Effect of denosumab on trabecular bone score in de novo kidney transplant recipients

BACKGROUND: Kidney transplant recipients (KTR) are at risk to lose bone mass. The trabecular bone score (TBS) represents a recently developed parameter of lumbar spine trabecular bone texture that correlates with the occurrence of fractures. METHODS: We analysed the 1-year changes in TBS in 44 de novo KTR that were randomized 1:1 to denosumab or no treatment. TBS was derived from dual energy X-ray absorptiometry and was correlated with 1-year areal bone mineral density (aBMD) changes at the lumbar spine and total hip. Correlations were also performed with parameters of peripheral bone microarchitecture and bone strength at the distal tibia and distal radius, as assessed by high-resolution peripheral quantitative computed tomography (HRpQCT) and micro-finite element analysis. RESULTS: The baseline TBS in KTR amounted to 1.312 ± 0.101, which is lower than the TBS of an age-matched normal control population (range 1.364-1.471). The TBS correlated positively with aBMD at the lumbar spine (Spearman's ρ = 0.56; P < 0.001) and total hip (ρ = 0.33; P < 0.05). The baseline TBS also correlated with HRpQCT-derived total (ρ = 0.49; P < 0.05) and trabecular volumetric BMD (ρ = 0.57; P < 0.01) and trabecular separation (ρ = -0.46; P < 0.05) at the tibia. Denosumab treatment led to an increase in TBS, paralleling the BMD changes at the lumbar spine. CONCLUSIONS: The TBS is a useful additional score of bone health, which may help to better define fracture risk. Treatment with denosumab led to improved trabecular bone texture in de novo KTR in addition to its beneficial effect on BMD.