Effects of osteoporosis drug treatments on cortical and trabecular bone in the femur using DXA-based 3D modeling

Effects of Abaloparatide on Bone Mineral Density in Proximal Femoral Regions Corresponding to Arthroplasty Gruen Zones: A Study of Postmenopausal Women with Osteoporosis

BACKGROUND

Low hip bone mineral density (BMD) in patients who undergo total hip arthroplasty (THA) increases the risk of periprosthetic fractures, implant instability, and other complications. Recently, emphasis has been placed on bone health optimization: treating low BMD prior to a planned orthopaedic implant procedure in an effort to normalize BMD and reduce the potential risk of future complications. Abaloparatide is a U.S. Food and Drug Administration-approved osteoanabolic agent for men and postmenopausal women with osteoporosis and a candidate drug for bone health optimization that, in addition to benefits at the spine, increases hip BMD and reduces nonvertebral fracture risk. We hypothesized that abaloparatide would improve BMD in proximal femoral regions surrounding a virtual THA stem.

METHODS

This post hoc analysis obtained dual x-ray absorptiometry (DXA) hip scans from 500 randomly selected postmenopausal women with osteoporosis from the Phase-3 Abaloparatide Comparator Trial in Vertebral Endpoints (ACTIVE, NCT01343004) study after 0, 6, and 18 months of abaloparatide (250 patients) or placebo (250 patients). Hip DXA scans underwent 3-dimensional (3D) modeling via 3D-Shaper, followed by virtual resection of the proximal femur and simulated placement of a tapered, flat-wedge hip stem that guided delineation of the Gruen zones that were fully (zones 1 and 7) or largely (zones 2 and 6) captured in the scanning region. Integral, cortical, and trabecular volumetric BMD, cortical thickness, and cortical surface BMD (the product of cortical volumetric BMD and cortical thickness) were determined for each zone.

RESULTS

Compared with placebo, the abaloparatide group showed greater increases in integral volumetric BMD in all zones at months 6 and 18; cortical surface BMD in zones 1, 6, and 7 at month 6; cortical thickness, cortical volumetric BMD, and cortical surface BMD in all zones at month 18; and trabecular volumetric BMD in zones 1 and 7 at months 6 and 18.

CONCLUSIONS

Abaloparatide increases BMD in proximal femoral regions that interact with and support femoral stems, suggesting that abaloparatide may have value for preoperative or potentially perioperative bone health optimization in patients with osteoporosis undergoing THA.

LEVEL OF EVIDENCE

Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Effects of differences in dose and frequency of teriparatide on bone structure in Proximal Femur. - Analysis by DXA-based 3D-modeling (3D-SHAPER Software) -TRIPLE-BONE study (The effects of TeRIParatide preparation on bone mineraL density increase and BONE structure)

Trends toward more favorable improvement of the cortical bone parameters by once-weekly (56.5 μg once a week) and twice-weekly teriparatide (28.2 μg twice a week), and that of the trabecular bone parameters by once-daily (1/D) teriparatide (20 μg/day once a day) were shown.

PURPOSE

To examine the effects of differences in the amount of teriparatide (TPTD) per administration and its dosing frequency on the bone structure in the proximal femur by dual-energy X-ray absorptiometry (DXA)-based 3D-modeling (3D-SHAPER software).

METHODS

This was a multicenter retrospective study. Patients aged 50 years or older with primary osteoporosis who continuously received once-/twice-weekly (1・2/W, n = 60) or 1/D TPTD (n = 14) administration for at least one year were included in the study. Measurement regions included the femoral neck (FN), trochanter (TR), femoral shaft (FS), and total proximal hip (TH). Concurrently, the bone mineral density (BMD) and Trabecular Bone Score (TBS) were measured.

RESULTS

The cross-sectional area, cross-sectional moment of inertia, and section modulus in the FS were significantly improved in the 1・2/W TPTD group, as compared to the 1/D TPTD group. However, significant improvement of the cortical thickness and buckling ratio in the FN was observed in the 1/D TPTD group, as compared to the 1・2/W TPTD group. Trabecular BMD values in the FS and TH were significantly increased in the 1/D TPTD group, as compared to the 1・2/W TPTD group, while the cortical BMD values in the TR, FS, and TH were significantly increased in the 1・2/W TPTD group, as compared to the 1/D TPTD group.

CONCLUSION

Trends toward more favorable improvement of the cortical bone by 1・2/W TPTD and that of the trabecular bones by 1/D TPTD were observed.

Primary Hyperparathyroidism: Assessment of the Effects of Parathyroidectomy Using Dual X-Ray Absorptiometry, Trabecular Bone Score, and Dual X-Ray Absorptiometry-Based Three-Dimensional Modeling

OBJECTIVE

This study aimed to evaluate the bone microstructure to determine whether curative surgery of primary hyperparathyroidism produces changes in bone mineral density (BMD), trabecular bone score (TBS), and three-dimensional (3D) dual x-ray absorptiometry (DXA) parameters and whether these changes are comparable.

