The Effect of Corticosteroids on Urinary Calcium Excretion: A Pilot Study

Aim: Corticosteroids are the main drugs in the treatment of nephrotic syndrome and bronchial hyperreactivity and can be used for long periods in high doses. From clinical use and experiments, systemic corticosteroids are known to cause hypercalciuria. In this study we aim to determine the effect of corticosteroids on urinary calcium excretion and to assess related parameters in children with chronic disease. Material and Method: Thirty-nine children with nephrotic syndrome and bronchial hyperreactivity from ages 1-15 and 15 same-aged healthy controls of the same sex are included in the study. Nineteen patients with nephrotic syndrome using 2 mg/kg/day oral prednisolone are included in group 1, and 20 patients with bronchial hyperreactivity who use inhaled 2x200 µgr budesonide are included in group 2. All children%u2019s bone formation (serum osteocalcin and alkaline phosphatase), resorption (urine deoxypyridinoline crosslinks/creatinine), and metabolism markers (parathyroid hormone, calcium, and phosphate) were analyzed. Results: Post-treatment urinary calcium/creatinine ratio was increased in the nephrotic syndrome group. Osteocalcine levels were found decreased in nephrotic syndrome patients who take oral prednisolone treatment. Urine deoxypyridinoline crosslinks/creatinine ratio levels were found low in both nephrotic syndrome and bronchial hyperreactivity patients, contrary to expectations.Discussion: In this study we found that oral prednisolone usage increased renal calcium excretion while inhaled budesonide did not increase renal calcium excretion. We believe that oral prednisolone repressed the bone formation. To further investigate low urine deoxypyridinoline crosslinks/creatinine ratio, more prospective studies with a greater number of participants are required