Chronic kidney disease and fragility fracture

History of fragility fracture is associated with cardiovascular mortality in hemodialysis patients: the Q-Cohort study

INTRODUCTION

In patients undergoing dialysis, major bone fracture is associated with a high risk of mortality, including death of cardiovascular (CV) origin. In the present study, we aimed to determine whether a history of fragility fracture is a predictor of CV death in patients undergoing hemodialysis with long-term follow-up.

MATERIALS AND METHODS

In total, 3499 patients undergoing hemodialysis were analyzed for 10 years. We evaluated the history of fragility fracture in each patient at enrollment. The primary outcome was CV death. A Cox proportional hazard model and a competing risk approach were applied to determine the association between a history of fragility fracture and CV death.

RESULTS

A total of 346 patients had a history of fragility fracture at enrollment. During a median follow-up of 8.8 years, 1730 (49.4%) patients died. Among them, 621 patients experienced CV death. Multivariable Cox analyses after adjustment for confounding variables showed that a history of fragility fracture was associated with CV death (hazard ratio, 1.47; 95% confidence interval, 1.16-1.85). In the Fine-Gray regression model, a history of fragility fracture was an independent risk factor for CV death (subdistribution hazard ratio, 1.36; 95% confidence interval, 1.07-1.72).

CONCLUSION

In a large cohort of patients undergoing hemodialysis, a history of fragility fracture was an independent predictor of CV death.

Fibroblast growth factor 23 and its role in bone diseases

Fibroblast growth factor 23 (FGF23) has been casually linked to numerous hypophosphatemic bone diseases, however connection with bone loss or fragility fractures is still a matter of debate. The purpose of this review is to explore and summarise the known actions of FGF23 in various pathological bone conditions. Besides implication in bone mineralisation, elevated FGF23 showed a pathological effecton bone remodelling, primarily by inhibiting osteoblast function. Unlike the weak association with bone mineral density, high values of FGF23 have been connected with fragility fracture prevalence. This review shows that its effects on bone are concomitantly present on multiple levels, affecting both qualitative and quantitative part of bone strength, eventually leading to impaired bone strength and increased tendency of fractures. Recognising FGF23 as a risk factor for the development of bone diseases and correcting its levels could lead to the reduction of morbidity and mortality in specific groups of patients.

Effects of bisphosphonates and treadmill exercise on bone and kidney in adenine-induced chronic kidney disease rats

INTRODUCTION

The increasing prevalence of osteoporosis and chronic kidney disease (CKD) due to the aging of society has highlighted the need for development of effective treatments for elderly patients. This study examined whether the combination of treadmill exercise therapy and alendronate (ALN) can improve bone mineral density (BMD) and bone strength without worsening renal function in adenine-induced CKD model rats.

MATERIALS AND METHODS

8-week-old male Wistar rats (n = 70) were divided into experimental groups based on the treatment protocol, i.e., non-CKD (control), vehicle only (CKD), ALN only, exercise only, and combined ALN plus exercise. A 0.75% adenine diet was used to induce CKD. Groups were killed at either 20 or 30 weeks of age. Comprehensive assessments included serum and urine biochemistry tests, renal histology, bone histomorphometry, BMD measurement, micro-computed tomography examinations, and biomechanical testing.

RESULTS

Blood biochemistry tests, urine analyses and histological evaluations of the kidney demonstrated that ALN treatment did not worsen renal function or kidney fibrosis in moderate-stage CKD model rats. Both ALN and treadmill exercise significantly suppressed bone resorption (p < 0.05-p < 0.01). Moreover, ALN monotherapy and combined ALN and treadmill exercise significantly improved BMD of the lumbar spine and femur, bone microstructure, and trabecular bone strength (p < 0.05-p < 0.01). Treadmill exercise was also shown to decrease cortical porosity at the mid-diaphysis of the femur and improve kidney fibrosis.

CONCLUSION

The combination of ALN and treadmill exercise is effective in improving BMD, the microstructure of trabecular and cortical bone, and bone strength, without compromising renal function in adenine-induced CKD model rats.

Risk factors for refracture after proximal femur fragility fracture

Introduction

Proximal femur fragility fractures (PFFFs) are a growing worldwide concern. Recognizing the risk factors for subsequent fracture is essential for secondary prevention. This study aimed to analyze the risk factors for refracture and mortality rates in patients who suffered a PFFF.

Methods

Patients aged 65 years or older with PFFF who underwent surgical treatment during the year of 2017 in the same institution were retrospectively analyzed and at least four years after the index fracture were evaluated.

Results

From a total of 389 patients, 299 patients were included, with a median age of 83 years, and 81% female. Thirty-two (10.7%) suffered a refracture, with a mean time to refracture of 19.8 ± 14.80 months, being the female sex a risk factor for refracture (OR-4.69; CI [1.05-20.95]). The 1-year mortality rate was 15.4%. Seventy-three (24.4%) patients had previous fragility fractures. After the index fracture, 79% remained untreated for osteoporosis. No statistical association was found between antiosteoporotic treatment and refracture. Patients with refracture had higher prefracture functional level compared with patients without refracture (OR-1.33; CI [1.08-1.63]) and were discharged more often to rehabilitation units (31% versus 16%, P =.028). After 4 years of follow-up, patients with refracture had lower functional level compared with patients without. Chronic kidney disease was a risk factor (P = .029) for early refracture (<24 months).

Conclusion

Female sex and higher prefracture functional level may increase the risk of refracture. Chronic kidney disease was associated with a shorter refracture time. Despite having a PFFF or other fragility fractures, the majority of patients remained untreated for osteoporosis.

Association between depressive symptoms and bone density in elderly patients with non-dialysis dependent chronic kidney disease

BACKGROUND

Depression is a disease that is commonly accompanied by elderly chronic kidney disease (CKD) patients, but when the two diseases are accompanied, etiology or combination are not well known. We aimed to evaluate the etiology of CKD and comorbid depression by investigating bone disorders that are observed in persons affected by both CKD and depression.

METHODS

We conducted a cross-sectional study with a total of 646 patients with CKD. We compared the sociodemographic factors, kidney function, markers for CKD-Mineral and Bone Disorder (CKD-MBD) and bone mineral density according to the depressive symptoms. We conducted a univariate and multivariate logistic regression analysis to calculate odd ratios (95 % confidence interval) between depressive symptoms and low bone mineral density.