METHODS

We retrospectively studied 85 patients (60 women and 25 men, 60.4 ± 12.5 years) diagnosed with primary hyperparathyroidism and undergoing parathyroidectomy. Mean percent changes in BMD (lumbar spine [LS], femoral neck [FN], total hip [TH], and 1/3 radius), TBS and 3D-DXA parameters (trabecular volumetric BMD (vBMD), cortical vBMD, integral vBMD, cortical surface density (sBMD), and cortical thickness at TH) after surgery (12, 24, and/or 36 months) were calculated and compared, and we sought the determinants of these changes.

RESULTS

After parathyroidectomy, BMD presented statistically significant mean increases in LS, FN, and TH during the first 3 years after surgery (P < .001), accompanied by an improvement in all 3D-DXA parameters, but there were no significant changes in 1/3 radius BMD or TBS. Cortical sBMD, trabecular vBMD, and integral vBMD reached mean increases of similar magnitude to those of FN and TH BMD. Age and preoperative serum levels of parathyroid hormone and carboxy-terminal telopeptide of type 1 collagen were significantly associated with percent changes after surgery.

CONCLUSION

We found a benefit of parathyroidectomy for bone, with significant percent increases in LS, FN, and TH BMD up to the third year after surgery, and a qualitative benefit for the hip in both its trabecular and cortical compartments and bone strength.

Areal bone mineral density, trabecular bone score and 3D-DXA analysis of proximal femur in psoriatic disease

Objectives

To evaluate bone mineral density (BMD) and bone quality, with assessment of the cortical and trabecular compartments, in patients with psoriasis (PsO) alone or with psoriatic arthritis (PsA).

Methods

Patients with PsA and patients with PsO alone were evaluated and compared to control subjects matched for age, sex and body mass index category. Areal BMD (aBMD) was determined for the lumbar spine, femoral neck, total hip and total body using dual-energy X-ray absorptiometry (DXA). Bone quality was evaluated by using trabecular bone score (TBS) at the lumbar spine, and by 3D DXA-based analysis (3D Shaper) for the proximal femur.

Results

One hundred ninety-six subjects including 52 patients with PsA and 52 patients with PsO and their respective paired controls were analyzed. Patients with PsA had comparable aBMD, TBS and 3D DXA analysis parameters compared to their paired controls. After adjustment for confounders, patients with PsO alone were characterized by a higher aBMD at the left femur and higher cortical 3D DXA derived parameters (total hip cortical surface BMD and total hip cortical thickness) than their paired controls. TBS was decreased in PsO compared to their controls.

Conclusion

Patients with PsA had normal bone mass and bone quality parameters. Patients with PsO were characterized by higher femoral neck bone density by DXA and cortical parameters by 3D DXA-based analysis, supporting no increased risk for hip fracture. Conversely, bone texture by TBS assessment was decreased in patients with PsO, which may be associated with impaired vertebral bone resistance.

Alteration of Volumetric Bone Mineral Density Parameters in Men with Spinal Cord Injury

Spinal cord injury (SCI) induces severe losses of trabecular and cortical volumetric bone mineral density (vBMD), which cannot be discriminated with conventional dual-energy X-ray absorptiometry (DXA) analysis. The objectives were to: (i) determine the effects of SCI on areal BMD (aBMD) and vBMD determined by advanced 3D-DXA-based methods at various femoral regions and (ii) model the profiles of 3D-DXA-derived parameters with the time since injury. Eighty adult males with SCI and 25 age-matched able-bodied (AB) controls were enrolled in this study. Trabecular and cortical vBMD, cortical thickness and derived strength parameters were assessed by 3D-SHAPER® software at various femoral subregions. Individuals with SCI had significantly lower integral vBMD, trabecular vBMD, cortical vBMD, cortical thickness and derived bone strength parameters (p < 0.001 for all) in total proximal femur compared with AB controls. These alterations were approximately to the same degree for all three femoral subregions, and the difference between the two groups tended to be greater for cortical vBMD than trabecular vBMD. There were minor differences according to the lesion level (paraplegics vs tetraplegics) for all 3D-DXA-derived parameters. For total proximal femur, the decreasing bone parameters tended to reach a new steady state after 5.1 years for integral vBMD, 7.4 years for trabecular vBMD and 9.2 years for cortical vBMD following SCI. At proximal femur, lower vBMD (integral, cortical and trabecular) and cortical thickness resulted in low estimated bone strength in individuals with SCI. It remains to be demonstrated whether these new parameters are more closely associated with fragility fracture than aBMD.

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.

High-Intensity Exercise and Geometric Indices of Hip Bone Strength in Postmenopausal Women on or off Bone Medication: The MEDEX-OP Randomised Controlled Trial

