Histologic evolution of bone disease 6 months after successful kidney transplantation.

BACKGROUND

The histologic patterns of bone disease, as well as the evolution of renal osteodystrophy after kidney transplantation (Tx), are not well defined. Information in this regard is scarce and contradictory.

METHODS

Before and 6 months after Tx, analysis of biochemical, hormonal, and bone histomorphometric parameters were performed. Twenty patients (14 men and 6 women) entered the study. Median age was 36.5 (range, 20 to 55) years, and median time on dialysis was 22 (9 to 88) months.

RESULTS

Bone histomorphometric diagnoses at pre-Tx were adynamic bone disease, 12; mixed bone disease, 3; mild disease, 3; and osteitis fibrosa, 2. After Tx, 11 had adynamic bone disease; 8, mild disease; and 1, osteomalacia. As a whole, dynamic parameters improved significantly in patients who had adynamic bone. Five of the 12 with this diagnosis completely recovered their bone turnover. Pre-Tx hyperparathyroidism bone features improved or resolved, but 5 of the 8 patients had low-turnover bone disease (adynamic disease, 4; osteomalacia, 1). Three of them had persistence of aluminum and/or iron deposits on bone surface, and the other 2 had hypophosphatemia and high intact parathyroid hormone levels. Overall, biochemical parameters tended toward normalization. Serum intact parathyroid hormone before Tx was correlated negatively with post-Tx trabecular thickness.

CONCLUSION

Six months after Tx, bone histology remained abnormal. The high turnover bone disease improved in all cases, but in most of them low turnover bone disease emerged. Nearly half of the cases with pre-Tx adynamic bone disease recovered their bone turnover completely with some improvement observed in the majority of the remaining cases.