RESULTS

Individuals with CKD and depressive symptoms were associated with lower level of education attained, living alone, exercising less, low 24-hour urine phosphorus, and low bone density. Depressive symptoms were significantly associated with low bone density in lowest parts (1.55 [1.06-2.29]) and in total hip (1.72 [1.17-2.53]) even after adjusting for diabetes mellitus, hypertension, kidney function, proteinuria, age, sex, smoking, and body mass index.

LIMITATIONS

A cross-sectional design was used in this study and the bone biopsy for diagnosis of CKD-MBD was not done because of invasiveness and practical difficulties.

CONCLUSION

Low bone density was associated with depressive symptoms in elderly patients with non-dialysis chronic kidney disease.

Perioperative Management and Outcomes of Hip Fracture Patients with Advanced Chronic Kidney Disease

Aims

To explore clinical characteristics, perioperative management and outcomes of Hip Fracture patients with advanced Chronic Kidney Disease (HF-aCKD) compared to the general Hip Fracture population without aCKD (HF-G) within a large volume tertiary hospital in Western Australia.

Methods

Retrospective chart review of patients admitted with hip fracture (HF) to a single large volume tertiary hospital registered on Australian and New Zealand Hip Fracture Registry (ANZHFR). We compared baseline demographic and clinical frailty scale (CFS) of HF-aCKD (n = 74), defined as eGFR < 30 mls/min/1.73 m2, with HF-G (n = 452) and determined their outcomes at 120 days.

Results

We identified 74 (6.97%) HF patients with aCKD. General demographics were similar in HF-aCKD and HF-G populations. 120-days mortality for HF-aCKD was double that of HF-G population (34% vs 17%, P = .001). For dialysis patients, 120-days mortality was triple that of HF-G population (57%). Except for the fit category of HF-aCKD group, higher CFS was associated with higher 120-days mortality in both groups. Of all HF-aCKD patients, 96% had operative intervention and 48% received blood transfusion. There were no new starts to dialysis peri-operatively. Each point reduction in eGFR below 12 mL/min/1.73 m2 was associated with 3% increased probability of death in hospital.

Conclusions

120-days mortality was double in HF-aCKD and triple in HF-dialysis that of the HF-G within our institution. Clinical frailty scale can be useful in predicting mortality after HF in frail aCKD patients. High rate of blood transfusions was observed in HF-aCKD group. Further studies with larger HF-aCKD numbers are required to explore these associations in detail.

The impact of chronic kidney disease and dialysis therapy on outcomes of elderly patients with hip fractures: A systematic review and meta-analysis

BACKGROUND AND AIMS

Hip fractures are a commonly occurring comorbidity in patients with chronic kidney disease. To evaluate the comparative rates of post-operative complications, revision surgery, and mortality after hip fracture surgery in chronic kidney disease patients undergoing hemodialysis.

METHODS

A systematic search of the academic literature was performed according to the PRISMA guidelines across five databases: Web of Science, EMBASE, CENTRAL, Scopus, and MEDLINE. A random-effect meta-analysis was conducted to evaluate the overall comparative risks of post-operative complications in chronic kidney disease patients.

RESULTS

Out of 993 studies, 11 eligible studies were included in the review, with a total of 72618 chronic kidney disease patients (mean age: 75.3  ±  3.0 years), and 50566 healthy controls (75.3  ±  2.6 years). Meta-analysis revealed a higher risk of post-operative complications (Odd's ratio: 1.76), revision surgeries (1.69), and mortality-related outcomes (2.47) after hip fracture surgery in chronic kidney disease patients undergoing hemodialysis as compared to chronic kidney disease patients not undergoing hemodialysis.

CONCLUSION

We report higher risks of post-operative complications, revision surgery, and mortality in chronic kidney disease patients undergoing hemodialysis as compared to chronic kidney disease patients not undergoing hemodialysis.

Fracture risk associated with glucocorticoid-induced osteoporosis in Japan

INTRODUCTION

Glucocorticoid-induced osteoporosis (GIOP) is associated with elevated fracture risk. Practice guidelines have been published to reduce this risk but are insufficiently followed in everyday practice. The objectives of this study were to estimate fracture incidence in patients exposed to oral glucocorticoids and to analyse the impact of glucocorticoid use on fracture incidence.

MATERIALS AND METHODS

This retrospective cohort study was performed using the Medical Data Vision (MDV) claims database from Japan. All patients aged ≥ 18 years initiating oral glucocorticoids and fulfilling Japanese guideline criteria for starting prophylactic osteoporosis treatment between 2009 and 2019 were identified. These were matched to a cohort of unexposed controls using propensity score matching. Fracture incidence in the two cohorts were compared using a Fine-Gray proportional sub-distribution hazard model.

RESULTS

13,090 glucocorticoid-exposed cases were compared to 13,090 unexposed controls. The 1-year fracture rate (all sites) was 9.3 [95% CI 8.8-9.8] in cases and 5.8 [5.4-6.2] in controls. One-year vertebral fracture rates were 4.3 [4.0-4.7] and 2.3 [2.1-2.6] respectively. In the multivariate analysis, the use of glucocorticoids was associated with an increase in the incidence of osteoporotic fractures (hazard ratio: 1.63 [1.51-1.76]). The glucocorticoid-associated risk tended to be higher in subgroups of patients with rheumatoid arthritis, asthma, COPD and in those aged < 65 years.

CONCLUSION

Oral glucocorticoid use is associated with an increase in fracture incidence. It is necessary to raise awareness of GIOP and to take public health measures to change the perceptions and behaviour of doctors prescribing glucocorticoids.

