Long-Term Effect of Denosumab on Bone Disease in Patients with CKD

Background The effect of long-term denosumab therapy and of denosumab discontinuation on the cortical bone of the hip regions in dialysis patients has not been studied. Methods This retrospective study investigated the cortical and trabecular compartments and estimated strength indices of the hip region, obtained using 3D-SHAPER software, after a maximum of 5 years of denosumab therapy in 124 dialysis patients. A Wilcoxon signed-rank test was used to identify the differences in each parameter before and after denosumab initiation. Similarly, we investigated the changes in these parameters after denosumab discontinuation in 11 dialysis patients. Results Integral and trabecular volumetric bone mineral densities (BMD) were significantly lower at the start of denosumab therapy than those in 1 year before denosumab initiation. After starting denosumab, areal BMD (median change +7.7% [interquartile range (IQR), +4.6 to +10.6]), cortical volumetric BMD (median change +3.4% [IQR, +1.0 to +4.7]), cortical surface BMD (median change +7.1% [IQR, +3.4 to +9.4]), and cortical thickness (median change +3.2% [IQR, +1.8 to +4.9]) showed a significantly higher trend for 3.5 years, which then stabilized at a higher value compared with baseline. A similar trend in the trabecular volumetric BMD (median change +9.8% [IQR, +3.8 to +15.7]) was observed over 2.5 years, with a higher value maintained thereafter. The whole area of the hip region improved after denosumab therapy. Similar trajectories were also found in the estimated strength indices. Conversely, at 1 year after denosumab discontinuation, these 3D parameters and estimated strength indices tended to largely worsen. The lateral aspect of the greater trochanter was the most pronounced location showing volumetric BMD loss. Conclusions The BMD of both cortical and trabecular components in the hip region was significantly higher after starting denosumab therapy. However, these measurements exhibited a trend of declining substantially after the discontinuation of denosumab.