SAT-405 CORRELATION OF SERUM CALCIUM, INORGANIC PHOSPHATE, ALKALINE PHOSPHATASE AND PARATHORMONE WITH BONE MINERAL DENSITY IN CHILDREN WITH RELAPSING NEPHROTIC SYNDROME

Abstract

Children with relapsing (frequent relapse,FR and infrequent relapse,IFR) nephrotic syndrome (NS) are prone to develop low bone mineral density (BMD) due to disease process and or drugs. But the correlation of BMD with metabolic factors like, calcium (Ca). inorganic phosphate (IP), alkaline phosphatase (ALP) and parathormone are not very clear in these patients. So, the study was conducted to evaluate correlation of metabolic factors with BMD in children with relapsing NS. Cross sectional analytical study was carried out on 30 children: 21 frequent relapsers (FR; Group I), and 9 infrequent relapsers (IFR; Group II) undergo follow up in the pediatric nephrology unit of Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, Bangladesh, during the period from December, 2014 to November, 2015. Children between 5 to 15 years who fulfilled ISKDC criteria for diagnosis of NS with normal renal function and who were on alternate days steroid therapy were the participants of this study and children with abnormal renal function or who received cyclosporine or calcium supplement, or who had clinical evidence of any systemic illness were excluded from the study. All of the participants were subject to complete history taking, thorough clinical examination, laboratory investigations [serum creatinine, phosphorus (P), calcium (Ca), parathyroid hormone [PTH], and alkaline phosphatase (ALP)]. Bone mineral density was measured at the lumbar spinal region (L2-L4) using dual-energy X-ray absorptiometry (DXA). Mean age of the sample was 7.73±2.90 years while male to female ratio was 22/8. Serum Ca was lower while, serum P, ALP, and PTH were higher in Group I than that of Group II though difference was statistically insignificant (P= 0.3516). In group I, children had significantly lower Z-scores in BMD values (-2.70±1.28) compared to Group II (-1.30±1.54) and P value was significant (P=0.0317). Osteopenia was documented by DXA scan in 27% and osteoporosis in 53% and 20% patients were normal. On multivariate analysis, total dose of prednisolone (P=0.03693), serum calcium (P=0.03608), and phosphorus (P=0.04314) had linear relationship with dependent variable BMD Z-score. On univariate regression analysis, inverse relationship were observed between Parathormone (P =0.049) and serum Alkaline Phosphatase Level (P=0.00) with BMD Z Score. It can be inferred that, children with relapsing nephrotic syndrome are at risk for Metabolic Bone Disease, especially those receiving higher doses of steroids. Regular BMD evaluation and appropriate therapeutic interventions are recommended for these children.