Abstract
Background and Aims
Following kidney transplantation despite improvement of kidney function, calcium and phosphate turnover and vitamin D metabolism, the risk of fractures is high. Moreover, most kidney transplant recipients (KTRs) have preexisting CKD mineral bone disease and osteopenia or osteoporosis are prevalent complications aggravated by immunosuppressive therapy, especially glucocorticoids and cyclosporine, which negatively affect KTRs risk of fractures and mortality. Treatment with bisphosphonates has been suggested to improve bone mineral density (BMD) in KTRs, nevertheless the evidence of such a therapeutic approach are scarce. The aim of this study is to evaluate the effectiveness of bisphosphonates treatment in post kidney transplantation BMD.
Method
We conducted a single center retrospective analysis on the effect of bisphosphonate treatment on bone mineral density in patients after kidney transplantation. Patients eligible for entering the study were adult (>18 years) KTRs with two valid BMD measurements either by hip or spine dual energy X-ray (DEXA). The primary BMD measurement was performed before the initiation of bisphosphonate treatment. We also evaluated the BMD course in KTRs who had two valid measurements after operation but received no treatment (control group). Patients that received other forms or treatment (calcitriol or vitamin D analogs) were excluded from the study. BMD was evaluated using the average t-score at the examined site of interest. Kidney function was evaluated with eGFR, using the CKD-EPI formula.
Results
Overall, out of 185 KTRs actively monitored, 26 met the aforementioned criteria and were included in the study. Bisphosphonate treatment was administered in 16 patients (10 men) with a mean age of 53.4±10.2 years while 10 patients (6 men) received no treatment (mean age 45.2±14.3 years, p=ns). There were no differences in baseline kidney function (eGFR), BMD, body mass index, or other baseline clinical characteristics between those patients that received treatment and the control group. Treatment was initiated 1.1±2.4 years after kidney transplantation, while in 9 patients was initiated in the early post transplant period (one month after operation) and overall it was administered for a period of 3.9±2.3 years. Bisphosphonates were administered in all patients as per os treatment (10 patients received risedronate sodium, 4 ibandronic acid and 2 alendronate sodium). Bone density was improved significantly in all but 2 patients that received treatment (BMD from -1.91±1.3 to -1.3±1.4, p=0.0114). Those that received no treatment showed an overall minor non significant bone density improvement (BMD from -1.53±1.2 to -1.3±0.8, p=ns) after 4.2±1.4 years of follow up. ΔBMD was also found higher in treated patients (0.66±0.86 vs. 0.23±0.85, p=ns). Kidney function was not affected by treatment (eGFR before vs. after treatment, 65.3±14.4 vs. 65.5±15.2 ml/min/1.73 m2, p=ns, respectively) and remained unchanged in those that received no treatment as well.
Conclusion
Treatment with bisphosphonates is a safe and effective treatment option that significantly improves BMD after kidney transplantation.
Quantitative computed tomography assessment of bone mineral density after 2 years’ oral bisphosphonate treatment in postmenopausal osteoarthritis patients who underwent total knee arthroplasty
