Excess mortality following hip fracture in patients with diabetes according to age: a nationwide population-based cohort study of 154,047 hip fracture patients

Bone metabolism in diabetes: a clinician's guide to understanding the bone-glucose interplay

Skeletal fragility is an increasingly recognised, but poorly understood, complication of both type 1 and type 2 diabetes. Fracture risk varies according to skeletal site and diabetes-related characteristics. Post-fracture outcomes, including mortality risk, are worse in those with diabetes, placing these people at significant risk. Each fracture therefore represents a sentinel event that warrants targeted management. However, diabetes is a very heterogeneous condition with complex interactions between multiple co-existing, and highly correlated, factors that preclude a clear assessment of the independent clinical markers and pathophysiological drivers for diabetic osteopathy. Additionally, fracture risk calculators and routinely used clinical bone measurements generally underestimate fracture risk in people with diabetes. In the absence of dedicated prospective studies including detailed bone and metabolic characteristics, optimal management centres around selecting treatments that minimise skeletal and metabolic harm. This review summarises the clinical landscape of diabetic osteopathy and outlines the interplay between metabolic and skeletal health. The underlying pathophysiology of skeletal fragility in diabetes and a rationale for considering a diabetes-based paradigm in assessing and managing diabetic bone disease will be discussed.

Integrated analysis of genes shared between type 2 diabetes mellitus and osteoporosis

Background

The relationship between type 2 diabetes mellitus (T2DM) and osteoporosis (OP) has been widely recognized in recent years, but the mechanism of interaction remains unknown. The aim of this study was to investigate the genetic features and signaling pathways that are shared between T2DM and OP.

Methods

We analyzed the GSE76894 and GSE76895 datasets for T2DM and GSE56815 and GSE7429 for OP from the Gene Expression Omnibus (GEO) database to identify shared genes in T2DM and OP, and we constructed coexpression networks based on weighted gene coexpression network analysis (WGCNA). Shared genes were then further analyzed for functional pathway enrichment. We selected the best common biomarkers using the least absolute shrinkage and selection operator (LASSO) algorithm and validated the common biomarkers, followed by RT-PCR, immunofluorescence, Western blotting, and enzyme-linked immunosorbent assay (ELISA) to validate the expression of these hub genes in T2DM and OP mouse models and patients.

Results

We found 8,506 and 2,030 DEGs in T2DM and OP, respectively. Four modules were identified as significant for T2DM and OP using WGCNA. A total of 19 genes overlapped with the strongest positive and negative modules of T2DM and OP. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed these genes may be involved in pantothenate and CoA biosynthesis and the glycosaminoglycan biosynthesis-chondroitin sulfate/dermatan sulfate and renin-angiotensin system signaling pathway. The LASSO algorithm calculates the six optimal common biomarkers. RT-PCR results show that LTB, TPBG, and VNN1 were upregulated in T2DM and OP. Immunofluorescence and Western blot show that VNN1 is upregulated in the pancreas and bones of T2DM model mice and osteoporosis model mice. Similarly, the level of VNN1 in the sera of patients with T2DM, OP, and T2DM and OP was higher than that in the healthy group.

Conclusion

Based on the WGCNA and LASSO algorithms, we identified genes and pathways that were shared between T2DM and OP. Both pantothenate and CoA biosynthesis and the glycosaminoglycan biosynthesis-chondroitin sulfate/dermatan sulfate and renin-angiotensin systems may be associated with the pathogenesis of T2DM and OP. Moreover, VNN1 may be a potential diagnostic marker for patients with T2DM complicated by OP. This study provides a new perspective for the systematic study of possible mechanisms of combined OP and T2DM.