Kidney Function Change and All-Cause Mortality in Denosumab Users with and without Chronic Kidney Disease

Denosumab is approved for osteoporosis treatment in subjects with and without chronic kidney disease (CKD). Confirmation is required for its safety, treatment adherence, renal function effect, and mortality in patients with CKD. A retrospective cohort study was conducted to compare new users of denosumab in terms of their two-year drug adherence in all participants (overall cohort) and CKD participants (CKD subcohort), which was defined as baseline estimated glomerular filtration rate (eGFR) less than 60 mL/min/1.73 m2. The eGFR was calculated using the 2021 CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) equation. We defined high adherence (HA) users as receiving three or four doses and low adherence (LA) users as receiving one or two doses. All-cause mortality was analyzed using Kaplan-Meier curves and Cox regression models. In total, there were 1142 subjects in the overall cohort and 500 subjects in the CKD subcohort. HA users had better renal function status at baseline than LD users in the overall cohort. A decline in renal function was only observed among LD users in the overall cohort. In the CKD subcohort, no baseline renal function difference or renal function decline was demonstrated. The all-cause mortality rate of HA users was lower than LA users in both the overall cohort and CKD. A randomized control trial is warranted to target this unique population to confirm our observations.

Effects of osteoporosis medications on bone fracture in patients with chronic kidney disease

PURPOSE OF THE STUDY

The risk of bone fracture is high in patients with chronic kidney disease (CKD), and aggressive treatment to reduce fragility fracture risk is the major strategy. However, the outcomes of osteoporosis medications in patients with CKD remain unclear.

STUDY DESIGN

Patients with stage 3-5 CKD during 2011-2019 were enrolled. Patients were divided into two groups based on receiving osteoporosis medications (bisphosphonates, raloxifene, teriparatide or denosumab) or not. Two groups were matched at a 1:1 ratio by using propensity scores. The outcomes of interest were bone fractures, cardiovascular (CV) events and all-cause mortality. Cox proportional hazard regression models were applied to identify the risk factors. Additional stratified analyses by cumulative dose, treatment length and menopause condition were performed.

RESULTS AND CONCLUSIONS

67 650 patients were included. After propensity score matching, 1654 patients were included in the study and control group, respectively. The mean age was 70.2±12.4 years, and 32.0% of patients were men. After a mean follow-up of 3.9 years, the incidence rates of bone fracture, CV events and all-cause mortality were 2.0, 1.7 and 6.5 per 1000 person-months, respectively. Multivariate analysis results showed that osteoporosis medications reduced the risk of CV events (HR, 0.35; 95% CI, 0.18 to 0.71; p=0.004), but did not alleviate the risks of bone fracture (HR, 1.48; 95% CI, 0.73 to 2.98; p=0.28) and all-cause mortality (HR, 0.93; 95% CI, 0.67 to 1.28; p=0.65). Stratified analysis showed that bisphosphonates users have most benefits in the reduction of CV events (HR, 0.26; 95% CI, 0.11 to 0.64; p=0.003). In conclusion, osteoporosis medications did not reduce the risk of bone fractures, or mortality, but improved CV outcomes in patients with CKD.

Characterization of Medication Trends for Chronic Kidney Disease: Mineral and Bone Disorder Treatment Using Electronic Health Record-Based Common Data Model

Chronic kidney disease–mineral bone disorder (CKD-MBD) is the most common complication in CKD patients. Although there is a consensus on treatment guidelines for CKD-MBD, it remains uncertain whether these treatment recommendations reflect actual practice. Therefore, the aim of this study was to investigate the CKD-MBD medication trend in real-world practice. This was a retrospective and observational study using a 12-year period database transformed into a common data model from three tertiary university hospitals. Study populations were subjects initially diagnosed as CKD. The date of diagnosis was designated as the index date. New patients were categorized year to year from 2008 to 2019 with a fixed observation period of 365 days to check the prescription of CKD-MBD medications including calcium-containing phosphate binder, noncalcium-containing phosphate binder, aluminium hydroxide, vitamin D receptor activator (VDRA), and cinacalcet. The numbers of CKD patients in the three hospitals were 7555, 2424, and 5351, respectively. The proportion for patients with CKD-MBD medication prescription decreased yearly regardless of hospital and CKD stage (p for trend < 0.05). The use of aluminium hydroxide disappeared steadily while the use of VDRA increased annually in all settings. Despite these changes in prescription patterns, the mean value for CKD-MBD-related serologic markers was almost within target range. The proportion of the population within the target value was not significantly changed. Irrespective of hospital and CKD stage, similar trends of prescription for CKD-MBD medications were observed in real-world practice. Further research with a distributed network study may be helpful to understand medication trends in CKD-MBD treatment.

Effect of body mass index on vertebral and hip fractures in older people and differences according to sex: a retrospective Japanese cohort study

OBJECTIVES

The purpose of this study was to investigate the incidence of vertebral and hip fractures in the older people and to clarify the relationship between these fractures and body mass index (BMI) along with the impact of sex differences.DesignThis was a retrospective cohort study.SettingWe used administrative claims data between April 2010 and March 2018.

PARTICIPANTS

Older people aged ≥75 years who underwent health examinations in 2010 and were living in the Fukuoka Prefecture, Japan were included in the study. A total of 24 691 participants were included; the mean age was 79.4±4.3 years, 10 853 males and 13 838 females, and an the mean duration of observation was 6.9±1.6 years.

PRIMARY AND SECONDARY OUTCOME MEASURES

We estimated the incidence of vertebral and hip fractures by BMI category (underweight: <18.5 kg/m², normal weight: 18.5-24.9 kg/m², overweight and obese: ≥25.0 kg/m²) using a Kaplan-Meier curve in males and females and determined fracture risk by sex using Cox proportional hazards regression analyses.

RESULTS

The incidence of vertebral and hip fractures was 16.8% and 6.5%, respectively. The cumulative incidence of vertebral and hip fracture at the last observation (8 years) in each BMI groups (underweight/normal weight/overweight and obese) estimated using the Kaplan-Meier curve was 14.7%/10.4%/9.0% in males and 24.9%/23.0%/21.9% in females, and 6.3%/2.9%/2.4% in males and 14.1%/9.0%/8.1% in females, respectively, and both fractures were significantly higher in underweight groups regardless of sex. Multivariable Cox proportional hazards models showed that underweight was a significant risk factor only in males for vertebral fractures and in both males and females for hip fractures.

CONCLUSION

Underweight was associated with fractures in the ageing population, but there was a sex difference in the effect for vertebral fractures.

