High rates of death and hospitalization follow bone fracture among hemodialysis patients

Prolonged secondary hyperparathyroidism in adenine-induced CKD leads to skeletal changes consistent with skeletal hyporesponsiveness to PTH

High circulating parathyroid hormone (PTH) leading to secondary hyperparathyroidism is proposed to be a key driver of the skeletal phenotype of chronic kidney disease-mineral bone disorder (CKD-MBD) leading to high bone turnover and cortical bone deterioration. The association between high PTH and the skeletal phenotype is typically clearly demonstrated in preclinical models of CKD; however, clinical studies show the relationship between PTH and skeletal outcomes is not as clear. The clinical data have led to a proposed hyporesponsiveness to PTH in the CKD setting with unclear causes. In the current study, we assessed skeletally mature male C57BL/6J mice at 12-weeks and 21-weeks of adenine-induced CKD (Ad) with the second timepoint seven weeks longer than we have previously assessed. We found that serum BUN was high in Ad mice in both groups indicating the presence of kidney disease while PTH was higher in 21-wk Ad vs. 12-wk Ad. Despite the higher PTH, bone formation rate in 21-wk Ad mice was lower than 21-wk Ad mice. Additionally, immunohistochemical assessment of the PTH receptor, PTHR1, and RANKL, a key factor upregulated by PTH, showed a lower percentage of osteocytes positive for the proteins in 21-wk Ad vs. 12-wk Ad. Furthermore, regression analyses demonstrated a positive relationship between serum PTH and PTHR1 and RANKL at 12-weeks, but this relationship was lost by 21-weeks. Overall, these data indicate that prolonged exposure to continuously elevated PTH in adenine-induced CKD mice eventually led to an altered skeletal response indicating lower responsiveness of bone, particularly osteocytes, to the chronic PTH signal. This has implications for using PTH as a surrogate marker of bone outcomes in CKD as well as pointing to the need to better understand the time-based relationship between PTH and skeletal outcomes in CKD.

Hyperphosphatemia in Kidney Failure: Pathophysiology, Challenges, and Critical Role of Phosphorus Management

Phosphorus is one of the most abundant minerals in the body and plays a critical role in numerous cellular and metabolic processes. Most of the phosphate is deposited in bones, 14% is present in soft tissues as various organic phosphates, and only 1% is found in extracellular space, mainly as inorganic phosphate. The plasma inorganic phosphate concentration is closely maintained between 2.5 and 4.5 mg/dL by intertwined interactions between fibroblast growth factor 23 (FGF-23), parathyroid hormone (PTH), and vitamin D, which tightly regulate the phosphate trafficking across the gastrointestinal tract, kidneys, and bones. Disruption of the strict hemostatic control of phosphate balance can lead to altered cellular and organ functions that are associated with high morbidity and mortality. In the past three decades, there has been a steady increase in the prevalence of kidney failure (KF) among populations. Individuals with KF have unacceptably high mortality, and well over half of deaths are related to cardiovascular disease. Abnormal phosphate metabolism is one of the major factors that is independently associated with vascular calcification and cardiovascular mortality in KF. In early stages of CKD, adaptive processes involving FGF-23, PTH, and vitamin D occur in response to dietary phosphate load to maintain plasma phosphate level in the normal range. However, as the CKD progresses, these adaptive events are unable to overcome phosphate retention from continued dietary phosphate intake and overt hyperphosphatemia ensues. As these hormonal imbalances and the associated adverse consequences are driven by the underlying hyperphosphatemic state in KF, it appears logical to strictly control serum phosphate. Conventional dialysis is inadequate in removing phosphate and most patients require dietary restrictions and pharmacologic interventions to manage hyperphosphatemia. However, diet control comes with many challenges with adherence and may place patients at risk for inadequate protein intake and malnutrition. Phosphate binders help to reduce phosphate levels but come with a sizable pill burden and high financial costs and are associated with poor adherence and psychosocial issues. Additionally, long-term use of binders may increase the risk of calcium, lanthanum, or iron overload or promote gastrointestinal side effects that exacerbate malnutrition and affect quality of life. Given the aforesaid challenges with phosphorus binders, novel therapies targeting small intestinal phosphate absorption pathways have been investigated. Recently, tenapanor, an agent that blocks paracellular absorption of phosphate via inhibition of enteric sodium-hydrogen exchanger-3 (NHE3) was approved for the treatment of hyperphosphatemia in KF. While various clinical tools are now available to manage hyperphosphatemia, there is a lack of convincing clinical data to demonstrate improvement in outcomes in KF with the lowering of phosphorus level. Conceivably, deleterious effects associated with hyperphosphatemia could be attributable to disruptions in phosphorus-sensing mechanisms and hormonal imbalance thereof. Further exploration of mechanisms that precisely control phosphorus sensing and regulation may facilitate development of strategies to diminish the deleterious effects of phosphorus load and improve overall outcomes in KF.

The effects of type 1 and type 2 diabetes mellitus on bone health in chronic kidney disease

Fracture is an under-recognized but common complication of diabetes mellitus, with an incidence approaching twofold in type 2 diabetes mellitus (T2DM) and up to sevenfold in type 1 diabetes mellitus (T1DM) compared with that in the general population. Both T1DM and T2DM induce chronic hyperglycaemia, leading to the accumulation of advanced glycosylation end products that affect osteoblast function, increased collagen crosslinking and a senescence phenotype promoting inflammation. Together with an increased incidence of microvascular disease and an increased risk of vitamin D deficiency, these factors reduce bone quality, thereby increasing bone fragility. In T1DM, reduced anabolic stimuli as well as the presence of autoimmune conditions might also contribute to reduced bone mass and increased fragility. Diabetes mellitus is the most common cause of kidney failure, and fracture risk is exacerbated when chronic kidney disease (CKD)-related mineral and bone disorders are superimposed on diabetic changes. Microvascular pathology, cortical thinning and trabecular deterioration are particularly prominent in patients with T1DM and CKD, who suffer more fragility fractures than do other patients with CKD. This Review explores the pathophysiology of bone fragility in patients with diabetes mellitus and CKD and discusses techniques to predict fracture and pharmacotherapy that might reduce fracture risk.

Interpretable machine learning models for the prediction of all-cause mortality and time to death in hemodialysis patients

INTRODUCTION

The elevated mortality and hospitalization rates among hemodialysis (HD) patients underscore the necessity for the development of accurate predictive tools. This study developed two models for predicting all-cause mortality and time to death-one using a comprehensive database and another simpler model based on demographic and clinical data without laboratory tests.

METHOD

A retrospective cohort study was conducted from January 2017 to June 2023. Two models were created: Model A with 85 variables and Model B with 22 variables. We assessed the models using random forest (RF), support vector machine, and logistic regression, comparing their performance via the AU-ROC. The RF regression model was used to predict time to death. To identify the most relevant factors for prediction, the Shapley value method was used.

RESULTS

Among 359 HD patients, the RF model provided the most reliable prediction. The optimized Model A showed an AU-ROC of 0.86 ± 0.07, a sensitivity of 0.86, and a specificity of 0.75 for predicting all-cause mortality. It also had an R2 of 0.59 for predicting time to death. The optimized Model B had an AU-ROC of 0.80 ± 0.06, a sensitivity of 0.81, and a specificity of 0.70 for predicting all-cause mortality. In addition, it had an R2 of 0.81 for predicting time to death.

CONCLUSION

Two new interpretable clinical tools have been proposed to predict all-cause mortality and time to death in HD patients using machine learning models. The minimal and readily accessible data on which Model B is based makes it a valuable tool for integrating into clinical decision-making processes.

The Challenge of Fractures in Patients With Chronic Kidney Disease

OBJECTIVE

People with chronic kidney disease (CKD) are at increased risk of fractures in comparison to the non-CKD population, and fractures are associated with high mortality and worsening quality of life. However, the approach for evaluation of bone disease and fracture risk in CKD is different from the approach in the general population.

METHODS

The authors conducted a literature review of PubMed to include studies on pathophysiology of CKD mineral bone disorder, fracture risk assessment, and therapeutic options in the setting of CKD.

RESULTS

The higher risk observed in the CKD population is related to the complex interplay of changes in bone turnover (T), mineralization (M), and volume (V), along with other risk factors accumulated as glomerular filtration rate declines. The diagnosis of the type of renal osteodystrophy is not based only on assessment of bone density and traditional risk factors for osteoporosis. There are limitations of currently available fracture risk tools in the CKD population. Treatment choice should take into consideration the 3 components of the TMV classification along with the stage of kidney disease and comorbidities, but the assessment of these components has not been well established.

CONCLUSIONS

Current data are limited on efficacy and safety of treatments for fracture prevention in CKD. As new medications for the treatment of osteoporosis become available, there is an urgency to establish more clear guidelines for the diagnosis, fracture risk stratification, and treatment of bone disease in CKD.

Osteosarcopenia in Chronic Kidney Disease: An Overlooked Syndrome?

BACKGROUND

Healthy ageing relies on maintaining physiological systems, particularly the musculoskeletal system (MKS). After 50, declines in bone density, muscle mass and strength increase the risk of osteoporosis and sarcopenia, leading to frailty, fractures and higher healthcare costs. Osteosarcopenia, combining osteoporosis and sarcopenia, is rising because of the ageing population. Chronic kidney disease (CKD) exacerbates this condition through disruptions in mineral metabolism, hormonal imbalances and inflammation, further compromising musculoskeletal health.

AIMS

This review examines the pathophysiology of osteosarcopenia associated with CKD, focusing on the role of mineral and hormonal disturbances, chronic inflammation and endocrine dysfunction. It aims to increase clinical awareness and highlight the need for early diagnosis and intervention to mitigate the burden of osteosarcopenia on the quality of life and healthcare systems in ageing CKD populations.

METHODS

A narrative review of the current literature was conducted, summarising evidence on the mechanisms underlying osteosarcopenia in CKD, including mineral metabolism alterations, inflammatory processes and hormonal imbalances.

RESULTS

Osteosarcopenia is a recognised consequence of CKD, contributing to increased morbidity and mortality. The pathophysiology of osteosarcopenia in CKD is multifactorial, involving disruptions in mineral metabolism, inflammation, endocrine dysfunction and physical inactivity. CKD-mineral and bone disorder (CKD-MBD) leads to alterations in calcium, phosphate, parathyroid hormone (PTH), fibroblast growth factor 23 (FGF-23) and vitamin D metabolism, resulting in impaired bone mineralisation and increased fracture risk. Simultaneously, CKD accelerates muscle wasting through systemic inflammation, anabolic resistance and metabolic derangements, increasing the risk of sarcopenia. Sarcopenic obesity, inflammaging and hormonal dysregulation further exacerbate bone muscle deterioration. Emerging evidence suggests that osteosarcopenia in CKD is a consequence of interconnected pathophysiological pathways rather than isolated conditions. Diagnosis remains challenging because of overlapping clinical features, necessitating integrated assessment tools. Targeted therapeutic strategies, including mineral metabolism correction, resistance exercise and anabolic interventions, are essential to mitigate osteosarcopenia's progression and improve patient outcomes in CKD.

