Journal of Bone and Mineral Research最新文献

Bone mineral density (BMD) is only one of several bone strength determinants affected by osteoporosis therapies. Trabecular Bone Score (TBS), a gray-level texture index determined from lumbar spine (LS) dual-X-ray absorptiometry scans, is an indirect measure of bone microarchitecture independent of and complementary to BMD and clinical risk factors. In the Active-Controlled Fracture Study in Postmenopausal Women with Osteoporosis at High Risk (ARCH), monthly subcutaneous romosozumab 210 mg for 12 mo followed by 24-mo open-label weekly oral alendronate 70 mg (romosozumab-to-alendronate) significantly reduced fracture risk compared to 36-mo alendronate alone in postmenopausal women with osteoporosis and prior fracture. This analysis evaluated tissue thickness-adjusted TBS (TBSTT) in a subgroup of patients from ARCH who had post-hoc TBS measurements at baseline and at least one post-baseline visit at months 12, 24, and 36. Baseline characteristics were similar between romosozumab-to-alendronate (n = 190) and alendronate alone (n = 188). Romosozumab led to significantly greater gains in TBSTT vs alendronate at month 12 (least squares mean difference, 3.6%), with greater gains maintained after transition to alendronate and persisting at months 24 (2.9%) and 36 (2.3%; all p<.001). Romosozumab-to-alendronate increased the percentage of individual patients with "normal" TBSTT from 28.9% at baseline to 48.1%, 43.9%, and 45.4% at months 12, 24, and 36, respectively, and decreased the percentage of individual patients with degraded TBSTT from 52.6% to 33.3%, 36.0%, and 33.5%, respectively (all p<.001). A similar but smaller trend was observed with alendronate alone from baseline through month 36 (p ≤.012). Changes in TBSTT and LS BMD were largely unrelated from baseline to month 12 (romosozumab-to-alendronate, r2 = 0.065; alendronate alone, r2 = 0.021) and month 36 (r2 = 0.058; r2 = 0.057, respectively). In postmenopausal women with osteoporosis and prior fracture, 12-mo romosozumab followed by 24-mo alendronate significantly improved bone microarchitecture estimated by TBSTT more than 36-mo alendronate alone.

Epidural steroid injections (ESIs) are a common and often effective treatment for radicular back pain. While oral glucocorticoids increase fracture incidence, little is known regarding fracture risk after ESI. This study investigated the incidence of fractures among individuals who received ESI and those who did not. We hypothesized that ESI exposure would be associated with an increased incidence of osteoporotic fractures and specifically vertebral fractures. Using 2005-2018 5% Medicare data, individuals with radicular pain who had ≥1 ESI and those who did not (non-ESI) were matched 1:10 by age, sex, and month of radicular pain diagnosis using exposure density sampling (EDS). Using a high-dimensional propensity score (HDPS) calculated based on the top 500 covariates across multiple data dimensions, ESI and non-ESI individuals were matched 1:1. Fractures were identified using validated ICD-9/10 diagnosis codes. Fracture incidence rate (IR) was calculated by group, and hazard ratios (HR) compared using Cox regression. 25 062 ESI patients and 221 735 non-ESI patients who met eligibility criteria were identified using EDS. Mean age was 76 yr (74% female). Among ESI-treated individuals, there were 2296 fractures, IR 49.1 (95% CI: 47.2-51.2) per 1000 person yr. For non-ESI individuals, there were 11 917 fractures, IR 35.2 (95% CI: 34.5-35.8). Individuals who received ESI had a greater hazard of fracture at typical osteoporotic sites, HR 1.39 (95% CI 1.33-1.46) by EDS and 1.32 (1.12-1.54) by HDPS, and a greater hazard of vertebral fracture, 1.54 (1.45-1.64) by EDS and 1.69 (1.38-2.07) by HDPS. Patients who received greater cumulative ESI doses (≥3 in 1 yr) had a higher risk of fractures within the first 6 mo of follow-up. ESI exposure in older individuals is associated with an increased risk of fracture, suggesting there may be lasting detrimental skeletal effects of ESI. Further research into strategies to reduce fracture risk in this population is warranted.