Age and sex effects on FGF23-mediated response to mild phosphate challenge

BACKGROUND

During aging, there is a normal and mild loss in kidney function that leads to abnormalities of the kidney-bone metabolic axis. In the setting of increased phosphorus intake, hyperphosphatemia can occur despite increased concentrations of the phosphaturic hormone FGF23. This is likely from decreased expression of the FGF23 co-receptor Klotho (KL) with age; however, the roles of age and sex in the homeostatic responses to mild phosphate challenges remain unclear.

METHODS

Male and female 16-week and 78-week mice were placed on either normal grain-based chow or casein (higher bioavailable phosphate) diets for 8 weeks. Gene expression, serum biochemistries, micro-computed tomography, and skeletal mechanics were used to assess the impact of mild phosphate challenge on multiple organ systems. Cell culture of differentiated osteoblast/osteocytes was used to test mechanisms driving key outcomes.

RESULTS

Aging female mice responded to phosphate challenge by significantly elevating serum intact FGF23 (iFGF23) versus control diet; males did not show this response. Male mice, regardless of age, exhibited higher kidney KL mRNA with similar phosphate levels across both sexes. However, males and females had similar blood phosphate, calcium, and creatinine levels irrespective of age, suggesting that female mice upregulated FGF23 to maintain blood phosphorus, and compromised renal function could not explain the increased serum iFGF23. The 17β-estradiol levels were not different between groups, and in vivo bone steroid receptor (estrogen receptor 1 [Esr1], estrogen receptor 2 [Esr2], androgen receptor [Ar]) expression was not different by age, sex, or diet. Trabecular bone volume was higher in males but decreased with both age and phosphate challenge in both sexes. Cortical porosity increased with age in males but not females. In vitro studies demonstrated that 17β-estradiol treatment upregulated FGF23 and Esr2 mRNAs in a dose-dependent manner.

CONCLUSIONS

Our study demonstrates that aging female mice upregulate FGF23 to a greater degree during a mild phosphate challenge to maintain blood phosphorus versus young female and young/old male mice, potentially due to direct estradiol effects on osteocytes. Thus, the control of phosphate intake during aging could have modifiable outcomes for FGF23-related phenotypes.

Serum uric acid is associated with incident hip fractures in women and men - Results from a large Austrian population-based cohort study

OBJECTIVES

Serum markers that can be used to estimate the risk of bone fractures are rare, and findings for one candidate marker, uric acid, are heterogeneous. Our aim was to investigate the potential of serum uric acid (SUA) to predict hip fractures occurring in people aged 50 years and over.

STUDY DESIGN

During a medical prevention program over the period 1985-2005 in Vorarlberg, baseline data were collected on SUA levels and covariates (age, BMI, blood pressure, smoking status, diabetes, triglycerides and cholesterol) from 185,397 individuals, of whom 42,488 women and 35,908 men met the inclusion criteria of this population-based cohort study. Information on incident cancer and end-stage kidney disease was acquired from registries.

MAIN OUTCOME MEASURE

Incident hip fracture occurring in participants aged 50 years and over during the observation period 2003-2013.

RESULTS

SUA was associated with a rise in female hip fracture risk by 6% per unit increase (HR 1.06, 95 %-CI 1.01-1.10), and risk in the highest vs. lowest SUA quartile was significantly increased (HR 1.17, 95 %-CI 1.01-1.35), but not at hyperuricemic (>5.7 mg/dl) vs. normouricemic (≤5.7 mg/dl) levels. In men, hip fracture risk rose by 15 % per unit increase (HR 1.15, 95 %-CI 1.08-1.22), and risk was significantly higher in the highest vs. lowest SUA quartile (HR 1.50, 95 %-CI 1.17-1.91) as well as at hyperuricemic (>7.0 mg/dl) vs. normouricemic (≤7.0 mg/dl) levels (HR 1.48, 95 %-CI 1.19-1.84).

CONCLUSIONS

Our results link SUA with increased risk of hip fractures, particularly in men.

Type I Angiotensin II Receptor Blockade Reduces Uremia-Induced Deterioration of Bone Material Properties

Chronic kidney disease (CKD) is associated with a high incidence of fractures. However, the pathophysiology of this disease is not fully understood, and limited therapeutic interventions are available. This study aimed to determine the impact of type 1 angiotensin II receptor blockade (AT-1RB) on preventing CKD-related fragility fractures and elucidate its pharmacological mechanisms. AT-1RB use was associated with a lower risk of hospitalization due to fractures in 3276 patients undergoing maintenance hemodialysis. In nephrectomized rats, administration of olmesartan suppressed osteocyte apoptosis, skeletal pentosidine accumulation, and apatite disorientation, and partially inhibited the progression of the bone elastic mechanical properties, while the bone mass was unchanged. Olmesartan suppressed angiotensin II-dependent oxidation stress and apoptosis in primary cultured osteocytes in vitro. In conclusion, angiotensin II-dependent intraskeletal oxidation stress deteriorated the bone elastic mechanical properties by promoting osteocyte apoptosis and pentosidine accumulation. Thus, AT-1RB contributes to the underlying pathogenesis of abnormal bone quality in the setting of CKD, possibly by oxidative stress. © 2020 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Femoral neck shaft angle in relation to the location of femoral stress fracture in young military recruits: femoral head versus femoral neck stress fracture

OBJECTIVE

To evaluate the influences of the femoral neck shaft angle (FNSA) on the location of the femoral stress fracture and to assess the potential differences in FNSA between fractured and normal femurs.

MATERIALS AND METHODS

Thirty-seven patients with femoral stress fractures who underwent both plain hip radiographs and MRI, from January 2016 to September 2019, were retrospectively included. Patients were classified as having either femoral head stress fracture (group A, n = 26) or femoral neck stress fracture (group B, n = 11). The FNSA was measured in anteroposterior (AP) hip radiograph. The Mann-Whitney U testing was used to compare the continuous values between the two groups. A receiver operating characteristic (ROC) analysis was used to evaluate the value of FNSA for predicting the risk of femoral stress fracture.

