Management of Osteoporosis in CKD

Is denosumab an efficient and safe drug for osteoporosis in dialysis patients? Considerations and state of the art about its use in this setting

PURPOSE

In patients with chronic kidney disease (CKD), renal osteodystrophy may be associated with a progressive bone mass loss that increases fracture risk. Denosumab, a monoclonal antibody inhibiting osteoclast activity, is an antiresorptive medication used for the treatment osteoporosis.

METHODS

Its efficacy and safety were initially established in the FREEDOM study, showing a significant reduction in incident fractures in osteoporotic women treated with denosumab. Subsequent post hoc analyses showed its efficacy in patients stratified by kidney function, but these analyses did not include patients with advanced stages of CKD. The capability of denosumab in improving bone mineral density in uremic patients was evaluated in 12 studies including 461 dialysis patients with low bone mineral density. The improvement of bone mineral density was the final end point in these studies assessed during a follow-up of 6-60 months. Nine of these studies did not have hyperparathyroidism among criteria for patient inclusion and their participants may have low-turnover bone disease. Despite current recommendations, no patients underwent bone biopsy before denosumab therapy.

RESULTS

Overall, findings in these studies suggest that denosumab is a viable option for promoting bone mass recovery in patients with advanced stages of CKD having either high or low serum levels of PTH. However, the increase of bone mineral density was lower in patients with low serum markers of bone turnover at baseline. These studies also highlighted the need for calcium and vitamin D supplementation to prevent hypocalcemia that remains a serious concern.

CONCLUSIONS

Denosumab emerges as a potentially safe and effective option for enhancing bone health in CKD patients.

Management of chronic kidney disease: The current novel and forgotten therapies

Chronic kidney disease (CKD) is a progressive and incurable condition that imposes a significant burden on an aging society. Although the exact prevalence of this disease is unknown, it is estimated to affect at least 800 million people worldwide. Patients with diabetes or hypertension are at a higher risk of developing chronic kidney damage. As the kidneys play a crucial role in vital physiological processes, damage to these organs can disrupt the balance of water and electrolytes, regulation of blood pressure, elimination of toxins, and metabolism of vitamin D. Early diagnosis is paramount to prevent potential complications. Treatment options such as dietary modifications and medications can help slow disease progression. In our narrative review, we have summarized the available therapeutic options to slow the progression of chronic kidney disease. Many new drug treatments have recently become available, offering a beacon of hope and optimism in CKD management. Nonetheless, disease prevention remains the most critical step in disease management. Given the significant impact of CKD on public health, there is a pressing need for further research. With the development of new technologies and advancements in medical knowledge, we hope to find more effective diagnostic tools and treatments for CKD patients.

Diagnosis and therapeutic decisions of osteoporosis in chronic kidney disease

A 63-yr-old woman with end-stage CKD secondary to glomerulonephritis, on hemodialysis therapy, presented with scoliosis, back pain, and progressive loss of physical function for which corrective surgery was planned. Optimization of bone health was requested by the surgeon as a DXA scan had revealed osteoporosis at spine, hip, and forearm. Due to previous subtotal parathyroidectomy and normal parathyroid hormone and bone-specific alkaline phosphatase levels, a low bone turnover state was suspected. An iliac bone biopsy was performed and revealed low bone turnover, a mineralization defect, and severe osteoporosis. The patient was treated with calcium and intensified vitamin D supplementation, followed by a 2-yr course of teriparatide. Monitoring of bone turnover markers indicated a bone anabolic response to therapy, and a repeat DXA showed increases in BMD at spine and hip. A repeat biopsy at end of treatment showed normal bone turnover and mineralization. This case demonstrates the complicated bone health of patients with advanced CKD. As there are no randomized trials for fracture pretention in patients with CKD, care must be individualized and is often based on expert opinion. The use of bone biopsy is safe and informative in guiding therapy.

Improving Kidney Disease Care: One Giant Leap for Nephrology

Nephrology is an ever-evolving field of medicine. The importance of such a discipline is related to the high clinical impact of kidney disease. In fact, abnormalities of kidney function and/or structure are common in the general population, reaching an overall prevalence of about 10%. More importantly, the onset of kidney damage is related to a strikingly high risk of cardiovascular events, mortality, and progression to kidney failure which, in turn, compromises quality and duration of life. Attempts to comprehend the pathogenesis and molecular mechanisms involved in kidney disease occurrence have prompted the development and implementation of novel drugs in clinical practice with the aim of treating the 'specific cause' of kidney disease (including chronic kidney disease, glomerular disease, and genetic kidney disorders) and the main immunological complications following kidney transplantation. Herein, we provide an overview of the principal emerging drug classes with proved efficacy in the context of the aforementioned clinical conditions. This can represent a simplified guide for clinical nephrologists to remind them of the vast and heterogeneous armamentarium of drugs that should be used in the present and the future to improve the management of patients suffering from kidney disease.

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.

Effect of Denosumab on Bone Health, Vascular Calcification, and Health-Related Quality of Life in Hemodialysis Patients with Osteoporosis: A Prospective Observational Study

Background: Osteoporosis is common in hemodialysis (HD) patients, contributing to cardiovascular risks. Limited research exists on denosumab's efficacy in this group. Our study explores denosumab's effects on bone turnover markers (BTMs) and vascular calcification in chronic kidney disease-mineral bone disorder (CKD-MBD) patients. Methods: In a prospective single-center study, we investigated the effects of denosumab over 2 years on 30 HD patients from a cohort of 185. Annual assessments of bone mineral density (BMD), vascular calcification, and health-related quality of life (HRQL) were conducted and compared with an untreated group. Mineral and bone parameters were analyzed at specific intervals in the treatment group. Results: Denosumab notably raised femoral BMD in the initial year. Most bone turnover markers (BTMs) decreased, except for osteocalcin. Changes in T50 correlated with BTMs. Pre-denosumab supplementation of calcium and vitamin D helped manage mineral imbalances. Post denosumab, parathyroid hormone (PTH) levels increased initially, stabilizing after 3 months. No significant changes occurred in vascular calcification or HRQL. Conclusions: Denosumab exhibited varying effects on BMD improvement, with a stronger impact in the first year that diminished in the second year. Early PTH monitoring was crucial, and extending the administrative period may enhance BMD outcomes compared to the general population.

Fractal characteristics of the trabecular pattern of the mandible in patients with renal transplantation

OBJECTIVE

In this study, we examined the mandibular trabecular bone structures by performing fractal dimension (FD) analysis in patients who underwent renal transplantation (RTx).

METHODS

Our study is an observational study with 69 RTx patients and 35 control group patients. The mean FD values of the patient and control groups were calculated and compared. In addition, biochemical parathyroid hormone (PTH), serum calcium, phosphorus, alkaline phosphatase (ALP), and vitamin-D parameters and FD values of both groups were analyzed.

RESULTS

FD values were significantly lower in the patient group than in the healthy group (p < .05). In the RTx group compared to the control group, ALP (90.71 ± 34.25-66.54 ± 16.8, respectively) (p < .001) and PTH (75.76 ± 38.01-38.17 ± 12.39, respectively) (p < .001) values were higher. There was a positive correlation between the FD values and ALP (rspearman  = .305, p = .011) and a negative correlation between FD values and vitamin-D (rspearman  = .287, p = .017) of patients with RTx.

CONCLUSION

FD values were found to be lower in patients who underwent RTx compared to the control group. It should be considered that FD analysis can be a method that can be used to evaluate trabecular bone structure in patients undergoing RTx.