CONCLUSIONS

Osteosarcopenia is a growing concern in ageing CKD populations. Early diagnostic strategies and targeted interventions are essential to mitigate the impact of osteosarcopenia on patient outcomes and reduce associated healthcare costs. Increased clinical awareness and research into effective therapies are crucial for improving the quality of life for individuals affected by CKD and osteosarcopenia.

Effectiveness of rehabilitation in hospitalized hemodialysis patients as compared with rehabilitation in hospitalized patients not on hemodialysis: a retrospective cohort study

BACKGROUND

The effectiveness of rehabilitation aimed at improving the activities of daily living and physical functions may differ between hospitalized patients undergoing hemodialysis (HD) and not undergoing HD (non-HD). The aim of the present study was to compare the outcomes of rehabilitation between hospitalized HD and non-HD patients.

METHODS

This was a retrospective cohort study of inpatients who underwent rehabilitation. We measured the rehabilitation time (min/day), length of hospital stay (days), and the Barthel index (BI). In addition, at the time of admission and discharge, grip strength, isometric knee extension strength, 10 m walking speed, timed up and go test, and short physical performance battery were examined. The outcomes were then compared between the HD and non-HD groups.

RESULTS

This study was made up of 902 patients (non-HD group: 765, HD group: 137). Our analysis revealed a lower rehabilitation time [43.3 (0.6) vs. 38.8 (1.2) min/day] and longer hospital stay [48.5 (0.5) vs. 58.1 (2.3) days] in the HD group as compared with the non-HD group (p < 0.05). In addition, the 10 m walking speed [0.75 (0.02) vs. 0.66 (0.03) m/s], timed up and go test [20.8 (0.7) vs. 24.3 (1.0) sec], and short physical performance battery [6.3 (0.6) vs. 4.7 (0.6) points] at discharge were also significantly lower in the HD group as compared with the non-HD group (p < 0.05).

CONCLUSION

Rehabilitation efforts for HD patients need to be improved by securing more time for inpatient rehabilitation and promoting mobility function improvement for these patients.

Higher Serum Alkaline Phosphatase Is a Risk Factor of Death and Fracture: A Nationwide Cohort Study of Japanese Patients on Dialysis

Key Points

In the lower-parathyroid hormone (PTH) group, associations between serum alkaline phosphatase (ALP) and all-cause mortality were positive and linear. In the higher-PTH group, lower serum ALP tended to have higher risk than those with intermediate serum ALP. Serum ALP was independently and linearly associated with new hip fracture regardless of intact PTH level.

Background

Monitoring of serum alkaline phosphatase (ALP) is recommended in the management of CKD–mineral bone disorder because of associations with poor outcomes among patients on dialysis. However, such associations may have changed with several advances in the management of CKD–mineral bone disorder over the past decade.

Methods

Baseline data of 241,670 patients on dialysis (mean age, 69±12 years; male, 65.9%; median dialysis duration, 68 months) were extracted from a nationwide dialysis registry in Japan at the end of 2019. Outcomes, including all-cause and cardiovascular (CV) mortality and hip fracture, were evaluated using the registry at the end of 2020 and 2021. All-cause mortality was assessed using Cox regression analysis, whereas CV mortality and new hip fracture were assessed using competing-risks regression analysis. Multiple imputations for missing values were performed.

Results

Within the 2-year study period, a total of 40,449 patients (16.7%) died, including 13,562 CV deaths (5.6%). Of the 168,836 patients with no history of hip fracture at the end of 2019, 4136 (2.4%) suffered hip fracture within 2 years. Higher serum ALP was independently associated with higher all-cause and CV mortality and new hip fracture, but the association with CV mortality was marginal (hazard ratio, 1.21; 95% confidence interval [CI], 1.18 to 1.24; subhazard ratio, 1.07; 95% CI, 1.03 to 1.12 and subhazard ratio, 1.28, 95% CI, 1.19 to 1.38, respectively). There is a linear association between serum ALP and all-cause mortality among the lower parathyroid hormone (PTH) group, whereas lower serum ALP tended to have higher all-cause mortality than intermediate serum ALP among patients in the higher PTH group.

Conclusions

Higher serum ALP was independently and linearly associated with higher all-cause and CV mortality and new hip fracture in Japanese patients on dialysis. Higher serum ALP and higher intact PTH were synergistic in increasing all-cause and CV mortality but were not associated with new hip fracture.

Super-high levels of serum intact-parathyroid hormone and bone turnover markers descended with recuperating allograft function and a short-term high-dose methylprednisolone during preoperative period of renal transplantation: a retrospective cohort study

Background

Secondary hyperparathyroidism is an important factor of chronic kidney disease-mineral and bone disorder (CKD-MBD), which frequently results in maintenance dialysis patients having super-high levels of serum intact-parathyroid hormone (iPTH) and bone turnover markers (BTMs). This study aimed to investigate the immediate changes of iPTH and BTMs levels after renal transplantation during the perioperative period, and to explore the allograft function rapid recovery and the effect of high-dose glucocorticoids on serum iPTH and BTMs.

Methods

Between April 2018 and August 2021, a total of 346 Chinese kidney transplantation (KT) recipients (median age, 34.0 years; 236 males and 110 females; median dialysis duration, 12 months) were enrolled in this retrospective cohort study. The included patients had been undergoing maintenance dialysis for at least three months before transplant, and all of them accepted short-term high-dose methylprednisolone (MP) to prevent allograft rejection in the perioperative period. Allograft functions were evaluated and divided into different groups accorded to the CKD staging on the postoperative fifth day. Serum beta C-terminal crosslinking telopeptide of type I collagen (β-CTX), type 1N-terminal propeptide (P1NP), osteocalcin (OC), and iPTH were measured from fasting morning blood samples before surgery and on the postoperative fifth day with an electro-chemiluminescence immunoassay analyzer (2012; Roche Diagnostics).

Results

Among the participants, the graft functions were in CKD-II (n=134), CKD-III (n=137), CKD-IV (n=24), and CKD-V (n=51) after the postoperative fifth day. The changes of P1NP level [-95.8 (-84.0 to -2.4) ng/mL] and the OC level [-88.0 (-96.9 to -42.9) ng/mL] were significantly greater than those of the β-CTX level [-62.3 (-73.6 to 0) pg/mL] and the iPTH level [-57.6 (-15.6 to 11.9) pg/mL] (P<0.001). In the CKD-V group, the changes of β-CTX level [-0.7 (-43.15 to 0) pg/mL (+15.7%, P=0.61)] and the iPTH level [-8.69 (226.73 to 17.79) pg/mL (-22.8%), P=0.36] were less than those of the CKD-II group (P<0.001). β-CTX, P1NP, and OC levels related with iPTH (r=0.413, 0.459, 0.482, respectively, P<0.001), and iPTH level with estimated glomerular filtration rate (eGFR; r=-0.474, P<0.001).

Conclusions

The super-high levels of BTMs and iPTH rapidly descended with recuperating allograft function during the short-term, indicating that improvement of current dialysis equipment to achieve clean up iPTH could more favorably decrease BMTs and improve CKD-MBD. Osteogenesis markers P1NP and OC still decreased and were not affected in CKD-V group, indicating that high-dose glucocorticoids might strongly inhibit osteoblast activity.

Radiofrequency Echographic Multi Spectrometry-A Novel Tool in the Diagnosis of Osteoporosis and Prediction of Fragility Fractures: A Systematic Review

Background/Objectives: Given the significant economic and social burden of osteoporosis, there is growing interest in developing an efficient alternative to the traditional dual-energy X-ray absorptiometry (DXA). Radiofrequency Echographic Multi Spectrometry (REMS) is an innovative, non-ionizing imaging technique that recently emerged as a viable tool to diagnose osteoporosis and estimate the fragility fracture risk. Nevertheless, its clinical use is still limited due to its novelty and continuing uncertainty of long-term performance. Methods: In order to evaluate the accuracy of the REMS, a systematic review of the English-language literature was conducted. Three databases were searched for relevant publications from 1 January 2015 until 1 December 2024 using the keyword combinations "(radiofrequency echographic multi spectrometry OR REMS) AND (dual-energy X-ray absorptiometry OR DXA)". The initial search yielded 602 candidate articles. After screening the titles and abstracts following the eligibility criteria, 17 publications remained for full-text evaluation. Results: The reviewed studies demonstrated strong diagnostic agreement between REMS and DXA. Additionally, REMS showed enhanced diagnostic capabilities in cases where lumbar bone mineral density measurements by DXA were impaired by artifacts such as vertebral fractures, deformities, osteoarthritis, or vascular calcifications. REMS exhibited excellent intra-operator repeatability and precision, comparable to or exceeding the reported performance of DXA. The fragility score (FS), a parameter reflecting bone quality and structural integrity, effectively discriminated between fractured and non-fractured patients. Moreover, REMS proved to be a radiation-free option for bone health monitoring in radiation-sensitive populations or patients requiring frequent imaging to assess fracture risk. Conclusions: This current study underscores the robustness of REMS as a reliable method for diagnosing and monitoring osteoporosis and evaluating bone fragility via the FS. It also identifies critical knowledge gaps and emphasizes the need for further prospective studies to validate and expand the clinical applications of REMS across diverse patient populations.

Chronic Kidney Disease and Osteoarthritis: Current Understanding and Future Research Directions

Chronic kidney disease (CKD) is a significant public health concern. Osteoarthritis (OA), a common form of arthritis, has been shown to have a dramatically increased prevalence, particularly among individuals aged 40-50 and older, in the presence of CKD. Furthermore, CKD may exacerbate the progression and impact of OA. A survey study revealed that 53.9% of CKD patients undergoing long-term hemodialysis were diagnosed with OA. These findings underscore the potential association between CKD and OA. Uremic toxins, such as indoxyl sulfate, p-cresyl sulfate, transforming growth factor-β, and advanced glycation end-products, are regarded as potential risk factors in various CKD-related conditions, affecting bone and joint metabolism. However, whether these factors serve as a bridging mechanism between CKD and OA comorbidities, as well as their detailed roles in this context, remains unclear. Addressing the progression of OA in CKD patients and identifying effective treatment and prevention strategies is an urgent challenge that warrants immediate attention. This review focuses on describing and discussing the molecular pathological mechanisms underlying CKD-associated OA and the possible therapeutic strategies.

