TREATMENT OF ESTABLISHED BONE LOSS AFTER RENAL TRANSPLANTATION WITH ETIDRONATE1

BACKGROUND: Osteoporosis is a well-documented complication of organ transplantation. Bisphosphonates have been shown to be effective in preventing corticosteroid-induced osteoporosis in renal transplant recipients, but data are lacking for treatment of established osteoporosis. This study reports our clinical experience of treatment with the bisphosphonate etidronate in a single renal transplant center. METHODS: To establish the effectiveness of etidronate in treating established low bone mineral density (BMD), all newly transplanted patients treated with etidronate were compared with controls. Twenty-five patients treated with etidronate (14 males, 11 females) and 24 controls (15 males, 9 females) were identified from the cohort of patients who underwent transplantation between January 1, 1994, and December 31, 1996. RESULTS: There was no difference in mean age, weight, or cumulative dose of corticosteroids between the treatment and control groups. The baseline BMD measurement was performed at 10.4 +/- 5.3 months after transplantation for treated patients and at 10.7 +/- 4.5 months for controls (P=0.78). Over the subsequent 1-year study period, patients treated with etidronate demonstrated a greater increase in BMD at sites with a preponderance of trabecular bone. Lumbar spine BMD increased 4.3 +/- 6.1% in the treatment group versus 0.55 +/ -5.3% in controls (P<0.03) and trochanter BMD increased 10.3 +/- 11.9% and 2.2 +/- 5.7%, respectively, in the treatment and control groups (P<0.02). CONCLUSIONS: This study establishes the effectiveness of etidronate for treatment of low BMD in renal transplant recipients. Patients selected for treatment had lower baseline BMD than control subjects, yet still showed a clinically important increase in BMD.