Clinical Features and Long-Term outcomes of Patients with Late Steroid Resistant/Sensitive Nephrotic Syndrome: A Single Center Study

Objective: To find out clinical features and long-term outcomes of idiopathic childhood nephrotic syndrome(NS) patients with late steroid resistance(LSR)/late steroid sensitiveness(LSS). Patients and Methods: A retrospective chart review was performed on 480 patients diagnosed with idiopathic childhood NS at Asan Medical Center Children's Hospital from 1990 to 2013. Twenty-four patients whose responsiveness to steroids changed over a minimum 2 year follow-up period (2-17.5 years) were investigated. All patients had undergone a renal biopsy. Results: Among 480 nephrotic children, 428 (89%) were sensitive to the first steroid course. Of those who initially responded, 11 (2.5%) developed resistance to steroid therapy after relapses. LSR mostly developed between 1 month and 1 year after the initial episode. Six patients showed a minimal change and five showed focal segmental glomerulosclerosis (FSGS). Nine (82%) responded to cyclosporine or methylprednisolone pulse therapy. Of these, two had no further relapse, whereas the other seven experienced several relapses that ranged in length from 1.1 to 13.9 years. Three of the nine who initially responded to immunosuppression went on to experience several changes in steroid responsiveness. Two (18%) with resistance to immunosuppressants, including steroids, eventually progressed to end stage renal disease. Among the 52 patients (11%) who were initially steroid resistant, 13 (23%) were converted to steroid sensitive at relapses. Among these, 9 showed minimal change and 4 showed FSGS. Two had no further relapse and the other 11 responded to steroids on subsequent relapses ranging in length from 1.3 to 9.4 years. All these patients have had no further changes in steroid responsiveness with normal renal function. Conclusions: In this study, 2.5% of initial steroid responders and 25% of initial steroid non-responders changed their responsiveness to steroids at subsequent relapses. Eighteen percent of LSR patients developed end stage renal disease. All of the LSS patients showed preserved normal renal function. Responsiveness to immunosuppressants seemed to be the most important factor determining longterm outcomes in LSR/LSS patients.