Oral phosphate binders and incident osteoporotic fracture in patients on dialysis

BACKGROUND

End-stage kidney disease (ESKD) has an elevated risk of osteoporotic fractures in relation to mineral and bone disorder (MBD) as well as conventional risks of osteoporosis. We investigated the association between oral phosphate binders, the mainstay of MBD treatment, and osteoporotic fracture in dialysis patients.

METHODS

We obtained data from the National Health Insurance database for incident dialysis patients without a history of osteoporotic fractures. Participants were categorized into four groups based on their initial 1-year prescription profiles: calcium-based phosphate binder (CBPB), non-calcium-based phosphate binder (NCBPB), both CBPB and NCBPB (mixed), and non-phosphate binder (non-user) groups. The primary outcome was the occurrence of new-onset osteoporotic fractures after 1 year of dialysis. Secondary outcomes included cardiovascular events and mortality.

RESULTS

Out of 69 368 incident dialysis patients, 22 326, 5020, 2853 and 39 169 were included in the CBPB, NCBPB, mixed and non-user groups, respectively. The overall risk of osteoporotic fractures was lower in patients taking any phosphate binders compared with non-users. Specifically, only the CBPB group showed a reduced risk of vertebral [adjusted hazard ratio (aHR) 0.83 (0.76-0.92)], hip [aHR 0.81 (0.74-0.89)] and distal radius [aHR 0.88 (0.78-0.99)] fractures compared with non-users. This relationship presented in a time-dependent manner with fracture risk reduction in patients taking CBPB for 3-6 months [aHR 0.9 (0.83-0.99)] and ≥6 months [aHR 0.83 (0.78-0.89)], compared with those using CBPB for <3 months. Additionally, only the CBPB group had a lower risk of MACE, cardiac arrest and ventricular arrhythmia than non-users. All phosphorus binder groups showed a reduced mortality risk compared with non-users.

CONCLUSIONS

Our findings indicate that the using phosphate binders in ESKD patients is lowers the risk of osteoporotic fractures. Notably, those taking CBPB had a reduced risk without increasing cardiovascular events or mortality compared with non-users.

The Impact of a Western Diet High in Phosphate on the CKD-MBD in an Alport Syndrome Model

Background

Chronic kidney disease - mineral bone disorder (CKD-MBD) is a syndrome that begins early in CKD, contributes to CKD-associated mortality, and includes components of FGF23 elevation, αklotho deficiency, CKD-stimulated vascular disease, and renal osteodystrophy. Hyperphosphatemia, occurring in later stages of CKD, is also driven by mechanisms of CKD-MBD, and has been shown to stimulate vascular calcification. In a mouse model of Alport CKD that is resistant to vascular calcification, we examine the effects of a high-phosphate Western-type diet on the CKD-MBD, and test whether the diet promotes induction of vascular calcification.

Methods

An X-linked Col4a5 deficient murine homolog of Alport Syndrome (CKD) and wild type (WT) littermates were fed an animal protein 1.2% high phosphate diet or a standard vegetable protein diet. At disease progression equivalent to CKD stage 4-5, we examined kidney histology for fibrosis, blood for BUN (marker of CKD), and markers of CKD-MBD disease progression, kidney tissue for klotho production, and aorta histology and tissue mRNA and protein analysis for vascular calcification.

Results

The Western high Pi diet produced hyperphosphatemia in the CKD animals compared to WT and increased plasma PTH (1880 from 110 pg / ml), FGF23 c-term (670 from 120 pg / ml), and FGF23 intact (3780 from 280 pg / ml), and reduced kidney klotho mRNA and protein (57-67% reduction) (all p < 0.01). Referenced against the CKD animals fed vegetable-based diet, the Western high phosphate-fed CKD animals showed higher levels of plasma PTH and FGF23s. In the wild-type control mice with normal renal function, Western diet produced increased PTH, intact FGF23, and reduced renal klotho (all p <0.01). Vascular smooth muscle transdifferentiation and vascular calcification was not induced by Western high phosphate diet in this model of CKD.

Conclusions

Our results show that a Western-style high-phosphate diet advances elements of the CKD-MBD. Renal klotho, FGF23 and PTH are affected by diet even with normal kidney function, suggesting a need for early intervention in the management of phosphate homeostasis as a component of CKD therapy. Additionally, CKD, klotho, and FGF23 all are associated with early aging. Therefore, our findings suggest that a Western high Pi diet accelerates aging and would contribute to the systemic complications of CKD - cardiac disease, osteodystrophy, and vascular disease.

Association between psoas muscle mass index and bone mineral density in patients undergoing hemodialysis

Patients undergoing dialysis are at risk of osteoporosis and sarcopenia because of mineral and bone disorders or malnutrition. Additionally, maintaining muscle mass is important to prevent osteoporosis. The psoas muscle mass index (PMI) was recently used to evaluate muscle mass. However, few studies have evaluated the association between the PMI and bone mineral density (BMD); therefore, we examined the association between PMI and BMD in the femoral neck (FN) of 80 patients (45 males, age, 71 (60-76) years; dialysis duration, 74 (36-140) months) undergoing hemodialysis. FN-BMD was measured using dual-energy X-ray absorptiometry, and PMI was evaluated using psoas muscle areas on computed tomography. FN-BMD and PMI were significantly higher in males than in females. In a correlation analysis, sex, BMI, serum creatinine levels, HbA1c levels, and PMI were positively correlated with FN-BMD, whereas age, history of bone fracture, difficulty in walking and bone-specific alkaline phosphatase level were negatively correlated. In the multivariate regression analysis using clinical factors significantly correlated to FN-BMD, including PMI, both sex (standardized coefficient: 0.249, p = 0.028) and PMI (standardized coefficient: 0.249, p = 0.038) were extracted. Multivariable linear regression analysis using PMI and traditional osteoporosis factors revealed that PMI was significantly and independently associated with FN-BMD (standardized coefficient: 0.308, p = 0.010). In conclusion, PMI was positively associated with FN-BMD. Attention should be paid to the possibility of decreased BMD with decreased muscle mass.

Lower serum magnesium levels are associated with a higher risk of fractures and vascular calcifications in hemodialysis patients

Background

Magnesium (Mg) deficiency seems to be associated with altered bone metabolism and vascular calcifications (VC). This study aimed to evaluate the association between serum Mg levels and incident bone fragility fractures and VC in a cohort of prevalent hemodialysis (HD) patients.

Methods

We performed a retrospective study of 206 patients, with a mean age of 68.3 ± 13.1 years; 121 (59%) were male, and the median follow-up time was 58 months.

Results

Thirty-seven episodes of fragility fractures were identified with a median HD vintage of 42 months-an incidence rate of 29 per 1000 person-years. Patients with fractures showed lower Mg levels compared with those without fractures (P < .001) and more VC (P = .01). In a Cox regression analysis, time to fragility fracture was independently associated with serum Mg <2.2 mg/dL (P < .001), in a model adjusted to age, female gender, HD vintage, diabetes mellitus, body mass index, albumin, parathyroid hormone, active vitamin D therapy and the presence of VC. Patients with Mg serum levels <2.2 mg/dL had a 1.32-fold higher risk of fragility fractures (P < .001).

Conclusions

This study showed that the incidence of bone fragility fractures in HD patients is high and is significantly associated with lower Mg levels and with the presence of more VC.

Vitamin D status and intermediate vascular and bone outcomes in chronic kidney disease: a secondary post hoc analysis of IMPROVE-CKD

BACKGROUND AND AIMS

Cardiovascular disease is the leading cause of death in patients with chronic kidney disease (CKD) and has been associated with abnormalities of mineral metabolism and vascular calcification. Vitamin D influences parathyroid hormone values and calcium and phosphate metabolism, and may play a role in vascular function and bone health. We aimed to test our hypothesis that vitamin D deficiency is associated with arterial stiffness, aortic calcification and lower bone mineral density (BMD) in patients with CKD.

METHODS

A cross-sectional analysis was performed using baseline data from the IMpact of Phosphate Reduction On Vascular Endpoints in CKD (IMPROVE-CKD) study cohort. Clinical and laboratory parameters were compared between those with and without vitamin D deficiency, defined as 25-hydroxyvitamin D (25(OH)D) <50 nmol/L. Univariable and multivariable linear regression analyses were performed to assess associations between serum 25(OH)D levels and pulse wave velocity (PWV), augmentation index (AIx), abdominal aortic calcification (measured by the Agatston score) and lumbar spine BMD.

RESULTS

Baseline 25(OHD) values were available in 208 out of 278 IMPROVE-CKD study participants, with a mean value of 70.1 ± 30.7 nmol/L. Of these, 57 (27%) patients had vitamin D deficiency. Those with 25(OH)D deficiency were more likely to have diabetes (56% vs 38%), cardiovascular disease (54% vs 36%) and lower serum calcium (2.29 ± 0.13 vs 2.34 ± 0.13 mmol/L). On univariable and multivariable regression analyses, baseline 25(OH)D values were not associated with PWV, the AIx, Agatston score or BMD.

CONCLUSION

Baseline 25(OH)D levels were not associated with intermediate markers of vascular function and BMD in patients with CKD stages 3b and 4.

Risk factors and clinical prediction models for osteoporosis in pre-dialysis chronic kidney disease patients

BACKGROUND

Osteoporosis in pre-dialysis chronic kidney disease (CKD) patients has been overlooked, and the risk factors of osteoporosis in these patients have not been adequately studied.

OBJECTIVE

To identify risk factors for osteoporosis in pre-dialysis CKD patients and develop predictive models to estimate the likelihood of osteoporosis.

METHODS

Dual-energy X-ray absorptiometry was used to measure bone mineral density, and clinical examination results were collected from 326 pre-dialysis CKD patients. Binary logistic regression was employed to explore the risk factors associated with osteoporosis and develop predictive models.

RESULTS

In this cohort, 53.4% (n = 174) were male, 46.6% (n = 152) were female, and 21.8% (n = 71) were diagnosed with osteoporosis. Among those diagnosed with osteoporosis, 67.6% (n = 48) were female and 32.4% (n = 23) were male. Older age and low 25-(OH)-Vitamin D levels were identified as risk factors for osteoporosis in males. For females, older age, being underweight, higher bone alkaline phosphatase (NBAP), and advanced CKD (G5) were significant risk factors, while higher iPTH was protective. Older age, being underweight, and higher NBAP were risk factors for osteoporosis in the G1-4 subgroup. In the G5 subgroup, older age and higher NBAP increased the risk, while high 25-(OH)-Vitamin D or iPTH had protective effects. Nomogram models were developed to assess osteoporosis risk in pre-dialysis patients based on gender and renal function stage.