Growth-plate (GP) injures in limbs and other sites can impair GP function and cause deceleration of bone growth, leading to progressive bone lengthening imbalance, deformities and/or physical discomfort, decreased motion and pain. At present, surgical interventions are the only means available to correct these conditions by suppressing the GP activity in the unaffected limb and/or other bones in the ipsilateral region. Here, we aimed to develop a pharmacologic treatment of GP growth imbalance that involves local application of nanoparticles-based controlled release of a selective retinoic acid nuclear receptor gamma (RARγ) agonist drug. When RARγ agonist-loaded nanoparticles were implanted near the medial and lateral sides of proximal tibial growth plate in juvenile C57BL/6j mice, the GP underwent involution and closure. Overall tibia length was shortened compared to the contralateral element implanted with drug-free control nanoparticles. Importantly, when the RARγ agonist nanoparticles were implanted on the lateral side only, the adjacent epiphysis tilted toward the lateral site, leading to apical angulation of the tibia. In contrast to the local selectivity of these responses, systemic administration of RARγ agonists led to GP closure at many sites, inhibiting skeletal growth over time. Agonists for RARα and RARβ elicited no obvious responses over parallel regimens. Our findings provide novel evidence that RARγ agonist-loaded nanoparticles can control activity, function and directionality of a targeted GP, offering a potential and clinically-relevant alternative or supplementation to surgical correction of limb length discrepancy and angular deformities.

Fracture risk calculators, such as the Fracture Risk Assessment Tool (FRAX), calculate the risk of major osteoporotic (MOF) and hip fracture, but do not account for the excess risk of fracture in people with diabetes. We examined the predictive performance of FRAX without BMD in ethnically diverse, older patients with diabetes. Patients included were between ages 65-89 from the Kaiser Permanente Northern California Diabetes Registry and not already taking osteoporosis medications. Race and ethnicity were self-identified. We calculated FRAX without BMD based on baseline characteristics and assessed how well FRAX predicted MOF and hip fracture over follow-up. Predictive performance was based on measures of discrimination (area under the receiver operator curve, AUC) and calibration (observed-to-predicted ratio, O/P). We identified 96 914 patients (47.0% female), of whom 5383 (5.6%) and 1767 (1.8%) had MOF and hip fracture, respectively, over a mean follow-up of 4.3 years. The AUC for MOF and hip fracture were 0.72 and 0.77, respectively. FRAX mildly underestimated MOF and hip fracture rates (O/P 1.2 for both) overall. Discrimination was similar by race and ethnicity and diabetes duration but was worse in those over age 75 (AUC < 0.7). In some groups, there were substantial calibration errors, such as Hispanic women (O/P: 1.8 and 1.5), Black men (O/P: 1.5 and 1.8), those with duration of diabetes ≥20 years (O/P: 1.6 and 1.5), and those over the age of 80 (O/P: 1.4 and 1.2) for MOF and hip fracture, respectively. While the discriminatory performance of FRAX without BMD was good overall in patients with diabetes, it underestimated risk in Hispanic women, Black men, those with long duration of diabetes, and in the oldest patients with diabetes. These algorithmic biases suggest that diabetes-specific tools may be needed to stratify fracture risk in patients with diabetes.

The socioeconomic burden of hip fractures, the most severe osteoporotic fracture outcome, is increasing and the current clinical risk assessment lacks sensitivity. This study aimed to develop a method for improved prediction of hip fracture by incorporating measurements of bone microstructure and composition derived from high-resolution peripheral quantitative computed tomography (HR-pQCT). In a prospective cohort study of 3028 community-dwelling women aged 75 to 80, all participants answered questionnaires and underwent baseline examinations of anthropometrics and bone by dual x-ray absorptiometry (DXA) and HR-pQCT. Medical records, a regional x-ray archive, and registers were used to identify incident fractures and death. Prediction models for hip, major osteoporotic fracture (MOF), and any fracture were developed using Cox proportional hazards regression and machine learning algorithms (neural network, random forest, ensemble, and XGBoost). In the 2856 (94.3%) women with complete HR-pQCT data at 2 tibia sites (distal and ultra-distal), the median follow-up period was 8.0 years, and 217 hip, 746 MOF, and 1008 any type of incident fracture occurred. In Cox regression models adjusted for age, BMI, clinical risk factors (CRF), and femoral neck bone mineral density (FN BMD) the strongest predictors of hip fracture were tibia total volumetric BMD and cortical thickness. The performance of the Cox regression-based prediction models for hip fracture was significantly improved by HR-pQCT (time-dependent AUC; area under receiver operating characteristic curve at 5 years of follow-up 0.75 [0.64-0.85]), compared to a reference model including CRFs and FN BMD (AUC = 0.71 [0.58-0.81], p<.001) and a FRAX risk score model (AUC = 0.70 [0.60-0.80], p<.001). The Cox regression model for hip fracture had a significantly higher accuracy than the neural network-based model, the best-performing machine learning algorithm, at clinically relevant sensitivity levels. We conclude that the addition of HR-pQCT parameters improves the prediction of hip fractures in a cohort of older Swedish women.

