Risk Factors for Idiopathic Nephrotic Syndrome Relapse in Pediatric Age.

Introduction. Eighty percent of children with primitive nephrotic syndrome (NS) will have at least one relapse in their life. Specific risk factors could be associated with a higher incidence of relapses and a worse prognosis. This study aims to deepen the demographic and onset-related risk factors in children with known diagnosis of primitive NS attending the Pediatric Nephrology Unit of the University Hospital of Padua. Methods. Observational, descriptive study of all children (1-11 years old) with a known diagnosis of Primitive NS who attended our Pediatric Nephrology Unit between 1 January 2002 and 31 March 2023. Results. 49 patients were involved. 79.5% had at least one episode of NS relapse during their lifetime. 69.4% were classified as frequently relapsing or steroid-dependent NS. The relapse risk factor "non-Western ethnicity" was related to a worse prognosis and steroid-dependent NS classification (p = 0.041). The onset-related risk factor "thrombocytosis" appears to be related to a better prognosis (p = 0.03). Conclusion. The relapse risk factors "non-Western ethnicity" and "thrombocytosis" are characterized by worse and better prognosis, respectively. This evidence could support the follow-up of primitive NS in pediatric age.