The effects of steroid therapy on bone parameters in patients steroid sensitive nephrotic syndrome

ABSTRACTThe Effects of Steroid Therapy on Bone Prametres in Patients Steroid SensitiveNephrotic SyndromeIn this study we have examined the effects of corticosteroid therapy on bone metabolismin nephrotic syndrome. Sixty-nine patients with idiopathic nephrotic syndrome (age:7.0±2,5years) and 21 healthy controls (age: 6.4±3,5 years) were enrolled in the study. The patientswere grouped into 3 groups: Group 1: Patients who were on remission but still receivingsteroid therapy, Group 2: Patients who were on remission and free of steroids within the lastyear and Group 3: Patients with active nephrotic syndrome and receiving steroid therapy. Thepatients received steroid treatment according to a standard protocol. Serum total calcium,ionized calcium, phosphorus, alkaline phosphatase, magnesium, parathyroid hormone,25(OH)D, serum cystatin C, urine protein, urine creatinine and urine cystatin C levelsmeasured in all patients including the control group. In addition, lumbar spine bone mineraldensity Z scores were measured in the patient group. The serum ionized calcium levels werelower (p=0.019) and serum cystatin C levels were higher (p=0,007) in Group 1 wherecompared with Group 2. The lumbar spine bone mineral density Z scores were lower inGroup 2 however with no statistical significance (p=0,394). The serum calcium levels ofGroup 3 patients were lower than Group 1 patients (p=0,010). The 25(OH)D levels in Group3 patients were higer than Group 1 patients (p=0.040). Although none of the patients inremission had vit D insufficiency the 25(OH)D levels were lower than the nomal controlsrespectively (p=0.035 for Group 1), (p=0,009 for Group 2). The high levels of parathyroidhormone and low levels of magnesium in patient groups compared with normal controlsindicated the presence of secondary hyperparathyroidism.In patients with nephrotic syndrome, although there are no parameters to show the earlyeffects of steroid treatment on bone metabolism, the increase in serum cystatin C levels maybe an early indication of changes in bone metabolism and may be used as a parameter inevaluating patients receiving steroid therapy.Key words: Nephrotic syndrome, corticosteroid, cystatin C, parathyroid hormone,25(OH)D