Use of trabecular bone score for risk stratification of patients with monoclonal gammopathy of undetermined significance

Trabecular Bone Score as a Complementary Tool for the Assessment of Bone Mineral Density in Patients with Asymptomatic Monoclonal Gammopathies

Background/Objectives: Monoclonal gammopathies, such as Monoclonal Gammopathy of Undetermined Significance (MGUS) and Smoldering Multiple Myeloma (SMM), are conditions marked by the overproduction of specific monoclonal proteins. Patients with these conditions are known to have a higher risk of fractures compared to the general population, yet there are no established guidelines for assessing or managing their skeletal health. The Trabecular Bone Score (TBS), which can be calculated from DXA images of the lumbar spine, provides additional insights into bone microarchitecture. Methods: This study aimed to determine whether TBS can serve as a supplementary tool in assessing bone loss in MGUS and SMM patients. Conducted from 2020 to 2023, the study involved 148 participants-74 diagnosed with a myeloma precursor state and 74 healthy controls-who underwent simultaneous DXA and TBS measurements. Results: The results indicated a weak positive correlation (R = 0.405) between DXA and TBS T-scores, suggesting that other factors may influence the measurements. When analyzed separately, the correlations remained weak for both MGUS (R = 0.250) and SMM (R = 0.485). Interestingly, discrepancies were noted in T-score classifications; for instance, a patient classified as normal via DXA could be deemed osteopenic or osteoporotic with TBS. Conclusions: Overall, the findings suggest that incorporating TBS alongside DXA can enhance the accuracy of bone density assessments, facilitating earlier diagnosis and treatment initiation for osteoporosis in asymptomatic patients with monoclonal gammopathies.

High rate of progression to symptomatic multiple myeloma in patients with smoldering myeloma and isolated osteoporotic vertebral fracture

Multiple myeloma (MM) frequently causes vertebral fractures (VF). Some are lytic lesions and others have the aspect of benign osteoporotic fractures not requiring anti-myeloma treatment. We explored outcome of these patients with smoldering myeloma (SM) and osteoporotic VF. In this retrospective bi-centric study, patients were identified using a systematic keyword search on electronic medical records. Patients with SM and isolated VF of osteoporotic aspect without indications for myeloma-specific therapy were included. Overall, 13 (7 %) of the 184 identified patients had SM and VF confirmed to be osteoporotic (median number of VF was 3). During follow-up, 12 (92 %) patients evolved to symptomatic MM, 7 (54 %) of them within 18 months (early progressors). Myeloma defining events were new lytic bone lesions in 7 patients (53.8 %). The serum calcium level was significantly higher in the early progressor group (median 2.35 IQR [2.31-2.38] and 2.28 IQR [2.21-2.29] respectively, p = 0.003). Early progressors had a higher number of VF at diagnosis (3.0 [2.0-5.5] vs 1.0 [1.0-2.5], p = 0.18) and more frequently evolved to symptomatic MM because of lytic bone lesions (5 [71 %] vs 2 [33 %], p = 0.13) compared to late progressors. VF of osteoporotic appearance in the context of SM is a rare situation but at high risk of rapid progression to symptomatic MM, suggesting that they may represent bone fragility linked to MM infiltration rather than solely osteoporotic fractures. Further studies are needed to assess if earlier treatment might be beneficial in this population.

Risk Factors for Fragility Fractures in Chronic Lymphocytic Leukemia

Abnormal bone health and fragility fractures (FF) are more common in patients with chronic lymphocytic leukemia (CLL). We hypothesize that there may be risk factors in CLL patients with osteoporosis that increase the risk of FFs. We conducted a cohort study encompassing all patients diagnosed with CLL from January 1, 2000, to July 31, 2020, utilizing International Classification of Diseases (ICD) codes related to abnormal bone health (osteopenia, osteoporosis, and/or presence of FF) within a single tertiary care institution. Of the 89 patients included, 55 (62%) were female with a mean age of 68 ± 11 years at cohort entry. Fifty-nine (66%) had at least one FF present (pFF) and 30 (34%) did not have an FF (nFF). There were no differences in IGHV (Immunoglobulin heavy chain variable region gene) mutation status, chromosomal abnormalities, or the presence of a complex karyotype. The spine accounted for 81% of identified FF. T-score <-2.5 was more common in those without FF (pFF 38% vs. nFF 71%, P = 0.02). DXA evaluation was not conducted for 36 (40%) individuals within the cohort. Risk factors for fragility fractures included male sex (relative risk [RR] 8.1, 95% confidence interval [CI] 2.1-31.7), diabetes mellitus (RR 1.4, 95% CI 1.04-1.8), smoking (RR 1.3, 95% CI 1.02-1.8), Rai stage >0 (RR 1.4, 95% CI 1.04-1.9), and T-score >-2.5 (RR 1.8, 95% CI 1.1-3.1). There is a high frequency of vertebral FFs in people with CLL despite T-scores not being in the osteoporotic range. Increased awareness to screen and treat vertebral FFs in people with CLL is needed.

