BONE MINERAL DENSITY (BMD) OVER TIME IN PEDIATRIC RENAL TRANSPLANT (TX) PATIENTS.

Abstract

900 BMD of the spine and total body in pediatric renal TX patients decreases with age and years post-TX. To evaluate BMD over time in pediatric renal TX patients, we studied 21 pediatric renal TX patients with BMD of spine and total body by dual energy x-ray absorption at entry to the study and at follow-up (FU) 1.4±0.4 (X±SD) years later. Age, weight, total prednisone dose since transplant, serum calcium, phosphorus, and creatinine were recorded at initial exam and at FU. Age was 15±4 years at FU. Time post-TX at initial evaluation was 2.2±2.0 years and at FU was 3.6±1.9 years. Serum calcium, phosphorus, and creatinine were within the normal range at both initial exam and FU in all patients. Maintenance immunosuppression consisted of prednisone, cyclosporine, and azathioprine in all patients. Total body BMD Z score at FU inversely correlated with time on dialysis+time post-TX+FU time (r=−0.50,p=0.022). At initial exam spine BMD Z score correlated with total body BMD Z score (r=0.91, p<0.001); at FU spine BMD Z score also correlated with total body BMD (r=0.75,p<0.001). During FU, spine BMD Z score decreased 0.48±1.06 (paired t=2.09,p=0.049) and total body BMD Z score decreased 0.31±0.66 (paired t=2.18, p=0.042). The change in spine BMD Z score from initial to FU exam correlated with age (r=0.49,p=0.023), cumulative prednisone dose from initial to FU exam (r=0.60, p=0.004), and cumulative prednisone dose from initial to FU exam per body weight (r=0.70, P<0.001). The change in total body BMD Z score correlated with cumulative prednisone dose from initial to FU exam per body weight (r=0.54, p=0.012). BMD of the spine and total body in pediatric renal TX patients continues to decrease with increasing time post-TX and increasing cumulative corticosteroid dose. Strategies to improve BMD, both initially post-TX and later post-TX, need to be developed for these pediatric renal TX patients.