To compare the effects of high-intensity resistance and impact training (HiRIT) to low-intensity, Pilates-based exercise (LiPBE) on proximal femur geometry and explore the influence of antiresorptive medication on those effects. Postmenopausal women with low bone mass, on or off antiresorptive bone medications were randomly allocated, stratified on medication intake, to eight months of twice-weekly, supervised HiRIT (Onero™) or LiPBE (Buff Bones®). 3D hip software was used to analyse proximal femur DXA scans. Outcomes included femoral neck (FN) and total hip (TH), volumetric (e.g. vBMC, vBMD) and geometric (e.g. cortical thickness, cross-sectional area [CSA], section modulus [Z]) indices of bone strength. Data were analysed using analysis of variance. Scans of 102 women were examined: LiPBE, 43; HiRIT, 37; LiPBE-med, 11; HiRIT-med, 11. HiRIT improved TH trabecular vBMC and vBMD (3.1 ± 1.1% versus - 1.2 ± 1.2%, p = 0.008; and 1.5 ± 1.0% versus - 1.6 ± 1.2%, p = 0.042, respectively) and FN and TH total vBMC (2.0 ± 0.8% versus - 0.2 ± 0.7%, p = 0.032; and 0.7 ± 0.4% versus - 0.8 ± 0.6%, p = 0.032, respectively), compared to losses in LiPBE. HiRIT also increased Z while LiPBE did not (p = 0.035). The combination of HiRIT and medication achieved greater improvements in FN total and trabecular vBMD, total BMC, CSA and Z than HiRIT alone. HiRIT improved geometric parameters of proximal femur strength, while LiPBE exercise was largely ineffective. Medication may enhance some HiRIT effects. Findings suggest reduced hip fracture risk in response to HiRIT.Trial registration number ACTRN12617001511325.

Abaloparatide Effects on Cortical Volumetric BMD and Estimated Strength Indices of Hip Subregions by 3D-DXA in Women With Postmenopausal Osteoporosis

In ACTIVE, abaloparatide increased areal BMD (aBMD) of the hip and femoral neck vs teriparatide and placebo in women with osteoporosis. Previously, 3D-processing of dual X-ray absorptiometry (DXA) scans of a subgroup of ACTIVE subjects showed similar increases in trabecular volumetric BMD (Tb.vBMD) and greater increases in cortical vBMD (Ct.vBMD) of the total hip with abaloparatide vs teriparatide. The current analyses from this subgroup describe 2D- and 3D-DXA data for hip subregions. Randomly selected subjects from ACTIVE (n = 250/treatment group) who received 18 mo of placebo, abaloparatide 80 µg, or open-label teriparatide 20 µg by daily subcutaneous injection underwent hip DXA at baseline, and mo 6 and 18 of treatment. Areal BMD of the femoral neck, trochanter, and femoral shaft was determined using standard 2D-DXA and 3D-SHAPER software to retrospectively evaluate changes from baseline in volumetric parameters of these 3 hip subregions, including trabecular and cortical segmentation. Changes in biomechanical parameters cross-sectional moment of inertia (CSMI), section modulus (Z), and buckling ratio were also evaluated. Femoral neck, trochanter, and shaft aBMD increased in the abaloparatide and teriparatide groups at mo 6 and 18 vs placebo, with greater increases for abaloparatide vs teriparatide at the femoral neck at mo 6 and the shaft at mo 6 and 18. All 3 subregions showed similar significant increases in Tb.vBMD with abaloparatide and teriparatide vs placebo, whereas Ct.vBMD of all 3 subregions showed greater increases after 18 mo of abaloparatide vs teriparatide. Biomechanical parameters improved in all subregions with abaloparatide and teriparatide vs placebo, with greater improvements in CSMI and Z of the femoral neck and lower shaft after 6 and 18 mo of abaloparatide vs teriparatide. Differential femoral neck and shaft Ct.vBMD responses may explain the greater increases in CSMI and Z of those subregions with abaloparatide vs teriparatide.

Skeletal disorders associated with the growth hormone-insulin-like growth factor 1 axis

Growth hormone (GH) and insulin-like growth factor 1 (IGF1) are important regulators of bone remodelling and metabolism and have an essential role in the achievement and maintenance of bone mass throughout life. Evidence from animal models and human diseases shows that both GH deficiency (GHD) and excess are associated with changes in bone remodelling and cause profound alterations in bone microstructure. The consequence is an increased risk of fractures in individuals with GHD or acromegaly, a condition of GH excess. In addition, functional perturbations of the GH-IGF1 axis, encountered in individuals with anorexia nervosa and during ageing, result in skeletal fragility and osteoporosis. The effect of interventions used to treat GHD and acromegaly on the skeleton is variable and dependent on the duration of the disease, the pre-existing skeletal state, coexistent hormone alterations (such as those occurring in hypogonadism) and length of therapy. This variability could also reflect the irreversibility of the skeletal structural defect occurring during alterations of the GH-IGF1 axis. Moreover, the effects of the treatment of GHD and acromegaly on locally produced IGF1 and IGF binding proteins are uncertain and in need of further study. This Review highlights the pathophysiological, clinical and therapeutic aspects of skeletal fragility associated with perturbations in the GH-IGF1 axis.

Bone Analysis Using Trabecular Bone Score and Dual-Energy X-Ray Absorptiometry-Based 3-Dimensional Modeling in Postmenopausal Women With Primary Hyperparathyroidism

OBJECTIVE

Predominance of bone loss in cortical sites with relative preservation of trabecular bone, even in postmenopausal women, has been described in primary hyperparathyroidism (PHPT). The aim of this study was to evaluate bone microarchitectural differences using dual-energy x-ray absorptiometry (DXA), trabecular bone score (TBS), and DXA-based 3-dimensional (3D) modeling (3D-DXA) between postmenopausal women diagnosed with PHPT (PM-PHPT) and healthy postmenopausal controls.

