Olivier Lamy

Trabecular bone score: a noninvasive analytical method based upon the DXA image.

The trabecular bone score (TBS) is a gray‐level textural metric that can be extracted from the two‐dimensional lumbar spine dual‐energy X‐ray absorptiometry (DXA) image. TBS is related to bone microarchitecture and provides skeletal information that is not captured from the standard bone mineral density (BMD) measurement. Based on experimental variograms of the projected DXA image, TBS has the potential to discern differences between DXA scans that show similar BMD measurements. An elevated TBS value correlates with better skeletal microstructure; a low TBS value correlates with weaker skeletal microstructure. Lumbar spine TBS has been evaluated in cross‐sectional and longitudinal studies. The following conclusions are based upon publications reviewed in this article: 1) TBS gives lower values in postmenopausal women and in men with previous fragility fractures than their nonfractured counterparts; 2) TBS is complementary to data available by lumbar spine DXA measurements; 3) TBS results are lower in women who have sustained a fragility fracture but in whom DXA does not indicate osteoporosis or even osteopenia; 4) TBS predicts fracture risk as well as lumbar spine BMD measurements in postmenopausal women; 5) efficacious therapies for osteoporosis differ in the extent to which they influence the TBS; 6) TBS is associated with fracture risk in individuals with conditions related to reduced bone mass or bone quality. Based on these data, lumbar spine TBS holds promise as an emerging technology that could well become a valuable clinical tool in the diagnosis of osteoporosis and in fracture risk assessment.

TBS (Trabecular Bone Score) and Diabetes-Related Fracture Risk

CONTEXT Type 2 diabetes is associated with increased fracture risk but paradoxically greater bone mineral density (BMD). Trabecular bone score (TBS) is derived from the texture of the spine dual x-ray absorptiometry (DXA) image and is related to bone microarchitecture and fracture risk, providing information independent of BMD. OBJECTIVE This study evaluated the ability of lumbar spine TBS to account for increased fracture risk in diabetes. DESIGN AND SETTING We performed a retrospective cohort study using BMD results from a large clinical registry for the province of Manitoba, Canada. PATIENTS We included 29,407 women 50 years old and older with baseline DXA examinations, among whom 2356 had diagnosed diabetes. MAIN OUTCOME MEASURES Lumbar spine TBS was derived for each spine DXA examination blinded to clinical parameters and outcomes. Health service records were assessed for incident nontraumatic major osteoporotic fractures (mean follow-up 4.7 years). RESULTS Diabetes was associated with higher BMD at all sites but lower lumbar spine TBS in unadjusted and adjusted models (all P < .001). The adjusted odds ratio (aOR) for a measurement in the lowest vs the highest tertile was less than 1 for BMD (all P < .001) but was increased for lumbar spine TBS [aOR 2.61, 95% confidence interval (CI) 2.30-2.97]. Major osteoporotic fractures were identified in 175 women (7.4%) with and 1493 (5.5%) without diabetes (P < .001). Lumbar spine TBS was a BMD-independent predictor of fracture and predicted fractures in those with diabetes (adjusted hazard ratio 1.27, 95% CI 1.10-1.46) and without diabetes (hazard ratio 1.31, 95% CI 1.24-1.38). The effect of diabetes on fracture was reduced when lumbar spine TBS was added to a prediction model but was paradoxically increased from adding BMD measurements. CONCLUSIONS Lumbar spine TBS predicts osteoporotic fractures in those with diabetes, and captures a larger portion of the diabetes-associated fracture risk than BMD.

