over 2 years of age, urinary tract anomalies were also the leading cause of CKD (48,8%), followed by glomerulopathies (16,3%) and hereditary renal disorders (15,5%). CONCLUSIONS: Anomalies within the urinary tract are the predominant cause of CKD in children, irrespective of age. Male predominance concerned only children up to 2 years of age. The second causative factor for CKD in the youngest children is acute kidney injury, mainly in the perinatal period. Glomerulopathies and hereditary renal disorders are significant etiological factors for CKD in older children.