High prevalence of spine–femur bone mineral density discordance and comparison of vertebral fracture risk assessment using femoral neck and lumbar spine bone density in Korean patients

Artificial Intelligence-enabled Chest X-ray Classifies Osteoporosis and Identifies Mortality Risk

A deep learning model was developed to identify osteoporosis from chest X-ray (CXR) features with high accuracy in internal and external validation. It has significant prognostic implications, identifying individuals at higher risk of all-cause mortality. This Artificial Intelligence (AI)-enabled CXR strategy may function as an early detection screening tool for osteoporosis. The aim of this study was to develop a deep learning model (DLM) to identify osteoporosis via CXR features and investigate the performance and clinical implications. This study collected 48,353 CXRs with the corresponding T score according to Dual energy X-ray Absorptiometry (DXA) from the academic medical center. Among these, 35,633 CXRs were used to identify CXR- Osteoporosis (CXR-OP). Another 12,720 CXRs were used to validate the performance, which was evaluated by the area under the receiver operating characteristic curve (AUC). Furthermore, CXR-OP was tested to assess the long-term risks of mortality, which were evaluated by Kaplan‒Meier survival analysis and the Cox proportional hazards model. The DLM utilizing CXR achieved AUCs of 0.930 and 0.892 during internal and external validation, respectively. The group that underwent DXA with CXR-OP had a higher risk of all-cause mortality (hazard ratio [HR] 2.59, 95% CI: 1.83-3.67), and those classified as CXR-OP in the group without DXA also had higher all-cause mortality (HR: 1.67, 95% CI: 1.61-1.72) in the internal validation set. The external validation set produced similar results. Our DLM uses CXRs for early detection of osteoporosis, aiding physicians to identify those at risk. It has significant prognostic implications, improving life quality and reducing mortality. AI-enabled CXR strategy may serve as a screening tool.

The association of lipid metabolism with bone metabolism and the role of human traits: a Mendelian randomization study

Background

The impact of lipid metabolism on bone metabolism remains controversial, and the extent to which human traits mediate the effects of lipid metabolism on bone metabolism remains unclear.

Objective

This study utilized mendelian randomization to investigate the effects of blood lipids on bone mineral density (BMD) at various skeletal sites and examined the mediating role of human traits in this process.

Methods

We leveraged genetic data from large-scale genome-wide association studies on blood lipids (n=1,320,016), forearm bone mineral density (FA-BMD) (n=10,805), lumbar spine bone mineral density (LS-BMD) (n=44,731), and femoral neck bone mineral density (FN-BMD) (n=49,988) to infer causal relationships between lipid and bone metabolism. The coefficient product method was employed to calculate the indirect effects of human traits and the proportion of mediating effects.

Results

The results showed that a 1 standard deviation(SD) increase in HDL-C, LDL-C and TC was associated with a decrease in LS-BMD of 0.039 g/cm2, 0.045 g/cm2 and 0.054 g/cm2, respectively. The proportion of mediating effects of systolic blood pressure (SBP) on HDL-C to LS-BMD was 3.17%, but suppression effects occurred in the causal relationship of LDL-C and TC to LS-BMD. Additionally, the proportion of mediating effects of hand grip strength (HGS) on the TC to LS-BMD pathway were 6.90% and 4.60% for the left and right hands, respectively.

Conclusion

In conclusion, a negative causal relationship was established between lipid metabolism and bone metabolism. Our results indicated that SBP and HGS served as mediators for the effects of lipid metabolism on bone metabolism.

Clinical Significance of Discordance between Hip and Spine Bone Mineral Density in Korean Elderly Patients with Hip Fractures

The clinical significance of BMD discordance has not yet been elucidated. The objective of this study was to evaluate the clinical significance of BMD discordance between the hip and spine for hip fractures. The BMD was measured and related factors were investigated in 109 elderly patients hospitalized for a hip fracture (fracture group) and 109 patients hospitalized without a hip fracture (non-fracture group). BMD discordance of the hip and spine was classified as minor discordance (normal and osteopenia, and osteopenia and osteoporosis) and major discordance (normal and osteoporosis). The risk of hip fracture was calculated according to the type of discordance: no discordance, low hip, and lower spine. There was no significant difference between the general characteristics of the fracture group and the non-fracture group. The rate of BMD discordance and low hip discordance were significantly higher in the fracture group (53.2%, 43.1%) than in the non-fracture group (28.4%, 19.3%). The odds ratio of hip fracture was 2.86 times higher in patients with BMD discordance than in those without discordance and 3.42 times higher in the patients with low hip discordance than in those without no hip discordance. The presence of discordance, particularly when there is low hip discordance, might be related to the hip fractures.