Effects of zoledronate versus placebo on spine bone mineral density and microarchitecture assessed by the trabecular bone score in postmenopausal women with osteoporosis: A three‐year study

The trabecular bone score (TBS) is an index of bone microarchitectural texture calculated from anteroposterior dual‐energy X‐ray absorptiometry (DXA) scans of the lumbar spine (LS) that predicts fracture risk, independent of bone mineral density (BMD). The aim of this study was to compare the effects of yearly intravenous zoledronate (ZOL) versus placebo (PLB) on LS BMD and TBS in postmenopausal women with osteoporosis. Changes in TBS were assessed in the subset of 107 patients recruited at the Department of Osteoporosis of the University Hospital of Berne, Switzerland, who were included in the HORIZON trial. All subjects received adequate calcium and vitamin D3. In these patients randomly assigned to either ZOL (n = 54) or PLB (n = 53) for 3 years, BMD was measured by DXA and TBS assessed by TBS iNsight (v1.9) at baseline and 6, 12, 24, and 36 months after treatment initiation. Baseline characteristics (mean ± SD) were similar between groups in terms of age, 76.8 ± 5.0 years; body mass index (BMI), 24.5 ± 3.6 kg/m2; TBS, 1.178 ± 0.1 but for LS T‐score (ZOL–2.9 ± 1.5 versus PLB–2.1 ± 1.5). Changes in LS BMD were significantly greater with ZOL than with PLB at all time points (p < 0.0001 for all), reaching +9.58% versus +1.38% at month 36. Change in TBS was significantly greater with ZOL than with PLB as of month 24, reaching +1.41 versus–0.49% at month 36; p = 0.031, respectively. LS BMD and TBS were weakly correlated (r = 0.20) and there were no correlations between changes in BMD and TBS from baseline at any visit. In postmenopausal women with osteoporosis, once‐yearly intravenous ZOL therapy significantly increased LS BMD relative to PLB over 3 years and TBS as of 2 years.

Severe spontaneous vertebral fractures after denosumab discontinuation: three case reports

Osteoporosis treatments are usually given for a limited period of time in order to balance benefits and risks. We report three cases of postmenopausal women without any previous fragility fracture who presented severe spontaneous vertebral fractures after denosumab discontinuation. We think that the occurrence of these fractures could be explained by the severe rebound effect observed after denosumab discontinuation and that a consensus regarding the end of treatment with denosumab has to be defined.

Clinical Features of 24 Patients With Rebound‐Associated Vertebral Fractures After Denosumab Discontinuation: Systematic Review and Additional Cases

We aimed to study the clinical and imaging characteristics of patients sustaining vertebral fractures after denosumab discontinuation. For this purpose, we conducted a computerized advanced literature search that identified 13 published cases, and we additionally included another 11 new cases from our centers. Twenty‐four postmenopausal women with vertebral fracture(s) after denosumab discontinuation, experiencing 112 fractures in total, were analyzed. The mean number of fractures per patient was 4.7. The most commonly affected vertebrae were T12 and L1. All fractures occurred 8 to 16 months after the last denosumab injection. Eighty‐three percent of the patients were treatment naïve, whereas 33% had prevalent vertebral fractures. Five (23%) patients were on concurrent aromatase inhibitor treatment. When patients were divided according to treatment duration with an arbitrary cut‐off of 2 years, those with ≤2 years of denosumab treatment had fewer fractures compared with those with >2 years (mean ± SEM fractures 3.2 ± 0.7 versus 5.2 ± 1.4, p = 0.055). Vertebroplasty was used in 5 patients, resulting in additional clinical vertebral fractures in all cases. We conclude that vertebral fracture(s) after denosumab discontinuation are in the majority of patients multiples, and they occur a few months after the effect of the last dose is depleted. Therefore, patients should not delay or omit denosumab doses. Fractures are typically osteoporotic, located at the lower thoracic and the upper lumbar spine. Vertebroplasty is an unsuccessful treatment strategy for such patients.