Quercetin suppresses ovariectomy-induced osteoporosis in rat mandibles by regulating autophagy and the NLRP3 pathway

With the aging population and the popularity of implant prostheses, an increasing number of postmenopausal osteoporosis (PMOP) patients require implant restorations; however, poor bone condition affects the long-term stability of implant prostheses. This study aimed to investigate the therapeutic effect of quercetin (QR) compared with alendronate (ALN), the primary treatment for PMOP, on mandibular osteoporosis (OP) induced by ovariectomy (OVX) in female rats. Adult female rats were treated with QR (50 mg/kg/day), ALN (6.25 mg/kg/week) by gavage for 8 weeks, chloroquine (CQ, 10 mg/kg/twice a week), and cytokine release inhibitory drug 3 (MCC950, 10 mg/kg/three times a week) by intraperitoneal injection for 8 weeks after bilateral OVX. Blood samples were collected prior to euthanasia; the mandibles were harvested and subjected to micro-computed tomography (micro-CT) and pathological analysis. QR administration controlled weight gain and significantly improved the bone microstructure in OVX rats, increasing bone mass, and bone mineral density (BMD), reducing bone trabecular spacing, and decreasing osteoclast numbers. Western blotting, real-time quantitative PCR (RT-qPCR), and serum markers confirmed that QR inhibited interleukin- 1β (IL-1β) and interleukin-18 (IL-18) on the nucleotide-binding oligomerization domain (NOD)-like receptor (NLR) protein 3 (NLRP3) pathway thereby inhibiting osteoclast differentiation, immunofluorescence and western blotting also confirmed that QR inhibited autophagy in OVX rats and suppressed the number of tartrate-resistant acid phosphatase (TRAP)-stained positive osteoclasts. The findings suggest that QR may protect the bone structure and prevent bone loss in osteoporotic rats by inhibiting the NLRP3 pathway and autophagy in osteoclasts with comparable effects to ALN, thus QR may have the potential to be a promising alternative supplement for the preventive and therapeutic treatment of PMOP.

Osteoporosis in Renal Disease

Introduction

Osteoporosis is a disorder characterized by decreased bone mass and skeletal fragility with increased fracture risk. Chronic kidney disease presents with wide range of bone metabolic disorders, including osteoporosis. Osteoporosis prevalence is high in early stages of CKD; whereas in late stages, it coexists with renal osteodystrophy.

Risk factors

Risk factors for osteoporosis include advancing age, low bone mineral density (BMD), glucocorticoid therapy, smoking, alcohol intake, etc.

Diagnosis

The diagnosis of osteoporosis in renal disease is made after assessment of BMD, in addition to exclusion of chronic kidney disease-mineral bone disorder (CKD-MBD), eliciting history of prior fragility fractures and relevant laboratory investigations.

Management

The treatment of osteoporosis varies with the different stages of CKD, with management in stages 1-3 being similar to the general population. Special emphasis must be laid on prevention of fractures as well.

Changes in Bone Quality after Treatment with Etelcalcetide

INTRODUCTION

Secondary hyperparathyroidism is associated with osteoporosis and fractures. Etelcalcetide is an intravenous calcimimetic for the control of hyperparathyroidism in patients on hemodialysis. Effects of etelcalcetide on the skeleton are unknown.

METHODS

In a single-arm, open-label, 36-week prospective trial, we hypothesized that etelcalcetide improves bone quality and strength without damaging bone-tissue quality. Participants were 18 years or older, on hemodialysis ≥1 year, without calcimimetic exposure within 12 weeks of enrollment. We measured pretreatment and post-treatment areal bone mineral density by dual-energy X-ray absorptiometry, central skeleton trabecular microarchitecture by trabecular bone score, and peripheral skeleton volumetric bone density, geometry, microarchitecture, and estimated strength by high-resolution peripheral quantitative computed tomography. Bone-tissue quality was assessed using quadruple-label bone biopsy in a subset of patients. Paired t tests were used in our analysis.

RESULTS

Twenty-two participants were enrolled; 13 completed follow-up (mean±SD age 51±14 years, 53% male, and 15% White). Five underwent bone biopsy (mean±SD age 52±16 years and 80% female). Over 36 weeks, parathyroid hormone levels declined 67%±9% ( P < 0.001); areal bone mineral density at the spine, femoral neck, and total hip increased 3%±1%, 7%±2%, and 3%±1%, respectively ( P < 0.05); spine trabecular bone score increased 10%±2% ( P < 0.001); and radius stiffness and failure load trended to a 7%±4% ( P = 0.05) and 6%±4% increase ( P = 0.06), respectively. Bone biopsy demonstrated a decreased bone formation rate (mean difference -25±4 µ m 3 / µ m 2 per year; P < 0.01).

CONCLUSIONS

Treatment with etelcalcetide for 36 weeks was associated with improvements in central skeleton areal bone mineral density and trabecular quality and lowered bone turnover without affecting bone material properties.

CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER

The Effect of Etelcalcetide on CKD-MBD (Parsabiv-MBD), NCT03960437.

Current and Emerging Markers and Tools Used in the Diagnosis and Management of Chronic Kidney Disease-Mineral and Bone Disorder in Non-Dialysis Adult Patients

Chronic kidney disease (CKD) is a significant public health concern associated with significant morbidity and has become one of the foremost global causes of death in recent years. A frequent comorbidity of CKD is secondary hyperparathyroidism (SHPT), exemplified by high serum parathyroid hormone (PTH) levels. The mineral metabolism disturbances resulting from CKD and progression to SHPT are currently considered part of the definition of chronic kidney disease-mineral and bone disorder (CKD-MBD). However, CKD-MBD does not only include abnormalities in laboratory-measured parameters; it is a complex condition characterized by dysregulation of bone turnover, mineralization, growth and strength, accompanied by vascular or another soft-tissue calcification. Together, this increases the risk of bone fractures, cardiovascular disease, and overall mortality in CKD-MBD patients. Monitoring serum markers is essential in diagnosing SHPT and CKD-MBD, and there are several recognized indicators for prognosis, optimal clinical management and treatment response in late-stage kidney disease patients receiving dialysis. However, far fewer markers have been established for patients with non-dialysis CKD. This review provides an overview of current and emerging markers and tools used in the diagnosis and management of CKD-MBD in non-dialysis adult patients.

Denosumab Use in Chronic Kidney Disease Associated Osteoporosis: A Narrative Review

Chronic kidney disease (CKD) and hemodialysis (HD) patients have a high incidence of bone disease and increased fracture risk, making effective management of their bone health a clinical challenge. Denosumab, a human monoclonal antibody, has been investigated as a therapeutic option in this patient population. In this review, we summarize the current evidence on the efficacy and safety of denosumab in CKD and HD patients. A comprehensive search of the relevant literature was conducted, including randomized controlled trials, observational studies, and meta-analyses. The findings suggest that denosumab reduces the risk of fractures and improves bone mineral density in all stages of CKD. The results of this review support the use of denosumab as a promising option for managing bone disease in CKD and HD patients.

