BONE-MINERAL DENSITY AFTER RENAL-TRANSPLANTATION IN CHILDREN

longitudinal bone mineral changes after renal transplantation were stu died in 14 children aged 8 +/- 4 years. Combination immunosuppressive therapy was given to all patients (prednisone, azathioprine, cyclospor ine). Bone mineral density (BMD) measurements of the first through fou rth lumbar vertebrae by dual-energy X-ray absorptiometry were performe d within 1 year preceding renal transplantation and 6, 12, and 24 mont hs afterward (MO, M6, M12, and M24, respectively). The results of BMD obtained in grams of hydroxyapatite per square centimeter of spine pro jected area were subsequently transformed to standard deviation scores for a normal pediatric population. In addition, we used a mathematica l spine volume correction to give the results in grams per cubic centi meter. All patients had a well-functioning renal graft at M6, M12, and M24 and a normal serum creatinine level. Significant decreases in BMD , standard deviation score, and spine volume-corrected BMD were observ ed 6 months after renal transplantation (p<0.05, p<0.01, and p<0.01 re spectively); the median loss of BMD and spine volume-corrected BMD was 9.2% and 15.6% at M6, respectively, and the median serum parathyroid hormone level dropped from 125 to 34 pg/ml. Between M6 and M12, BMD in creased significantly up to 95% (median) of pretransplantation values and reached 97.2% (median) at M24. Similar but less marked improvement was observed in spine volume-corrected BMD results, reaching 87.7% an d 87.4% at M12 and M24, respectively. A negative correlation was found between the cumulative prednisone dose and BMD in grams per square ce ntimeter at M6 (r(2) = 0.603; p = 0.006), M12 (r(2) = 0.532; p = 0.015 ), and M24 (r(2) = 0.40; p = 0.014). There was no correlation between cumulative prednisone dose and spine volume-corrected BMD or standard deviation score. Mean 6-month cyclosporine levels dia not correlate wi th any measure of BMD. We conclude that after renal transplantation ch ildren have a significant decrease of BMD during the first 6 months af ter the operation, despite normal graft function and growth improvemen t.