Background: Fracture risk is high after renal transplantation, but suboptimal renal function and associated high skeletal retention of potent nitrogen-containing bisphosphonates raise concern with their use. The less potent and less firmly bone bound second generation non-nitrogen containing bisphosphonate clodronate, shown to be effective in decreasing fracture risk in osteoporosis, represents an attractive and potentially safer alternative in these patients. The objective was to evaluate the efficacy and safety of one year oral clodronate in renal transplant recipients (Tx) with e-GFR ≧30 ml/min/1.73m2 and high fracture risk.
Methods: Tx patients with available DXA BMD and conventional spinal radiographs before and 1 year after starting clodronate were included. Demographic, laboratory and BMD data were collected. Spinal X-rays were evaluated for vertebral fractures (VF) using the Genant scoring system, and non-vertebral fractures (NVF) documented.
Results: Thirty-one Tx patients (18 female), mean age 44.8±9.2 yrs, time since Tx 4.3±5.3yrs, eGFR 56 ml/min/1.73m2 were studied. Mean serum values at start treatment were: creatinine 115±23 μmol/l, corrected calcium 2.71±0.18 mmol/l, PTH 23±18 pmol/l, alkaline phosphatase 146.6±99.6 IU/L, P1NP 99.5±65.2 ng/ml. Mean BMD T-scores were -1.68±1.66 at the lumbar spine (LS) and -1.86±1.38 at the femoral neck (FN). 6 patients had 9 VF and 5 patients had 7 NVF. After 12 months treatment, s.calcium decreased to 2.66 mmol/l (p=0.031), bone turnover normalized and renal function remained stable. BMD increased +2.0% at LS (p=0.066) and stabilised at FN. There were no new fractures. Treatment was well tolerated and there were no adverse effects.
Conclusion: Our data demonstrate that clodronate is effective and safe in renal Tx patients with eGFR>30 ml/min/1.73m2, high bone turnover and high fracture risk. One year treatment significantly decreased serum calcium, normalised bone turnover, increased LS BMD, stabilised FN BMD, prevented further VF/NVF, and did not affect renal function. Whether these beneficial effects are maintained in the longer-term remains to be established.
Disclosure: The authors declared no competing interests.