Recommendations of the Spanish Society of Nephrology for the management of mineral and bone metabolism disorders in patients with chronic kidney disease: 2021 (SEN-MM)

As in 2011, when the Spanish Society of Nephrology (SEN) published the Spanish adaptation to the Kidney Disease: Improving Global Outcomes (KDIGO) universal Guideline on Chronic Kidney Disease-Mineral and Bone Disorder (CKD-MBD), this document contains an update and an adaptation of the 2017 KDIGO guidelines to our setting. In this field, as in many other areas of nephrology, it has been impossible to irrefutably answer many questions, which remain pending. However, there is no doubt that the close relationship between the CKD-MBD/cardiovascular disease/morbidity and mortality complex and new randomised clinical trials in some areas and the development of new drugs have yielded significant advances in this field and created the need for this update. We would therefore highlight the slight divergences that we propose in the ideal objectives for biochemical abnormalities in the CKD-MBD complex compared to the KDIGO suggestions (for example, in relation to parathyroid hormone or phosphate), the role of native vitamin D and analogues in the control of secondary hyperparathyroidism and the contribution of new phosphate binders and calcimimetics. Attention should also be drawn to the adoption of important new developments in the diagnosis of bone abnormalities in patients with kidney disease and to the need to be more proactive in treating them. In any event, the current speed at which innovations are taking place, while perhaps slower than we might like, globally drives the need for more frequent updates (for example, through Nefrología al día).

Evocalcet Rescues Secondary Hyperparathyroidism-driven Cortical Porosity in CKD Male Rats

To elucidate the effect of evocalcet, a new oral calcimimetic to bone of secondary hyperparathyroidism (SHPT) with chronic kidney disease (CKD), the rats were 5/6 nephrectomized and fed on a high-phosphate diet. The treated rats were then divided into vehicle groups and evocalcet administered groups. The rats in the vehicle groups exhibited increased levels of serum PTH and inorganic phosphate (Pi) levels, high bone turnover, and severe cortical porosity, mimicking SHPT (CKD-SHPT rats). The cortical bone of the CKD-SHPT rats showed broad demineralization around the osteocytes, suppression of Phex/small integrin-binding ligand N-linked glycoprotein-mediated mineralization in the periphery of the osteocytic lacunae, and increased levels of osteocytic cell death, all of which were considered as the first steps of cortical porosity. In contrast, evocalcet ameliorated the increased serum PTH levels, the enlarged osteocytic lacunae, and the cortical porosity of the CKD-SHPT rats. Osteocytes of CKD-SHPT rats strongly expressed PTH receptor and Pit1/Pit2, which sense extracellular Pi, indicating that PTH and Pi affected these osteocytes. Cell death of cultured osteocytes increased in a Pi concentration-dependent manner, and PTH administration rapidly elevated Pit1 expression and enhanced osteocytic death, indicating the possibility that the highly concentrated serum PTH and Pi cause severe perilacunar osteolysis and osteocytic cell death. It is likely therefore that evocalcet not only decreases serum PTH but also reduces the exacerbation combined with PTH and Pi to the demineralization of osteocytic lacunae and osteocytic cell death, thereby protecting cortical porosity in CKD-SHPT rats.

Is Adynamic Bone Always a Disease? Lessons from Patients with Chronic Kidney Disease

Renal osteodystrophy (ROD) is a common complication of end-stage kidney disease that often starts early with loss of kidney function, and it is considered an integral part in management of patients with chronic kidney disease (CKD). Adynamic bone (ADB) is characterized by suppressed bone formation, low cellularity, and thin osteoid seams. There is accumulating evidence supporting increasing prevalence of ADB, particularly in early CKD. Contemporarily, it is not very clear whether it represents a true disease, an adaptive mechanism to prevent bone resorption, or just a transitional stage. Several co-players are incriminated in its pathogenesis, such as age, diabetes mellitus, malnutrition, uremic milieu, and iatrogenic factors. In the present review, we will discuss the up-to-date knowledge of the ADB and focus on its impact on bone health, fracture risk, vascular calcification, and long-term survival. Moreover, we will emphasize the proper preventive and management strategies of ADB that are pivotal issues in managing patients with CKD. It is still unclear whether ADB is always a pathologic condition or whether it can represent an adaptive process to suppress bone resorption and further bone loss. In this article, we tried to discuss this hard topic based on the available limited information in patients with CKD. More studies are needed to be able to clearly address this frequent ROD finding.

Pediatric CKD-MBD: existing and emerging treatment approaches

The effects of bone and mineral metabolism on skeletal formation, as well as vascular and soft tissue calcifications, define chronic kidney disease-metabolic bone disease (CKD-MBD). Treatment recommendations center on establishing adequate vitamin D status, phosphate control through diet restriction and phosphate binders, and the use of vitamin D analogs for specific indications. Several emerging bone-promoting therapies have now been studied in adults with CKD, including bisphosphonates and denosumab. These approaches are associated with improved bone mass and, in some cases, decreased fracture rates in adults with CKD-MBD and are of potential interest for some children with CKD-MBD. In children with CKD and immobilization and/or muscle weakness, bisphosphonates appear to be an effective treatment to increase bone mass; baseline assessment and careful monitoring of bone density and/or bone biopsy findings are important in consideration of any new bone therapies for children with CKD-MBD.

Definition, Assessment, and Management of Vitamin D Inadequacy: Suggestions, Recommendations, and Warnings from the Italian Society for Osteoporosis, Mineral Metabolism and Bone Diseases (SIOMMMS)

In the recent years, both the prescriptions of serum 25(OH)D levels assay, and vitamin D supplementation are constantly increasing, as well as the costs to be incurred relating to these specific aspects. As in many other countries, the risk of vitamin D deficiency is particularly high in Italy, as recently confirmed by cohort studies in the general population as well as in patients with metabolic bone disorder. Results confirmed the North-South gradient of vitamin D levels described among European countries, despite the wide use of supplements. Although vitamin D supplementation is also recommended by the Italian Medicine Agency for patients at risk for fragility fracture or for initiating osteoporotic medication, the therapeutic gap for osteoporosis in Italy is very high. There is a consistent proportion of osteoporotic patients not receiving specific therapy for osteoporosis following a fragility fracture, with a poor adherence to the recommendations provided by national guidelines and position paper documents. The failure or inadequate supplementation with vitamin D in patients on antiresorptive or anabolic treatment for osteoporosis is thought to further amplify the problem and exposes patients to a high risk of re-fracture and mortality. Therefore, it is important that attention to its possible clinical consequences must be given. Thus, in light of new evidence from the literature, the SIOMMMS board felt the need to revise and update, by a GRADE/PICO system approach, its previous original recommendations about the definition, prevention, and treatment of vitamin D deficiency in adults, released in 2011. Several key points have been here addressed, such as the definition of the vitamin D status: normality values and optimal values; who are the subjects considered at risk of hypovitaminosis D; opportunity or not of performing the biochemical assessment of serum 25(OH)D levels in general population and in subjects at risk of hypovitaminosis D; the need or not to evaluate baseline serum 25(OH)D in candidate subjects for pharmacological treatment for osteoporosis; how and whether to supplement vitamin D subjects with hypovitaminosis D or candidates for pharmacological treatment with bone active agents, and the general population; how and whether to supplement vitamin D in chronic kidney disease and/or chronic liver diseases or under treatment with drugs interfering with hepatic metabolism; and finally, if vitamin D may have toxic effects in the subject in need of supplementation.

Treatment of secondary hyperparathyroidism in non-dialysis CKD: an appraisal 2022s

The situation of secondary hyperparathyroidism (sHPT) in CKD patients not on dialysis (ND-CKD) is probably best characterised by the KDIGO CKD-MBD Update 2017 guideline 4.2.1 stating that the optimal PTH levels is not known in these stages. Furthermore, new caution became recommended with regard to the routine use of active vitamin D analogues in early CKD stages and moderate sHPT phenotypes, due to their potential risks for hypercalcaemia and hyperphosphataemia aggravation. Nevertheless, there is still a substantial clinical need to prevent the development of parathyroid gland autonomy with its associated consequences of bone and vascular damage including fracture risks and cardiovascular events. Therefore, we now attempt to review the current guideline-based and clinical practice management of sHPT in ND-CKD including their strengths and weaknesses, favouring individualised approaches respecting calcium and phosphate homeostasis. We further comment on extended-release calcifediol (ERC) as a new differential therapeutic option now also available in Europe, and on a potentially novel understanding of a required vitamin D saturation in more advanced CKD stages. There is no doubt, however, that knowledge gaps will remain in this issue unless powerful RCTs with hard and meaningful endpoints are performed.

