Denosumab improves bone mineral density and microarchitecture in rheumatoid arthritis: randomized controlled trial by HR-pQCT

[Systemic versus local demineralization in rheumatoid arthritis : Insights into the bone]

Inflammatory rheumatic diseases, such as rheumatoid arthritis (RA), are characterized by local and systemic bone demineralization. Local demineralization is manifested in the periarticular region of the inflamed joints, particularly at the metacarpophalangeal and metatarsophalangeal joints. Local demineralization shows a significant correlation with inflammatory activity, whereas systemic osteoporosis, predominantly affecting the spine and hip, is typically associated with a prolonged disease duration, glucocorticoid treatment and immobilization. The receptor activator of the nuclear factor-kB ligand (RANKL)/osteoprotegerin (OPG) system and the Wnt signaling pathway play a pivotal role in regulating bone metabolism and are themselves negatively influenced by inflammatory cytokines such as tumor necrosis factor alpha (TNF-alpha) and interleukin (IL)-6. The diagnostics include both imaging procedures and procedures for bone mineral density measurement, employing techniques such as high-resolution peripheral quantitative computed tomography (HR-pQCT) and dual energy X‑ray absorptiometry (DXA). These are used for quantification of the bone mineral density. The objective of therapeutic approaches is to reduce disease activity and modulate signaling pathways in order to slow down demineralization and reduce the risk of fractures.

Denosumab in the Management of Glucocorticoid-Induced Osteoporosis: Long-Term Efficacy and Secondary Fracture Outcomes

Objectives: Osteoporosis is a common complication in patients undergoing long-term corticosteroid therapy, particularly those with rheumatological and immunological conditions. Denosumab has shown potential in enhancing bone density and reducing fracture risk in such patients. This study evaluates the effectiveness of denosumab in osteoporosis management among corticosteroid-treated individuals. Methods: Between 2013 and 2022, 390 osteoporosis patients who received denosumab (60 mg subcutaneously every 6 months) for ≤18 months were enrolled. Patients were categorized based on corticosteroid use, and age-matching was applied to ensure comparability. Bone mineral density (BMD) and trabecular bone score (TBS) at the lumbar spine and femoral neck were assessed, and secondary fractures during the follow-up period were recorded. Results: Over the 18-month follow-up, both groups showed improvements in lumbar spine T-scores. The corticosteroid group increased from -2.1 ± 1.2 to -2.0 ± 1.3 (p < 0.001), while the non-corticosteroid group improved from -2.6 ± 1.2 to -2.4 ± 1.2 (p = 0.003). However, logistic regression analysis revealed that corticosteroid use remained a significant risk factor for secondary fractures (odds ratio: 1.69; 95% confidence interval: 1.11-2.56, p = 0.014), despite denosumab treatment. Conclusions: This retrospective study observed stabilization and a modest increase in BMD and TBS among corticosteroid users. Although differences in secondary fractures persisted between groups, denosumab shows potential for managing corticosteroid-induced osteoporosis. The study's focus on Taiwanese patients limits its generalizability, and future research should include diverse populations to enhance applicability.

Individual trabecula segmentation validation in first- and second-generation high-resolution peripheral computed tomography compared to micro-computed tomography in the distal radius and tibia

High-resolution peripheral quantitative computed tomography (HR-pQCT) has been used for in vivo 3D visualization of trabecular microstructure. Second-generation HR-pQCT (HR-pQCT II) has been shown to have good agreement with first generation HR-pQCT (HR-pQCT I). Advanced Individual Trabecula Segmentation (ITS) decomposes the trabecula network into individual plates and rods. ITS based on HR-pQCT I showed a strong correlation to ITS based on micro-computed tomography (μCT) and identified trabecular changes in metabolic bone diseases. ITS based on HR-pQCT II has new potential because of the enhanced resolution but has yet to be validated. The objective of this study was to assess the agreement between ITS based on HR-pQCT I, HR-pQCT II, and μCT to assess the capability of ITS on HR-pQCT images as a tool for studying bone structure. Freshly frozen tibia and radius bones were scanned in the distal region using HR-pQCT I at 82 μm, HR-pQCT II at 60.7 μm, and μCT at 37 μm. Images were registered, binarized, and ITS analysis was performed. Bone volume fraction (pBV/TV, rBV/TV), number density (pTb.N, rTb.N), thickness (pTb.Th, rTb.Th), and plate-to-rod (PR) ratio (pBV/rBV) of trabecular plates and rods were obtained. Paired Student's t-tests with post hoc Bonferroni analysis were used to examine the differences. Linear regression was used to determine the correlation coefficient. The HR-pQCT I parameters were different from the μCT measurements. The HR-pQCT II parameters were different from the μCT measurements except for rTb.N, and the HR-pQCT I parameters were different from the HR-pQCT II measurements except for pTb.Th. The strong correlation between HR-pQCT II and μCT microstructural analysis (R2 = 0.55-0.94) suggests that HR-pQCT II can be used to assess changes in plate and rod microstructure and that values from HR-pQCT I can be corrected.