RESULTS

The FNSA was significantly higher in group A (median 135.9°, range 129.5-138.6°) than group B (median 124.3°, range 119.5-129.0°) (p < 0.001), but there were no significant differences in other clinical factors. Furthermore, the FNSA was significantly higher at the fractured femurs (median 135.9°, range 129.9-138.6°) than contralateral normal femurs (median 127.9°, range 123.8-132.1°) in the patients with unilateral femoral head stress fracture (n = 22) (p < 0.001). The ROC analysis revealed that the area under curve (AUC), sensitivity, and specificity for predicting the risk of femoral head stress fracture were 0.807, 72.7%, and 68.2%, respectively, at a FNSA cutoff of 131.0°.

CONCLUSION

FNSA was associated with the location of the femoral stress fracture. In addition, FNSA could serve as a predictive factor for the risk of femoral head stress fractures.

Proton pump inhibitor use and risk of hip fracture in patients with type 2 diabetes

Type 2 diabetes mellitus (T2DM) is associated with a high rate of comorbidity, including osteoporosis and peptic ulcers. Proton pump inhibitors (PPIs) are a group of acid-suppressing drugs commonly used for treating peptic ulcers. However, observational studies have reported an association between PPI therapy and osteoporotic fractures. This study investigated the association between PPI use and hip fracture (HFx) among patients with T2DM. We conducted this population-based propensity-matched retrospective cohort study using the National Health Insurance Research Database in Taiwan. Patients newly diagnosed with T2DM between 2000 and 2008 were identified. After excluding those who previously used PPIs or suffered HFx, 398,885 patients were recruited (44,341 PPI users; 354,544 non-users). HFx risk data from 2000 to 2013 were collected to calculate the cumulative rate of HFx in these two groups. Sensitivity analyses were conducted to evaluate the effects of PPI dose. After propensity score matching of 1:4, 44,431 and 177,364 patients were assigned to the PPI user and non-user groups, respectively. PPI user group showed an increased risk of HFx with an adjusted hazard ratio of 1.41 (95% CI 1.29–1.54) without dose–response relationship. Thus, there is an increased risk of HFx in patients with T2DM receiving long-term PPI treatment.

Effect of renal dialysis on mortality and complications following hip fracture surgery in elderly patients: A population based retrospective cohort study

Hip fractures in older patients requiring dialysis are associated with high mortality. The primary aim of this study was to evaluate the specific burden of dialysis on 30-day mortality following hip fracture surgery. The secondary aim was to determine the burden of dialysis on overall survival as well as several postoperative complications.A retrospective cohort study was conducted using data from the Korean National Health Insurance Research Database. Patients were aged ≥65 years and underwent hip fracture surgery during the period from 2009 to 2015. To construct a matched cohort, each dialysis patient was matched to 4 non-dialysis patients based on age, sex, hospital type, anesthesia type, and comorbidities. Survival status was determined 30 days after surgery and at the end of the study period.In total, 96,289 patients were identified. Among them, 1614 dialysis patients were included and matched to 6198 non-dialysis patients. During the 30-day postoperative period, there were 102 mortality events in the dialysis group and 127 in the non-dialysis group, for an adjusted hazard ratio of 3.12 (95% confidence interval, 2.42-4.09). Overall, by the end of the study period, there were 1120 mortality events in the dialysis group and 2731 in the non-dialysis group, for an adjusted hazard ratio of 1.97 (95% confidence interval, 1.83-2.1). These findings may be limited by the characteristics of the administrative database.The 30-day mortality rate was 3-fold higher in the dialysis group than in the non-dialysis group, while the overall mortality rate was approximately 2-fold higher in the dialysis group than in the non-dialysis group. These findings suggest that caution in the perioperative period is required in dialysis patients undergoing hip fracture surgery. The results of our study represent only an association between dialysis and mortality. Further studies are necessary to investigate the possible causal effect of dialysis on mortality and complications after hip fracture surgery.

Evaluation of bone densitometry by dual-energy x-ray absorptiometry as a fracture prediction tool in women with chronic kidney disease

Background

The 2017 KDIGO guidelines establish a 2B grade recommendation in favor of testing Bone Mineral Density (BMD) by DXA to assess osteoporotic fracture (OPF) risk in patients with CKD G3a-G5D. Still, controversy remains because large studies evaluating it for this particular population are lacking.

Aim

To establish the clinical performance of BMD measured by DXA in the evaluation of fracture risk in women with CKD.

Methods

We conducted a 43 year retrospective cohort study with 218 women ≥18 years-old with CKD and BMD measurement by DXA of total hip and lumbar spine. Clinical (age, year of CKD onset, comorbidities, BMI, transplant status, treatment), and biochemical (PTH, corrected calcium, phosphate, vitamin D [25 (OH) D3], creatinine, and albumin), parameters were collected from hospital records. All osteoporotic fractures (as defined by the WHO) found in the clinical and radiologic files were registered.

Results

218 women with a median age of 60 years (40–73 IQ range) and a CKD evolution time of 12 years (7–18 IQ range) were evaluated. Forty-eight (28.23%) presented an OPF. These women were older (57 vs 69 years, p =0.0072) and had a lower BMD. CKD stage did not influence fracture incidence. In the multivariate analysis we found that for each standard deviation decrease in hip and lumbar spine T-Score, the overall fracture risk was 2.7 and 2.04 times higher, respectively. More than 50% of fractures took place within the first ten years of follow-up, especially with GFR <30 mL/min/m² and osteoporosis. Diabetes and hypothyroidism accelerated fracture onset, while renal transplant delayed it. In the ROC analysis, the AUC was largest with the total hip (0.7098, p =0.000) and lumbar spine (0.6916, p = 0.000).

Conclusions

BMD measured by DXA is a useful fracture prediction tool for women with CKD, having a sensibility and specificity similar to that in the general population. It seems to be appropriate for the diagnosis, treatment decisions, and follow-up of patients with renal failure.

Biomarkers of Bone Turnover Identify Subsets of Chronic Kidney Disease Patients at Higher Risk for Fracture

BACKGROUND

We sought to identify biomarkers that indicate low turnover on bone histomorphometry in chronic kidney disease (CKD) patients, and subsequently determined whether this panel identified differential risk for fractures in community-dwelling older adults.

