Epidemiology of Pediatric Nephrotic Syndrome: Real-World Data from Brazil.

Introduction: The present study aimed to describe the clinical and demographic characteristics of nephrotic syndrome in children from a large, highly genetically admixed Latin American country and to identify key challenges in managing pediatric nephrotic syndrome in Brazil. Methods: This observational, multicenter study included a patient sample from 21 pediatric nephrology centers. Descriptive statistics were employed to analyze the outcomes. Results: Data were collected from 597 patients; 333 (56%) were male, with a median age of 3.5 years (interquartile range [IQR], 2.2-6.0) at disease onset. There was no consensus among centers regarding initial treatment duration, criteria of response to treatment, although all patients received corticosteroids. After a median follow-up of 4.3 years (IQR, 2.0-7.4), 423 (71.0%) patients were classified as steroid-sensitive, and 172 (28.9%) as steroid-resistant. Progressive kidney dysfunction (chronic kidney disease [CKD] stages 4/5) was observed in 35 (5.9%) patients. Despite 224 patients undergoing kidney biopsy and 172 being classified as steroid-resistant, only 8 (1.3%) children underwent genetic testing. Electron microscopy was performed in only 19 kidney biopsies. Conclusion: Despite the inherent limitations of observational studies, this investigation presents valuable clinical and demographic data on nephrotic syndrome from a previously underrepresented region. It highlights significant unmet medical needs in Brazil, including the need for consensus on treatment protocols and standardized definitions of responses to treatment. In addition, the near absence of genetic testing in steroid-resistant nephrotic syndrome represents a critical gap that requires prompt intervention.