Effect of Growth Hormone and Estrogen Replacement Therapy on Bone Mineral Density in Women with Turner Syndrome: A Meta-Analysis and Systematic Review

Osteoporosis is a serious implication of Turner syndrome (TS). Common methods for the treatment of TS are growth hormone (GHT) and estrogen replacement therapy (ERT). We examined the relationship between the treatment of TS and bone mineral density (BMD) of the lumbar spine. The purpose of our study was to show the currency of BMD states among patients with TS for treatment with GHT and ERT. We searched databases for studies published from inception to April 2023. The articles were related to TS, osteoporosis, ERT, GHT, BMD and treatment patients with TS. We applied the selection criteria: lumbar spine values at L1-L4; dual-energy X-ray absorptiometry (DXA); treatment which was applied: one group of articles: ERT and two group of articles: GHT; results performed as means ± SD. In total, 79 articles were analyzed, of which 20 studies were included and 5 were considered for meta-analysis. The total number of women in the articles selected was 71. Based on the results of the meta-analysis, the effect of ERT on BMD demonstrated a significant increase in BMD (the standardized mean difference in the random model was 0.593 g/cm2, 95% CI: 0.0705 to 1.116; p = 0.026), which showed that treatment with estrogen particularly increases bone mass during treatment, which contributes to reducing the risk of fractures. The effect of GHT on BMD demonstrated a non-significant decrease in BMD in patients with TS. The results for growth hormone show that this therapy does not improve bone density. However, our review emphasizes the beneficial effect of supplementing growth hormone (GH) on the clinical presentation of TS.

Prevalence and Risk Factors of T-Score Spine-Hip Discordance in Patients with Osteoporotic Vertebral Compression Fracture

Background: T-score discordance between the spine and hip is commonly observed when dual energy X-ray absorptiometry (DXA) is used to diagnose osteoporosis. However, information is scarce regarding the prevalence and risk factors for this problem in Korea. This study evaluated the prevalence of major/minor discordance and associated risk factors in elderly Korean patients with osteoporotic vertebral compression fractures (OVCFs).Methods: This study included 200 patients (37 men, 163 women) treated for thoracic or lumbar compression fractures between January 2015 and August 2021. DXA was performed to examine T‐scores and determine the prevalence of discordance, defined as a difference between the T-score categories of the femur and spine in the same individual. The t-tests, χ2 tests, and regression analyses were used to assess the associated risk factors of T-score discordance among the subjects.Results: T-score concordance, minor discordance, and major discordance were observed in 137 (68.5%), 59 (29.5%), and 4 (2%) patients with OVCFs, respectively. The spinal T-score was lower than the femoral T-score in all major discordance and 81.3% (48/59) of minor discordant cases. Overall, the only factor related to T-score discordance was the age at fracture (odds ratio, -0.01; P=0.014).Conclusions: The results of this study showed that a significant number of subjects (31.5%) showed spine-hip discordance, even with a mean age in their 80s. More attention should be paid to the appropriate evaluation and management of elderly patients with OVCFs. Moreover, a longitudinal study is necessary to verify the clinical importance of T-score discordance in this population.

Prevalence, Clinical Implication, and Cause of Spine Hip Discordance in Elderly Patients with Fragility Hip Fracture

BACKGROUND

Spine-hip discordance (SHD) increases fracture risk. However, its prevalence and clinical implications have not been investigated in patients with hip fractures. This study determined the prevalence and association of SHD with mortality and investigated the cause of SHD in patients with hip fractures.

METHODS

This study included patients admitted for fragility hip fractures between 2011 and 2020. All patients underwent dual energy X-ray absorptiometry and anteroposterior and lateral views of the lumbosacral spine during admission. Data on demographics, diagnosis, American Society of Anesthesiologists score, and mortality were collected. A T-score difference of more than 1.5 between L1-4 and the femur neck was considered discordant, and 3 groups (lumbar low [LL] discordance, no discordance [ND], and femur neck low [FL] discordance) were compared. In the discordance group, lumbar radiographs were reviewed to determine the cause of discordance.

RESULTS

Among 1,220 eligible patients, 130 were excluded due to patient refusal or bilateral hip implantation; therefore, this study included 1,090 patients (271 male and 819 female). The prevalence of LL, ND, and FL was 4.4%, 66.4% and 29.2% in men and 3.9%, 76.1%, and 20.0% women. Mortality was not associated with discordance. The most common causes of discordance were physiological in the LL group and pathological in the FL group for both sexes.

CONCLUSIONS

Patients with hip fractures showed lower rates of ND and higher rates of FL compared to the general population. True discordance should be carefully judged for pathological and artifact reasons. The clinical implications of SHD require further investigation.

Comparative Analysis of T-score Discordance between a Registry-Based Korean Population and Atypical Femoral Fracture Patients of a Single Institution

Background

The purpose of this study was to analyze the epidemiology of T-score discordance between the spine and femur in the South Korean population and compare the prevalence of T-score discordance between the Korean osteoporosis population and atypical femoral fracture (AFF) patients.