Endocrine manifestations of chronic kidney disease and their evolving management: A systematic review

BACKGROUND

Chronic Kidney Disease (CKD) shows a wide range of renal abnormalities including the excretory, metabolic, endocrine, and homeostatic function of the kidney. The prognostic impact of the 'endocrine manifestations' which are often overlooked by clinicians cannot be overstated.

METHODS AND OBJECTIVES

A systematic review was attempted to provide a comprehensive overview of all endocrine abnormalities of CKD and their evolving principles of management, searching databases of PubMed, Embase, and Scopus and covering the literature between 2002 and 2022.

RESULTS

The endocrine derangements in CKD can be attributed to a myriad of pathologic processes, in particular decreased clearance, impaired endogenous hormone production, uremia-induced cellular dysfunction, and activation of systemic inflammatory pathways. The major disorders include anemia, hyperprolactinemia, insulin resistance, reproductive hormone deficiency, thyroid hormone deficiency, and serum FGF (Fibroblast Growth Factor) alteration. Long-term effects of CKD also include malnutrition and increased cardiovascular risk. The recent times have unveiled their detailed pathogenesis and have seen an evolution in the principles of management which necessitates a revision of current guidelines.

CONCLUSION

Increased advertence regarding the pathology, impact, and management of these endocrine derangements can help in reducing morbidity as well as mortality in the CKD patients by allowing prompt individualized treatment. Moreover, with timely and appropriate intervention, a long-term reduction in complications, as well as an enhanced quality of life, can be achieved in patients with CKD.

Efficacy and Safety of Romosozumab Among Postmenopausal Women With Osteoporosis and Mild-to-Moderate Chronic Kidney Disease

Patients with osteoporosis and chronic kidney disease (CKD) are at increased risk of fracture and associated negative outcomes, including increased mortality. The present post hoc analysis of two randomized, multicenter, phase 3 clinical trials-Fracture Study in Postmenopausal Women with Osteoporosis (FRAME) and Active-Controlled Fracture Study in Postmenopausal Women with Osteoporosis at High Risk (ARCH)-investigated the efficacy and safety of romosozumab in postmenopausal women with osteoporosis and mild-to-moderate CKD. The analysis included data from 7147 patients from FRAME and 4077 from ARCH. Eighty-one percent of patients from FRAME and 85% from ARCH had mild or moderate reduction in estimated glomerular filtration rate (eGFR) at baseline, and part of this reduction is likely age related. During the 1-year double-blind phases of the trials, patients received romosozumab 210 mg sc or placebo monthly in FRAME and romosozumab 210 mg sc monthly or alendronate 70 mg po weekly in ARCH. Bone mineral density (BMD) at the lumbar spine, total hip, and femoral neck and vertebral and nonvertebral fractures were assessed at baseline and month 12. In both trials, the least-square mean percent change from baseline BMD was significantly greater in the romosozumab groups versus controls across all kidney function categories at month 12. Romosozumab reduced the relative risk of new vertebral fractures at month 12 among patients with eGFR of 30-59, 60-89, and ≥90 mL/min by 72% (95% confidence interval [CI] 14-91; p = 0.017), 70% (40-85; p < 0.001), and 84% (30-96; p = 0.005), respectively, in FRAME versus placebo, and by 51% (5-75; p = 0.04), 19% (-28 to 49; p = 0.39), and 57% (1-81, p = 0.04), respectively, in ARCH versus alendronate. Incidences of adverse events, asymptomatic decreases in serum calcium, and evolution of kidney function during the studies were similar across all baseline kidney function groups. Romosozumab is an effective treatment option for postmenopausal women with osteoporosis and mild-to-moderate reduction in kidney function, with a similar safety profile across different levels of kidney function. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Clinical utility of bone turnover markers in patients with chronic kidney disease

PURPOSE OF REVIEW

The burden of fractures is very high in patients with chronic kidney disease (CKD). It is increasingly recognized that knowledge of bone turnover is of paramount importance in guiding mineral metabolism and osteoporosis therapy in CKD. Bone histomorphometry is the gold standard to assess bone turnover, but is seldomly performed in clinical practice. Bone turnover markers (BTMs) may be the long awaited noninvasive diagnostic that may help to close the therapeutic gap in patients with advanced CKD presenting with bone fragility.

RECENT FINDINGS

Mounting evidence indicates that BTMs may be useful in skeletal and nonskeletal risk stratification, in guiding mineral metabolism and osteoporosis therapy, and in monitoring the therapeutic response.

SUMMARY

BTMs provide information that is complementary to other clinical tests. It may be envisioned that in the near future, the assessment of nonkidney cleared BTMs may become part of routine clinical evaluation and monitoring of bone health in CKD patients, integrated with clinical risk factors, imaging data and, eventually, bone histomorphometry. Panels of BTMs will likely be more informative than single markers, and the same might hold true for trends as opposed to single time point data.

Association between Anti-Osteoporotic Drugs and Risk of Acute Kidney Injury: A Cross-Sectional Study Using Disproportional Analysis and a Pharmacovigilance Database

The number of fractures related to osteoporosis is expected to increase. Therefore, clarifying the risk of acute kidney injury (AKI) associated with each type of anti-osteoporotic drug may avoid discontinuation of osteoporosis pharmacotherapy due to onset of AKI. This cross-sectional study using disproportional analysis and a pharmacovigilance database assessed the risk of AKI with various anti-osteoporotic drugs by analyzing data entered into the US Food and Drug Administration's Adverse Event Reporting System (FAERS) from April 2014 to March 2021 and the Medical Data Vision (MDV) database in Japan in November 2021. All anti-osteoporotic drugs were investigated, including bisphosphonates, selective estrogen receptor modulators, denosumab, romosozumab, abaloparatide, and teriparatide. In the analysis of FAERS data, disproportionality for decreasing AKI was observed for oral ibandronate [reporting odds ratios (ROR) 0.22, 95% confidence interval (CI) 0.09-0.45, P < 0.01], bazedoxifene (ROR 0.26, 95% CI 0.05-0.77, P = 0.01), and intravenous ibandronate (ROR 0.39, 95% CI 0.14-0.86, P = 0.01). In the analysis of the MDV data, the incidence of AKI was lower in patients taking intravenous ibandronate [odds ratio (OR) 0.22, 95% CI 0.06-0.89, P = 0.03], and the incidence of AKI was higher in patients taking oral alendronate (OR 2.40, 95% CI 2.08-2.77, P < 0.01). Risk of AKI may differ even among oral anti-osteoporotic drugs, and the evidence of this association should be assessed further in future drug safety studies. This article is protected by copyright. All rights reserved.

Kidney Transplantation, Immunosuppression and the Risk of Fracture: Clinical and Economic Implications

Rationale & Objective

Disorders of bone and mineral metabolism frequently develop with advanced kidney disease, may be exacerbated by immunosuppression after kidney transplantation, and increase the risk of fractures.

Study Design

Retrospective database study.

Setting & Participants

Kidney-only transplant recipients aged ≥18 years from 2005 to 2016 in the United States captured in US Renal Data System records, which integrate Organ Procurement and Transplantation Network/United Network for Organ Sharing records with Medicare billing claims.