Effects of Exemestane and Tamoxifen Treatment on Bone Texture Analysis Assessed by TBS in Comparison With Bone Mineral Density Assessed by DXA in Women With Breast Cancer

We performed an analysis of a substudy of the randomized Tamoxifen Exemestane Adjuvant Multinational trial to determine the effects of exemestane (EXE) and tamoxifen (TAM) adjuvant treatment on bone mineral density (BMD) measured by dual-energy X-ray absorptiometry compared with the trabecular bone score, a novel grey-level texture measurement that correlates with 3-dimensional parameters of bone texture in postmenopausal women with hormone receptor-positive breast cancer for the first time. In total, 36 women were randomized to receive TAM (n = 17) or EXE (n = 19). Patients receiving TAM showed a mean increase of BMD in lumbar spine from baseline of 1.0%, 1.5%, and 1.9% and in trabecular bone score of 2.2%, 3.5%, and 3.3% at 6-, 12-, and 24-mo treatment, respectively. Conversely, patients receiving EXE showed a mean decrease from baseline in lumbar spine BMD of -2.3%, -3.6%, and -5.3% and in trabecular bone score of -0.9%, -1.7%, and -2.3% at 6-, 12-, and 24-mo treatment, respectively. Changes in trabecular bone score from baseline at spine were also significantly different between EXE and TAM: p = 0.05, 0.007, and 0.006 at 6, 12, and 24 mo, respectively. TAM induced an increase in BMD and bone texture analysis, whereas EXE resulted in decreases. The results were independent from each other.

Severe rebound-associated vertebral fractures after denosumab discontinuation: nine clinical cases report

Context Denosumab inhibits bone resorption, increases bone mineral density, and reduces fracture risk. Denosumab was approved for the treatment of osteoporosis and the prevention of bone loss in some oncological situations. Denosumab discontinuation is associated with a severe bone turnover rebound (BTR) and a rapid loss of bone mineral density. The clinical consequences of the BTR observed after denosumab discontinuation are not known. Cases Description We report 9 women who presented 50 rebound-associated vertebral fractures (RAVFs) after denosumab discontinuation. A broad biological and radiological assessment excluded other causes than osteoporosis. These 9 cases are unusual and disturbing for several reasons. First, all vertebral fractures (VFs) were spontaneous, and most patients had a high number of VFs (mean = 5.5) in a short period of time. Second, the fracture risk was low for most of these women. Third, their VFs occurred rapidly after last denosumab injection (9-16 months). Fourth, vertebroplasty was associated with a high number of new VFs. All the observed VFs seem to be related to denosumab discontinuation and unlikely to the underlying osteoporosis or osteopenia. We hypothesize that the severe BTR is involved in microdamage accumulation in trabecular bone and thus promotes VFs. Conclusion Studies are urgently needed to determine 1) the pathophysiological processes involved, 2) the clinical profile of patients at risk for RAVFs, and 3) the management and/or treatment regimens after denosumab discontinuation. Health authorities, physicians, and patients must be aware of this RAVF risk. Denosumab injections must be scrupulously done every 6 months but not indefinitely.

Risks and benefits of percutaneous vertebroplasty or kyphoplasty in the management of osteoporotic vertebral fractures

Vertebral fracture (VF) is the most common osteoporotic fracture and is associated with high morbidity and mortality. Conservative treatment combining antalgic agents and rest is usually recommended for symptomatic VFs. The aim of this paper is to review the randomized controlled trials comparing the efficacy and safety of percutaneous vertebroplasty (VP) and percutaneous balloon kyphoplasty (KP) versus conservative treatment. VP and KP procedures are associated with an acceptable general safety. Although the case series investigating VP/KP have all shown an outstanding analgesic benefit, randomized controlled studies are rare and have yielded contradictory results. In several of these studies, a short-term analgesic benefit was observed, except in the prospective randomized sham-controlled studies. A long-term analgesic and functional benefit has rarely been noted. Several recent studies have shown that both VP and KP are associated with an increased risk of new VFs. These fractures are mostly VFs adjacent to the procedure, and they occur within a shorter time period than VFs in other locations. The main risk factors include the number of preexisting VFs, the number of VPs/KPs performed, age, decreased bone mineral density, and intradiscal cement leakage. It is therefore important to involve the patients to whom VP/KP is being proposed in the decision-making process. It is also essential to rapidly initiate a specific osteoporosis therapy when a VF occurs (ideally a bone anabolic treatment) so as to reduce the risk of fracture. Randomized controlled studies are necessary in order to better define the profile of patients who likely benefit the most from VP/KP.