CONCLUSION

Risk factors for osteoporosis vary by gender and renal function stages. The nomogram clinical prediction models we constructed may aid in the rapid screening of patients at high risk of osteoporosis.

Benefits of Continuous Outpatient Orthopedic Consultations for Both Upper and Lower Body on the Mortality Rates of Hemodialysis Patients

BACKGROUND

The purpose of the present observational study was to examine whether there is a difference in prognosis for hemodialysis patients with or without continued orthopedic outpatient visits over five years.  Methods: One hundred and thirteen hemodialysis patients who visited the dialysis center of Takagi Hospital, Okawa, Japan, as of December 2017 were included in this study. Data were collected from the medical records until December 2022. All 113 patients were divided into two groups: patients who continuously visited the orthopedic outpatient department (n = 59) and those who did not (n = 54). Patients who had orthopedic consultation were divided into three semi-groups: patients who consulted for the upper body (n = 11), the lower body (n = 22), and both the upper and lower bodies (n = 26).

RESULTS

During the five-year follow-up period, 13 out of 59 patients (22.0%) who had orthopedic consultation died, and this ratio tended to be lower compared to the mortality rate of patients without orthopedic consultation (37.0%) but not significant (P < 0.08). Duration of hemodialysis was significantly longer in patients with orthopedic consultation (P = 0.009). The mortality rate was significantly lower in patients who consulted for both upper and lower bodies than those without orthopedic consultation (P < 0.05, respectively). These differences were not observed in patients who consulted for only upper or lower bodies.

CONCLUSION

The mortality of hemodialysis patients was significantly lower in the group which was undertaking continuous outpatient orthopedic consultations for both upper and lower bodies, which suggested that periodical consultation with orthopedics might be critical for hemodialysis patients.

Hip geometry and strength remain stable the first year after kidney transplantation-an ibandronate/placebo post hoc analysis

The sensitivity of bone mineral density (BMD) to identify patients with high fracture risk after kidney transplantation is low, therefore alternative tools are needed. Hip Structure Analysis (HSA) provides an estimation of hip structural geometry and strength based on conventional DXA scans for hip analyses. We aimed to investigate the effect of antiresorptive therapy on hip geometrical and strength parameters by HSA. In a post hoc analysis of a 12-month randomized, double-blind, placebo-controlled trial evaluating the effect of ibandronate in addition to active vitamin D and calcium in kidney transplant recipients (KTR), we re-analyzed dual total hip and femoral neck DXA scans to measure cortical bone thickness (CBT) in the femoral neck (CBTNECK), calcar (CBTCALCAR), and shaft (CBTSHAFT), along with femur neck width, hip axis length, and to estimate buckling ratio and strength index. DXA measurements were performed within 5 weeks after transplantation and repeated at 10 weeks and 1-year post-transplant. The study included a total of 127 de novo KTR with estimated glomerular filtration rate >30 mL/min at baseline. The 5 geometrical and the strength and stability hip parameters remained stable over the first post-transplant year irrespective of antiresorptive therapy. We detected no statistically significant between-group differences in any of the HSA measures. Change in geometrical hip parameters and buckling ratio over the study duration was not correlated with change in plasma parathyroid hormone or change in dual total hip BMD. In this study, the so far largest of HSA in KTR, antiresorptive therapy with ibandronate for 12 months did not affect measures of hip geometry or strength. Clinical Trial Registration: www.clinicaltrials.gov as NCT00423384, EudraCT number 2006-003884-30.

Bisphosphonate Use after Kidney Transplantation Is Associated with Lower Fracture Risk

Key Points

Bisphosponate use may decrease the risk of fracture in patients receiving kidney transplant. Identifying those at risk of fracture after kidney transplant is critical.

Background

Kidney transplant recipients are at higher risk of fractures compared with the general population. The use of bisphosphonates has been shown to increase bone mineral density after transplantation but has not been shown to lower fracture rates. In this study, we aim to determine whether exposure to bisphosphonates is associated with lower incidence of nonvertebral fractures after kidney transplantation.

Methods

We conducted a retrospective review for all Southern California Kaiser Permanente kidney transplant recipients with osteoporosis transplanted between 2000 and 2019. Baseline variables were collected. Those prescribed an oral bisphosphonate were compared with those who were not. The primary outcome was nonvertebral fracture. Chi-square test was used to evaluate categorical variables and Wilcoxon rank-sum test for continuous variables. Propensity scores were generated to balance covariates in the bisphosphonate and nonbisphosphonate groups. Cause-specific hazard and subdistribution (Fine–Gray) methods were performed for competing risk analysis. Death-censored graft survival was evaluated as a secondary outcome using standard Cox regression.

Results

There were 489 patients included in the study, 203 of which were in the bisphosphonate group. The cause-specific hazard model suggested a 64% lower risk of nonvertebral fracture in the bisphosphonate group (P = 0.02). The Fine–Gray hazard model treating death as a competing risk did not show lower relative incidence of nonvertebral fracture. Bisphosphonate treatment was associated with lower death-censored graft failure (P = 0.002).

Conclusions

Bisphosphonate use after kidney transplantation may be associated with a lower risk of nonvertebral fracture after transplant. Bisphosphonate use in this study was also associated with lower death-censored graft failure. Caution is advised when interpreting these results given the retrospective nature of the study.

Clinical Utility of Bone Turnover Markers in Chronic Kidney Disease

Chronic kidney disease (CKD) often leads to mineral and bone disorders (CKD-MBDs), which are nearly universal in patients undergoing dialysis. CKD-MBD includes abnormal calcium-phosphate metabolism, vascular and soft tissue calcification, and bone abnormalities (renal osteodystrophy [ROD]). Bone fragility in CKD occurs due to low bone mass and poor bone quality, and patients with CKD have higher fracture and mortality rates. Bone histomorphometry is the gold standard for ROD diagnosis; however, it is labor-intensive and expensive. The Kidney Disease Improving Global Outcomes clinical practice guidelines on CKD-MBD suggest serum parathyroid hormone (PTH) and bone-specific alkaline phosphatase (bone ALP) for predicting bone turnover in ROD. In this review, we focus on the role of PTH and bone turnover markers, intact procollagen type N-terminal propeptide of type I collagen, bone ALP, and tartrate-resistant acid phosphatase 5b in diagnosing ROD, predicting fractures, and guiding treatment in patients with CKD.

Cardiac Biomarkers are Associated with Incident Fracture Risk in Advanced Chronic Kidney Disease

Cardiovascular disease is associated with increased fracture risk in the general population. Few data exist on the association between cardiovascular health and incident fracture risk in patients with advanced CKD, a high-risk population for fractures. We aimed to assess the link between fracture risk and cardiovascular health in a prospective cohort of 210 patients with CKD stage G4-5. Incident fractures were recorded during a prospective follow-up of 5 years. Laboratory parameters, abdominal aortic calcification score, echocardiography, ultrasound assessment of brachial artery flow-mediated dilatation and carotid intima-media thickness, and maximal stress ergometry were obtained at baseline. A total of 51 fractures were observed in 40 (19%) patients during follow-up. In separate multivariable Cox proportional hazards models adjusted for age, gender, and baseline eGFR, TnT (HR 1.007, CI 95% 1.003-1.010, p < 0.001) and ProBNP (HR 1.000, CI 95% 1.000-1.000, p = 0.017) were associated with incident fractures and the association persisted after adjusting for coronary artery disease (CAD). The patients unable to perform the ergometry test had a higher risk of incident fractures compared to others (36.1% vs 15.5%, p = 0.009). A cardiovascular composite risk score summarizing TnT, ProBNP, and ergometry data was independently associated with incident fractures in a multivariable Cox model (HR 1.373, CI 95% 1.180-1.599, p < 0.001). Patients with the lowest score were observed with no fractures, while patients with the highest score were observed with a fracture risk of 40.5% during follow-up. Risk of incident fractures is associated with biomarkers of cardiovascular health and a composite cardiovascular risk score in patients with advanced CKD.

Lower body bone fractures have high mortality rates and poor prognosis in the patients with hemodialysis

INTRODUCTION

The objective of the current study was to investigate the association between lower body bone fractures occurring during maintenance hemodialysis and prognosis.

METHODS

This study included 151 hemodialysis patients at the dialysis center of our hospital as of December 2017, and data were systematically gathered from medical records over a period of 5 years, concluding in December 2022.

RESULTS

Fourteen patients, 3.0 per 100 person-years, in 151 hemodialysis patients suffered from lower body bone fractures. The ratio of males was significantly lower, and age was significantly higher in the lower body bone fracture group than in the no lower body bone fracture group. Duration of hemodialysis prior to entry into this study was significantly shorter in the lower body bone fracture group than in the no lower body bone fracture group. Serum albumin was significantly lower and alkaline phosphatase was significantly higher in the lower body bone fracture group than in the no lower body bone fracture group. Mortality rate was significantly higher in the lower body bone fracture group (85.7%) compared to no lower body bone fracture group (28.5%) (p = 0.01). Kaplan-Meier survival curves for mortality showed that lower body bone fracture group had poor prognosis compared to no lower body bone fracture group. Multivariable-adjusted odds ratio for mortality were significantly higher for cases with lower body bone fractures.

CONCLUSION

Lower body bone fractures have high mortality rates and poor prognosis in the patients with hemodialysis.

Geriatric nutritional risk index and quality of life among elderly hemodialysis patients: a cross-sectional study

Background

Nutritional problems are considered one of the main complications of hemodialysis, and the geriatric nutritional risk index (GNRI) is a new instrument for assessing geriatric nutritional status. The present study sought to evaluate the relationship between the GNRI and quality of life (QOL) among elderly hemodialysis patients.

Methods

In the present analytical cross-sectional study, 110 hemodialysis individuals were selected by applying a simple random sampling method, among whom 57 and 53 were males and females, respectively (mean: 70.3±6.93 years). Demographic characteristics, GNRI, and QOL status were determined. The data were analyzed using SPSS 20 software and descriptive statistics, Pearson's correlation, ANOVA, independent sample t-tests, and multiple linear regression analysis.

Results

The mean GNRI and mean total QOL were respectively obtained 93.903±11.067 and 20.95 ± 4.89. Among females, a significant direct relationship was observed between GNRI and total QOL (P = 0.010, r = 0.352), autonomy (P = 0.004, r = 0.389), and pleasure (P = 0.015, r = 0.333), while GNRI was not directly and significantly related to QOL in males (P = 0.161, r = 0.188).

Conclusion

Due to the presence of a significant association between Geriatric GNRI and QOL among elderly hemodialysis patients, particularly among females, highlighting the importance of addressing nutritional status in optimizing well-being.

