Clinical Features of Idiopathic Nephrotic Syndrome and Factors Associated with its Relapse in Children: A Population-Based Study

Background: Idiopathic Nephrotic Syndrome (INS), which is caused by a defect in the glomerular filtration barrier, is the most common chronic glomerular disease in children. Objectives: The present study aimed to assess the clinical features of INS and some recurrence-related factors in children. Methods: This population-based, cross-sectional study was conducted on 302 children with INS referring to the Pediatric Nephrology Clinic of Imam Reza Hospital of Kermanshah city, Iran, during 1998-2018. Results: The mean age (SD) at the time of diagnosis and the follow-up duration were 4.87 (2.89) years and 49.83 (37.52) months, respectively. The numbers of boys and girls were 185 (61.9%) and 114 (38.1%), respectively. The mean number (SD) of recurrences, annual recurrence rate during the follow-up, and the time to the first recurrence after responding to treatment were 1.71 (1.91), 0.48 (0.77), and 10.15 (10.63) months, respectively. The most common type of INS was steroid-dependent/frequent relapse, with a frequency of 151 (50.5%). Furthermore, 33 (11.0%) and 266 (89.0%) patients were resistant and respondent to treatment, respectively. There was a statistically significant relationship between age at the time of diagnosis and the type of INS (P = 0.007). Conclusions: This study revealed a statistically significant association between higher age and steroid resistance. However, in steroid responders, there was no relationship between gender, age at the time of diagnosis, and the time to the first recurrence, and the recurrence rate.