Osteocalcin Level in Children with Steroid Dependent/Frequently Relapsing and Steroid Resistant Nephrotic Syndrome

Background: Children with nephrotic syndrome (NS) may be at risk for metabolic bone disease because of biochemical derangement caused by renal disease as well as steroid therapy. Osteocalcin (OC) functions as an inhibitor of bone mineralization. We aimed to evaluate linear growth and bone turnover markers (including serum osteocalcin) in children with steroid-dependant/frequently-relapsing and steroid resistant NS in comparison to a matched control group. Methods: Our study was a cross-sectional study conducted at children’s hospital, Cairo University, Egypt from July 2014 to August 2015. The study included 60 patients, aged 2 - 15 years recruited from outpatient nephrology clinic. Twenty eight age- and sex- matched healthy children were included as a control group. Serum OC was measured by immune-radiometric assay. Results: Serum OC levels were significantly higher in both SDNS/FRNS and SRNS than in control group, with P value 0.02 and 0.01, respectively. There was statistically significant negative correlation between OC and serum calcium. There was a negative correlation between height for age percentile and number of relapses. There were also negative correlations between height for age percentile and steroids, cyclophosphamide and cyclosporine duration of treatment. We found that both of our patients groups (SDNS/FRNS and SRNS) showed lower height for age percentile compared to control group (P = 0.017 and 0.001 respectively). Conclusions: Height as a growth parameter is more affected when recurrent relapses occur with multiple courses of steroid therapy. Use of OC as screening tool is recommended for bone turnover while patients on steroids.