Lumbar bone mineral density in renal transplant patients on neoral and tacrolimus: a four-year prospective study

Abstract

Background: This prospective study was designed to investigate the long-term evolution of bone mineral density (BMD) in kidney transplant recipients.

Methods: In 86 patients with functioning grafts, 65 on tacrolimus-based immunosuppression and 21 on cyclosporine-based immunosuppression, laboratory parameters and BMD measurements in lumbar spine (L2-L4) and femoral neck (FN) were performed by DEXA in the first month after transplantation (baseline) and yearly thereafter up to the fourth year.

Results: BMD did not change at 12 months in lumbar spine nor in the FN. Detailed analysis identified three patterns of BMD in lumbar spine at 12 months: BMD remained stable in 27 patients (31.4%), decreased >2% in 31 (36.0%) and increased >2% in 28 (32.6%). Patients with no change or gain presented a parallel increase of BMD in FN (P<0.001 in both groups). On multivariate analysis, the variables associated with no change or lumbar BMD loss were total prednisone dose in grams at 12 months (OR 1.402; 95% CI 1.038-1.893; P=0.028), calcitriol levels at 12 months (OR 0.936; 95% CI 0.892-0.982; P=0.007) and lumbar BMD at baseline (OR 1.006; 95% CI 1.002-1.010; P=0.002). Late treatment with calcium supplements and calcitriol did not improve osteopenia.

Conclusions: One third of patients had bone loss mainly during the first year of follow-up. Bone loss was associated to higher baseline BMD, high steroid dose, and lower calcitriol levels at 1 year. Late administration of calcitriol and calcium supplements did not improve posttransplant osteopenia. More than 50% of patients were osteopenic 4 years after transplantation.