Exposures

Various immunosuppression regimens in the first 3 months after kidney transplantation.

Outcomes

The development of fractures, as ascertained using diagnostic codes on Medicare billing claims.

Analytical Approach

We used multivariable Cox regression with inverse propensity weighting to compare the incidence of fractures >3 months-to-3 years after kidney transplantation associated with various immunosuppression regimens compared to a reference regimen of antithymocyte globulin (TMG) or alemtuzumab (ALEM) with tacrolimus + mycophenolic acid + prednisone using inverse probability treatment weighting.

Results

Overall, fractures were identified in 7.5% of kidney transplant recipients (women, 8.8%; men, 6.7%; age < 55 years, 5.9%; age ≥ 55 years, 9.3%). In time-varying regression, experiencing a fracture was associated with a substantially increased risk of subsequent death within 3 months (adjusted hazard ratio [aHR], 3.06; 95% confidence interval [CI], 2.45-3.81). Fractures were also associated with increased Medicare spending (first year: $5,122; second year: $10,890; third year: $11,083; [P < 0.001]). Induction with TMG or ALEM and the avoidance or early withdrawal of steroids significantly reduced the risk of fractures in younger (aHR, 0.63; 95% CI, 0.54-0.73) and older (aHR, 0.83; 95% CI, 0.74-0.94) patients. The avoidance or early withdrawal of steroids with any induction was associated with a reduced risk of fractures in women.

Limitations

This was a retrospective study which lacked data on immunosuppression levels.

Conclusions

Fractures after kidney transplantation are associated with significantly increased mortality risk and costs. The early avoidance or early withdrawal of steroids after induction with TMG or ALEM reduces the risk of fractures after kidney transplantation and should be considered for patients at high-risk of this complication, including older adults and women.

Alkaline Phosphatase: An Old Friend as Treatment Target for Cardiovascular and Mineral Bone Disorders in Chronic Kidney Disease

Alkaline phosphatase (ALP) is an evolutionary conserved enzyme and widely used biomarker in clinical practice. Tissue-nonspecific alkaline phosphatase (TNALP) is one of four human isozymes that are expressed as distinct TNALP isoforms after posttranslational modifications, mainly in bone, liver, and kidney tissues. Beyond the well-known effects on bone mineralization, the bone ALP (BALP) isoforms (B/I, B1, B1x, and B2) are also involved in the pathogenesis of ectopic calcification. This narrative review summarizes the recent clinical investigations and mechanisms that link ALP and BALP to inflammation, metabolic syndrome, vascular calcification, endothelial dysfunction, fibrosis, cardiovascular disease, and mortality. The association between ALP, vitamin K, bone metabolism, and fracture risk in patients with chronic kidney disease (CKD) is also discussed. Recent advances in different pharmacological strategies are highlighted, with the potential to modulate the expression of ALP directly and indirectly in CKD–mineral and bone disorder (CKD-MBD), e.g., epigenetic modulation, phosphate binders, calcimimetics, vitamin D, and other anti-fracture treatments. We conclude that the significant evidence for ALP as a pathogenic factor and risk marker in CKD-MBD supports the inclusion of concrete treatment targets for ALP in clinical guidelines. While a target value below 120 U/L is associated with improved survival, further experimental and clinical research should explore interventional strategies with optimal risk–benefit profiles. The future holds great promise for novel drug therapies modulating ALP.

Information and consensus document for the detection and management of chronic kidney disease

Chronic kidney disease (CKD) is a major public health problem worldwide that affects more than 10% of the Spanish population. CKD is associated with high comorbidity rates, poor prognosis and major consumption of health system resources. Since the publication of the last consensus document on CKD seven years ago, little evidence has emerged and few clinical trials on new diagnostic and treatment strategies in CKD have been conducted, apart from new trials in diabetic kidney disease. Therefore, CKD international guidelines have not been recently updated. The rigidity and conservative attitude of the guidelines should not prevent the publication of updates in knowledge about certain matters that may be key in detecting CKD and managing patients with this disease. This document, also prepared by 10 scientific associations, provides an update on concepts, clarifications, diagnostic criteria, remission strategies and new treatment options. The evidence and the main studies published on these aspects of CKD have been reviewed. This should be considered more as an information document on CKD. It includes an update on CKD detection, risk factors and screening; a definition of renal progression; an update of remission criteria with new suggestions in the older population; CKD monitoring and prevention strategies; management of associated comorbidities, particularly in diabetes mellitus; roles of the Primary Care physician in CKD management; and what not to do in Nephrology. The aim of the document is to serve as an aid in the multidisciplinary management of the patient with CKD based on current recommendations and knowledge.

High-mobility group box chromosomal protein-1 deletion alleviates osteoporosis in OVX rat model via suppressing the osteoclastogenesis and inflammation

Background

Osteoporosis is a skeletal metabolic disease that constitutes a great threaten to human health. However, there is currently no gold standard for its treatment. High-mobility group box chromosomal protein-1 (HMGB-1) has been reported to play an important role in various orthopedic diseases. Till now, its role in osteoporosis remains elusive.

Methods

Rats underwent ovariectomy (OVX) were used to construct a postmenopausal model of osteoporosis. Then, rats were divided into sham groups without OVX surgery, OVX model group, HMGB-1 knockdown (HMGB-1 KD) OVX model groups. The expression of HMGB1 was evaluated by qRT-PCR and western blotting. Subsequently, the changes of trabeculae were evaluated by micro-computed tomography (CT) assay. Skeletal necrosis and metabolism were further analyzed by hematoxylin–eosin (HE) staining, Alcian blue staining and Masson’s trichrome staining. The contents of serum alkaline phosphatase (ALP) and osteocalcin were detected by ELISA assay. Expression of osteoclast-associated receptor (OSCAR) and tartrate-resistant acid phosphatase (TRAP) were determined to investigate the effects of HMGB-1 loss on osteoclastogenesis.

Results

Single HMGB-1 deletion exerted no significant effect on rat trabeculae, serum ALP and osteocalcin. Noticeably, HMGB1 knockdown dramatically ameliorated OVX-induced changes in above indexes. Trabeculae structures of OVX rats were sparse with disorder arrangement, which were greatly recovered after HMGB-1 deletion. Enhanced osteoclastogenesis was observed in OVX rats by increasing number of TRAP + cells and expression of TRAP and OSCAR, and loss of HMGB1 ameliorated osteoclastogenesis in OVA rats. Moreover, HMGB-1 deletion antagonized OVX-evoked downregulation of osteoblast activity markers osterix (OSX), collagen type I alpha 1(COL1A1) and distal-less homeobox 2 (DLX2) protein. Furthermore, loss of HMGB-1 attenuated fluctuation of inflammatory factors in OVX rats. Additionally, HMGB-1 deficiency inhibited OVX-evoked activation of the Toll-like receptor (TLR) 4/NF-κB signaling pathway. Moreover, reactivating the TLR4 signaling further aggravated OVX-induced osteoporosis, which was reversed by HMGB1 knockdown.

Conclusion

HMGB-1 deletion alleviated OVX-triggered osteoporosis by suppressing osteoclastogenesis and inflammatory disorder via the inhibition of the TLR4 signaling. Therefore, HMGB-1 may be a promising therapeutic target for osteoporosis.