METHODS

Among CKD patients who underwent iliac crest bone biopsies and histomorphometry, we evaluated candidate biomarkers to differentiate low turnover from other bone disease. We applied this biomarker panel to 641 participants in the Health Aging and Body Composition Study (Health ABC) study with estimated glomerular filtration rate (eGFR) less than 60 mL/min/1.73 m2 who were followed for fracture. Cox proportional hazards models evaluated the association of bone mineral density (BMD) with fracture risk and determined whether biomarker-defined low bone turnover modified fracture risk at any level of BMD.

RESULTS

In 39 CKD patients age 64 ± 13 years, 85% female, with mean eGFR 37 ± 14 mL/min/1.73 m2 who underwent bone biopsy, lower fibroblast growth factor (FGF)-23, higher ɑ-Klotho, and lower parathyroid hormone (PTH) indicated low bone turnover in accordance with bone histomorphometry parameters (individual area under the curve = 0.62, 0.73, and 0.55 respectively; sensitivity = 22%, specificity = 100%). In Health ABC, 641 participants with CKD were age 75 ± 3 years , 49% female, with mean eGFR 48 ± 10 mL/min/1.73 m2. For every SD lower hip BMD at baseline, there was an 8-fold higher fracture risk in individuals with biomarker-defined low turnover (hazard ratio 8.10 [95% CI, 3.40-19.30]) vs a 2-fold higher risk in the remaining individuals (hazard ratio 2.28 [95% CI, 1.69-3.08]) (Pinteraction = .082).

CONCLUSIONS

In CKD patients who underwent bone biopsy, lower FGF-23, higher ɑ-Klotho, and lower PTH together had high specificity for identifying low bone turnover. When applied to older individuals with CKD, BMD was more strongly associated with fracture risk in those with biomarker-defined low turnover.

Chronic Kidney Disease Increases the Risk of Hip Fracture: A Prospective Cohort Study in Korean Adults

This study was conducted to examine the association between renal function and hip fracture. We followed up 352,624 Korean adults, who participated in health examinations during 2009-2010 until 2013. Kidney function was assessed by creatinine-based estimated glomerular filtration rate (eGFR) and albuminuria using urine reagent strip results. The incidence of hip fracture was examined by hospital discharge records. Hazard ratios (HRs) for hip fracture were calculated using Cox proportional hazard models after adjusting for multiple confounders. During a mean follow-up of 4.0 years, 1177 participants suffered a hip fracture. Lower eGFR and more severe albuminuria were associated with a higher risk of hip fracture. The HRs for hip fracture were 1.89 (95% confidence interval [CI] 1.47-2.43) and 3.75 (95% CI 2.30-6.11) among participants with eGFRs of 30 to 44 and 15 to 29 mL/min/1.73m² relative to those with an eGFR ≥60 mL/min/1.73m² , respectively. The HRs were 1.30 (95% CI 1.02-1.65) for moderate albuminuria and 1.58 (95% CI 1.07-2.35) for severe albuminuria (p for trend = 0.002). Participants with albuminuria had a higher risk of hip fracture than those without albuminuria, even when they belonged to the same eGFR category (HR = 1.75 versus 3.30 for an eGFR of 30 to 44 mL/min/1.73m² ; HR = 2.72 versus 7.84 for an eGFR of 15 to 29 mL/min/1.73m² ). The effects of each 10 mL/min/1.73m² decrease in eGFR were stronger with advancing albuminuria severity (p_interaction = 0.016). In conclusion, both low eGFR and albuminuria were risk factors for incident hip fracture in Korean adults. Moreover, these factors exerted a synergistic effect on the risk of hip fracture. © 2020 American Society for Bone and Mineral Research.

Glomerular filtration rate is associated with trabecular bone score in patients with type 2 diabetes mellitus

AIMS

The present study aimed to evaluate the trabecular and cortical bone components using Trabecular Bone Score (TBS) and its association with estimated-Glomerular Filtration Rate (e-GFR) in T2DM patients.

METHODS

An assessment both of bone mineral density (BMD) and vertebral bone microarchitecture was performed in all patients using TBS iNsight® software version 3.0.2.0. Furthermore, the total population was divided into two groups based on the value of the eGFR (eGFR < o > at 60 ml/min/1.73 m²).

RESULTS

TBS value was lower in patients with low e-GFR than that in patients with higher e-GFR (1.246 ± 0.125 vs 1.337 ± 0.115, respectively, p = 0.013 adjusted by gender and age) while there was no difference in total BMD value between two groups. In the multivariate model taking into account several possible confounders, such as age, gender, duration of diabetes, BMI, LDL cholesterol, serum calcium and HbA1c, the correlation between e-GFR and TBS remained significant (p: 0.046).

CONCLUSIONS

In individuals with T2DM and reduced kidney function, TBS provides information independent of BMD, age and gender. TBS may be a useful additional tool to predict fracture risk in this unique population.

FGF23-klotho axis as predictive factors of fractures in type 2 diabetics with early chronic kidney disease

BACKGROUND

The aim of our study was to evaluate the relevance of FGF23-klotho axis in the predisposition for bone fractures in type 2 diabetic patients with early chronic kidney disease.

METHODS

In a prospective study we included 126 type 2 diabetic patients with CKD stages 2-3 (from 2010 to 2017). We used descriptive statistics, ANOVA and chi-square test. Our population was divided into two groups according to the occurrence of a bone fracture event or not, and the groups were compared considering several biological and laboratorial parameters. We employed a multiple regression model to identify risk factors for bone fracture events and hazard ratios (HR) were calculated using a backward stepwise likelihood ratio (LR) Cox regression.

RESULTS

Patients with a fracture event displayed higher levels of FGF-23, Phosphorus, PTH, TNF-α, OxLDL, HOMA-IR, calcium × phosphorus product and ACR and lower levels of Osteocalcin, α-Klotho, 25(OH)D3 and eGFR compared with patients without a fracture event (p < 0.001). The number of patients with a fracture event was higher than expected within inclining CKD stages (χ2, p = 0.06). The occurrence of fracture and the levels of TNF- α, klotho, 25(OH)D3 and OxLDL were found to predict patient entry into RRT (p < 0.05). Age, osteocalcin, α-Klotho and FGF-23 independently influenced the occurrence of bone fracture (p < 0.05).