Calcium-based phosphate binders and bone mineral density in patients undergoing hemodialysis: a retrospective cohort study

BACKGROUND

Calcium supplements are commonly prescribed to prevent fractures in patients with osteoporosis. Nonetheless, they are generally eschewed in hemodialysis patients because they increase vascular calcification and induce cardiovascular disease. This retrospective cohort study aimed to investigate the effect of calcium-based phosphate binders (CBPB) on bone mineral density (BMD) in hemodialysis patients.

METHODS

Outpatients on dialysis who underwent BMD measurement from January to December 2017, whose data on BMD trends and CBPB administration were recorded over the next 4 years, were enrolled. Patients receiving anti-osteoporotic medications were excluded. The association between the presence and duration of CBPB administration and changes in BMD was evaluated.

RESULTS

The femoral neck's BMD decreased from 0.836 g/cm2 (0.702-0.952) to 0.764 g/cm2 (0.636-0.896) (P < 0.001) in the non-CBPB group (patients who never received CBPB over 4 years, n = 32). The CBPB group (n = 56) exhibited only a minute decrease from 0.833 g/cm2 (0.736-0.965) to 0.824 g/cm2 (0.706-0.939) (P = 0.004). Multivariate linear regression analysis revealed better BMD maintenance in the CBPB group [β-coefficient (95% CI): 0.033 (0.001-0.065); P = 0.046] than in the non-CBPB group. Additionally, the prolonged-CBPB administration group showed superior BMD preservation [β-coefficient (95% CI): 0.038 (0.001-0.076); P = 0.042].

CONCLUSION

CBPB administration may be associated with BMD maintenance.

Effect of denosumab on the incidence of fractures and mortality in patients undergoing hemodialysis: A retrospective cohort study

BACKGROUND

Patients undergoing hemodialysis are at an elevated risk of fractures; however, substantial evidence for osteoporosis treatment in this population is lacking. We explored the efficacy of denosumab, an anti-IgG2 antibody that targets the receptor activator of nuclear factor-kappa B ligand, in reducing fracture incidence and all-cause mortality in patients undergoing hemodialysis.

METHODS

This retrospective cohort study-conducted from December 2013 to December 2022-evaluated the effects of denosumab on fracture incidence and all-cause mortality. Patients who initiated denosumab treatment during the study period were defined as the denosumab group, while those without a history of denosumab administration were defined as the non-denosumab group. Kaplan-Meier curves and log-rank tests were used to assess survival and fracture/mortality risks, respectively. Cox proportional hazards models were used to analyze both fractures and all-cause mortality.

RESULTS

Among 214 patients undergoing hemodialysis, 52 (24.3%) received denosumab. The median age was 73.0 ± 11.5 years, with 92 (43.0%) females, and the median dialysis duration was 59 months (interquartile range, 6-126). During the study, thirty-seven non-denosumab-treated patients had fractures compared to eight in the denosumab group. No significant differences were observed in the unadjusted model (HR, 0.53; 95% confidence interval (CI), 0.24-1.14). Adjusting for competing mortality and clinical factors, the HR remained at 0.64 (95% CI, 0.27-1.51). Regarding all-cause mortality, we found a statistically significant difference in the unadjusted model (HR, 0.61 [95% CI, 0.38-0.98]). A significant reduction in mortality was observed in the adjusted model (HR, 0.46 [95% CI, 0.26-0.80]). Notably, the denosumab group showed a significant decrease in mortality, particularly in cardiovascular disease-related cases (HR, 0.33 [95% CI, 0.14-0.78]).

CONCLUSIONS

Denosumab may reduce all-cause mortality in patients undergoing hemodialysis, particularly in those with cardiovascular complications. This finding offers a promising direction for osteoporosis treatment in patients undergoing hemodialysis.

Vertebral fractures in patients with CKD and the general population: a call for diagnosis and action

Vertebral fractures (VFs) are the most common osteoporotic fractures in the general population, and they have been associated with high mortality, decreased quality of life, and high risk of subsequent fractures, especially when recent, multiple, or severe. Currently, VF diagnosis and classification determine fracture risk and the most appropriate anti-osteoporotic treatment. However, VFs are clearly underdiagnosed, especially in patients with chronic kidney disease (CKD), and CKD-associated osteoporosis has been disregarded until recently. VFs are associated with higher morbidity and mortality, and their prevalence and incidence differ depending on the grade of renal dysfunction (CKD G1-G5) and/or the type of renal replacement therapy (dialysis or transplantation). In addition to classical risk factors [such as higher age, female sex, reduced bone mineral density, diabetes and steroid use], various other factors have been associated with an increased risk of VFs in CKD, including CKD grade, haemodialysis vintage, time since renal transplantation, low or high intact parathyroid hormone and phosphate levels, and/or vitamin D and K1 deficiencies. Importantly, several clinical societies have recently modified their algorithms according to the fracture risk classification (including the presence of VFs) and determined the most appropriate anti-osteoporotic treatment for the general population. However, there are no specific guidelines addressing this topic in patients with CKD despite an important paradigm shift regarding the prognostic value of bone mineral density in 2017 after the publication of the CKD-Mineral and Bone Disorder Kidney Disease: Improving Global Outcomes guidelines. A proactive attitude towards diagnosis, treatment, and research is proposed to avoid therapeutic nihilism.

Two Weeks of Continuous Opioid Treatment in an Adenine-Induced Mouse Model of Chronic Kidney Disease Exacerbates the Bone Inflammatory State and Increases Osteoclasts

Patients with chronic kidney disease (CKD) report high pain levels, but reduced renal clearance eliminates many analgesic options; therefore, 30-50% of CKD patients have chronic opioid prescriptions. Opioid use in CKD is associated with higher fracture rates. Opioids may directly alter bone turnover directly through effects on bone cells and indirectly via increasing inflammation. We hypothesized that continuous opioid exposure would exacerbate the high bone turnover state of CKD and be associated with elevated measures of inflammation. Male C57Bl/6J mice after 8 weeks of adenine-induced CKD (AD) and non-AD controls (CON) had 14-day osmotic pumps (0.25-µL/hr release) containing either saline or 50-mg/mL oxycodone (OXY) surgically implanted in the subscapular region. After 2 weeks, all AD mice had elevated blood urea nitrogen, parathyroid hormone, and serum markers of bone turnover compared to controls with no effect of OXY. Immunohistochemical staining of the distal femur showed increased numbers of osteocytes positive for the mu opioid and for toll-like receptor 4 (TLR4) due to OXY. Osteocyte protein expression of tumor necrosis factor-α (TNF-α) and RANKL were higher due to both AD and OXY so that AD + OXY mice had the highest values. Trabecular osteoclast-covered surfaces were also significantly higher due to both AD and OXY, resulting in AD + OXY mice having 4.5-fold higher osteoclast-covered surfaces than untreated CON. These data demonstrate that opioids are associated with a pro-inflammatory state in osteocytes which increases the pro-resorptive state of CKD.

Association of serum sodium levels with fractures and mortality in patients undergoing maintenance hemodialysis

BACKGROUND

Hyponatremia is implicated in pathological bone resorption and has been identified as a risk factor for bone fracture in the general population. However, there are limited data on the association between serum sodium levels and fracture risk in patients undergoing hemodialysis (HD).

METHODS

We analyzed a historical cohort of 2220 maintenance HD patients to examine the association between serum sodium levels and the risk of fracture and mortality. We also examined the association between serum sodium levels and osteoporosis, based on metacarpal bone mineral density, in a subcohort of 455 patients with available data. In addition, we examined the association between serum sodium levels and bone turnover markers in a separate cross-sectional cohort of 654 maintenance HD patients.

RESULTS

During a median follow-up of 5.4 years, 712 patients died, 113 experienced clinical fractures, and 64 experienced asymptomatic vertebral fractures. Lower serum sodium levels were associated with an increased risk of mortality (HR 1.06 per 1 mEq/L decrease; 95% CI 1.03-1.09) but not with the risk of clinical fracture (HR 1.04 per 1 mEq/L decrease; 95% CI 0.97-1.11). A similar lack of association was observed for asymptomatic vertebral fracture and any fracture. Serum sodium levels were also not associated with osteoporosis in a subcohort with available data (n = 455) or with bone alkaline phosphatase or tartrate-resistant acid phosphatase-5b in a separate cross-sectional cohort.

CONCLUSION

Serum sodium levels were associated with mortality but not with fracture risk, osteoporosis, or bone turnover markers in maintenance HD patients.

Roles of Parathyroid Hormone and Fibroblast Growth Factor 23 in Advanced Chronic Kidney Disease

Parathyroid hormone (PTH) and fibroblast growth factor 23 (FGF23) each play a central role in the pathogenesis of chronic kidney disease (CKD)-mineral and bone disorder. Levels of both hormones increase progressively in advanced CKD and can lead to damage in multiple organs. Secondary hyperparathyroidism (SHPT), characterized by parathyroid hyperplasia with increased PTH secretion, is associated with fractures and mortality. Emerging evidence suggests that these associations may be partially explained by PTH-induced browning of adipose tissue and increased energy expenditure. Observational studies suggest a survival benefit of PTHlowering therapy, and a recent study comparing parathyroidectomy and calcimimetics further suggests the importance of intensive PTH control. The mechanisms underlying the regulation of FGF23 secretion by osteocytes in response to phosphate load have been unclear, but recent experimental studies have identified glycerol-3-phosphate, a byproduct of glycolysis released by the kidney, as a key regulator of FGF23 production. Elevated FGF23 levels have been shown to be associated with mortality, and experimental data suggest off-target adverse effects of FGF23. However, the causal role of FGF23 in adverse outcomes in CKD patients remains to be established. Further studies are needed to determine whether intensive SHPT control improves clinical outcomes and whether treatment targeting FGF23 can improve patient outcomes.

Outcomes Following Surgical Fixation of Upper Extremity Fractures in Patients with Chronic Kidney Disease

Purpose

Moderate to severe (stage III-IV) chronic kidney disease (CKD) and end stage renal disease (ESRD) have been shown to be independent risk factors for sustaining a fragility fracture. High rates of complications and mortality are associated with fracture fixation in patients with CKD, but existing literature is limited. It is unknown how CKD stage III-IV or ESRD affects outcomes in upper-extremity fractures. We hypothesize that patients with CKD stage III-IV or ESRD will have high complication rates after surgical fixation of upper extremity fractures.

Methods

We identified all patients between 2008 and 2018 who underwent operative fixation of an upper extremity fracture proximal to the distal radius with a diagnosis of CKD stage III-IV or ESRD at the time of injury. Those with an acute kidney injury at the time of injury or a history of a kidney transplant were excluded. Demographics, medical complications, and surgical complications were collected retrospectively. Data on readmissions within 90 days and mortality within 1 year were also collected.