Pharmacological treatment of osteoporosis: 2022 update

Background: Osteoporosis is a skeletal disorder characterized by compromised bone strength resulting in a predisposition to fracture. Osteoporosis-related fractures can lead to pain, disability, and increased healthcare costs. We aimed to explore the guidelines and criteria for selecting medications for osteoporosis.Current Concepts: Osteoporosis medications can be classified mainly as antiresorptive drugs and osteogenesis promoters. The former includes selective estrogen receptor modulators, bisphosphonates, and receptor activators of nuclear factor kappa-B ligand inhibitors, e.g., denosumab. The latter includes human parathyroid hormone, e.g., teriparatide, and the dual-action agent, romosozumab. Selective estrogen receptor modulators (raloxifene or bazedoxifene) can be considered suitable for younger postmenopausal women with low spine bone mineral density. It also can be used for patients with low glomerular filtration rates due to low excretion in urine and patients who need dental care. Bisphosphonate has a residual effect on bone; therefore, osteonecrosis of the jaw and atypical fractures should be considered as side effects for its long-term use. Presently, denosumab is the most potent antiresorptive agent, but its favorable skeletal effects can be reversed quickly after its cessation. Therefore, subsequent antiresorptive treatment is mandatory. Romosozumab is a dual-action agent that simultaneously stimulates bone formation and inhibits bone resorption. It also needs a subsequent antiresorptive treatment.Discussion and Conclusion: Tailored treatment is needed in a patient with osteoporosis. Even in the case of the same bone density, the risk of fracture and the fracture sites differ depending on age. After setting an achievable goal of bone density within a suitable period, the appropriate medication should be selected.

Efficacy of Osteoporosis Medications for Patients With Chronic Kidney Disease: An Updated Systematic Review and Network Meta-Analysis

Background: Chronic kidney disease (CKD) is associated with bone and mineral metabolism. In this study we evaluated the comparative efficacies and safety of osteoporosis medications in patients with CKD or a history of kidney transplantation, and make recommendations for the best choice of osteoporosis treatment among patients with CKD or a history of kidney transplantation. Methods: We systemically searched for randomized controlled trials published in PubMed, Embase, and Cochrane databases up to June 2020. Network-meta analysis was used to compare the relative effectiveness of different treatments. A random-effects model was used when heterogeneity was expected. The safety of different treatments was also evaluated in terms of reported major adverse events. Results: A total of 17 studies with data from 10,214 patients who had stage 2-5 CKD, were receiving dialysis, or had a history of kidney transplantation were included in the network meta-analysis. Treatment with teriparatide, denosumab, alendronate, and raloxifene were all associated with a significantly reduced risk of fractures compared to treatment with placebos [teriparatide: odds ratio (OR) = 0.19, 95% confidence interval (CI): 0.10-0.35; denosumab: OR = 0.40, 95% CI: 0.27-0.58; alendronate: OR = 0.61, 95% CI: 0.40-0.92; raloxifene: OR = 0.52, 95% CI: 0.41-0.67]. The rank probability and the surface under the cumulative ranking (SUCRA) values suggested that teriparatide ranked the highest for improvement in vertebral bone mineral density (BMD) (SUCRA = 97.8%), whereas denosumab ranked the highest for improvement in femoral neck BMD (SUCRA = 88.3%). Conclusion: Teriparatide and denosumab seem to be the most effective treatments for preventing bone loss and reducing the risk of fracture in our network comparison. However, because of the limitations and potential biases in the reviewed studies, there is still some uncertainty about the best treatment options for osteoporosis in patients with CKD or a history of kidney transplantation. Systematic Review Registration: [PROSPERO], identifier [CRD42020209830].

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

PURPOSE OF THE STUDY

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

STUDY DESIGN

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

RESULTS AND CONCLUSIONS

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

Prevalence and risk factors of osteoporosis in saudi end-stage renal disease patients on hemodialysis

Background:

Objective:

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Diosmin, a citrus fruit-derived phlebotonic bioflavonoid protects rats from chronic kidney disease-induced loss of bone mass and strength without deteriorating renal function

Kidney Disease: Improving Global Outcomes (KDIGO) 2017 Clinical Practice Guideline recommended treatment decisions for patients with chronic kidney disease (CKD) with osteoporosis and/or high risk of fracture. Bisphosphonates, the first-line...

Bone and Mineral Disease in Kidney Transplant Recipients

After kidney transplantation, mineral and bone disorders are associated with higher risk of fractures and consequent morbidity and mortality. Disorders of calcium and phosphorus, vitamin D deficiency, and hyperparathyroidism are also common. The epidemiology of bone disease has evolved over the past several decades due to changes in immunosuppressive regimens, mainly glucocorticoid minimization or avoidance. The assessment of bone disease in kidney transplant recipients relies on risk factor recognition and bone mineral density assessment. Several drugs have been trialed for the treatment of post-transplant mineral and bone disorders. This review will focus on the epidemiology, effect, and treatment of metabolic and skeletal derangements in the transplant recipient.

Recent Advances in the Role of Diet in Bone and Mineral Disorders in Chronic Kidney Disease

PURPOSE OF REVIEW

Chronic kidney disease mineral and bone disease (CKD-MBD) is a common complication of kidney disease and is strongly influenced by diet. The purpose of this manuscript is to review recent advances in the role of diet in CKD-MBD over the last 5 years.

RECENT FINDINGS

Many of the recent studies examining the role of diet in CKD-MBD have focused on the adverse effects of high phosphorus consumption on bone health and metabolism. In general, the studies have shown that high phosphorus consumption worsens markers of bone and mineral metabolism but that eating a diet with a calcium to phosphorus ratio closer to 1:1 can attenuate some of these effects. Recent studies also showed that dietary counseling is efficacious for improving markers of CKD-MBD. High consumption of phosphorus aggravates CKD-MBD. Dietary counseling may ameliorate these effects, for example, by consuming diets with higher calcium to phosphorus ratios.

Muscle-bone axis in children with chronic kidney disease: current knowledge and future perspectives

Bone and muscle tissue are developed hand-in-hand during childhood and adolescence and interact through mechanical loads and biochemical pathways forming the musculoskeletal system. Chronic kidney disease (CKD) is widely considered as both a bone and muscle-weakening disease, eventually leading to frailty phenotype, with detrimental effects on overall morbidity. CKD also interferes in the biomechanical communication between two tissues. Pathogenetic mechanisms including systemic inflammation, anorexia, physical inactivity, vitamin D deficiency and secondary hyperparathyroidism, metabolic acidosis, impaired growth hormone/insulin growth factor 1 axis, insulin resistance, and activation of renin-angiotensin system are incriminated for longitudinal uncoordinated loss of bone mineral content, bone strength, muscle mass, and muscle strength, leading to mechanical impairment of the functional muscle-bone unit. At the same time, CKD may also interfere in the biochemical crosstalk between the two organs, through inhibiting or stimulating the expression of certain osteokines and myokines. This review focuses on presenting current knowledge, according to in vitro, in vivo, and clinical studies, concerning the pathogenetic pathways involved in the muscle-bone axis, and suggests approaches aimed at preventing bone loss and muscle wasting in the pediatric population. Novel therapeutic targets for preserving musculoskeletal health in the context of CKD are also discussed.

