Two-year outcome of the ISKDC regimen and frequent-relapsing risk in children with idiopathic nephrotic syndrome

Abstract

Background and objectives: Early identification of frequently relapsing children with idiopathic nephrotic syndrome is desirable.

Design, setting, participants, & measurements: The relapse status and clinical data of patients previously registered (January of 1993 to December of 2001) in a multicenter prospective study of the International Study of Kidney Disease in Children regimen were analyzed for risk of frequent relapsers over a 2-year follow-up period.

Results: Of 166 children with nephrotic syndrome (113 boys and 53 girls; median age=5.1 years), 145 (87.3%, median age=5.5 years) children were steroid-sensitive, and 21 (12.7%, median age=2.9 years) children were steroid-resistant. Of 145 children with steroid-sensitive nephrotic syndrome, 32 (22.1%, median age=4.2 years) children experienced frequent relapses over 2 years. The time to initial response was significantly longer (10 versus 7 days, P<0.001, log-rank test) in the 32 frequent relapsers than in the 106 nonfrequent relapsers. The time from start of initial treatment to first relapse was significantly shorter (2.6 versus 6.1 months, P<0.001, log-rank test) in the 32 frequent relapsers than in the 57 infrequent relapsers. In a Cox regression model, the time to initial response ≥9 days and the duration from start of initial treatment to first relapse <6 months were significant predictors of frequent relapses (unadjusted and adjusted).

Conclusions: Initial remission time ≥9 days and first relapse within 6 months were associated with frequent relapses. These findings may also be useful also in selecting potential frequent relapsers for clinical trials.

Figure 1.

Status of 166 children with nephrotic syndrome 2 years from the start of initial treatment. Data are shown as median if applicable. N/A, not applicable; time for relapse, time from start of initial treatment to first relapse; time for remission, time from start of initial treatment to disappearance of proteinuria.

Figure 2.

Kaplan–Meier analysis of relapse-free ratio in children with steroid-sensitive nephrotic syndrome.

Figure 3.

Initial remission ratio and relapse-free ratio in nephrotic syndrome. Kaplan–Meier analysis of time for initial remission (A) and time for first relapse (B). P values are from log-rank test. FRNS, frequent-relapsing nephrotic syndrome; IRNS, infrequent-relapsing nephrotic syndrome.

Figure 4.

Frequent relapse-free ratio stratified by times for initial remission and first relapse. Frequent relapse related with time to initial response (A) and time from start of initial treatment to first relapse (B). P values are from log-rank test.