Temporal trends in the incidence, treatment, and outcomes of hip fracture in older patients initiating dialysis in the United States

Unseen Threefold Mortality After the First Ten Days in Hemodialysis Patients Following Joint Arthroplasty: A Nationwide Retrospective Cohort Study of 1,287 Arthroplasty Patients on Hemodialysis

BACKGROUND

The study addresses the growing number of hemodialysis (HD) patients undergoing joint arthroplasty, who are at higher risk of complications and mortality. Previous research has often overlooked deaths after discharge. This study aimed to examine early outcomes in a large nationwide cohort of patients who underwent arthroplasty for elective and fracture-related reasons.

METHODS

Between 2016 and 2022, a study was conducted using the e-Nabız database of the Türkiye Ministry of Health, focusing on patients aged 18 years and above who underwent elective or fracture-related arthroplasty. This study included 1,287 patients reliant on dialysis who underwent total hip arthroplasty, total knee arthroplasty, or hemiarthroplasty (HA), with 7.7% of them receiving dialysis for the first time. Propensity score matching was used to create an equally sized group of non-dialysis-dependent patients, ensuring demographic balance in terms of age, sex, a comorbidity index, and surgery type. The primary objective was to compare mortality rates 10, 30, and 90 days after arthroplasty.

RESULTS

The first-time dialysis patients who underwent HA had significantly higher 30- and 90-day mortality rates compared to the chronic dialysis group (P = .040 and P < .001, respectively). Also, the HD patients consistently exhibited higher 90-day mortality rates across all surgery types. With total knee arthroplasty, HD patients had a mortality rate of 8.7%, in stark contrast to 0% among non-HD patients (P < .001). Similarly, with total hip arthroplasty, HD patients had a 12% mortality rate, while non-HD patients had a markedly lower rate of 2.7% (P = .008). In the case of HA, HD patients had a significantly elevated 90-day mortality rate of 31.9%, in contrast to 17.1% among non-HD patients (P < .001).

CONCLUSIONS

Joint arthroplasty has higher rates of mortality and complications among HD patients. Surgical decisions must be based on patients' overall health, necessitating collaboration among specialists. These patients should be closely monitored.

Clonal haematopoiesis, ageing and kidney disease

Clonal haematopoiesis of indeterminate potential (CHIP) is a preclinical condition wherein a sizeable proportion of an individual's circulating blood cells are derived from a single mutated haematopoietic stem cell. CHIP occurs frequently with ageing - more than 10% of individuals over 65 years of age are affected - and is associated with an increased risk of disease across several organ systems and premature death. Emerging evidence suggests that CHIP has a role in kidney health, including associations with predisposition to acute kidney injury, impaired recovery from acute kidney injury and kidney function decline, both in the general population and among those with chronic kidney disease. Beyond its direct effect on the kidney, CHIP elevates the susceptibility of individuals to various conditions that can detrimentally affect the kidneys, including cardiovascular disease, obesity and insulin resistance, liver disease, gout, osteoporosis and certain autoimmune diseases. Aberrant pro-inflammatory signalling, telomere attrition and epigenetic ageing are potential causal pathophysiological pathways and mediators that underlie CHIP-related disease risk. Experimental animal models have shown that inhibition of inflammatory cytokine signalling can ameliorate many of the pathological effects of CHIP, and assessment of the efficacy and safety of this class of medications for human CHIP-associated pathology is ongoing.

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%.

Hip hemiarthroplasty for the treatment of femoral neck fractures in dialysis patients

OBJECTIVES

This study sought to delineate the postoperative outcomes in dialysis patients undergoing hip hemiarthroplasty (HHA) for the treatment of femoral neck fractures (FNF) in order to better optimise pre- and postoperative management and minimise short-term morbidity and mortality rates.

METHODS

16,955 patients who had undergone HHA for femoral neck fractures from 2005 to 2018 were isolated from a multi-institutional surgical registry, of which 343 (2.0%) were on dialysis and 16,612 (98.0%) were not. The cohorts were identified/analysed for differences in their comorbidities, demographic factors, and 30-day postoperative complications using Fischer's exact tests and Mann-Whitney U-tests. Coarsened exact matching (CEM) was implemented in order to control for baseline difference in demographics and comorbidities. Multivariate logistic regression analyses were used to assess the impact of dialysis as an independent risk factor for various complications, including reoperations, readmissions, and mortality.