Raloxifene in the Treatment of Osteoporosis in Postmenopausal Women with End-Stage Renal Disease: A Systematic Review and Meta-Analysis

As a selective estrogen receptor modulator (SERM), raloxifene is used in healthy postmenopausal women to prevent bone loss and reduce fractures. However, the benefit of raloxifene is uncertain in the treatment of osteoporosis among patients with end-stage renal disease (ESRD) or those who require maintenance dialysis. We assessed the safety and efficacy of raloxifene in this particular population. Studies were selected from PubMed, Springer, CNKI (Chinese National Knowledge Infrastructure) and Wanfang Database. Randomized controlled trials (RCTs) and prospective studies with control/placebo groups were included. Five studies were included with a total of 244 participants (121 patients in the raloxifene group and 123 patients in the placebo/control group). The median duration of treatment was 12 months. The incidence rate of side effects of raloxifene was 0/121 (0%). There was a significant improvement of lumbar spine bone mineral density (BMD) levels in the raloxifene group compared with the placebo group (MD: 33.88, 95% CI: 10.93, 56.84, p=0.004). There was no significant difference concerning the improvement of femoral neck BMD (MD: 8.42, 95% CI: -10.21, 27.04, p=0.38), intact parathyroid hormone (iPTH) (MD: -12.62, 95% CI: -35.36, 10.13, p=0.28), calcium (MD: -0.08, 95% CI: -0.61, 0.44, p=0.76), phosphorus (MD: 0.18, 95% CI: -0.12, 0.48, p=0.23) or bone alkaline phosphatase (BAP) (MD: -4.33, 95% CI: -14.44, 5.79, p=0.40). Raloxifene seems to be effective in improving the lumbar spine BMD in postmenopausal women with ESRD. More large RCTs are necessary to evaluate the long-term safety of raloxifene in uremic patients.

Smoking and risk of fractures requiring hospitalization in hemodialysis patients: a nationwide cohort study in Japan

BACKGROUND

Smoking is a well-established lifestyle risk factor for fractures in the general population, but evidence specific to hemodialysis populations is lacking. This nationwide cohort study used data from the Japanese Society for Dialysis Therapy Renal Data Registry to examine the association between smoking status and fractures.

METHODS

A total of 154,077 patients (64.2% men; mean age, 68 years) aged ≥20 years undergoing maintenance hemodialysis thrice a week at the end of 2016 were followed for 1 year. Among these, 19,004 (12.3%) patients were current smokers. Standardized incidence rate ratios of hospitalization due to any fracture were calculated and analyzed by multivariable logistic regression analysis, controlling for potential confounders. Propensity score matching and subgroup analyses were also performed as sensitivity analyses.

RESULTS

During the 1-year follow-up period, 3,337 fractures requiring hospitalization (1,201 hip, 479 vertebral, and 1,657 other fractures) occurred in 3,291 patients. The age- and sex-standardized incidence ratio for current smokers was 1.24 (95% confidence interval, 1.12-1.39) relative to non-smokers. Standardized incidence ratios were similar after stratification by age group and sex. Multivariable logistic regression analysis revealed a 1.25-fold higher risk of any fracture requiring hospitalization (95% confidence interval, 1.10-1.42) in current smokers relative to non-smokers in a fully adjusted model. Propensity score matching showed similar results (odds ratio, 1.25; 95% confidence interval, 1.05-1.48). Subgroup analyses for baseline covariates revealed no significant interactions.

CONCLUSIONS

Smoking is a significant risk factor for any fracture requiring hospitalization in hemodialysis patients.

Bone Biopsy for Histomorphometry in Chronic Kidney Disease (CKD): State-of-the-Art and New Perspectives

The use of bone biopsy for histomorphometric analysis is a quantitative histological examination aimed at obtaining quantitative information on bone remodeling, structure and microarchitecture. The labeling with tetracycline before the procedure also allows for a dynamic analysis of the osteoblastic activity and mineralization process. In the nephrological setting, bone biopsy is indicated to confirm the diagnosis of subclinical or focal osteomalacia and to characterize the different forms of renal osteodystrophy (ROD). Even if bone biopsy is the gold standard for the diagnosis and specific classification of ROD, the use of this approach is very limited. The main reasons for this are the lack of widespread expertise in performing or interpreting bone biopsy results and the cost, invasiveness and potential pain associated with the procedure. In this regard, the sedation, in addition to local anesthesia routinely applied in Italian protocol, significantly reduces pain and ameliorates the pain perception of patients. Concerning the lack of widespread expertise, in Italy a Hub/Spokes model is proposed to standardize the analyses, optimizing the approach to CKD patients and reducing the costs of the procedure. In addition, new tools offer the possibility to evaluate the osteogenic potential or the ability to form bone under normal and pathological conditions, analyzing mesenchymal stem cells and their ability to differentiate in the osteogenic lineage. In the same way, circulating microRNAs are suggested as a tool for exploring osteogenic potential. The combination of different diagnostic approaches and the optimization of the bioptic procedure represent a concrete solution to spread the use of bone biopsy and optimize CKD patient management.

Is dual-energy absorptiometry accurate in the assessment of bone status of patients with chronic kidney disease?

Several patients with chronic kidney disease (CKD) have deteriorated bone status. Estimation of bone status using DXA has limitations especially in patients with CKD accompanying aortic calcifications. Quantitative CT and the trabecular bone score could be more accurate methods to estimate bone status for patients with CKD and vascular calcifications.

INTRODUCTION

It remains unclear whether dual-energy absorptiometry (DXA) is appropriate for the assessment of bone status in patients with chronic kidney disease (CKD), a disease that impacts bone health. The aims of this study were to compare DXA and central quantitative computed tomography (cQCT) and to evaluate bone status in patients with pre-dialysis CKD.

METHODS

This retrospective study included 363 healthy control subjects whose bone mineral density (BMD) was evaluated with DXA and 117 CKD patients whose BMD was evaluated using both cQCT and DXA. Diagnostic discordance was assessed between the lumbar spine (LS) and femur neck (FN) from DXA or between two modalities. The trabecular bone score (TBS) was extracted from DXA images. The volume of abdominal aortic calcification (AAC) was calculated using CT images from cQCT.

RESULTS

Using LS DXA T-score, osteoporosis was less common in the CKD group than in controls. Patients with normal LS BMD using DXA were reclassified into osteopenia or osteoporosis using cQCT in CKD patients. Among discordant subjects between FN and LS in DXA, a higher BMD of LS was more common in CKD patients than in controls. CKD patients had lower TBS than controls despite having the same diagnosis using DXA. AAC volume negatively correlated with BMD from cQCT and with TBS but not with BMD from DXA.

CONCLUSIONS

TBS and cQCT could accurately assess bone status in CKD patients since DXA may overestimate LS BMD, likely due to an increased AAC volume.

Pharmacological interventions versus placebo, no treatment or usual care for osteoporosis in people with chronic kidney disease stages 3-5D

BACKGROUND

Chronic kidney disease (CKD) is an independent risk factor for osteoporosis and is more prevalent among people with CKD than among people who do not have CKD. Although several drugs have been used to effectively treat osteoporosis in the general population, it is unclear whether they are also effective and safe for people with CKD, who have altered systemic mineral and bone metabolism.

OBJECTIVES

To assess the efficacy and safety of pharmacological interventions for osteoporosis in patients with CKD stages 3-5, and those undergoing dialysis (5D).