Bone mineral density (BMD) levels achieved on osteoporosis treatment are predictive of subsequent fracture risk, and T-score > -2.5 has been proposed as a minimum treatment target for women with osteoporosis. Knowing the likelihood of attaining target T-scores with different medications for different baseline BMD levels can help determine appropriate initial treatment for individual patients. In this post hoc analysis, we estimated the probability of achieving a non-osteoporotic T-score (> -2.5 or ≥ -2.0) at the total hip (TH) or lumbar spine (LS) in postmenopausal women >60 years old treated with denosumab for either 3 or 10 years in the FREEDOM trial and its long-term extension. In women with baseline TH T-scores of -2.7, -3.0, and -3.5, the probabilities of achieving target T-scores > -2.5 with 3 years of denosumab were 71%, 12%, and 0.1%, respectively. At LS, for baseline T-scores of -2.7, -3.0, and -3.5, the probabilities were 86%, 59%, and 11%, respectively. Longer treatment duration of up to 10 years increased the probability of achieving target T-scores. The baseline T-scores that permitted at least 50% of women to achieve a target T-score > -2.5 was -2.8 at TH and -3.1 at LS after 3 years and -3.0 at TH and -3.7 at LS after 10 years of treatment. To achieve higher treatment targets (T-scores ≥ -2.0), overall probabilities were lower at both skeletal sites, particularly for TH, even with longer treatment duration. Our results demonstrate that the probability of achieving T-score targets with denosumab is dependent on baseline BMD, skeletal site, and treatment duration. Knowing the probability of achieving treatment targets for different baseline TH and LS T-scores can help determine whether denosumab is an appropriate first choice of treatment in individual patients.

HIV-related mortality has fallen due to scale-up of antiretroviral therapy (ART), so more women living with HIV (WLH) now live to reach menopause. Menopausal estrogen loss causes bone loss, as do HIV and certain ART regimens. However, quantitative bone data from WLH are few in Africa. A cross-sectional study of women aged 40-60 years (49% WLH) was conducted in Harare, Zimbabwe. Menopause status, fracture history, HIV status and treatment, and anthropometry were collected, and radial/tibial peripheral Quantitative Computed Tomography (pQCT) scans performed. pQCT outcomes were: distal radius and tibia trabecular volumetric bone mineral density (vBMD), total area, and compressive bone strength (BSIc); proximal radius and tibia cortical vBMD, bone mineral content (BMC), cortical thickness, bone area, and stress-strain index (SSI). Linear regression determined differences by HIV status, minimally adjusted for age and menopause status, and further adjusted for height and fat mass. Relationships between pQCT parameters and major osteoporotic fracture history were explored using univariate logistic regression. In WLH, linear regression assessed associations between HIV and ART durations on pQCT measures. 384 women mean(SD) age 49.7(5.8) years had pQCT data. WLH had lower absolute pQCT measures at all sites. Overall, HIV-related deficits were robust to adjustment for age, menopause status, height, and fat mass: WLH had lower trabecular vBMD (radius -7.3 [-12.5; -2.0]%, tibia -5.4 [-9.1; -1.7]%), and cortical vBMD (radius -3.5 [-5.9; -1.1]%, tibia -1.1[-1.6; -0.5]%). Strength estimates were lower in WLH and of similar magnitude at the radius and tibia. Longer HIV duration was associated with lower radius bone area, BMC, estimates of bone strength, independent of ART duration. Trabecular deficits predominate in WLH, though with age cortical compartment bone loss may increase in importance. This is particularly concerning as these differences were observed at the radius, a common site of postmenopausal osteoporotic fracture.

