Hip geometry and strength remain stable the first year after kidney transplantation-an ibandronate/placebo post hoc analysis

The sensitivity of bone mineral density (BMD) to identify patients with high fracture risk after kidney transplantation is low, therefore alternative tools are needed. Hip Structure Analysis (HSA) provides an estimation of hip structural geometry and strength based on conventional DXA scans for hip analyses. We aimed to investigate the effect of antiresorptive therapy on hip geometrical and strength parameters by HSA. In a post hoc analysis of a 12-month randomized, double-blind, placebo-controlled trial evaluating the effect of ibandronate in addition to active vitamin D and calcium in kidney transplant recipients (KTR), we re-analyzed dual total hip and femoral neck DXA scans to measure cortical bone thickness (CBT) in the femoral neck (CBT_NECK), calcar (CBT_CALCAR), and shaft (CBT_SHAFT), along with femur neck width, hip axis length, and to estimate buckling ratio and strength index. DXA measurements were performed within 5 weeks after transplantation and repeated at 10 weeks and 1-year post-transplant. The study included a total of 127 de novo KTR with estimated glomerular filtration rate >30 mL/min at baseline. The 5 geometrical and the strength and stability hip parameters remained stable over the first post-transplant year irrespective of antiresorptive therapy. We detected no statistically significant between-group differences in any of the HSA measures. Change in geometrical hip parameters and buckling ratio over the study duration was not correlated with change in plasma parathyroid hormone or change in dual total hip BMD. In this study, the so far largest of HSA in KTR, antiresorptive therapy with ibandronate for 12 months did not affect measures of hip geometry or strength. Clinical Trial Registration: www.clinicaltrials.gov as NCT00423384, EudraCT number 2006-003884-30.