RESULTS

Upon CEM-matching (L1-statistic <0.001), weighted multivariate logistic regression analyses demonstrated dialysis to be an independent risk factor for minor complications (OR 3.051, p < 0.001), pneumonia (OR 3.943, p < 0.001), urinary tract infections (UTIs) (OR 2.684, p < 0.001), major complications (OR 1.892, p < 0.001), unplanned intubation (OR 2.555, p = 0.047), cardiac arrest (OR 11.897, p < 0.001), deep vein thrombosis (DVT), (OR 2.610, p = 0.049), and mortality (OR 2.960, p < 0.001).

CONCLUSIONS

Dialysis independently increased the risk for unplanned intubation, cardiac arrest, blood transfusions, pneumonia, DVT, and mortality. In communicating postoperative expectations, surgeons should aim to clarify the patients' preferences and potential resuscitation designations prior to surgical intervention due to the increased risk of serious complications. A lower threshold of suspicion for DVT in this population is reasonable. Identifying high-risk patient populations that may experience increased rates of complications, with the ensuing financial expenditures, due to medical complexity rather than subpar management may help providers avoid penalties in caring for these patients.

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

BACKGROUND AND AIMS

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

METHODS

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

RESULTS

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

CONCLUSION

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

Energy, Waves, and Forces in Bilateral Fracture of the Femoral Necks: Two Case Presentations and Updated Critical Review

Two case reports and an updated critical review on bilateral fractures of the femoral neck are presented. Bilateral fractures of the femoral neck have been investigated for at least 80 years and are treated as rare cases. The primary cause is usually considered an external shock; however, aside from high energy shocks (e.g., falling and impact with hard, rigid surfaces, traffic accidents, etc.) the underlying causes of femoral neck frailty have not yet been fully understood. Although not exhaustive, the review spans cases reported as early as 1944 and compares their conclusions in line with medicine developments at the time of the reports until present. The discussion is perhaps controversial at times; it brings to the fore the energy balance between shock waves and stress waves. The two cases reported here add to the review, one highlighting the biomechanics, and the other supporting more recent findings on metabolic disorders, which ultimately lead to enhanced frailty of the femoral neck. Investigation of the fractures has been performed with X-ray radiographs, MRI, and CT, with a follow up using a Doppler US to check blood flow in the lower zone of the limbs. The second case was investigated both for fractures and metabolic diseases, e.g., type I diabetes and kidney failure (dialysis). In Case 1 the second fracture was not observable at the time of admission, and therefore two surgery operations were performed at seven days interval. Taperloc Complete prostheses (Zimmer Biomet) were applied. Case 2 suffered a second fracture in the right hip in the segment above the knee and required better fixation with cables. Despite this, she returned one month later with a new crack in the femur. Case 1 is a typical case of wear consequences on the biomechanics of the hill pad-tibia-femur-femoral neck system, where tension of the neck occurred due to a stress wave rather than a shock wave. This can be proven by the absence of a second fracture from the images first acquired, the only evidence being pain and walking difficulty. Case 2 shows that metabolic diseases can dramatically enhance the frequency of bilateral femoral neck fractures.

Bone Fragility in Chronic Kidney Disease Stage 3 to 5: The Use of Vitamin D Supplementation

Frequently silent until advanced stages, bone fragility associated with chronic kidney disease-mineral and bone disease (CKD-MBD) is one of the most devastating complications of CKD. Its pathophysiology includes the reduction of active vitamin D metabolites, phosphate accumulation, decreased intestinal calcium absorption, renal alpha klotho production, and elevated fibroblast growth factor 23 (FGF23) levels. Altogether, these factors contribute firstly to secondary hyperparathyroidism, and ultimately, to micro- and macrostructural bone changes, which lead to low bone mineral density and an increased risk of fracture. A vitamin D deficiency is common in CKD patients, and low circulating 25(OH)D levels are invariably associated with high serum parathyroid hormone (PTH) levels as well as with bone mineralization defects, such as osteomalacia in case of severe forms. It is also associated with a variety of non-skeletal diseases, including cardiovascular disease, diabetes mellitus, multiple sclerosis, cancer, and reduced immunological response. Current international guidelines recommend supplementing CKD patients with nutritional vitamin D as in the general population; however, there is no randomized clinical trial (RCT) evaluating the effect of vitamin D (or vitamin D+calcium) supplementation on the risk of fracture in the setting of CKD. It is also unknown what level of circulating 25(OH)D would be sufficient to prevent bone abnormalities and fractures in these patients. The impact of vitamin D supplementation on other surrogate endpoints, including bone mineral density and bone-related circulating biomarkers (PTH, FGF23, bone-specific alkaline phosphatase, sclerostin) has been evaluated in several RTCs; however, the results were not always translated into an improvement in long-term outcomes, such as reduced fracture risk. This review provides a brief and comprehensive update on CKD-related bone fragility and the use of natural vitamin D supplementation in these patients.