Bone Health in Patients With Type 2 Diabetes

The association between type 2 diabetes mellitus (T2DM) and skeletal fragility is complex, with effects on bone at the cellular, molecular, and biomechanical levels. As a result, people with T2DM, compared to those without, are at increased risk of fracture, despite often having preserved bone mineral density (BMD) on dual-energy x-ray absorptiometry (DXA). Maladaptive skeletal loading and changes in bone architecture (particularly cortical porosity and low cortical volumes, the hallmark of diabetic osteopathy) are not apparent on routine DXA. Alternative imaging modalities, including quantitative computed tomography and trabecular bone score, allow for noninvasive visualization of cortical and trabecular compartments and may be useful in identifying those at risk for fractures. Current fracture risk calculators underestimate fracture risk in T2DM, partly due to their reliance on BMD. As a result, individuals with T2DM, who are at high risk of fracture, may be overlooked for commencement of osteoporosis therapy. Rather, management of skeletal health in T2DM should include consideration of treatment initiation at lower BMD thresholds, the use of adjusted fracture risk calculators, and consideration of metabolic and nonskeletal risk factors. Antidiabetic medications have differing effects on the skeleton and treatment choice should consider the bone impacts in those at risk for fracture. T2DM poses a unique challenge when it comes to assessing bone health and fracture risk. This article discusses the clinical burden and presentation of skeletal disease in T2DM. Two clinical cases are presented to illustrate a clinical approach in assessing and managing fracture risk in these patients.

Establishment and validation of a nomogram clinical prediction model for osteoporosis in senile patients with type 2 diabetes mellitus

This study aimed to develop a predictive nomogram model to estimate the odds of osteoporosis (OP) in elderly patients with type 2 diabetes mellitus (T2DM) and validate its prediction efficiency. The hospitalized elderly patients with T2DM from the Affiliated Hospital of North Sichuan Medical University between July 2022 and March 2023 were included in this study. We sorted them into the model group and the validation group with a ratio of 7:3 randomly. The selection operator regression (LASSO) algorithm was utilized to select the optimal matching factors, which were then included in a multifactorial forward stepwise logistic regression to determine independent influencing factors and develop a nomogram. The discrimination, accuracy, and clinical efficacy of the nomogram model were analyzed utilizing the receiver operating characteristic (ROC) curve, calibration curve, and clinical decision curve analysis (DCA). A total of 379 study participants were included in this study. Gender (OR = 8.801, 95% CI 4.695-16.499), Geriatric Nutritional Risk Index (GNRI) < 98 (OR = 4.698, 95% CI 2.416-9.135), serum calcium (Ca) (OR = 0.023, 95% CI 0.003-0.154), glycated hemoglobin (HbA1c) (OR = 1.181, 95% CI 1.055-1.322), duration of diabetes (OR = 1.076, 95% CI 1.034-1.119), and serum creatinine (SCr) (OR = 0.984, 95% CI 0.975-0.993) were identified as independent influencing factors for DOP occurrence in the elderly. The area under the curve (AUC) of the nomogram model was 0.844 (95% CI 0.797-0.89) in the modeling group and 0.878 (95% CI 0.814-0.942) in the validation group. The nomogram clinical prediction model was well generalized and had moderate predictive value (AUC > 0.7), better calibration, and better clinical benefit. The nomogram model established in this study has good discrimination and accuracy, allowing for intuitive and individualized analysis of the risk of DOP occurrence in elderly individuals. It can identify high-risk populations and facilitate the development of effective preventive measures.

Characteristics of bone metabolism in the male patients with diabetic neuropathy

BACKGROUND

This study aimed to evaluate the characteristics of bone metabolism and fracture risk in the type 2 diabetes mellitus (T2DM) patients with distal symmetric polyneuropathy (DSPN).

METHODS

A total of 198 T2DM individuals were recruited from January 2017 to December 2020. Patients with DSPN were evaluated by strict clinical and sensory thresholds. Biochemical parameters and bone mineral density (BMD) were measured. The BMD, bone turnover markers, and probability of fracture were compared between two groups, and the factors related to BMD and probability of hip fracture in 10 years were further explored.

