title: Variability of diagnostic criteria and treatment of idiopathic nephrotic syndrome across European countries.
abstract: The aim of the surveys conducted by the Idiopathic Nephrotic Syndrome Working Group of the ESPN was to study the possible variability of treatment in Europe at different stages of the disease by means of questionnaires sent to members of the Working Group. Four surveys have been completed: treatment of the first flare, treatment of the first relapse and the issue of steroid dependency, use of rituximab, and the management of steroid-resistant patients. A uniform treatment of the first flare was applied in only three countries, and ten additional centers have adopted one of the three main protocols. Reported treatment of the first relapse was relatively uniform, whereas the use of additional immunosuppressants in steroid dependency was widely variable. Rituximab had already been used in hundreds of patients, although the formal evidence of efficiency in steroid dependency was relatively recent at the time of the survey. The definition of steroid resistance was variable in the European centers, but strikingly, the first-line treatment was uniform throughout the centers and included the combination of prednisone plus calcineurin antagonists.
  
  
  CONCLUSIONS
  The variability in the approach of idiopathic nephrotic syndrome is unexpectedly large and affects treatment of the first flare, strategies in the case of steroid dependency, as well as the definitions of steroid resistance. What is Known: • Steroids and immunosuppressants are the universal treatment of idiopathic nephrotic syndrome. What is New: • The variability of treatments and strategy of treatment in European centers of pediatric nephrology.
authors.affiliation: Pediatric Nephrology Unit, Université Sorbonne Paris Cité, APHP Robert-Debré, 48 Bd Sérurier, 75019, Paris, France. georges.deschenes@aphp.fr.
authors.forename: Georges
authors.identifier: http://orcid.org/0000-0002-5158-2915
authors.initials: G
authors.lastname: Deschênes
authors.affiliation: Division of Nephrology and Dialysis, Bambino Gesù Children's Hospital and Research Institute, Piazza Sant'Onofrio, 4, 00165, Rome, Italy.
authors.forename: Marina
authors.initials: M
authors.lastname: Vivarelli
authors.affiliation: Nephrology Dialysis Transplantation Unit, Città della Salute e della Scienza, Regina Margherita Children's Hospital, Corso Bramante, 88, 10126, Turin, Turin, Italy.
authors.forename: Licia
authors.initials: L
authors.lastname: Peruzzi
mesh_terms: D002648:Child; D018450:Disease Progression; D004359:Drug Therapy, Combination; D005060:Europe; D005938:Glucocorticoids / Q000008:administration & dosage* / Q000009:adverse effects; D006801:Humans; D007166:Immunosuppressive Agents / Q000008:administration & dosage* / Q000009:adverse effects; D009404:Nephrotic Syndrome / Q000188:drug therapy*; D011241:Prednisone / Q000008:administration & dosage* / Q000009:adverse effects; D012008:Recurrence; D000069283:Rituximab / Q000008:administration & dosage* / Q000009:adverse effects; D011795:Surveys and Questionnaires; D016896:Treatment Outcome
chemical_list: D005938:Glucocorticoids; D007166:Immunosuppressive Agents; D000069283:Rituximab; D011241:Prednisone
keywords: Guidelines; Prednisone; Proteinuria; Rituximab; Steroid dependency; Steroid resistance