Results

Thirty-five patients were identified. Three patients had ESRD. Fractures included two clavicle, twelve proximal humerus, one humeral shaft, ten distal humerus, five olecranon, two ulnar shaft, one radial shaft, and two both-bone forearm fractures. In total, 91.4% of fractures were closed injuries. Surgical complications occurred in 40% of patients. The reoperation rate was 11.4%, and all cases of reoperation involved hardware removal. The all-cause 90-day readmission rate was 34.3%. The 1-year mortality rate was 8.6%.

Conclusions

Surgical complications occurred in 40% of patients with CKD stage III-IV or ESRD who underwent fixation for an upper extremity fracture. It is important to counsel these patients regarding their high risk for complications. Further research is needed to investigate and identify how to mitigate risk.

Type of study/level of evidence

Prognostic IV.

Outcomes Following Surgical Fixation of Distal Radius Fractures in Patients With Chronic Kidney Disease

Purpose

Moderate-to-severe chronic kidney disease (CKD, stages III-IV) and end-stage renal disease (ESRD or CKD stage V) are known to be independent risk factors for fragility fracture. Altered bone and mineral metabolism contributes to greater complications and mortality rates in the setting of fractures, although most existing literature is limited to hip fractures. We hypothesized that patients with moderate-to-severe CKD or ESRD would have greater complication rates after surgical treatment of distal radius fractures compared with those without CKD.

Methods

We retrospectively identified all patients at a level 1 trauma center between 2008 and 2018 who had a diagnosis of stage III-IV CKD or ESRD at the time of operative fixation of a distal radius fracture. We recorded demographic data, comorbidities, and surgical complications. Data for readmissions within 90 days and 1-year mortality were collected. A 2:1 sex-matched control group without CKD who underwent distal radius fixation was selected for comparison, with age-adjusted analysis.

Results

A total of 32 patients with CKD (78.1% CKD stage III/IV, 21.9% ESRD) and 62 without CKD were identified. The mean age was 67 ± 12 years in the CKD group and 55 ± 15 years in the control group. The CKD group had a higher Charlson Comorbidity Index (5.7 vs 2.0). Surgical complication rate in the CKD group was 12.5% (12.0% CKD III/IV; 14.3% ESRD). Neither early nor late surgical complication rates were statistically different from those in patients without CKD. Reoperation rate as well as 30- and 90-day readmission rates were similar between groups. Overall, 1-year mortality was greater in the CKD group (9.4% vs 0%).

Conclusions

Surgical complications and readmission rates are similar in patients with and without CKD after distal radius fracture fixation. However, 1-year mortality rate is significantly higher after distal radius fixation in patients with moderate-to-severe CKD or ESRD.

Type of study/level of evidence

Prognostic IIIa.

The Relationship Between Fracture and Mortality in a Chinese Maintenance Hemodialysis Patients Cohort

Background

Patients on maintenance hemodialysis have an increased risk of fracture. However, the relationship between fracture and poor prognosis is not clear.

Methods

A total of 182 maintenance hemodialysis patients were enrolled in the study. The relationship between fracture and poor prognosis (cardiovascular events, stroke, malignancy and 5-year all-cause mortality) were analyzed.

Results

21 of 182 patients had a history of fracture at the time of enrollment. 26 patients had a new fracture after enrollment. A total of 57 fractures occurred in 47 patients, the most common fracture site was the rib. Patients with fracture group had a higher proportion of elderly and female, higher serum phosphorus and B-type natriuretic peptide and lower hemoglobin, albumin, and potassium compared with those without fracture. Age (OR=3.809, 95% CI: 1.064-8.966, p=0.038), hemoglobin (OR=0.961, 95% CI: 0.925-0.997, p=0.035), and serum phosphorus (OR=3.325, 95% CI:1.104-10.019, p=0.033) were the independent risk factors of new fractures in MHD patients. The incidence of malignancy and 5-year all-cause mortality in patients with fracture was higher than those without fracture (p<0.05). But there was no significant difference in the incidence of acute myocardial infarction or stroke.

Conclusion

25.8% of maintenance hemodialysis patients had at least one fracture, with rib fractures accounting for the highest proportion. Age, hemoglobin and serum phosphorus were the independent risk factors of new fractures. The incidence of malignancy and 5-year all-cause mortality in patients with fracture was higher than those without fracture, but there was no significant difference in the incidence of acute myocardial infarction and stroke.

Ten tips on how to assess bone health in patients with chronic kidney disease

Patients with chronic kidney disease (CKD) experience a several-fold increased risk of fracture. Despite the high incidence and the associated excess morbidity and premature mortality, bone fragility in CKD, or CKD-associated osteoporosis, remains a blind spot in nephrology with an immense treatment gap. Defining the bone phenotype is a prerequisite for the appropriate therapy of CKD-associated osteoporosis at the patient level. In the present review, we suggest 10 practical 'tips and tricks' for the assessment of bone health in patients with CKD. We describe the clinical, biochemical, and radiological evaluation of bone health, alongside the benefits and limitations of the available diagnostics. A bone biopsy, the gold standard for diagnosing renal bone disease, is invasive and not widely available; although useful in complex cases, we do not consider it an essential component of bone assessment in patients with CKD-associated osteoporosis. Furthermore, we advocate for the deployment of multidisciplinary expert teams at local, national, and potentially international level. Finally, we address the knowledge gaps in the diagnosis, particularly early detection, appropriate "real-time" monitoring of bone health in this highly vulnerable population, and emerging diagnostic tools, currently primarily used in research, that may be on the horizon of clinical practice.

The Effect of Antihypertensive Therapy on Skeletal Muscle Mass and Bone Mineral Density in Patients With End-Stage Kidney Disease

OBJECTIVE

Sarcopenia and osteoporosis substantially influence health and lifespan. However, the variables affecting skeletal muscle mass (SMM) or bone mineral density (BMD) remain unknown.

DESIGN AND METHODS

From August 1, 2018 to July 31, 2019, we conducted a single-center, observational cohort study with 291 Japanese adult patients on maintenance hemodialysis due to end-stage kidney disease, who had their femoral neck BMD measured using dual-energy X-ray absorptiometry. After 1-year follow-up, we measured annual changes of BMD (ΔBMD) and SMM (ΔSMM), which were calculated through a modified creatinine index (mg/kg/day) using age, sex, serum creatinine, and single-pooled Kt/V for urea. The factors associated with ΔSMM/ΔBMD or progressive loss of SMM/BMD, defined as ΔSMM/ΔBMD < 0 per year, respectively, were analyzed with multivariable, linear regression or logistic regression models.

RESULTS

The median age of the patients was 66 years and 33% were female. Dialysis vintage and β-blocker-use were inversely correlated to ΔSMM. In comparison to nonusers, β-blockers users had 2.5-fold higher SMM loss odd ratios [95% confidence interval, 1.3-4.8]. The risk for SMM loss caused by β-blockers was not increased in users of renin-angiotensin system inhibitors. The ΔBMD was negatively correlated to the usage of calcium channel blockers. The risk of developing osteosarcopenia, which was defined as annual loss of both SMM and BMD, increased in calcium channel blockers users.

CONCLUSIONS

The use of β-blockers is associated with an elevated risk of developing sarcopenia, whereas renin-angiotensin system inhibitors may minimize this effect in patients with end-stage kidney disease. Use of calcium channel blocker therapy was associated with a faster decline of BMD.

Effectiveness of calcimimetics on fractures in dialysis patients with secondary hyperparathyroidism: meta-analysis of randomized trials

INTRODUCTION

This study aimed to assess the effectiveness of calcimimetics in reducing the risk of fractures in dialysis patients with secondary hyperparathyroidism (SHPT).

MATERIAL AND METHODS

A comprehensive literature search was conducted using PubMed, Embase, and Cochrane Library for articles published through December 9, 2023. The quality of each trial was evaluated using the Cochrane Collaboration tool. Meta-analysis was performed using a random-effects model, and effect measures across studies were synthesized. The risk ratio (RR) and 95% confidence interval (CI) were used to quantify the risk of fracture.

RESULTS

We identified seven studies involving 6481 dialysis patients with SHPT. The administration of calcimimetics reduced fracture incidence compared to placebo or conventional treatment (RR: 0.50, 95% CI 0.29-0.88, p = 0.02). Calcimimetics demonstrated a low number needed to treat (NNT) to prevent an incident fracture (NNT: 47).

CONCLUSION

The use of calcimimetics offers a significant benefit in reducing the risk of fractures in patients undergoing dialysis with SHPT.

Fracture Management in Chronic Kidney Disease: Challenges and Considerations for Orthopedic Surgeons

Orthopedic surgeons treating fractures need to consider comorbidities, including chronic kidney disease (CKD), which affects millions worldwide. CKD patients are at elevated risk of fractures due to osteoporosis, especially in advanced stages. In addition, fractures in CKD patients pose challenges due to impaired bone healing and increased post-fracture complications including surgical site infection and nonunion. In this article, we will discuss factors that must be considered when treating fractures in CKD patients. Perioperative management includes careful adjustment of hemodialysis schedules, selection of anesthetic methods, and addressing bleeding tendencies. Tourniquet usage for fractures in limbs with arteriovenous fistulae should be cautious. Pain medication should be administered carefully, with opioids like hydromorphone preferred over nonsteroidal anti-inflammatory drugs. Medical management after fractures should address underlying factors and include physical rehabilitation to reduce the risk of subsequent fractures. A comprehensive approach to fracture management in CKD patients can improve outcomes.

Long-term effects of denosumab on bone mineral density and turnover markers in patients undergoing hemodialysis

INTRODUCTION

Denosumab, a fully human anti-RANKL monoclonal antibody, is a widely used osteoporosis treatment that is increasingly being used in patients undergoing dialysis; however, its long-term efficacy and safety in these patients remain unknown.

MATERIALS AND METHODS

This observational study comprised individuals aged ≥ 20 years undergoing hemodialysis and receiving denosumab. After denosumab administration, we analyzed the long-term changes in bone mineral density (BMD) and levels of bone turnover markers (BTMs) and calcium.

RESULTS

The study included 45 patients who have been receiving denosumab for a median duration of 3.8 (interquartile range, 2.5-6.7) years. Tartrate-resistant acid phosphatase 5b (TRACP-5b) levels decreased from a median of 595 (434-778) mU/dL at baseline to 200 (141-430) mU/dL after 6 months of denosumab administration (P < 0.001) and remained low thereafter. Similarly, bone-specific alkaline phosphatase (BAP) levels decreased from a median of 18.2 (15.9-25.8) μg/L at baseline to 12.4 (9.9-15.6) μg/L after 6 months (P < 0.001) and remained low thereafter. Meanwhile, BMD, as assessed with dual energy X-ray absorptiometry and measured at the distal 1/3 of the radius, did not decrease (0.465 ± 0.112 g/cm2 at baseline vs. 0.464 ± 0.112 g/cm2 after administration; P = 0.616). Regarding hypocalcemia, corrected calcium levels reached were the lowest at 7 days after administration and normalized within 30 days.