RESULTS

Compared with type 2 diabetes mellitus without distal symmetric polyneuropathy (T2DN-) patients, type 2 diabetes mellitus with distal symmetric polyneuropathy (T2DN+) patients had lower level of cross-linked C-telopeptide (CTX) (0.32 ± 0.19 vs 0.38 ± 0.21 ng/mL, p = 0.038) and higher level of bone-specific alkaline phosphatase (BALP) (15.28 ± 5.56 vs 12.58 ± 4.41 μg/mL, p = 0.003). T2DN+ patients had higher BMD of lumbar L1-L4 (1.05 ± 0.19 vs 0.95 ± 0.37, p = 0.027) and higher probability of hip fracture (0.98 ± 0.88 vs 0.68 ± 0.63, p = 0.009) as compared to T2DN- individuals. Univariate correlation analysis showed that BALP level (coefficient (coef) = -0.054, p = 0.038), CTX level (coef = -2.28, p = 0.001), and hip fracture risk (coef = -1.02, p < 0.001) were negatively related to the BMD of L1-L4. As for the risk of hip fracture evaluated by WHO Fracture Risk Assessment Tool (FRAX), age (coef = 0.035, p < 0.001), use of insulin (coef = 0.31, p =0.015), and levels of BALP (coef = 0.031, p = 0.017) and CTX (coef = 0.7, p = 0.047) were positively related to the risk of hip fracture. Multivariate regression analysis showed that CTX level (coef = -1.41, p = 0.043) was still negatively related to BMD at the lumbar spine.

CONCLUSION

This study indicates that T2DM patients with DSPN have special bone metabolism represented by higher BALP level and lower CTX level which may increase BMD at the lumbar spine.

Sarm1 knockout prevents type 1 diabetic bone disease in females independent of neuropathy

Patients with diabetes have a high risk of developing skeletal diseases accompanied by diabetic peripheral neuropathy (DPN). In this study, we isolated the role of DPN in skeletal disease with global and conditional knockout models of sterile-α and TIR-motif-containing protein-1 (Sarm1). SARM1, an NADase highly expressed in the nervous system, regulates axon degeneration upon a range of insults, including DPN. Global knockout of Sarm1 prevented DPN, but not skeletal disease, in male mice with type 1 diabetes (T1D). Female wild-type mice also developed diabetic bone disease but without DPN. Unexpectedly, global Sarm1 knockout completely protected female mice from T1D-associated bone suppression and skeletal fragility despite comparable muscle atrophy and hyperglycemia. Global Sarm1 knockout rescued bone health through sustained osteoblast function with abrogation of local oxidative stress responses. This was independent of the neural actions of SARM1, as beneficial effects on bone were lost with neural conditional Sarm1 knockout. This study demonstrates that the onset of skeletal disease occurs rapidly in both male and female mice with T1D completely independently of DPN. In addition, this reveals that clinical SARM1 inhibitors, currently being developed for treatment of neuropathy, may also have benefits for diabetic bone through actions outside of the nervous system.

Comparison between Orthopaedic Trauma versus Arthroplasty Fellowship Training on Outcomes of Total Hip Arthroplasty for Femoral Neck Fracture

BACKGROUND

This study aimed to identify differences in patient characteristics, perioperative management methods, and outcomes for total hip arthroplasty (THA) for femoral neck fracture (FNF) when performed by orthopaedic surgeons who have arthroplasty versus orthopaedic trauma training.

METHODS

This study was a multicenter, retrospective review of 636 patients who underwent THA for FNF between 2010 and 2019. There were 373 patients who underwent THA by an arthroplasty surgeon, and 263 who underwent THA by an orthopaedic trauma surgeon. Comorbidities, management methods, and outcomes were compared between patients operated on by orthopaedic surgeons who had arthroplasty versus trauma training.

RESULTS

Arthroplasty-trained surgeons had shorter operative times (102 vs 128 minutes, P<0.0001) and utilized tranexamic acid more frequently than trauma-trained surgeons (48.8 vs 18.6%, P<0.0001). Orthopaedic trauma surgeons more frequently utilized an anterior approach. Patients of arthroplasty-trained surgeons had lower rates of complications including pulmonary embolism (1.6 vs 6.5%, P=0.0019) and myocardial infarction (1.6 vs 11.0%, P<0.0001). Similarly, patients of arthroplasty-trained surgeons were discharged faster (5.3 vs 7.9 days, P<0.0001) with greater ambulation capacity (92.2 vs 57.2 feet, P<0.0001). Dislocation, periprosthetic joint infection, and revision were similar between both groups. When adjusted for covariates, there was no difference in 90-day, 1-year, or 2-year mortality.