Cost effectiveness and cost utility of risedronate for osteoporosis treatment and fracture prevention in women: a Swiss perspective

Abstract Objectives: To assess the incremental cost-effectiveness ratio (ICER) and incremental cost-utility ratio (ICUR) of risedronate compared to no intervention in postmenopausal osteoporotic women in a Swiss perspective. Methods: A previously validated Markov model was populated with epidemiological and cost data specific to Switzerland and published utility values, and run on a population of 1,000 women of 70 years with established osteoporosis and previous vertebral fracture, treated over 5 years with risedronate 35 mg weekly or no intervention (base case), and five cohorts (according to age at therapy start) with eight risk factor distributions and three lengths of residual effects. Results: In the base case population, the ICER of averting a hip fracture and the ICUR per quality-adjusted life year gained were both dominant. In the presence of a previous vertebral fracture, the ICUR was below €45,000 (£30,000) in all the scenarios. For all osteoporotic women ≥ 70 years of age with at least one risk factor, the ICUR was below €45,000 or the intervention may even be cost saving. Age at the start of therapy and the fracture risk profile had a significant impact on results. Conclusion: Assuming a 2-year residual effect, that ICUR of risedronate in women with postmenopausal osteoporosis is below accepted thresholds from the age of 65 and even cost saving above the age of 70 with at least one risk factor.

Response to Letter: Severe Rebound-Associated Vertebral Fractures After Denosumab Discontinuation.

W e thank Dr. Rao and colleagues for their comments. We reply point by point. First, the number of published figures and/or images depends on the editorial policy and the demands of the reviewers. For each patient, images of fractures or reports of radiologists are available on request. Second, we agree that the transiliac bone biopsy is better than the vertebral biopsy to assess the status of bone structure and remodeling. As reported in the article, all of these women were referred at our center several months after the occurrence of vertebral fractures (VFs). Third, discontinuation of denosumab results in bone turnover marker (BTM) rebound, which remains elevated 30months after the last dose. It is therefore not possible, on the basis of elevated BTM, to distinguish patients with (9 to 16months after the last dose) and thosewithoutVFs during this period. Fourth, we agree that the BTMrebound is one part of the explanation for the risk of VFs. For the moment, BMT rebound is the best marker and the best explanation for several reasons. First, womenwho discontinued denosumab after 10 years had a severe bone mineral density decrease that reached levels lower than baseline: 10-year denosumab gain of 8.2%61.7%; 1-year off treatment loss of212.5%6 1.4%; net loss of 25.4% 6 1.8% (1). Second, very few pathologies are associated with such elevation of BTM. Third, the number of VFs per patient is abnormally high to be explained only by the lumbar bone mineral density or the fracture risk assessment tool estimate. Fourth, the increased riskofVFs after vertebroplasty is unusually high. Whatever the case and regardless of the mechanisms involved, the facts are there. It was urgent to inform. This was the role of our article. Since then, the risk of VFs after denosumab discontinuation has been recognized. The risk of VFs after denosumab discontinuation in the pivotal study Fracture Reduction Evaluation of Denosumab in Osteoporosis Every 6 Months was presented at the 2016 American Society for Bone and Mineral Research Congress (2). Among subjects who sustained new VFs, there was a greater incidence of multiple new VFs in the denosumab (34/56, 60.7%) as in the placebo (10/29, 34.5%)group.Otherwise, the SwissAgency forTherapeutic Products recognized the link between denosumab discontinuation and increased risk of multiple VFs in December 2016 (http://www.swissmedic.ch/index.html?lang5en.). We agree that it is urgent to be able to better identify patients at risk for VFs after denosumab discontinuation. The biopsy of transiliac bone can help us to understand the mechanisms, but it is not easy topropose it in clinical routine.