CONCLUSION

The study showed long-term suppression of TRACP-5b and BAP levels and sustaining BMD after denosumab administration over an extended period in patients undergoing hemodialysis.

Evaluating Osteoporosis in Chronic Kidney Disease: Both Bone Quantity and Quality Matter

Bone strength is determined not only by bone quantity [bone mineral density (BMD)] but also by bone quality, including matrix composition, collagen fiber arrangement, microarchitecture, geometry, mineralization, and bone turnover, among others. These aspects influence elasticity, the load-bearing and repair capacity of bone, and microcrack propagation and are thus key to fractures and their avoidance. In chronic kidney disease (CKD)-associated osteoporosis, factors traditionally associated with a lower bone mass (advanced age or hypogonadism) often coexist with non-traditional factors specific to CKD (uremic toxins or renal osteodystrophy, among others), which will have an impact on bone quality. The gold standard for measuring BMD is dual-energy X-ray absorptiometry, which is widely accepted in the general population and is also capable of predicting fracture risk in CKD. Nevertheless, a significant number of fractures occur in the absence of densitometric World Health Organization (WHO) criteria for osteoporosis, suggesting that methods that also evaluate bone quality need to be considered in order to achieve a comprehensive assessment of fracture risk. The techniques for measuring bone quality are limited by their high cost or invasive nature, which has prevented their implementation in clinical practice. A bone biopsy, high-resolution peripheral quantitative computed tomography, and impact microindentation are some of the methods established to assess bone quality. Herein, we review the current evidence in the literature with the aim of exploring the factors that affect both bone quality and bone quantity in CKD and describing available techniques to assess them.

Proteinuria screening and risk of bone fracture: a retrospective cohort study using a nationwide population-based database

Background and hypothesis

Proteinuria is associated with an increased risk of kidney function deterioration, cardiovascular disease, or cancer. Previous reports suggesting an association between kidney dysfunction and bone fracture may be confounded by concomitant proteinuria and were inconsistent regarding the association between proteinuria and bone fracture. Therefore, we aimed to evaluate the association using a large administrative claims database in Japan.

Methods

Using the DeSC database, we retrospectively identified individuals with laboratory data including urine dipstick test between August 2014 and February 2021. We evaluated the association between proteinuria and vertebral or hip fracture using multivariable Cox regression analyses adjusted for various background factors including kidney function. We also performed subgroup analyses stratified by sex and kidney function and sensitivity analyses with Fine & Gray models considering death as a competing risk.

Results

We identified 603 766 individuals and observed 21 195 fractures. With reference to the negative proteinuria group, the hazard ratio for hip or vertebral fracture was 1.10 [95% confidence interval (CI), 1.05-1.14] and 1.16 (95%CI, 1.11-1.22) in the trace and positive proteinuria group, respectively, in the Cox regression analysis. The subgroup analyses showed similar trends. The Fine & Gray model showed a subdistribution hazard ratio of 1.09 (95%CI, 1.05-1.14) in the trace proteinuria group and 1.15 (95% CI, 1.10-1.20) in the positive proteinuria group.

Conclusions

Proteinuria was associated with an increased risk of developing hip or vertebral fractures after adjustment for kidney function. Our results highlight the clinical importance of checking proteinuria for predicting bone fractures.

Trabecular Bone Score Improves Early After Successful Kidney Transplantation Irrespective of Antiresorptive Therapy and Changes in Bone Mineral Density

Background

Trabecular bone score (TBS) is a new tool to assess trabecular bone microarchitecture based on standard dual-energy x-ray absorptiometry (DXA) of lumbar spine images. TBS may be important to assess bone quality and fracture susceptibility in kidney transplant recipients (KTRs). This study aimed to investigate the effect of different bone therapies on TBS in KTRs.

Methods

We reanalyzed DXA scans to assess TBS in 121 de novo KTRs at baseline, 10 wk, and 1 y. This cohort, between 2007 and 2009, participated in a randomized, placebo-controlled trial evaluating the effect of ibandronate versus placebo in addition to vitamin D and calcium.

Results

Although bone mineral density (BMD) Z scores showed a subtle decrease in the first weeks, TBS Z scores increased from baseline to 10 wk for both treatment groups, followed by a slight decline at 12 mo. When comparing treatment groups and adjusting for baseline TBS, there were no differences found in TBS at 12 mo (P = 0.419). Correlation between TBS and BMD at baseline was weak (Spearman's ρ = 0.234, P = 0.010), and change in TBS was not correlated with changes in lumbar spine BMD in either of the groups (ρ = 0.003, P = 0.973).

Conclusions

Treatment with ibandronate or vitamin D and calcium did not affect bone quality as measured by TBS in de novo KTRs, but TBS increased early, irrespective of intervention. Changes in TBS and BMD during the study period were not correlated, indicating that these measurements reflect different aspects of bone integrity. TBS may complement BMD assessment in identifying KTRs with a high fracture risk.

Interrelationships between sarcopenia, bone turnover markers and low bone mineral density in patients on hemodialysis

BACKGROUND

Hemodialysis (HD) patients are at risk for sarcopenia (SP) and bone loss, which may impact falls and bone fragility and lead to poor prognosis. Patients with HD and those with osteoporosis (OP) are still underdiagnosed and untreated. The aims of the present study were to evaluate the factors that affect bone mineral density (BMD) loss in HD patients, and explore traditional and novel approaches to manage chronic kidney disease-mineral-bone disorder (CKD-MBD).

METHODS

Patients who underwent regular HD at the First Affiliated Hospital of Soochow University were retrospectively evaluated. According to the WHO osteoporosis criteria, patients were categorized into three groups: normal BMD, osteopenia, and osteoporosis. Demographic and clinical data, skeletal muscle mass, and bone turnover markers(BTM) were compared between the three groups. The correlation between bone density and muscle mass was calculated, and related risk factors were analyzed.

RESULTS

This study enrolled 130 HD patients, 36 patients were diagnosed with sarcopenia (27.7%), 44 patients were diagnosed with osteopenia (33.8%), 19 patients were diagnosed with osteoporosis (14.6%), and 23 patients were diagnosed with osteosarcopenia (17.7%). The SMI was positively correlated with the BMD of the lumbar spine (r = 0.23, p < 0.01) and femoral neck (r = 0.22, p < 0.05). In ordinal logistic regression analysis, the odds ratio (OR) for low BMD was high for patients with sarcopenia (OR = 5.894, 95% CI 1.592-21.830, p < 0.01), older age (OR = 1.095, 95% CI 1.041-1.153, p < 0.001), higher TRACP-5b levels (OR = 1.597, 95% CI 1.230-2.072, p < 0.01), and lower 25-OH vitamin D levels (OR = 0.631, 95% CI 0.544-0.733, p < 0.001).

CONCLUSION

The preservation of skeletal muscle mass could be important to prevent a BMD decrease in HD patients. Adequate intake of vitamin D and control of TRACP-5b levels will help reduce the occurrence and progression of osteopenia/sarcopenia in HD patients.

Vitamin D Therapy in Adults With CKD: A Systematic Review and Meta-analysis

RATIONALE & OBJECTIVE

Vitamin D is widely used to manage chronic kidney disease-mineral and bone disorder (CKD-MBD). We evaluated the effects of vitamin D therapy on mortality, cardiovascular, bone, and kidney outcomes in adults with CKD.

STUDY DESIGN

Systematic review of randomized controlled trials (RCT) with highly sensitive searching of MEDLINE, Embase, and CENTRAL, through February 25, 2023.

SETTING & STUDY POPULATIONS

Adults with stage 3, 4, or 5 CKD, including kidney failure treated with dialysis. Recipients of a kidney transplant were excluded.

SELECTION CRITERIA FOR STUDIES

RCTs with≥3 months of follow-up evaluating a vitamin D compound.

DATA EXTRACTION

Data were extracted independently by three investigators.

ANALYTICAL APPROACH

Treatment estimates were summarized using random effects meta-analysis. Primary review endpoints were all-cause death, cardiovascular death, and fracture. Secondary outcomes were major adverse cardiovascular events, hospitalization, bone mineral density, parathyroidectomy, progression to kidney failure, proteinuria, estimated glomerular filtration rate, hypercalcemia, hyperphosphatemia, biochemical markers of CKD-MBD, and various intermediate outcome measures of cardiovascular disease. Risk of bias was assessed using the Cochrane Risk of Bias (RoB) 2 tool. Evidence certainty was adjudicated using GRADE.

RESULTS

Overall, 128 studies involving 11,270 participants were included. Compared with placebo, vitamin D therapy probably had no effect on all-cause death (relative risk [RR], 1.04; 95% CI, 0.84-1.24); and uncertain effects on fracture (RR, 0.68; 95% CI, 0.37-1.23) and cardiovascular death (RR, 0.73; 95% CI, 0.31-1.71). Compared with placebo, vitamin D therapy lowered serum parathyroid hormone and alkaline phosphatase, but increased serum calcium.

LIMITATIONS

Data were limited by trials with short-term follow-up periods, small sample size, and the suboptimal quality.

CONCLUSIONS

Vitamin D therapy did not reduce the risk of all-cause death in people with CKD. Effects on fracture and cardiovascular and kidney outcomes were uncertain.

TRIAL REGISTRATION

Registered at PROSPERO with study number CRD42017057691.

PLAIN-LANGUAGE SUMMARY

Chronic kidney disease (CKD) is associated with increased risk of death, cardiovascular disease, and fractures. This excess risk is thought to be related to changes in bone and mineral metabolism, leading to the development of CKD-mineral and bone disorder (CKD-MBD) which is characterized by vascular calcification and reduced bone quality. Vitamin D is commonly used in the treatment of this condition. We reviewed randomized controlled trials examining the effect of vitamin D therapy in CKD. We found that vitamin D therapy affects serum biomarkers, including an increase in serum calcium. However, it probably has no effect on risk of all-cause death in CKD, and the effects on other clinical bone, cardiovascular, and kidney outcomes are uncertain.