CONCLUSIONS

α-Klotho and FGF-23 levels may have a good clinical use as biomarkers to predict the occurrence of fracture events.

Effect of parathyroid hormone levels on the functional capacity and pulmonary function of patients on dialysis

Abstract Introduction: Chronic kidney disease is characterized as the gradual loss of kidney function, with patients on dialysis experiencing a decline in functional capacity and pulmonary function. One of the non-traditional risk factors is parathyroid hormone (PTH), which influences metabolism and the status of the disease. Objective: Assess the effect of parathyroid hormone levels on functional capacity and pulmonary function in patients on dialysis. Method: Cross-sectional study with hemodynamically stable dialysis patients of both sexes, aged 18 to 59 years, who did not gain more than 2.5kg between dialysis sessions. Two groups were created according to PTH blood levels: PTH (A), with values outside the normal range, and PTH (C), who exhibited normal levels of the hormone. Pulmonary function (PF) was assessed by spirometry and functional capacity (FC) via the six-minute walk test (6MWT). Results: The PTH A group displayed a negative association between PTH levels and PF, based on the values obtained for the spirometric variables forced expiratory volume in 1 second (FEV1) (r = -0.54) and forced vital capacity (FVC) (r= -0.69). The average distance walked by the PTH (C) group was 343.85 ± 98.14 meters. Conclusion: The results suggest that high PTH levels have a negative effect on the PF of patients on dialysis.

Risk of hip fracture in patients on hemodialysis versus peritoneal dialysis: A meta-analysis of observational studies

BACKGROUND

Bone and mineral metabolism disorders are common among end-stage renal disease (ESRD) patients, which could lead to hip fracture. It is unclear whether the hip fracture risk is different among patients on hemodialysis (HD) versus peritoneal dialysis (PD). This meta-analysis was conducted to evaluate the hip fracture risk in ESRD patients on HD, when compared to PD.

METHODS

A literature review was conducted in EMBASE, MEDLINE, and Cochrane databases through January 31, 2018 to identify studies that appraised the rate or risk of hip fracture among patients on HD, when compared to PD. Effect estimates from the individual studies were derived and consolidated utilizing random-effect, generic inverse variance approach of DerSimonian and Laird.

RESULTS

Five cohort studies with 1 276 677 ESRD patients were enrolled. HD status was associated with a significantly higher risk of hip fracture with the pooled odds ratio (OR) of 1.61 (95% confidence interval [CI] 1.50-1.73, I²  = 10.0%), compared with PD. When the analysis was limited to studies with confounder-adjusted analysis, the pooled OR of hip fracture among HD patients was 1.57 (95% CI 1.43-1.72, I²  = 13.6%). Funnel plots and Egger's regression test demonstrated no significant publication bias in our meta-analysis.

CONCLUSIONS

Among ESRD patients, HD status is associated with a 61% higher risk of hip fracture compared to PD.

Kidney Stones and Risk of Osteoporotic Fracture in Chronic Kidney Disease

Osteoporotic fracture associated with calcium dysregulation is more common in patients with kidney stones. However, little is known about the association of kidney stones and bone health status in patients with chronic kidney disease (CKD). This retrospective medical record-based study included 2282 patients with stable stage 3–4 CKD between 2007 and 2017. Of these, 113 patients were diagnosed with kidney stones. Propensity score matching for 226 patients with and without kidney stones showed that osteoporotic fracture occurred more often in patients with kidney stones (33, 29.2%) than in patients without kidney stones (16, 14.2%), resulting in rates of 5.56 and 2.63/100 patient-years, respectively (p < 0.01). In particular, Cox proportional hazard analysis revealed that kidney stones were significantly associated with osteoporotic fracture, even after adjusting for age, sex, body mass index, kidney stones, estimated glomerular filtration rate, excessive alcohol consumption, current smoking, and steroid use in patients with CKD stage 3–4 (hazard ratio, 2.32, 95% CI 1.24–4.34, p = 0.01). This study showed that the presence of kidney stones was a significant predictor for osteoporotic fracture in patients with CKD, suggesting that it should be considered as a clinical risk factor for osteoporotic fracture in them.

Paravertebral injection of botulinum toxin-A reduces lumbar vertebral bone quality

Aging has been associated with decreases in muscle strength and bone quality. In older patients, paravertebral muscle atrophy tends to coincide with vertebral osteoporosis. The purpose of this study was to investigate the effects of a paravertebral injection of botulinum toxin-A (BTX) on paravertebral muscle atrophy and lumbar vertebral bone quality. Forty 16-week-old female SD rats were randomly divided into four groups: (1) a control group (CNT); (2) a resection of erector spinae muscles group (RESM); (3) a botulinum toxin-A group (BTX), treated with 5U BTX by local injection into the paravertebral muscles bilaterally; and (4) a positive control group (OVX), treated by bilateral ovariectomy. Rats were sacrificed at 12 weeks post-surgery, and the lumbar vertebrae (L3-L6) were collected. Micro-CT scans showed that rats in the three experimental groups-particularly the OVX rats-had fewer trabeculae and trabecular connections than rats in the CNT group. BMD was significantly lower in rats in the OVX, RESM, and BTX groups than in the CNT group (p < 0.01). Vertebral compression testing revealed significantly lower maximum load, energy absorption, maximum stress, and elastic modulus values in the three experimental groups compared with the CNT group (p < 0.01); these parameters were lowest in the OVX group (p < 0.05). Our results demonstrate that local BTX injection causes sufficient muscle atrophy and dysfunction to result in local lumbar vertebral bone loss and quality deterioration in a model of paravertebral muscle atrophy. Clinical Significance: The muscular tissues surrounding the lumbar vertebrae should be preserved during clinical surgery to avoid loss of bone quality and mass in the adjacent bone. Maintaining paravertebral muscle strength is an important consideration for patients with early osteoporosis. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2664-2670, 2018.