Secondary Osteoporosis

Osteoporosis is a global public health problem, with fractures contributing to significant morbidity and mortality. Although postmenopausal osteoporosis is most common, up to 30% of postmenopausal women, > 50% of premenopausal women, and between 50% and 80% of men have secondary osteoporosis. Exclusion of secondary causes is important, as treatment of such patients often commences by treating the underlying condition. These are varied but often neglected, ranging from endocrine to chronic inflammatory and genetic conditions. General screening is recommended for all patients with osteoporosis, with advanced investigations reserved for premenopausal women and men aged < 50 years, for older patients in whom classical risk factors for osteoporosis are absent, and for all patients with the lowest bone mass (Z-score ≤ -2). The response of secondary osteoporosis to conventional anti-osteoporosis therapy may be inadequate if the underlying condition is unrecognized and untreated. Bone densitometry, using dual-energy x-ray absorptiometry, may underestimate fracture risk in some chronic diseases, including glucocorticoid-induced osteoporosis, type 2 diabetes, and obesity, and may overestimate fracture risk in others (eg, Turner syndrome). FRAX and trabecular bone score may provide additional information regarding fracture risk in secondary osteoporosis, but their use is limited to adults aged ≥ 40 years and ≥ 50 years, respectively. In addition, FRAX requires adjustment in some chronic conditions, such as glucocorticoid use, type 2 diabetes, and HIV. In most conditions, evidence for antiresorptive or anabolic therapy is limited to increases in bone mass. Current osteoporosis management guidelines also neglect secondary osteoporosis and these existing evidence gaps are discussed.

Market Consolidation and Innovation in US Dialysis

While patients with end-stage kidney disease have benefited from innovations in clinical therapeutics and care delivery, these changes have been primarily incremental and have not fundamentally transformed care delivery. Dialysis markets are highly concentrated, which may impede innovation. Unique features of the dialysis industry that have contributed to consolidation can help to explain links between consolidation and innovation. We discuss these unique features and then provide a framework for considering the effects of consolidation on innovation in dialysis that focuses on the following economic considerations: (1) industry characteristics, composition, and stage of consolidation, (2) innovation characteristics and relative profitability, (3) the role of government regulation, and (4) innovation from smaller providers and new entrants. We present examples of how these considerations have influenced the adoption of alternative dialysis technologies such as peritoneal dialysis and erythropoietin-stimulating agents, and we discuss how consolidated markets can both help and hinder recent policy initiatives to transform dialysis care delivery. Only by considering these important drivers of consolidation, future efforts can be successful in transforming end-stage kidney disease care.

Use of Sertraline in Hemodialysis Patients

Depression and anxiety are the most common psychiatric disorders in end-stage renal disease (ESRD) patients treated with hemodialysis (HD) and may correlate with lower quality of life and increased mortality. Depression treatment in HD patients is still a challenge both for nephrologists and psychiatrists. The possible treatment of depressive disorders can be pharmacological and non-pharmacological. In our article, we focus on the use of sertraline, the medication which seems to be relatively safe and efficient in the abovementioned population, taking under consideration several limitations regarding the use of other selective serotonin reuptake inhibitors (SSRIs). In our paper, we discuss different aspects of sertraline use, taking into consideration possible benefits and side effects of drug administration like impact on QTc (corrected QT interval) prolongation, intradialytic hypotension (IDH), chronic kidney disease-associated pruritus (CKD-aP), bleeding, sexual functions, inflammation, or fracture risk. Before administering the medication, one should consider benefits and possible side effects, which are particularly significant in the treatment of ESRD patients; this could help to optimize clinical outcomes. Sertraline seems to be safe in the HD population when provided in proper doses. However, we still need more studies in this field since the ones performed so far were usually based on small samples and lacked placebo control.

