Article of the Month - June 2020

Nephrotic syndrome in children is an uncommon condition which, similar to adults, has variable response to treatment. Identifying those who may be less likely to respond to usual treatments is important. Linking children who were born preterm or growth restricted to determine whether they respond differently to treatment of nephrotic syndrome will help management of these children. It is another important indication of the importance of the in-utero and early ex-utero environment on long term kidney health.

Association of low birth weight and prematurity with clinical outcomes of childhood nephrotic syndrome: a prospective cohort study.

Pediatr Nephrol, 2019; 34: 1599-1605. doi: 10.1007/s00467-019-04255-1

Konstantelo N, Banh T, Patel V et al.

Reviewed by Ayesa Mian

Background: Low birth weight (LBW)/ prematurity is associated with a reduced nephron endowment and glomerular hyperfiltration.  LBW/ premature children who subsequently develop glomerular disease may be anticipated to have a less favorable course.   New onset idiopathic nephrotic syndrome (NS) affects ~ 2 per 100,000 children/ year.    The best long term prognostic indicator is steroid responsiveness.   Steroid resistance is associated with a more challenging course and risk for progression to ESRD. 

Purpose: To determine the association of LBW and prematurity with clinical outcomes of childhood NS such as steroid resistance, development of a first relapse, time to first relapse, and frequently relapsing NS.

Study design: Prospective cohort study of children enrolled in the study: Insight into NS:  Investigating Genes, Health, and Therapeutics (INSIGHT).   Outcomes for children with NS born LBW/ prematurely were compared to those for children born with normal BW (NBW).  Data for outcomes was obtained by medical chart review; data for birth related information obtained from parental self-reported questionnaire.

Sample characteristics: 377 of 423 children diagnosed with NS between ages 1-18 y and followed from 1/1/ 1996 – 7/1/2016 at the Hospital for Sick Children in Toronto were included.   Children were excluded if they had congenital NS, disease involving multiple organs, secondary causes of NS or if data was missing re: BW, gestational age, date of diagnosis, or other clinical data.   In the final cohort, 12% (n=46) were LBW or premature.   Median BW 2098 g.

Results: Odds for having SRNS were 3.78 (90% CI 1.28-11.21) times higher among LBW/ premature children than NBW children.   An 8% decrease in odds of developing SRNS was observed for every 100 g increase in BW (adjusted odds ratio 0.92; 95% CI 0.86-0.98).  Median time to first relapse did not differ.

Implications: LBW/ prematurity are important clinical factors to consider when treating a child with NS as the higher association with steroid resistance could impact management.