PREVENTION OF CANCELLOUS BONE LOSS BUT PERSISTENCE OF RENAL BONE-DISEASE DESPITE NORMAL 1,25 VITAMIN-D LEVELS 2 YEARS AFTER KIDNEY-TRANSPLANTATION

Osteopenia has been observed to occur frequently after renal transplan tation. The present study was undertaken to assess whether an immunosu ppressive regimen combining cyclosporine with no or the lowest possibl e maintenance doses of glucocorticoid may prevent osteopenia after kid ney transplantation. Thirty-four patients were prospectively followed for two years. Serial blood drawings were done for determination of se rum indices of calcium and bone metabolism and an iliac crest bone bio psy was performed at time of transplantation. A second bone biopsy was done in 20 patients during the second year of observation. Creatinine clearance was 56+/-6 ml/min one year and 46+/-6 ml/min two years afte r transplantation. Serum parathyroid hormone levels were elevated in 2 4 patients at time of grafting, decreased significantly thereafter, bu t remained above the normal range. Ten patients had low or normal seru m parathyroid hormone levels at time of transplantation and showed a s ignificant increase after grafting. Two years after transplantation, t he mean cumulative dose of prednisone was 5.9+/-0.5 g. After the first six months, 30-40% of the patients were not on maintenance doses of s teroids, None of the patients experienced fractures, and cancellous bo ne volume was within or above the normal range in all repeat bone biop sies. It is of note that metabolic bone abnormalities did not resolve 1-2 years after transplantation despite normalization of serum 1,25 vi tamin D levels. The histologic abnormalities at this time were consist ent with the bone findings in renal failure suggesting resistance of b one to normal circulating levels of 1,25 vitamin D.