Secondary Osteoporosis

Osteoporosis is a global public health problem, with fractures contributing to significant morbidity and mortality. Although postmenopausal osteoporosis is most common, up to 30% of postmenopausal women, > 50% of premenopausal women, and between 50% and 80% of men have secondary osteoporosis. Exclusion of secondary causes is important, as treatment of such patients often commences by treating the underlying condition. These are varied but often neglected, ranging from endocrine to chronic inflammatory and genetic conditions. General screening is recommended for all patients with osteoporosis, with advanced investigations reserved for premenopausal women and men aged < 50 years, for older patients in whom classical risk factors for osteoporosis are absent, and for all patients with the lowest bone mass (Z-score ≤ -2). The response of secondary osteoporosis to conventional anti-osteoporosis therapy may be inadequate if the underlying condition is unrecognized and untreated. Bone densitometry, using dual-energy x-ray absorptiometry, may underestimate fracture risk in some chronic diseases, including glucocorticoid-induced osteoporosis, type 2 diabetes, and obesity, and may overestimate fracture risk in others (eg, Turner syndrome). FRAX and trabecular bone score may provide additional information regarding fracture risk in secondary osteoporosis, but their use is limited to adults aged ≥ 40 years and ≥ 50 years, respectively. In addition, FRAX requires adjustment in some chronic conditions, such as glucocorticoid use, type 2 diabetes, and HIV. In most conditions, evidence for antiresorptive or anabolic therapy is limited to increases in bone mass. Current osteoporosis management guidelines also neglect secondary osteoporosis and these existing evidence gaps are discussed.

Bone quality assessed by trabecular bone score in severe anorexia nervosa: A brief report

OBJECTIVE

Low bone mineral density (BMD) in anorexia nervosa (AN) leads to increased risk of fractures. Debate exists whether to medicinally treat young patients with AN based on abnormal dual-energy x-ray absorptiometry (DXA) scores or to weight restore and reassess when older. Trabecular bone score (TBS), a technology measuring bone quality, is used in conjunction with DXA. This report explores the potential additional value of TBS, in adults with severe AN, to augment the DXA diagnostic information.

METHOD

Seventy-one DXA scans were reanalyzed to obtain TBS results from patients (mean age: 36.3 years). Differences in laboratory, anthropometric values and concomitant DXA measurements in relation to TBS results are reported.

RESULTS

For the cohort, mean body mass index (BMI) was 13.6 kg/m² (SD: 2.1). The vast majority of patients had normal TBS with a mean of 1.395 (SD: 0.08) but, most patients (69%) had abnormal average DXA BMD Z-scores of -2.2 (SD: 1.2). The patients who also demonstrated degraded bone quality on TBS had significantly lower percent ideal body weight and elevated alkaline phosphatase compared to patients with normal TBS (p's < .05).

DISCUSSION

Low BMD treatment decisions in AN may be optimized by considering both DXA and TBS results.

Targeting anti-cancer agents to bone using bisphosphonates

The skeleton is affected by numerous primary and metastatic solid and hematopoietic malignant tumors, which can cause localized sites of osteolysis or osteosclerosis that can weaken bones and increase the risk of fractures in affected patients. Chemotherapeutic drugs can eliminate some tumors in bones or reduce their volume and skeletal-related events, but adverse effects on non-target organs can significantly limit the amount of drug that can be administered to patients. In these circumstances, it may be impossible to deliver therapeutic drug concentrations to tumor sites in bones. One attractive mechanism to approach this challenge is to conjugate drugs to bisphosphonates, which can target them to bone where they can be released at diseased sites. Multiple attempts have been made to do this since the 1990s with limited degrees of success. Here, we review the results of pre-clinical and clinical studies made to target FDA-approved drugs and other antineoplastic small molecules to bone to treat diseases affecting the skeleton, including osteoporosis, metastatic bone disease, multiple myeloma and osteosarcoma. Results to date are encouraging and indicate that drug efficacy can be increased and side effects reduced using these approaches. Despite these successes, challenges remain: no drugs have gone beyond small phase 2 clinical trials, and major pharmaceutical companies have shown little interest in the approach to repurpose any of their drugs or to embrace the technology. Nevertheless, interest shown by smaller biotechnology companies in the technology suggests that bone-targeting of drugs with bisphosphonates has a viable future.