METHODS

This retrospective study included 44 women with PM-PHPT (9 of whom had fractures) and 48 healthy women matched by age, body mass index, and years since menopause treated at Hospital Universitario Fundación Jiménez Díaz between 2008 and 2017. The bone mineral density (BMD) of the lumbar spine (LS), femoral neck, total hip (TH), and 1/3 radius was assessed using DXA, and trabecular volumetric BMD (vBMD), cortical vBMD, integral vBMD, cortical thickness, and cortical surface BMD at TH were assessed using a 3D-DXA software and TBS at LS.

RESULTS

The mean adjusted BMD values at LS, the femoral neck, and TH; TBS at LS; and TH 3D-DXA parameters (trabecular vBMD, integral vBMD, cortical thickness, and cortical surface BMD) were significantly reduced in women with PM-PHPT compared with those in the controls. However, differences in mean cortical vBMD were not statistically significant (P = .078). There were no significant differences in mean BMD, TBS, or the 3D-DXA parameters between patients with fractures and those without fractures. The 25-hydroxyvitamin D level appeared to be associated with TBS but not with DXA and 3D-DXA measurements.

CONCLUSION

PM-PHPT has significant involvement of the trabecular and cortical compartments of the bone, as determined by DXA, TBS, and 3D-DXA.

Analysis of the subsequent treatment of osteoporosis by transitioning from bisphosphonates to denosumab, using quantitative computed tomography: A prospective cohort study

Purpose

Denosumab reduces bone resorption and improves bone mineral density (BMD). Studies have analyzed subsequent treatment transitioning from bisphosphonates to denosumab based on dual-energy X-ray absorptiometry scanning (DXA). Quantitative computed tomography (QCT) can help assess cortical and trabecular bones separately in three dimensions without the interference of the surrounding osteophytes. In the present study, we analyzed the subsequent treatment transition from bisphosphonates to denosumab using QCT.

Methods

Thirty-two patients with postmenopausal osteoporosis to be treated with denosumab were recruited. The patients were divided into two groups (15 prior bisphosphonate and 17 naïve) based on their previous treatment. BMD of the lumbar spine and hip were evaluated by DXA and QCT at baseline and 12 months following denosumab treatment.

Results

The percentage change in volumetric BMD assessed by QCT at 12 months significantly improved in the naïve group compared with that in the prior bisphosphonate group. The region-specific assessment of femur at 12 months revealed that denosumab treatment was effective in both cortical and trabecular bones except the trabecular region of the prior bisphosphonate group.

Conclusion

Our study suggests that although denosumab treatment was useful in both treatment groups, BMD increase was significantly higher in the naïve group than in the prior-bisphosphonate group. Interestingly, in the prior-bisphosphonate group, denosumab treatment was more effective in the cortical region than the trabecular region. Our study offers insights into the subsequent treatment and permits greater confidence when switching to denosumab from bisphosphonates.

•

We analyzed the treatment transition from bisphosphonates to denosumab using QCT.

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Percentage change in volumetric BMD at 12 months significantly improved in the naïve group.

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Denosumab treatment was more effective on the cortical region than the trabecular region.

•

Our study offers insights into the subsequent treatment when switching to denosumab.

Feasibility, safety and effectiveness of a pilot 16-week home-based, impact exercise intervention in postmenopausal women with low bone mineral density

The feasibility and efficacy of home-based, impact exercise are unclear. This pilot impact exercise intervention was feasible and safe, and improved bone health and physical function in postmenopausal women with low bone density. Appropriately designed randomised controlled trials are now required to determine whether such interventions can reduce fracture risk.

INTRODUCTION

The feasibility and efficacy of impact exercise in postmenopausal women with low bone mineral density (BMD) are unclear. We aimed to determine adherence, safety and changes in BMD, bone microarchitecture and physical function following a pilot home-based, impact exercise intervention in postmenopausal women with low BMD.

METHODS

Fifty community-dwelling postmenopausal women with BMD T-scores < - 1.0 participated in 16 weeks of home-based impact exercise progressively increasing to 50 multi-directional unilateral hops on each leg daily. Bone density and structure were assessed by lumbar spine and hip dual-energy X-ray absorptiometry (DXA), 3D modelling (3D-SHAPER) of hip DXA scans and distal tibial high-resolution peripheral quantitative computed tomography scans. Physical performance was assessed by repeated chair stand time and stair climb time.

RESULTS

Forty-four women (mean ± SD age 64.5 ± 7.5 years) completed the intervention, with adherence of 85.3 ± 17.3%. Reasons for withdrawal were related soreness (n = 2), unrelated injury (n = 1) and loss of interest (n = 3). Femoral neck areal BMD increased by 1.13 ± 3.76% (p = 0.048). Trabecular volumetric BMD (vBMD) increased at the total hip (2.27 ± 7.03%; p = 0.038) and femoral neck increased (3.20 ± 5.39%; p < 0.001). Distal tibia total vBMD increased by 0.32 ± 0.88% (p = 0.032) and cortical cross-sectional area increased by 0.55 ± 1.54% (p = 0.034). Chair stand and stair climb time improved by 2.34 ± 1.88 s (p < 0.001) and 0.27 ± 0.49 s (p < 0.001), respectively.