Active Vitamin D Use and Fractures in Hemodialysis Patients: Results from the International DOPPS

Active vitamin D is commonly used to control secondary hyperparathyroidism in dialysis patients, but it is unknown whether active vitamin D directly improves bone strength, independently of its ability to suppress parathyroid hormone (PTH). We analyzed the association between the prescription of active vitamin D and incidence of any fracture and hip fracture in 41,677 in-center hemodialysis patients from 21 countries in phases 3 to 6 (2005 to 2018) of the Dialysis Outcomes and Practice Patterns Study (DOPPS). We used Cox regression, adjusted for PTH and other potential confounders, and used a per-protocol approach to censor patients at treatment switch during follow-up. We also used a facility preference approach to minimize confounding by indication. Overall, 55% of patients were prescribed active vitamin D at study enrollment. Event rates (per patient-year) were 0.024 for any fracture and 0.010 for hip fracture. The adjusted hazard ratio (95% confidence interval) comparing patients prescribed versus not prescribed active vitamin D was 1.02 (0.90 to 1.17) for any fracture and 1.00 (0.81 to 1.23) for hip fracture. In the facility preference approach, there was no difference in fracture rate between facilities with higher versus lower active vitamin D prescriptions. Thus, our results do not suggest a PTH-independent benefit of active vitamin D in fracture prevention and support the current KDIGO guideline suggesting the use of active vitamin D only in subjects with elevated or rising PTH. Further research is needed to determine the role of active vitamin D beyond PTH control. © 2023 American Society for Bone and Mineral Research (ASBMR).

Mortality After Hip and Spine Fractures in Patients With End-Stage Kidney Disease: A Systematic Review and Meta-Analysis

Fractures represent a major cause of disability in the elderly, and patients with fractures exhibit a higher mortality rate than those without. Fractures are also an important health problem among patients with end-stage kidney disease (ESKD) requiring hemodialysis, peritoneal dialysis, or kidney transplantation. To the best of our knowledge, no study in the literature has yet quantitatively summarized the mortality rates, and a summary of evidence on post-hip and spine fracture mortality in patients with ESKD is lacking. The purpose of this study is to quantitatively evaluate the mortality rate, one-year mortality rate, and five-year mortality rate after hip and spine fractures in patients with ESKD receiving kidney replacement therapy. The MEDLINE, Cochrane Central Register of Controlled Trials (CENTRAL), Embase, and ClinicalTrials.gov databases were comprehensively searched for reports on mortality rate and time-period mortality in patients with ESKD after hip or spine fractures up to June 2022. Prospective and retrospective cohort studies, as well as case series involving four or more patients, were included. Pooled mortality rate, one-year rate, and five-year mortality rate with 95% confidence intervals (CIs) were examined using a random-effects model. The risk of bias was assessed using the Joanna Briggs Institute (JBI) Prevalence Critical Appraisal Tool. Additionally, heterogeneity between studies was evaluated. A total of 26 studies were included in this meta-analysis. The one-year and five-year mortality rates after hip and spine fractures were 215.35-774.0 per 1,000 person-year and 148-194.1 per 1,000 person-year, respectively. After hip fractures, the one-year mortality rate was 27% (95% CI: 18-38%, I2 = 98%), whereas the five-year mortality rate was 56% (95% CI: 41-71%, I2 = 99%). After spine fractures, the one-year mortality rate was 10% (95% CI: 4-17%, I2 = 70%), whereas the five-year mortality rate was 48.3%. The post-fracture mortality rate was high in patients with ESKD, particularly within one year after the occurrence of fractures. Additionally, the five-year mortality rate after hip femoral or spine fractures was high at approximately 50%.

Association between CKD-MBD and mortality in older patients with advanced CKD-results from the EQUAL study

BACKGROUND

Chronic kidney disease-mineral and bone disorder (CKD-MBD) is a common complication of CKD; it is associated with higher mortality in dialysis patients, while its impact in non-dialysis patients remains mostly unknown. We investigated the associations between parathyroid hormone (PTH), phosphate and calcium (and their interactions), and all-cause, cardiovascular (CV) and non-CV mortality in older non-dialysis patients with advanced CKD.

METHODS

We used data from the European Quality study, which includes patients aged ≥65 years with estimated glomerular filtration rate ≤20 mL/min/1.73 m2 from six European countries. Sequentially adjusted Cox models were used to assess the association between baseline and time-dependent CKD-MBD biomarkers and all-cause, CV and non-CV mortality. Effect modification between biomarkers was also assessed.

RESULTS

In 1294 patients, the prevalence of CKD-MBD at baseline was 94%. Both PTH [adjusted hazard ratio (aHR) 1.12, 95% confidence interval (CI) 1.03-1.23, P = .01] and phosphate (aHR 1.35, 95% CI 1.00-1.84, P = .05), but not calcium (aHR 1.11, 95% CI 0.57-2.17, P = .76), were associated with all-cause mortality. Calcium was not independently associated with mortality, but modified the effect of phosphate, with the highest mortality risk found in patients with both hypercalcemia and hyperphosphatemia. PTH level was associated with CV mortality, but not with non-CV mortality, whereas phosphate was associated with both CV and non-CV mortality in most models.

CONCLUSIONS

CKD-MBD is very common in older non-dialysis patients with advanced CKD. PTH and phosphate are independently associated with all-cause mortality in this population. While PTH level is only associated with CV mortality, phosphate seems to be associated with both CV and non-CV mortality.

Efficacy and safety of medications for osteoporosis in kidney transplant recipients or patients with chronic kidney disease: A meta-analysis

This study conducted a meta-analysis to analyze the efficacy and safety of osteoporosis medications in kidney transplant recipients and patients with chronic kidney disease (CKD). PubMed, Embase, the Cochrane Central Register of Controlled Trials were searched from the date of their inception through October 21, 2022. We performed a meta-analysis of the efficacy and safety of osteoporosis medications in adult patients with stage 3-5 CKD or kidney transplant recipients enrolled in randomized clinical trials (RCTs). We calculated the standard mean deviations with 95% confidence intervals (CI) for bone mineral density (BMD) and T scores after 6 and 12 months treatment, pooled odds ratio and 95% CI for fracture risk, and summarized adverse events. The inclusion criteria were met by 27 studies. Out of this, 19 studies were included for the meta-analysis. In stage 3-4 CKD patients, alendronate increased lumbar spine BMD. In patients at stage 5 CKD and undergoing hemodialysis, alendronate and raloxifene increased lumbar spine BMD. After 6 months, the BMD of kidney transplant recipients was seen to be significantly increased; however, there was no difference after 12 months, and the risk of fracture did not reduce. Thus, there is no evidence that these medications reduce the risk of fracture, and their effect on BMD and fracture remains unproven. These medications may increase the incidence of adverse events and their safety needs to be further evaluated. Therefore, we cannot draw a definitive conclusion about the efficacy and safety of osteoporosis medications in the above group of patients.

[Diagnosis and treatment of osteoporosis in patients with chronic kidney disease : Joint guidelines of the Austrian Society for Bone and Mineral Research (ÖGKM), the Austrian Society of Physical and Rehabilitation Medicine (ÖGPMR) and the Austrian Society of Nephrology (ÖGN)]

DEFINITION AND EPIDEMIOLOGY

Chronic kidney disease (CKD): abnormalities of kidney structure or function, present for over 3 months. Staging of CKD is based on GFR and albuminuria (not graded). Osteoporosis: compromised bone strength (low bone mass, disturbance of microarchitecture) predisposing to fracture. By definition, osteoporosis is diagnosed if the bone mineral density T‑score is ≤ -2.5. Furthermore, osteoporosis is diagnosed if a low-trauma (inadequate trauma) fracture occurs, irrespective of the measured T‑score (not graded). The prevalence of osteoporosis, osteoporotic fractures and CKD is increasing worldwide (not graded). PATHOPHYSIOLOGY, DIAGNOSIS AND TREATMENT OF CHRONIC KIDNEY DISEASE-MINERAL AND BONE DISORDER (CKD-MBD): Definition of CKD-MBD: a systemic disorder of mineral and bone metabolism due to CKD manifested by either one or a combination of the following: abnormalities of calcium, phosphorus, PTH, or vitamin D metabolism; renal osteodystrophy; vascular calcification (not graded). Increased, normal or decreased bone turnover can be found in renal osteodystrophy (not graded). Depending on CKD stage, routine monitoring of calcium, phosphorus, alkaline phosphatase, PTH and 25-OH-vitamin D is recommended (2C). Recommendations for treatment of CKD-MBD: Avoid hypercalcemia (1C). In cases of hyperphosphatemia, lower phosphorus towards normal range (2C). Keep PTH within or slightly above normal range (2D). Vitamin D deficiency should be avoided and treated when diagnosed (1C).

DIAGNOSIS AND RISK STRATIFICATION OF OSTEOPOROSIS IN CKD

Densitometry (using dual X‑ray absorptiometry, DXA): low T‑score correlates with increased fracture risk across all stages of CKD (not graded). A decrease of the T‑score by 1 unit approximately doubles the risk for osteoporotic fracture (not graded). A T-score ≥ -2.5 does not exclude osteoporosis (not graded). Bone mineral density of the lumbar spine measured by DXA can be increased and therefore should not be used for the diagnosis or monitoring of osteoporosis in the presence of aortic calcification, osteophytes or vertebral fracture (not graded). FRAX can be used to aid fracture risk estimation in all stages of CKD (1C). Bone turnover markers can be measured in individual cases to monitor treatment (2D). Bone biopsy may be considered in individual cases, especially in patients with CKD G5 (eGFR < 15 ml/min/1.73 m2) or CKD 5D (dialysis).

SPECIFIC TREATMENT OF OSTEOPOROSIS IN PATIENTS WITH CKD

Hypocalcemia should be treated and serum calcium normalized before initiating osteoporosis therapy (1C). CKD G1-G2 (eGFR ≥ 60 ml/min/1.73 m2): treat osteoporosis as recommended for the general population (1A). CKD G3-G5D (eGFR < 60 ml/min/1.73 m2 to dialysis): treat CKD-MBD first before initiating osteoporosis treatment (2C). CKD G3 (eGFR 30-59 ml/min/1.73 m2) with PTH within normal limits and osteoporotic fracture and/or high fracture risk according to FRAX: treat osteoporosis as recommended for the general population (2B). CKD G4-5 (eGFR < 30 ml/min/1.73 m2) with osteoporotic fracture (secondary prevention): Individualized treatment of osteoporosis is recommended (2C). CKD G4-5 (eGFR < 30 ml/min/1.73 m2) and high fracture risk (e.g. FRAX score > 20% for a major osteoporotic fracture or > 5% for hip fracture) but without prevalent osteoporotic fracture (primary prevention): treatment of osteoporosis may be considered and initiated individually (2D). CKD G4-5D (eGFR < 30 ml/min/1.73 m2 to dialysis): Calcium should be measured 1-2 weeks after initiation of antiresorptive therapy (1C).

PHYSICAL MEDICINE AND REHABILITATION

Resistance training prioritizing major muscle groups thrice weekly (1B). Aerobic exercise training for 40 min four times per week (1B). Coordination and balance exercises thrice weekly (1B). Flexibility exercise 3-7 times per week (1B).