CONCLUSION

A THA performed for FNF by arthroplasty surgeons was associated with lower in-hospital morbidities and improved functional statuses at discharge. However, mortalities and complications after discharge were similar between both specialties when adjusted for confounding variables. Optimization of protocols may further improve outcomes for THA for FNF.

Preoperative Comorbidities Associated With Early Mortality in Hip Fracture Patients: A Multicenter Study

OBJECTIVE

Multiple comorbidities in hip fracture patients are associated with increased mortality and complications. The goal of this study was to characterize the relationship between specific patient factors including comorbidities and outcomes in geriatric hip fractures, including length of stay, unplanned ICU admission, discharge disposition, complications, and mortality.

METHODS

This is a retrospective review of a trauma database from five Level 1 and Level 2 trauma centers of patients with hip fractures of the femoral neck and intertrochanteric region who underwent treatment using hip pinning, hemiarthroplasty, total hip arthroplasty, cephalomedullary nailing, or dynamic hip screw fixation. Mortality was the primary outcome variable (including in-hospital mortality, 30-day mortality, 60-day mortality, and 90-day mortality). Secondary outcome variables included in-hospital adverse events, unplanned transfer to the ICU, postoperative length of stay, and discharge disposition. Regression analyses were used for evaluation of relationships between comorbidities as independent variables and primary and secondary outcomes as dependent variables.

RESULTS

Two thousand three hundred patients were included. The mortality was 1.8%, 7.0%, 10.9%, and 14.1% for in-hospital, 30-day, 60-day, and 90-day mortality, respectively. Diabetes and cognitive impairment present on admission were associated with mortality at all-time intervals. COPD was the only comorbidity that signaled in-hospital adverse event with an odds ratio of 1.67 (P = 0.012). No patient factors, time to surgery, or comorbidities signaled unplanned ICU transfer. Patients with renal failure and COPD had longer hospital stays after surgery.

CONCLUSION

Geriatric hip fractures continue to have high short-term morbidity and mortality. Identifying patients with increased odds of early mortality and adverse events can help teams optimize care and outcomes. Patients with diabetes, cognitive impairment, renal failure, and COPD may benefit from continued and improved medical optimization during the perioperative period as well as being more closely managed by a medicine team without delaying time to the operating room.

Contributors to impaired bone health in type 2 diabetes

Type 2 diabetes (T2D) is associated with numerous complications, including increased risk of fragility fractures, despite seemingly protective factors [e.g., normal bone mineral density and increased body mass index(BMI)]. However, fracture risk in T2D is underestimated by current fracture risk calculators. Importantly, post-fracture mortality is worse in T2D following any fracture, highlighting the importance of identifying high-risk patients that may benefit from targeted management. Several diabetes-related factors are associated with increased fracture risk, including exogenous insulin therapy, vascular complications, and poor glycaemic control, although detailed comprehensive studies to identify the independent contributions of these factors are lacking. The underlying pathophysiological mechanisms are complex and multifactorial, with different factors contributing during the course of T2D disease. These include obesity, hyperinsulinaemia, hyperglycaemia, accumulation of advanced glycation end products, and vascular supply affecting bone-cell function and survival and bone-matrix composition. This review summarises the current understanding of the contributors to impaired bone health in T2D, and proposes an updated approach to managing these patients.

Functional Heterogeneity Within Osteoclast Populations-a Critical Review of Four Key Publications that May Change the Paradigm of Osteoclasts

PURPOSE OF REVIEW

In this review, we critically evaluate the literature for osteoclast heterogeneity, including heterogeneity in osteoclast behavior, which has hitherto been unstudied and has only recently come to attention. We give a critical review centered on four recent high-impact papers on this topic and aim to shed light on the elusive biology of osteoclasts and focus on the variant features of osteoclasts that diverge from the classical viewpoint.