CONCLUSION

A 16-week home-based, impact exercise was feasible and may be effective in improving femoral neck areal BMD, total hip and distal tibial vBMD and physical function in postmenopausal women. Appropriately designed randomised controlled trials are now required to determine whether such interventions can reduce fracture risk in older populations.

A pilot study comparing daily teriparatide with monthly cycles of teriparatide and raloxifene

This 6-month pilot study in osteoporotic postmenopausal women evaluated cyclic TPD/RLX compared to daily subcutaneous TPD with the concept of optimizing bone formation. Compared to daily subcutaneous TPD, cyclic therapy showed comparable increase in spine BMD and favorable effects on total proximal femur BMD and cortical thickness.

PURPOSE

There is no cure for osteoporosis; better medications or different approaches with current agents are needed. We hypothesized that monthly cycles of teriparatide (TPD) followed by raloxifene (RLX) might promote ongoing bone formation. Additionally, as TPD might initially adversely affect hip BMD, such effects may be mitigated by a cyclic approach. Therefore, this 6-month pilot study evaluated the effect of cyclic TPD/RLX compared to daily subcutaneous TPD on bone markers, BMD, trabecular bone score (TBS), and hip parameters assessed by 3D modeling.

METHODS

Postmenopausal osteoporotic women (n=26) were randomized to open-label TPD 20 daily or alternating monthly cycles of TPD followed by monthly RLX 60 mg daily. BMD was measured at the lumbar spine (LS), femur, and radius by DXA. To further assess LS BMD, QCT and opportunistic CT (L1 Hounsfield units [HU]) were performed. LS TBS and hip cortical and trabecular parameters were assessed using DXA. Baseline group comparisons were performed by unpaired T-test with change over time evaluated by repeated measures ANOVA.

RESULTS

Participant mean age, BMI, and lowest T-score were 67.0 years, 26.0 kg/m², and -2.7; no between-group differences in serum chemistries, 25(OH)D, or BMD were observed. LS-BMD increased (p<0.001) with TPD or TPD/RLX as measured by DXA (4.8%/5.2%), QCT (13%/9.4%), or HU (15.6%/10.2%) with no between-group difference. TPD/RLX produced beneficial between-group differences in total proximal femur BMD (1.5%, p<0.05) and cortical thickness (1.6%, p<0.05).

CONCLUSION

Compared with daily TPD, cyclic TPD/RLX comparably increased spine BMD and might have favorable effects on proximal femur BMD and cortical thickness.

Trabecular and cortical bone involvement in rheumatoid arthritis by DXA and DXA-based 3D modelling

Rheumatoid arthritis (RA) patients had a higher risk of developing low bone mineral density (BMD) or osteoporosis. RA patients on classic disease-modifying antirheumatic drug (c-DMARD) therapy showed significantly lower BMD than controls, while no significant differences in most parameters were found between RA patients receiving biological disease-modifying antirheumatic drugs (b-DMARDs) and controls. The 3D analysis allowed us to find changes in the trabecular and cortical compartments.

INTRODUCTION

To evaluate cortical and trabecular bone involvement of the hip in RA patients by dual-energy X-ray absorptiometry (DXA) and 3D analysis. The secondary end-point was to evaluate bone involvement in patients treated with classic (c-DMARD) or biological (b-DMARD) disease-modifying antirheumatic drug therapies and the effect of the duration of the disease and corticosteroid therapy on 3D parameters.

METHODS

A cross-sectional study of 105 RA patients and 100 subjects as a control group (CG) matched by age, sex, and BMI was carried out. BMD was measured by DXA of the bilateral femoral neck (FN) and total hip (TH). The 3D analyses including trabecular and cortical BMD were performed on hip scans with the 3D-Shaper software.

RESULTS

FN and TH BMD and trabecular and cortical vBMD were significantly lower in RA patients. The c-DMARD (n = 75) group showed significantly lower trabecular and cortical vBMD than the CG. Despite the lower values, the b-DMARD group (n = 30) showed no significant differences in most parameters compared with the CG. The trabecular and cortical 3D parameters were significantly lower in the group with an RA disease duration of 1 to 5 years than in the CG, and the trabecular vBMD was significantly lower in the group with a duration of corticosteroid therapy of 1 to 5 years than in the CG, while no significant differences were found by standard DXA in the same period.

CONCLUSIONS

RA patients had a higher risk of developing low BMD or osteoporosis than controls. RA patients receiving c-DMARD therapy showed significantly lower BMD than controls, while no significant differences in most parameters were found between RA patients receiving b-DMARDs and controls. 3D-DXA allowed us to find changes in trabecular and cortical bone compartments in RA patients.

Differential effects of abaloparatide and teriparatide on hip cortical volumetric BMD by DXA-based 3D modeling

In postmenopausal osteoporotic women in ACTIVE, abaloparatide reduced fracture risk and increased areal bone mineral density (BMD) more than teriparatide at the hip and wrist. DXA-based 3D modeling showed significantly greater increases in hip cortical volumetric BMD with abaloparatide versus teriparatide. This may explain differences reported in aBMD by DXA.