Erythropoietin treatment and the risk of hip fractures in hemodialysis patients

Erythropoietin (EPO) is the primary regulator of bone marrow erythropoiesis. Mouse models have provided evidence that EPO also promotes bone remodeling and that EPO-stimulated erythropoiesis is accompanied by bone loss independent of increased red blood cell production. EPO has been used clinically for three decades to treat anemia in end-stage renal disease, and notably, although the incidence of hip fractures decreased in the United States generally after 1990, it rose among hemodialysis patients coincident with the introduction and subsequent dose escalation of EPO treatment. Given this clinical paradox and findings from studies in mice that elevated EPO affects bone health, we examined EPO treatment as a risk factor for fractures in hemodialysis patients. Relationships between EPO treatment and hip fractures were analyzed using United States Renal Data System (USRDS) datasets from 1997 to 2013 and Consolidated Renal Operations in a Web-enabled Network (CROWNWeb) datasets for 2013. Fracture risks for patients treated with <50 units of EPO/kg/week were compared to those receiving higher doses by multivariable Cox regression. Hip fracture rates for 747,832 patients in USRDS datasets (1997-2013) increased from 12.0 per 1000 patient years in 1997 to 18.9 in 2004, then decreased to 13.1 by 2013. Concomitantly, average EPO doses increased from 11,900 units/week in 1997 to 18,300 in 2004, then decreased to 8,800 by 2013. During this time, adjusted hazard ratios for hip fractures with EPO doses of 50-149, 150-299, and ≥ 300 units/kg/week compared to <50 units/kg/week were 1.08 (95% confidence interval [CI], 1.01-1.15), 1.22 (95% CI, 1.14-1.31), and 1.41 (95% CI, 1.31-1.52), respectively. Multivariable analyses of 128,941 patients in CROWNWeb datasets (2013) replicated these findings. This study implicates EPO treatment as an independent risk factor for hip fractures in hemodialysis patients and supports the conclusion that EPO treatment may have contributed to changing trends in fracture incidence for these patients during recent decades. Published 2021. This article is a U.S. Government work and is in the public domain in the USA. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Secular trends in hip fracture incidence and subsequent mortality in dialysis patients and the general population in Sweden

BACKGROUND

Declining trends of hip fracture incidence in dialysis patients were reported from USA and Japan while studies from Europe are lacking. We investigated trends in hip fracture incidence and subsequent mortality in Swedish dialysis patients, comparing with the Swedish general population.

METHODS

We used the population-based Swedish national database of fractures and the Swedish National Renal Registry to retrieve data on hip fractures incidence and subsequent mortality for years 2007-2016. Trends for age-standardized hip fracture incidence rate (ASR_{hip fracture}) and age-standardized 30-day (ASMR_30day) and 180-day (ASMR_180day) post-hip fracture mortality rate in Swedish general population were evaluated by joinpoint regression analysis. Standardized incidence ratios of hip fracture (SIR) and standardized mortality ratios (SMR) were calculated for Swedish dialysis patients.

RESULTS

In the general population, ASR_{hip fracture} declined significantly: in women from 2007 and in men from 2009. In dialysis patients, SIR was 3-5 times higher compared to the general population and declined over time in women but not in men. In general population, mortality (ASMR_30day and ASMR_180day) declined significantly in women and men. In dialysis patients, post-fracture mortality (SMR, mainly for 180-day mortality) remained two-fold higher than in general population with no consistent trend towards improvement.

CONCLUSIONS

Hip fracture incidence and subsequent mortality fell among women and men in the Swedish general population. In dialysis patients, hip fracture incidence declined in women but not in men while post-fracture mortality did not improve, and the incidence and subsequent mortality remained 3 to 5-fold and 2-fold higher than in the general population.

Bone Fragility Fractures in CKD Patients

Chronic kidney diseases (CKD) are associated with mineral and bone diseases (MBD), including pain, bone loss, and fractures. Bone fragility related to CKD includes the risk factors observed in osteoporosis in addition to those related to CKD, resulting in a higher risk of mortality related to fractures. Unawareness of such complications led to a poor management of fractures and a lack of preventive approaches. The current guidelines of the Kidney Disease Improving Global Outcomes (KDIGO) recommend the assessment of bone mineral density if results will impact treatment decision. In addition to bone density, circulating biomarkers of mineral, serum bone turnover markers, and imaging techniques are currently available to evaluate the fracture risk. The purpose of this review is to provide an overview of the epidemiology and pathogenesis of CKD-associated bone loss. The contribution of the current tools and other techniques in development are discussed. We here propose a current view of how to better predict bone fragility and the therapeutic options in CKD.