RECENT FINDINGS

Osteoclasts originate from the myeloid lineage and are best known for their unique ability to resorb bone. For decades, osteoclasts have been defined simply as multinucleated cells positive for tartrate-resistant acid phosphatase activity and quantified relative to the bone perimeter or surface in histomorphometric analyses. However, several recent, high-profile studies have demonstrated the existence of heterogeneous osteoclast populations, with variable origins and functions depending on the microenvironment. This includes long-term persisting osteoclasts, inflammatory osteoclasts, recycling osteoclasts (osteomorphs), and bone resorption modes. Most of these findings have been revealed through murine studies and have helped identify new targets for human studies. These studies have also uncovered distinct sets of behavioral patterns in heterogeneous osteoclast cultures. The underlying osteoclast heterogeneity likely drives differences in bone remodeling, altering patient risk for osteoporosis and fracture. Thus, identifying the underlying key features of osteoclast heterogeneity may help in better targeting bone diseases.

Fractures in type 2 diabetes confer excess mortality: The Dubbo osteoporosis epidemiology study

PURPOSE

Diabetes and fractures are both associated with increased mortality, however the effect of the combination is not well-established. We examined the mortality risk following all types of fractures in type 2 diabetes (T2D).

METHODS

In the Dubbo Osteoporosis Epidemiology Study (1989-2017), participants were grouped according to T2D and/or incident fracture. Study outcome was all-cause mortality. First incident radiological fragility fracture and incident T2D diagnosis were time-dependent variables. Cox's proportional hazards models quantified mortality risk associated with T2D and incident fracture overall, as well as by fracture site, T2D duration and T2D medication type.

RESULTS

In 3618 participants (62% women), 272 had baseline and 179 developed T2D over median 13.0 years (IQR 8.2-19.6). 796 women (56 with T2D) and 240 men (25 with T2D) sustained a fracture. Compared to those without T2D or fracture, mortality risk increased progressively, in T2D without fracture, then no T2D with fracture, and was highest in those with T2D with fracture (adjusted hazard ratio (aHR) (95% CI) for women 2.62 (1.75-3.93) and men 2.61 (1.42-4.81)). Within T2D participants, incident fracture was associated with increased mortality (aHR for women 1.87 (1.10-3.16) and men 2.83 (1.41-5.68)), especially following hip/vertebral fractures in men (aHR 2.97 (1.29-6.83)) and non-hip non-vertebral fractures in women (aHR 2.42 (1.24-4.75)), and in T2D duration >5 years.

CONCLUSION

Any fracture in T2D conferred significant excess mortality. Individuals with T2D should be carefully monitored post-fracture, especially if T2D >5 years. Optimising fracture prevention and post-fracture management in T2D is critical and warrants further studies.

Assessment and treatment of osteoporosis and fractures in type 2 diabetes

There is substantial, and growing, evidence that type 2 diabetes (T2D) is associated with skeletal fragility, despite often preserved bone mineral density. As post-fracture outcomes, including mortality, are worse in people with T2D, bone management should be carefully considered in this highly vulnerable group. However, current fracture risk calculators inadequately predict fracture risk in T2D, and dedicated randomised controlled trials identifying optimal management in patients with T2D are lacking, raising questions about the ideal assessment and treatment of bone health in these people. We synthesise the current literature on evaluating bone measurements in T2D and summarise the evidence for safety and efficacy of both T2D and anti-osteoporosis medications in relation to bone health in these patients.

Impact of diabetes mellitus on risk of major complications after hip fracture: a systematic review and meta-analysis

BACKGROUND

The impact of diabetes mellitus (DM) on adverse outcomes in hip fracture patients is unclear. Furthermore, no review has synthesized evidence on this subject. Therefore, the current study was designed to answer the following research question: Does DM increase the risk of mortality and major systemic complications in patients with hip fractures?

METHODS

PubMed, Embase, and Google Scholar were searched from 1st January 2000 to 1st August 2021 for studies comparing DM and non-DM patients with hip fractures. Outcomes of interest were pooled using risk ratios (RR). The study was registered on PROSPERO (CRD42021268525).