INTRODUCTION

In ACTIVE, abaloparatide (ABL) increased bone mineral density (BMD) shown by dual-energy X-ray absorptiometry (DXA) while reducing fracture incidence in postmenopausal osteoporotic women. Changes in DXA BMD with ABL, 80 μg, were significantly greater than with open-label teriparatide (TPTD), 20 μg, at cortical sites including total hip, femoral neck, and 1/3 distal radius. The purpose of this study was to better understand the relative effects of ABL and TPTD on cortical and cancellous compartments in the proximal femur.

METHODS

Hip DXA images from a subset of randomly selected patients in the ACTIVE trial (n = 250/arm) were retrospectively analyzed using three-dimensional modeling methods (3D-SHAPER software) to evaluate changes from baseline at months 6 and 18.

RESULTS

Similar significant increases in trabecular volumetric BMD (vBMD, + 9%) and cortical thickness (+ 1.5%) were observed with ABL and TPTD by 3D-DXA at 18 months. In contrast, only ABL significantly increased cortical vBMD versus baseline (+ 1.3%), and changes in both cortical vBMD and cortical surface BMD were significantly greater with ABL versus TPTD. In the TPTD group, changes in cortical vBMD were inversely correlated with changes in serum CTX (carboxy-terminal telopeptide of type I collagen) and PINP (procollagen type I N-terminal propeptide), suggesting that higher bone turnover may have attenuated cortical gains.

CONCLUSION

These results suggest previously reported differences in areal BMD increases between ABL and TPTD may be due to differential effects on cortical vBMD. Further studies are warranted to investigate how these differences affect therapeutic impact on hip strength in postmenopausal women with osteoporosis.

3D DXA Hip Differences in Patients with Acromegaly or Adult Growth Hormone Deficiency

The skeleton is regulated by and responds to pituitary hormones, especially when the circulating levels are perturbed in disease. This study aims to analyse the between-group differences in 3D dual-energy X-ray absorptiometry (DXA) parameters at the hip site among patients with acromegaly or adult growth hormone deficiency (AGHD) and a healthy control group. The current cross-sectional study includes data for 67 adults, 20 with acromegaly, 14 with AGHD and 33 healthy controls. We obtained the areal bone mineral density (aBMD) outcomes using DXA and cortical and trabecular parameters using 3D-DXA software (3D-SHAPER). The mean-adjusted 3D-DXA parameters did not differ between acromegaly patients and the controls (p > 0.05); however, we found cortical bone impairment (−7.3% to −8.4%; effect size (ES) = 0.78) in AGHD patients (p < 0.05). Differences in the cortical bone parameters were more evident when comparing AGHD patients (−8.5% to −16.2%; ES = 1.22 to 1.24) with acromegaly patients (p < 0.05). In brief, the 3D mapping highlighted the trochanter as the site with greater cortical bone differences between acromegaly patients and the controls. Overall, AGHD patients displayed lower cortical parameters at the trochanter, femoral neck and intertrochanter compared to the controls and acromegaly patients. To sum up, 3D-DXA provided useful information about the characteristics of bone involvement in growth hormone (GH)-related disorders. Patients with AGHD showed distinct involvement of the cortical structure.

Usefulness of Trabecular CT Attenuation Measurement of Lumbar Spine in Predicting Osteoporotic Compression Fracture: Is the L4 Trabecular Region of Interest Most Relevant?

STUDY DESIGN

Retrospective study.

OBJECTIVE

The aim of this study was to evaluate the usefulness of computed tomography (CT) attenuation in defining trabecular region-of-interest (t-ROI) at lumbar vertebral body in the assessment of osteoporotic compression fracture (OCF) compared to spinal dual x-ray absorptiometry (DXA).

SUMMARY OF BACKGROUND DATA

Even though osteoporosis was not diagnosed in the bone mineral density measurement using DXA, we often experienced cases where the screw was weakly inserted due to low bone quality during screw insertion.

METHODS

A total of 188 patients who met the inclusion criteria were enrolled. We determined best cutoff value of the simple t-ROI attenuation at the most relevant level for predicting OCF. We assessed correlations between the simple t-ROI attenuation at the most relevant level and OCF rate, and investigate the association between the number of compression fracture and simple t-ROI attenuation at the most relevant level.

RESULTS

L4 ROI attenuation is the most accurate measurement for predicting osteoporotic compression fracture with an area under the curve of 0.798. The optimal cutoff point of L4 ROI attenuation was measured at 90.5 HU with 88.8% and 60.6% sensitivity and specificity, respectively. L4 ROI attenuation was significantly correlated with the osteoporotic compression fracture rate (r = -0.545, P < 0.001). The number of compression fracture (coefficient of determination R2 = 0.286; P < 0.001) was independently correlated with L4 ROI attenuation.

CONCLUSION

Simple t-ROI computed tomography attenuation is an accurate measurement tool in predicting OCF compared to DXA T-score. The value of L4 t-ROI attenuation is the most relevant measurement for predicting osteoporotic compression fracture, is an alternative to DXA, and can predict the number and rate of compression fractures. Spine surgeons should be aware of L4 t-ROI attenuation to make successful fusion in spine surgery for elderly patients group.Level of Evidence: 3.

