Abstract
OBJECTIVE: This study aims at determining the relationship between prednisolone cumulative dose and linear growth in pre-pubertal children with idiopathic nephrotic syndrome. METHOD: This cross-sectional study was conducted on all children with idiopathic nephrotic syndrome registered to the pediatric nephrology department at the main referral children's hospital in Southwestern Iran. Inclusion criteria included age (males <12 years; females <10 years), >6 months of use, and the minimum prednisolone cumulative dose of 152mg/kg. The exclusion criteria were individuals who had entered puberty or had other diseases affecting linear growth. Based on the prednisolone cumulative dose of ≥550mg/kg (four or more relapses), the children were divided into two groups. All data regarding age, height, and weight at disease onset and the last visit, bone age, and the parents' height were collected. Secondary variables including mid-parental target height and predicted adult height were also calculated. Height data were compared between the different rates of relapse. RESULTS: A total of 97 children (68% male) were enrolled. Their post-treatment mean height Z-score was less than that obtained before treatment (-0.584 vs. -0.158; p=0.001). Subjects with higher prednisolone cumulative doses were found to have more reduction in height Z-score (p=0.001). Post-treatment height prediction also showed less growth potential compared to pre-treatment target height (p=0.006). Thirty-three children (34.4%) had four or more relapses, among whom more mean-height Z-score decreases were found compared to those with less-frequent relapses (-0.84 vs. -0.28; p=0.04). CONCLUSION: This study showed the negative effect of cumulative dosages of prednisolone on linear growth, which was greater in children with four or more relapses.