RESULTS

Sixteen studies were included. Meta-analysis revealed a statistically significant increased risk of mortality in diabetics as compared to non-diabetics after 1 year (RR: 1.24 95% CI 1.08, 1.43 I2 = 62% p = 0.003). Pooled analysis of eight studies reporting adjusted mortality outcomes also demonstrated similar results (RR: 1.17 95% CI 1.09, 1.25 I2 = 74% p < 0.0001). We noted a statistically significant increase in the risk of cardiac complications (RR: 1.44 95% CI 1.17, 1.78 I2 = 19% p = 0.0005) and risk of renal failure in diabetics as compared to non-diabetics (RR: 1.32 95% CI 1.04, 1.68 I2 = 0% p = 0.02); but no difference in the risk of cerebrovascular (RR: 1.45 95% CI 0.74, 2.85 I2 = 47% p = 0.28), pulmonary (RR: 0.94 95% CI 0.73, 1.23 I2 = 8% p = 0.67) and thromboembolic complications (RR: 0.81 95% CI 0.56, 1.17 I2 = 28% p = 0.26).

CONCLUSION

Our results indicate that diabetics have an increased risk of mortality as compared to non-diabetics. Scarce data indicates that the risk of cardiac complications and renal failure are increased in patients with DM but there is no difference in the risk of cerebrovascular, pulmonary, or thromboembolic complications. Further studies are needed to strengthen the current conclusions.

The impact of perioperative glucose variability on outcomes after hip fracture

Diabetes is considered an independent risk factor for hip fracture. In the present study, we evaluated whether perioperative glucose variability (GV) was a significant predictor of the outcomes of patients with diabetes after hip fracture.We analyzed the characteristics and outcomes of all patients with hip fractures admitted to our hospital between September 2008 and December 2012. Patients with diabetes were grouped into tertiles for GV, and multivariate survival analysis included age, sex, fracture type, mean fasting plasma glucose, and GV.Among the 1099 patients included in this study, 239 (21.7%) had diabetes. Patients with diabetes were more likely to develop infectious complications (5.4% vs 2.8%, P = .045), and experience mortality postoperatively (1 month: 5.5% vs 2.7%, P = .052; 12 months: 15.1% vs 8.7%, P = .006). The postoperative mortality rate was increased across the GV tertiles, and GV was an independent predictor of 1- and 12-month mortality after surgery.Patients with diabetes had poor prognoses after hip fracture. Perioperative GV is an independent predictor of mortality in patients with diabetes. Therefore, GV might be considered a valid additional parameter to consider in the management of these patients.

Health related quality of life and mortality 10 years after a femoral neck fracture in patients younger than 70 years

BACKGROUND AND PURPOSE

A femoral neck fracture (FNF) may have long term effects on the patient's health related quality of life (HRQoL) and mortality, especially in patients younger than 70 years. These long-term effects are unknown since most studies have a short follow-up. The aim of this study was to investigate self-assessed hip function, HRQoL and factors associated with 10-years mortality after a FNF.

PATIENTS AND METHODS

A prospective multicenter study with a 10-year follow-up of patients aged 20-69 years with a displaced and non-displaced FNF treated with closed reduction and internal fixation. The self-administered questionnaires EuroQol 5 Dimension (EQ-5D) and Hip Disability Outcome Score (HOOS) were used. Results of EQ-5D and HOOS was compared to sex and age matched general population data of Sweden. All patients that were deceased had their death date recorded. Factors associated with mortality were assessed by regression analysis of the baseline data including age, gender, harmful alcohol consumption according to AUDIT, co-morbidity measured by ASA-grade, body mass index, osteoporosis measured by dual energy x-ray absorptiometry (DXA) and smoking. Prevalence of co-morbidities and smoking was compared to general population data.

RESULTS

From initial 182 included patients, 55 were deceased at 10-year follow-up, 4 were deregistered from public record and 35 declined participations. A total of 88 patients participated through self-administrated questionnaires. There were no significant differences in HOOS between gender and fracture type and the results were equivalent to general population data. The EQ-5D continued to improve compared to a 24-month follow-up (p = 0.006) but did not recover to pre-fracture level (p<0.001) though it was equivalent to general population data. Higher age, co-morbidity, osteoporosis and smoking were associated with increased mortality within 10 years after the fracture and the prevalence of co-morbidity and smoking was higher than the general population.

INTERPRETATION

Those patients who had survived 10 years after a FNF treated with CRIF had a HRQoL and hip function equivalent to age and sex matched general population of Sweden. However, a third of these relatively young patients had deceased 10 years after the hip fracture and they were more compromised than the general population.