The effect of an online exercise programme on bone health in paediatric cancer survivors (iBoneFIT): study protocol of a multi-centre randomized controlled trial

BACKGROUND

New approaches on paediatric cancer treatment aim to maintain long-term health. As a result of radiotherapy, chemotherapy or surgery, paediatric cancer survivors tend to suffer from any chronic health condition. Endocrine dysfunction represents one of the most common issues and affects bone health. Exercise is key for bone mass accrual during growth, specifically plyometric jump training. The iBoneFIT study will investigate the effect of a 9-month online exercise programme on bone health in paediatric cancer survivors. This study will also examine the effect of the intervention on body composition, physical fitness, physical activity, calcium intake, vitamin D, blood samples quality of life and mental health.

METHODS

A minimum of 116 participants aged 6 to 18 years will be randomized into an intervention (n = 58) or control group (n = 58). The intervention group will receive an online exercise programme and diet counselling on calcium and vitamin D. In addition, five behaviour change techniques and a gamification design will be implemented in order to increase the interest of this non-game programme. The control group will only receive diet counselling. Participants will be assessed on 3 occasions: 1) at baseline; 2) after the 9 months of the intervention; 3) 4 months following the intervention. The primary outcome will be determined by dual energy X-ray absorptiometry (DXA) and the hip structural analysis, trabecular bone score and 3D-DXA softwares. Secondary outcomes will include anthropometry, body composition, physical fitness, physical activity, calcium and vitamin D intake, blood samples, quality of life and mental health.

DISCUSSION

Whether a simple, feasible and short in duration exercise programme can improve bone health has not been examined in paediatric cancer survivors. This article describes the design, rationale and methods of a study intended to test the effect of a rigorous online exercise programme on bone health in paediatric cancer survivors. If successful, the iBoneFIT study will contribute to decrease chronic health conditions in this population and will have a positive impact in the society.

TRIAL REGISTRATION

Prospectively registered in isrctn.com: isrctn61195625 . Registered 2 April 2020.

Relationship between Insulin Resistance (HOMA-IR), Trabecular Bone Score (TBS), and Three-Dimensional Dual-Energy X-ray Absorptiometry (3D-DXA) in Non-Diabetic Postmenopausal Women

BACKGROUND

Insulin may play a key role in bone metabolism, where the anabolic effect predominates. This study aims to analyze the relationship between insulin resistance and bone quality using the trabecular bone score (TBS) and three-dimensional dual-energy X-ray absorptiometry (3D-DXA) in non-diabetic postmenopausal women by determining cortical and trabecular compartments.

METHODS

A cross-sectional study was conducted in non-diabetic postmenopausal women with suspected or diagnosed osteoporosis. The inclusion criteria were no menstruation for more than 12 months and low bone mass or osteoporosis as defined by DXA. Glucose was calculated using a Hitachi 917 auto-analyzer. Insulin was determined using an enzyme-linked immunosorbent assay (EIA). Insulin resistance was estimated using a homeostasis model assessment of insulin resistance (HOMA-IR). DXA, 3D-DXA, and TBS were thus collected. Moreover, we examined bone parameters according to quartile of insulin, hemoglobin A1C (HbA1c), and HOMA-IR.

RESULTS

In this study, we included 381 postmenopausal women. Women located in quartile 4 (Q4) of HOMA-IR had higher values of volumetric bone mineral density (vBMD) but not TBS. The increase was higher in the trabecular compartment (16.4%) than in the cortical compartment (6.4%). Similar results were obtained for insulin. Analysis of the quartiles by HbA1c showed no differences in densitometry values, however women in Q4 had lower levels of TBS. After adjusting for BMI, statistical significance was maintained for TBS, insulin, HOMA-IR, and HbA1c.

CONCLUSIONS

In non-diabetic postmenopausal women there was a direct relationship between insulin resistance and vBMD, whose effect is directly related to greater weight. TBS had an inverse relationship with HbA1c, insulin, and insulin resistance unrelated to weight. This might be explained by the formation of advanced glycosylation products (AGEs) in the bone matrix, which reduces bone deformation capacity and resistance, as well as increases fragility.

New technologies in the evaluation of bone fragility and its application in Endocrinology

Bone mineral density using dual-energy X-ray absorptiometry is the gold standard for the assessment of bone and an important predictor of fracture risk. However, most fragility fractures occur in people without densitometric osteoporosis, especially in endocrinological diseases. Fracture risk estimation tools such as FRAX have improved diagnostic sensitivity but do not include additional skeletal features. Bone microarchitecture research represents an improvement in the treatment of these patients. In this document members of the Mineral and Bone Metabolism Working Group of the Spanish Society of Endocrinology and Nutrition review new advances in dual-energy X-ray absorptiometry and other complex techniques for the study of bone microarchitecture as well as the available data on type 2 diabetes and parathyroid pathology.

Analysis of Bone Impairment by 3D DXA Hip Measures in Patients With Primary Hyperparathyroidism: A Pilot Study

CONTEXT

Primary hyperparathyroidism (PHPT) has been related to bone loss. Dual-energy x-ray absorptiometry (DXA) cannot distinguish between trabecular and cortical bone compartments but the recently developed three-dimensional (3D)-DXA software might overcome this issue.

