The effect of zoledronic acid on hip geometry in renal transplant recipients: a double-blind placebo-controlled randomized study.

Background: In renal transplant patients, bisphosphonates may prevent bone loss, but little is known about their effects on bone microarchitecture and geometrical hip parameters, as the key factors of bone stability. This study aimed to analyze the effect of zoledronic acid on the mentioned parameters in kidney transplant patients.

Methods: In this double-blind, randomized trial, 33 patients were followed for six months after administering either 4mg of zoledronic acid or a placebo. Bone mineral density (BMD) measurement of the spine, hip, radius, and whole body was obtained, and trabecular bone score (TBS) was evaluated using the software. Geometric assessment at the proximal femur was performed by the HSA program.

Results: Eighteen patients in the intervention group and 15 in the control group completed the study. The mean percentages of the changes in the BMD at the lumbar spine and whole body were significantly different between the placebo and intervention groups (-0.23% vs. 4.91% and -2.03% vs. 1.23%) (P < 0.05). Zoledronic acid appeared to enhance the subperiosteal diameter, endocortical diameter, and cross-sectional moment of inertia (CSMI) at the narrow neck in comparison with placebo (P < 0.05); however, no difference in TBS was observed between both groups (P > 0.05).

Conclusions: We concluded that a single administration of zoledronic acid might ameliorate bone loss at the lumbar spine and the whole body and maintain the subperiosteal diameter, endocortical diameter, and CSMI as parameters of bone strength at the narrow neck of the proximal femur after six months in renal-transplant recipients.

Trial Registration: This study was registered in IRCT (ID: IRCT20181202041821N1) on 04-05-2019.