Study design and patients
We retrospectively recruited children diagnosed with AAN between November 2015 and November 2020 in the Department of Nephrology at Children’s Hospital of Fudan University. Subjects were excluded if any of following were present: much missing data, severe liver damage or autoimmune diseases. All patients received a dose of MMF 10~15 mg/kg twice daily as induction or maintenance therapy of their underlying disease, including dispersible tables (Huadong Medicine, Hangzhou, China), capsules (Roche, Basel, Switzerland) and EC-MPS (Novartis, Basel, Switzerland). Prednisolone was initiated at a daily dose of 1~2 mg/kg/d. The protocol of dose adjustment varied according to patient’s clinical status. This study was approved by the Research Ethics Committee from Children’s Hospital of Fudan University (No. 2020-486) and was conducted in accordance with the Declaration of Helsinki. Informed consent was waived for this noninterventional retrospective study. The follow-up period was part of routine clinical care until death, loss and last inpatient visit.