Differential effects of teriparatide, denosumab and zoledronate on hip structural and mechanical parameters in osteoporosis; a real-life study.

ABSTRACT

PURPOSE: The aim of this study was to evaluate changes in hip geometry parameters following treatment with teriparatide (TPD), denosumab (Dmab) and zoledronate (ZOL) in real-life setting. METHODS: We studied 249 patients with osteoporosis (OP) with mean [SD] age of 71.5 [11.1] years divided into 3 treatment groups; Group A received TPD; n = 55, Group B (Dmab); n = 116 and Group C (ZOL); n = 78 attending a routine metabolic bone clinic. Bone mineral density (BMD) was measured by DXA at the lumbar spine (LS), total hip (TH) and femoral neck (FN) prior to treatment and after 2 years (Group A), after a mean treatment duration of 3.3 [1.3] years (Group B) and after 1, 2 and 3 doses of ZOL (Group C) to assess treatment response. Hip structural analysis (HSA) was carried out retrospectively from DXA-acquired femur images at the narrow neck (NN), the intertrochanter (IT) and femoral shaft (FS). RESULTS: Changes in parameters of hip geometry and mechanical strength were seen in the following treatment. Percentage change in cross-sectional area (CSA) 3.56[1.6] % p = 0.01 and cross-sectional moment of inertia (CSMI) 4.1[1.8] % p = 0.029 increased at the NN only in Group A. Improvement in HSA parameters at the IT were seen in group B CSA 3.3[0.67]% p < 0.001, cortical thickness (Co Th) 2.8[0.78]% p = 0.001, CSMI 5.9[1.3]% p < 0.001, section modulus (Z)6.2[1.1]% p < 0.001 and buckling ratio (BR) - 3.0[0.86]% p = 0.001 with small changes at the FS CSA 1.2[0.4]% p = 0.005, Z1.6 [0.76]%, p = 0.04. Changes at the IT were also seen in Group C (after 2 doses) CSA 2.5[0.77]% p = 0.017, Co Th 2.4[0.84]% p = 0.012, CSMI 3.9[1.3]% p = 0.017, Z5.2[1.16]% p < 0.001 and BR - 3.1[0.88]% p = 0.001 and at the NN (following 3 doses) outer diameter (OD) 4.0[1.4]% p = 0.0005, endocortical diameter(ED) 4.3[1.67% p = 0.009, CSA5.2[1.8]% p = 0.003, CSMI 9.3[3.8]% p = 0.019. CONCLUSIONS: Analysis of the effect of OP therapies on hip geometry is useful in understanding the mechanisms of their anti-fracture effect and may provide additional information on their efficacy.