Bone Turnover Status: Classification Model and Clinical Implications

Aim: To develop a practical model for classification bone turnover status and evaluate its clinical usefulness. Methods: Our classification of bone turnover status is based on internationally recommended biomarkers of both bone formation (N-terminal propeptide of type1 procollagen, P1NP) and bone resorption (beta C-terminal cross-linked telopeptide of type I collagen, bCTX), using the cutoffs proposed as therapeutic targets. The relationships between turnover subtypes and clinical characteristic were assessed in1223 hospitalised orthogeriatric patients (846 women, 377 men; mean age 78.1±9.50 years): 451(36.9%) subjects with hip fracture (HF), 396(32.4%) with other non-vertebral (non-HF) fractures (HF) and 376 (30.7%) patients without fractures. Resalts: Six subtypes of bone turnover status were identified: 1 - normal turnover (P1NP>32 μg/L, bCTX≤0.250 μg/L and P1NP/bCTX>100.0[(median value]); 2- low bone formation (P1NP ≤32 μg/L), normal bone resorption (bCTX≤0.250 μg/L) and P1NP/bCTX>100.0 (subtype2A) or P1NP/bCTX<100.0 (subtype 2B); 3- low bone formation, high bone resorption (bCTX>0.250 μg/L) and P1NP/bCTX<100.0; 4- high bone turnover (both markers elevated ) and P1NP/bCTX>100.0 (subtype 4A) or P1NP/bCTX<100.0 (subtype 4B). Compared to subtypes 1 and 2A, subtype 2B was strongly associated with nonvertebral fractures (odds ratio [OR] 2.0), especially HF (OR 3.2), age>75 years and hyperparathyroidism. Hypoalbuminaemia and not using osteoporotic therapy were two independent indicators common for subtypes 3, 4A and 4B; these three subtypes were associated with in-hospital mortality. Subtype 3 was associated with fractures (OR 1.7, for HF OR 2.4), age>75 years, chronic heart failure (CHF), anaemia, and history of malignancy, and predicted post-operative myocardial injury, high inflammatory response and length of hospital stay (LOS) above10 days. Subtype 4A was associated with chronic kidney disease (CKD), anaemia, history of malignancy and walking aids use and predicted LOS>20 days, but was not discriminative for fractures. Subtype 4B was associated with fractures (OR 2.1, for HF OR 2.5), age>75 years, CKD and indicated risks of myocardial injury, high inflammatory response and LOS>10 days. Conclusions: We proposed a classification model of bone turnover status and demonstrated that in orthogeriatric patients altered subtypes are closely related to presence of nonvertebral fractures, comorbidities and poorer in-hospital outcomes. However, further research is needed to establish optimal cut points of various biomarkers and improve the classification model.

Chronic kidney disease and vitamin D metabolism in human bone marrow-derived MSCs

Vitamin D that is synthesized in the skin or is ingested undergoes sequential steps of metabolic activation via a cascade of cytochrome P450 enzymatic hydroxylations in the liver and kidney to produce 1α,25-dihydroxyvitamin D (1α,25(OH)2 D). There are many tissues that are able to synthesize 1α,25(OH)2 D, but the biological significance of extrarenal hydroxylases is unresolved. Human marrow-derived mesenchymal stem cells (marrow stromal cells, hMSCs) give rise to osteoblasts, and their differentiation is stimulated by 1α,25(OH)2 D. In addition to being targets of 1α,25(OH)2 D, hMSCs can synthesize it; on the basis of those observations, we further examined the local autocrine/paracrine role of vitamin D metabolism in osteoblast differentiation. Research with hMSCs from well-characterized subjects provides an innovative opportunity to evaluate the effects of clinical attributes on the regulation of hMSCs. Like the renal 1α-hydroxylase, the enzyme in hMSCs is constitutively decreased with age and chronic kidney disease (CKD); both are regulated by PTH1-34, insulin-like growth factor 1, calcium, 1α,25(OH)2 D, 25(OH)D, and fibroblast growth factor 23. CKD is associated with impaired renal biosynthesis of 1α,25(OH)2 D, low bone mass, and increased fracture risk. Studies with hMSCs from CKD patients or aged subjects indicate that circulating 25(OH)D may have an important role in osteoblast differentiation on vitamin D metabolism and action in hMSCs.

Osteomacs and Bone Regeneration

PURPOSE OF REVIEW

Mounting evidence supporting the critical contribution of macrophages, in particular osteal macrophages, to bone regeneration is reviewed. We specifically examine the potential role of macrophages in the basic multicellular units coordinating lifelong bone regeneration via remodelling and bone regeneration in response to injury. We review and discuss the distinctions between macrophage and osteoclast contributions to bone homeostasis, particularly the dichotomous role of the colony-stimulating factor 1-colony-stimulating factor 1 receptor axis.

RECENT FINDINGS

The impact of inflammation associated with aging and other hallmarks of aging, including senescence, on macrophage function is addressed in the context of osteoporosis and delayed fracture repair. Resident macrophages versus recruited macrophage contributions to fracture healing are also discussed. We identify some of the remaining knowledge gaps that will need to be closed in order to maximise benefits from therapeutically modulating or mimicking the function of macrophages to improve bone health and regeneration over a lifetime.

Uremic Toxicity and Bone in CKD

Patients with chronic kidney disease (CKD), especially those on dialysis treatment, are at high risk of bone fracture. In CKD-mineral and bone disorder (CKD-MBD), secondary hyperparathyroidism in patients with advanced CKD induces bone abnormalities, and skeletal resistance to parathyroid hormone (PTH) starts in the early stages of kidney disease. Uremic toxins such as indoxyl sulfate and p-cresyl sulfate reduce the expression of PTH receptor as well as PTH-induced cyclic adenosine 3',5' monophosphate production in osteoblasts. CKD also impairs bone strength, especially quality. In a rat model, kidney damage reduces the bone-storage modulus and changes the cortical bone chemical composition with or without hyperparathyroidism. The oral charcoal adsorbent AST-120 improves CKD-induced bone abnormalities as blood levels of indoxyl sulfate decrease. Uremic osteoporosis, a new concept of CKD-related bone fragility, is a main cause of CKD-induced bone abnormalities, particularly impaired bone quality. There is limited information about the effect and safety of anti-osteoporotic drugs for patients with CKD, especially those on dialysis, but the use of AST-120 and renin-angiotensin system inhibitors may modulate bone quality and decrease the incidence of fracture. Thus, the management of CKD-MBD plus use of other therapeutic interventions for uremic osteoporosis is necessary to prevent bone fragility in patients with CKD.