This study analyzed the association of romosozumab, a human monoclonal antibody with bone-forming and bone resorption-inhibiting effects, and bisphosphonates with the development of cardiovascular disease among patients with osteoporosis. A new-user design was employed to address selection bias, and instrumental variable analysis was used to address confounding by indication. Japanese patients aged ≥40 years, diagnosed with osteoporosis or experienced a fragility fracture, were admitted to medical facilities covered by a commercial administrative claims database, and newly prescribed romosozumab or bisphosphonates after the commercialization of romosozumab in Japan (March 4, 2019) were included based on verification of a 180-day washout period. Cardiovascular disease (myocardial infarction or stroke) was identified based on information regarding diagnosis, medical procedures, and drug codes. Facility-level prescription preference for romosozumab was used as an instrumental variable, defined as the proportion of romosozumab prescribed at the patient's facility within 90 days prior to the index date. Of the 59 694 included prescriptions, 8808 were for romosozumab and 50 886 were for bisphosphonates. The mean age in the romosozumab group was higher than that in the bisphosphonates group (80.5 vs. 78.2 years, respectively), and most patients were females (85.3 vs. 80.2%, respectively). The incidence of cardiovascular disease within 1 year of prescription was 12.3 per 100 person-years for romosozumab versus 11.4 for bisphosphonates (unadjusted incidence rate ratio: 1.08, 95% confidence interval: 1.00-1.18). An instrumental variable analysis using the two-stage residual inclusion method yielded a hazard ratio of 1.30 (95% confidence interval: 0.88-1.90) for romosozumab compared with bisphosphonates over 1 year. Although possibly underpowered, this study showed that no definitive evidence of increased cardiovascular risk associated with romosozumab use compared with bisphosphonates was observed in patients with osteoporosis. These findings should be further validated by larger pharmacoepidemiological studies to alleviate clinicians' concerns about romosozumab's safety.

Bone turnover assessment and monitoring are essential for chronic kidney disease (CKD)-associated bone care. Patients with CKD suffer from significantly elevated fracture risk due to abnormally high or low bone turnover, which requires diametrically opposite treatments informed by patient-specific bone turnover data. However, a reliable, accessible, non-invasive bone turnover assessment and monitoring tool remains an unmet clinical need. Combining time-lapse (TL) analysis with high-resolution peripheral quantitative computed tomography (HR-pQCT) scans obtained over time allows for in vivo temporospatial bone remodeling assessment. This study aimed to evaluate the feasibility of applying TL HR-pQCT to assess and monitor local bone formation and resorption in patients with CKD. A customized TL HR-pQCT pipeline was developed on a second-generation HR-pQCT platform and optimized using ex vivo cadaveric phantom and in vivo scan-rescan HR-pQCT images. The annualized least significant change in bone formation and resorption were evaluated using in vivo longitudinal reproducibility images. Finally, the feasibility of the TL HR-pQCT pipeline in assessing and monitoring bone turnover was evaluated in patients with end stage kidney disease (ESKD; n = 9). We found that a 2-month time-lapse period was sufficient for the TL HR-pQCT pipeline to reliably assess and monitor local bone turnover in a cohort of patients with ESKD. We also demonstrated the importance of characterizing TL HR-pQCT precision metrics using longitudinal baseline/follow-up rather than short-term scan-rescan datasets. The TL HR-pQCT pipeline assessed a range of bone formation metrics consistent with the gold standard histomorphometric bone formation reported in the literature for patients with CKD and ESKD. Our findings highlight that TL HR-pQCT holds promise as a "virtual bone biopsy" that reliably assesses and monitors local bone turnover for CKD bone care. Subsequent work will focus on validating this TL HR-pQCT pipeline against the gold standard bone biopsy with quantitative histomorphometry.