Methods

A total of 12,422 subjects from the Korea National Health and Nutrition Examination Survey were reviewed retrospectively. T-score discordance was defined as a difference of ≥ 1 standard deviation between the lumbar spine (LS) and femoral neck (FN) bone mineral density (BMD). The prevalence of T-score discordance (low LS [LS BMD < FN BMD], low FN [LS BMD > FN BMD], and total [low LS + low FN]) was investigated in the osteoporosis and non-osteoporosis groups and stratified by sex and age. T-score discordance of 63 patients with AFFs diagnosed at a single institution was compared with that of the Korean osteoporosis population using propensity score matching.

Results

T-score discordance was prevalent in the Korean osteoporosis population (44.8%), and low LS discordance (37.5%) was more frequently seen than low FN discordance (7.2%) (p < 0.001). The prevalence of total and low LS discordance was significantly higher in AFF patients than in the Korean osteoporosis population (total discordance: 69.8% and 42.5%, respectively; low LS discordance: 63.5% and 31.7%, respectively; p < 0.001).

Conclusions

T-score discordance was highly prevalent in the Korean osteoporosis population, and low LS discordance was more common than low FN discordance. Nevertheless, the prevalence of low LS discordance was significantly higher in AFF patients than in the Korean osteoporosis population.

Metabolic activities affect femur and lumbar vertebrae remodeling, and anti-resorptive risedronate disturbs femoral cortical bone remodeling

Metabolic activities are closely correlated with bone remodeling and long-term anti-resorptive bisphosphonate treatment frequently causes atypical femoral fractures through unclear mechanisms. To explore whether metabolic alterations affect bone remodeling in femurs and lumbar vertebrae and whether anti-osteoporotic bisphosphonates perturb their reconstruction, we studied three mouse strains with different fat and lean body masses (BALB/c, C57BL6, and C3H mice). These mice displayed variable physical activity, food and drink intake, energy expenditure, and respiratory quotients. Following intraperitoneal calcein injection, double calcein labeling of the femoral diaphysis, as well as serum levels of the bone-formation marker procollagen type-I N-terminal propeptide and the bone-resorption marker C-terminal telopeptide of type-I collagen, revealed increased bone turnover in mice in the following order: C3H > BALB/c ≥ C57BL6 mice. In addition, bone reconstitution in femurs was distinct from that in lumbar vertebrae in both healthy control and estrogen-deficient osteoporotic mice with metabolic perturbation, particularly in terms of femoral trabecular and cortical bone remodeling in CH3 mice. Interestingly, subcutaneous administration of bisphosphonate risedronate to C3H mice with normal femoral bone density led to enlarged femoral cortical bones with a low bone mineral density, resulting in bone fragility; however, this phenomenon was not observed in mice with ovariectomy-induced femoral cortical bone loss. Together, these results suggest that diverse metabolic activities support various forms of bone remodeling and that femur remodeling differs from lumbar vertebra remodeling. Moreover, our findings imply that the adverse effect of bisphosphonate agents on femoral cortical bone remodeling should be considered when prescribing them to osteoporotic patients.

T-Score Discordance of Bone Mineral Density in Patients with Atypical Femoral Fracture

BACKGROUND

Although atypical femoral fracture (AFF) occurs more frequently in patients taking bisphosphonates and longer treatment is associated with higher risk, the causal relationship between AFF and bisphosphonates has not been established. Most patients with AFF have osteoporosis that is being treated with bisphosphonates, but we are not aware of any reports regarding the areal bone mineral density (aBMD) and discordance between the T-scores of the femur and spine in such patients. We investigated the prevalence of aBMD discordance and the characteristics of patients with AFF.

METHODS

Medical records for 63 consecutive patients treated for AFF were retrospectively evaluated, and 48 patients, all female, were eligible for the study. The average age at the time of fracture was 73.0 years, the average duration of bisphosphonate use was 68.5 months, and the average presumed age at bisphosphonate initiation was 67.2 years. We evaluated the prevalence of discordance, defined as a difference between the T-score categories of the femur and spine in the same individual as well as demographic differences between the discordance and concordance groups. We also compared the prevalence of discordance in patients with AFF with that in 114 female patients with intertrochanteric femoral fracture (ITFF).

RESULTS

T-score concordance, minor discordance, and major discordance were seen in 14 (29%), 32 (67%), and 2 (4%) of the patients with AFF, respectively. The prevalence of discordance was significantly higher in those with AFF (71%) than in those with ITFF (23%) (p < 0.001). The average age at bisphosphonate initiation in the AFF group was lower in the discordance group (65.7 years) than in the concordance group (70.7 years) (p = 0.04).

CONCLUSIONS

The prevalence of T-score discordance between the hip and lumbar spine was relatively high in patients with AFF, and the presumed age at the initiation of bisphosphonate therapy was younger in patients with discordant T-scores in this study.

LEVEL OF EVIDENCE

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