OBJECTIVE

To examine the differences in DXA-derived areal bone mineral density (aBMD) and 3D-DXA parameters at the hip site between patients with PHPT and a healthy control group.

DESIGN

Cross-sectional pilot study.

SETTING

Hospital.

PATIENTS

80 adults (59.5 ± 9.1 yrs), 40 with PHPT and 40 age- and sex-matched healthy controls.

MEASURES

aBMD (g/cm2) of the femoral neck, trochanter, shaft, and total hip was assessed using DXA. Cortical surface (sBMD, mg/cm2), cortical volumetric BMD (vBMD, mg/cm3), trabecular vBMD (mg/cm3), integral vBMD (mg/cm3) and cortical thickness (mm) was assessed using 3D-DXA software.

RESULTS

Mean-adjusted values showed lower aBMD (7.5%-12.2%, effect size: 0.51-1.01) in the PHPT group compared with the control group (all P < 0.05). 3D-DXA revealed bone impairment (3.7%-8.5%, effect size: 0.47-0.65) in patients with PHPT, mainly in cortical parameters (all P < 0.05). However, differences in trabecular vBMD were not statistically significant (P = 0.055). The 3D mapping showed lower cortical sBMD, cortical vBMD, and cortical thickness at the trochanter and diaphysis in the PHPT group (P < 0.05) compared with the control group. In both groups, the presence of osteopenia or osteoporosis is related to lower cortical bone.

CONCLUSIONS

aBMD and cortical 3D parameters are impaired in patients with PHPT versus healthy controls. The vBMD of the trabecular compartment seems to be affected, although to a lesser extent.

Radiofrequency echographic multi-spectrometry for the in-vivo assessment of bone strength: state of the art-outcomes of an expert consensus meeting organized by the European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO)

PURPOSE

The purpose of this paper was to review the available approaches for bone strength assessment, osteoporosis diagnosis and fracture risk prediction, and to provide insights into radiofrequency echographic multi spectrometry (REMS), a non-ionizing axial skeleton technique.

METHODS

A working group convened by the European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis met to review the current image-based methods for bone strength assessment and fracture risk estimation, and to discuss the clinical perspectives of REMS.

RESULTS

Areal bone mineral density (BMD) measured by dual-energy X-ray absorptiometry (DXA) is the consolidated indicator for osteoporosis diagnosis and fracture risk assessment. A more reliable fracture risk estimation would actually require an improved assessment of bone strength, integrating also bone quality information. Several different approaches have been proposed, including additional DXA-based parameters, quantitative computed tomography, and quantitative ultrasound. Although each of them showed a somewhat improved clinical performance, none satisfied all the requirements for a widespread routine employment, which was typically hindered by unclear clinical usefulness, radiation doses, limited accessibility, or inapplicability to spine and hip, therefore leaving several clinical needs still unmet. REMS is a clinically available technology for osteoporosis diagnosis and fracture risk assessment through the estimation of BMD on the axial skeleton reference sites. Its automatic processing of unfiltered ultrasound signals provides accurate BMD values in view of fracture risk assessment.

CONCLUSIONS

New approaches for improved bone strength and fracture risk estimations are needed for a better management of osteoporotic patients. In this context, REMS represents a valuable approach for osteoporosis diagnosis and fracture risk prediction.

Discrimination of osteoporosis-related vertebral fractures by DXA-derived 3D measurements: a retrospective case-control study

A retrospective case-control study assessing the association of DXA-derived 3D measurements with osteoporosis-related vertebral fractures was performed. Trabecular volumetric bone mineral density was the measurement that best discriminates between fracture and control groups.

INTRODUCTION

The aim of the present study was to evaluate the association of DXA-derived 3D measurements at the lumbar spine with osteoporosis-related vertebral fractures.

METHODS

We retrospectively analyzed a database of 74 postmenopausal women: 37 subjects with incident vertebral fractures and 37 age-matched controls without any type of fracture. DXA scans at the lumbar spine were acquired at baseline (i.e., before the fracture event for subjects in the fracture group), and areal bone mineral density (aBMD) was measured. DXA-derived 3D measurements, such as volumetric BMD (vBMD), were assessed using a DXA-based 3D modeling software (3D-SHAPER). vBMD was computed at the trabecular, cortical, and integral bone. Cortical thickness and cortical surface BMD were also measured. Differences in DXA-derived measurements between fracture and control groups were evaluated using unpaired t test. Odds ratio (OR) and area under the receiver operating curve (AUC) were also computed. Subgroup analyses according to fractured vertebra were performed.

RESULTS

aBMD of fracture group was 9.3% lower compared with control group (p < 0.01); a higher difference was found for trabecular vBMD in the vertebral body (- 16.1%, p < 0.001). Trabecular vBMD was the measurement that best discriminates between fracture and control groups, with an AUC of 0.733, against 0.682 for aBMD. Overall, similar findings were observed within the subgroup analyses. The L1 vertebral fractures subgroup had the highest AUC at trabecular vBMD (0.827), against aBMD (0.758).

CONCLUSION

This study showed the ability of cortical and trabecular measurements from DXA-derived 3D models to discriminate between fracture and control groups. Large cohorts need to be analyzed to determine if these measurements could improve fracture risk prediction in clinical practice.