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to 25 January 2021 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

Randomised controlled trials comparing any anti-osteoporotic drugs with a placebo, no treatment or usual care in patients with osteoporosis and CKD stages 3 to 5D were included.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies, assessed their quality using the risk of bias tool, and extracted data. The main outcomes were the incidence of fracture at any sites; mean change in the bone mineral density (BMD; measured using dual-energy radiographic absorptiometry (DXA)) of the femoral neck, total hip, lumbar spine, and distal radius; death from all causes; incidence of adverse events; and quality of life (QoL). Summary estimates of effect were obtained using a random-effects model, and results were expressed as risk ratios (RR) and their 95% confidence intervals (CI) for dichotomous outcomes, and mean difference (MD) for continuous outcomes. Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

MAIN RESULTS

Seven studies involving 9164 randomised participants with osteoporosis and CKD stages 3 to 5D met the inclusion criteria; all participants were postmenopausal women. Five studies included patients with CKD stages 3-4, and two studies included patients with CKD stages 5 or 5D. Five pharmacological interventions were identified (abaloparatide, alendronate, denosumab, raloxifene, and teriparatide). All studies were judged to be at an overall high risk of bias. Among patients with CKD stages 3-4, anti-osteoporotic drugs may reduce the risk of vertebral fracture (RR 0.52, 95% CI 0.39 to 0.69; low certainty evidence). Anti-osteoporotic drugs probably makes little or no difference to the risk of clinical fracture (RR 0.91, 95% CI 0.79 to 1.05; moderate certainty evidence) and adverse events (RR 0.99, 95% CI 0.98 to 1.00; moderate certainty evidence). We were unable to incorporate studies into the meta-analyses for BMD at the femoral neck, lumbar spine and total hip as they only reported the percentage change in the BMD in the intervention group. Among patients with severe CKD stages 5 or 5D, it is uncertain whether anti-osteoporotic drug reduces the risk of clinical fracture (RR 0.33, 95% CI 0.01 to 7.87; very low certainty evidence). It is uncertain whether anti-osteoporotic drug improves the BMD at the femoral neck because the certainty of this evidence is very low (MD 0.01, 95% CI 0.00 to 0.02). Anti-osteoporotic drug may slightly improve the BMD at the lumbar spine (MD 0.03, 95% CI 0.03 to 0.04, low certainty evidence). No adverse events were reported in the included studies. It is uncertain whether anti-osteoporotic drug reduces the risk of death (RR 1.00, 95% CI 0.22 to 4.56; very low certainty evidence).

AUTHORS' CONCLUSIONS

Among patients with CKD stages 3-4, anti-osteoporotic drugs may reduce the risk of vertebral fracture in low certainty evidence. Anti-osteoporotic drugs make little or no difference to the risk of clinical fracture and adverse events in moderate certainty evidence. Among patients with CKD stages 5 and 5D, it is uncertain whether anti-osteoporotic drug reduces the risk of clinical fracture and death because the certainty of this evidence is very low. Anti-osteoporotic drug may slightly improve the BMD at the lumbar spine in low certainty evidence. It is uncertain whether anti-osteoporotic drug improves the BMD at the femoral neck because the certainty of this evidence is very low. Larger studies including men, paediatric patients or individuals with unstable CKD-mineral and bone disorder are required to assess the effect of each anti-osteoporotic drug at each stage of CKD.

A generalized kernel machine approach to identify higher-order composite effects in multi-view datasets, with application to adolescent brain development and osteoporosis

In recent years, a comprehensive study of complex disease with multi-view datasets (e.g., multi-omics and imaging scans) has been a focus and forefront in biomedical research. State-of-the-art biomedical technologies are enabling us to collect multi-view biomedical datasets for the study of complex diseases. While all the views of data tend to explore complementary information of disease, analysis of multi-view data with complex interactions is challenging for a deeper and holistic understanding of biological systems. In this paper, we propose a novel generalized kernel machine approach to identify higher-order composite effects in multi-view biomedical datasets (GKMAHCE). This generalized semi-parametric (a mixed-effect linear model) approach includes the marginal and joint Hadamard product of features from different views of data. The proposed kernel machine approach considers multi-view data as predictor variables to allow a more thorough and comprehensive modeling of a complex trait. We applied GKMAHCE approach to both synthesized datasets and real multi-view datasets from adolescent brain development and osteoporosis study. Our experiments demonstrate that the proposed method can effectively identify higher-order composite effects and suggest that corresponding features (genes, region of interests, and chemical taxonomies) function in a concerted effort. We show that the proposed method is more generalizable than existing ones. To promote reproducible research, the source code of the proposed method is available at.

The Non-invasive Diagnosis of Bone Disorders in CKD

Abnormal bone metabolism is an integral part of the chronic kidney disease-mineral bone disorder (CKD-MBD). For several reasons, the difficult bone compartment was neglected for some time, but there has been renewed interest as a result of the conception of bone as a new endocrine organ, the increasing recognition of the cross-talk between bone and vessels, and, especially, the very high risk of osteoporotic fractures (and associated mortality) demonstrated in patients with CKD. Therefore, it has been acknowledged in different guidelines that action is needed in respect of fracture risk assessment and the diagnosis and treatment of osteoporosis in the context of CKD and CKD-MBD, even beyond renal osteodystrophy. These updated guidelines clearly underline the need to improve a non-invasive approach to these bone disorders in order to guide treatment decisions aimed at not only controlling CKD-MBD but also decreasing the risk of fracture. In this report, we review the current role of the most often clinically used or promising biochemical circulating biomarkers such as parathyroid hormone, alkaline phosphatases, and other biochemical markers of bone activity as alternatives to some aspects of bone histomorphometry. We also mention the potential role of classic and new imaging techniques for CKD patients. Information on many aspects is still scarce and heterogeneous, but many of us consider that it is indeed time for action, recognizing our definitely limited ability to base certain treatment decisions only on our current non-comprehensive knowledge.

The Role of Bone Biopsy in the Management of CKD-MBD

A bone biopsy is still considered the gold standard for diagnosis of renal osteodystrophy. It allows to measure both static and dynamic parameters of bone remodeling and is the only method able to evaluate mineralization and allows analysis of both cortical and trabecular bone. Although bone volume can be measured indirectly by dual-energy X-ray absorptiometry, mineralization defects, bone metal deposits, cellular number/activity, and even turnover abnormalities are difficult to determine by techniques other than qualitative bone histomorphometry. In this review, we evaluate the role of bone biopsy in the clinical practice.

Osteoporosis and Chronic Kidney Disease-Mineral and Bone Disorder (CKD-MBD): Back to Basics

Osteoporosis is defined as a skeletal disorder of compromised bone strength predisposing those affected to an elevated risk of fracture. However, based on bone histology, osteoporosis is only part of a spectrum of skeletal complications that includes osteomalacia and the various forms of renal osteodystrophy of chronic kidney disease-mineral and bone disorder (CKD-MBD). In addition, the label "kidney-induced osteoporosis" has been proposed, even though the changes caused by CKD do not qualify as osteoporosis by the histological diagnosis. It is clear, therefore, that such terminology may not be helpful diagnostically or in making treatment decisions. A new label, "CKD-MBD/osteoporosis" could be a more appropriate term because it brings osteoporosis under the official label of CKD-MBD. Neither laboratory nor noninvasive diagnostic investigations can discriminate osteoporosis from the several forms of renal osteodystrophy. Transiliac crest bone biopsy can make the diagnosis of osteoporosis by exclusion of other kidney-associated bone diseases, but its availability is limited. Recently, a classification of metabolic bone diseases based on bone turnover, from low to high, together with mineralization and bone volume, has been proposed. Therapeutically, no antifracture treatments have been approved by the US Food and Drug Administration for patients with kidney-associated bone disease. Agents that suppress parathyroid hormone (vitamin D analogues and calcimimetics) are used to treat hyperparathyroid bone disease. Antiresorptive and osteoanabolic agents approved for osteoporosis are being used off-label to treat CKD stages 3b-5 in high-risk patients. It has now been suggested that intermittent administration of parathyroid hormone as early as CKD stage 2 could be an effective management strategy. If confirmed in clinical trials, it could mitigate the retention of phosphorus and subsequently the rise in fibroblast growth factor 23 and may be beneficial for coexisting osteoporosis.