An inherently kidney-targeting near-infrared fluorophore based probe for early detection of acute kidney injury

Acute kidney injury (AKI) is common in hospital patients. Delayed diagnosis and treatment of AKI due to the lack of efficient early diagnosis is an important cause of its high mortality. While fluorescence imaging seems promising to non-intrusively interrogate AKI-related biomarkers, the low kidney contrast of many fluorophores conferred by their relatively low abundance of distribution in the kidney limits their application for AKI detection. Herein, we discovered a near-infrared fluorophore with inherent kidney-targeting ability. Based on this fluorophore, a fluorogenic probe (KNP-1) was developed by targeting peroxynitrite (ONOO^-), which is upregulated at the early onset of AKI. KNP-1 exhibits desirable kidney distribution after intravenous administration and is fluorescent only after activation by ONOO^-. These properties lead to excellent kidney contrast imaging results. KNP-1 is capable of detecting both nephrotoxin-induced and ischemia-reperfusion injury-induced AKI in live mice. Temporally resolved imaging of AKI-disease model mice with KNP-1 suggests a gradual increase in renal ONOO^- levels with disease progression. Notably, the upregulation of ONOO^- can be observed at least 24 h earlier than the clinically popular sCr and BUN methods. Blocking ONOO^- generation also proves beneficial. These results highlight the applicability of this inherently tissue targeting-based strategy for designing probes with desirable imaging contrast; potentiate ONOO^- as a biomarker and target for AKI early diagnosis and medical intervention; and imply the clinical relevance of KNP-1 for AKI early detection.

Cortical Bone Microarchitecture in Dialysis Patients

BACKGROUND

The incidence of skeletal fractures is high in dialysis patients. Current available tools are insufficient to predict bone fragility. We analyzed the microarchitecture in patients on dialysis therapy using bone biopsies and peripheral microcomputed tomography.

METHODS

We analyzed 12 trans-iliac bone biopsies of patients with recent fractures. Bone microarchitecture was assessed in the bone cores by histology (2D-), microcomputed tomography (3D-µCT), and high-resolution peripheral quantitative computed tomography (HR-pQCT) at the tibia.

RESULTS

Trabecular bone volume/tissue volume was similar in 2D histology and 3D-µCT (p = 0.40), while lower in HR-pQCT (p < 0.01). There was no correlation in trabecular microarchitectural indices between 2-histology and 3D-µCT, or HR-pQCT. The 3D-µCT cortical thickness (Ct.Th) were positively correlated with 2D (p < 0.05), but with HR-pQCT (p = 0.33). Ct.Th was lower in patients with ≥2 vertebral fractures than with one fracture.

CONCLUSIONS

3D-µCT is a reliable method for the measurement of cortical bone in bone biopsies. Prospective studies are awaited to address its value in discriminating fracture risk.

Hip Fracture Risk among Hemodialysis-Dependent Patients Prescribed Opioids and Gabapentinoids

BACKGROUND

Despite opioids' known association with hip fracture risk in the general population, they are commonly prescribed to patients with ESKD. Whether use of opioids or gabapentinoids (also used to treat pain in patients with ESKD) contributes to hip fracture risk in patients with ESKD on hemodialysis remains unknown.

METHODS

In a case-control study nested within the US Renal Data System, we identified all hip fracture events recorded among patients dependent on hemodialysis from January 2009 through September 2015. Eligible cases were risk-set matched on index date with ten eligible controls. We required >1 year of Medicare Parts A and B coverage and >3 years of part D coverage to study cumulative longer-term exposure. To examine new, short-term exposure, we selected individuals with >18 months of Part D coverage and no prior opioid or gabapentinoid use between 18 and 7 months before index. We used conditional logistic regression to estimate unadjusted and multivariable-adjusted odds ratios (ORs) and 95% confidence intervals (95% CI).

RESULTS

For the longer-term analyses, we identified 4912 first-time hip fracture cases and 49,120 controls. Opioid use was associated with increased hip fracture risk (adjusted OR, 1.39; 95% CI, 1.26 to 1.53). Subgroups of low, moderate, and high use yielded adjusted ORs of 1.33 (95% CI, 1.20 to 1.47), 1.53 (95% CI, 1.36 to 1.72), and 1.66 (95% CI, 1.45 to 1.90), respectively. The association with hip fractures was also elevated with new, short-term use (adjusted OR, 1.38; 95% CI, 1.25 to 1.52). There were no associations between gabapentinoid use and hip fracture.

CONCLUSIONS

Among patients dependent on hemodialysis in the United States, both short-term and longer-term use of opioid analgesics were associated with hip fracture events.

Simultaneous bilateral femoral neck fractures in a dialysis-dependent patient: case report and literature review

BACKGROUND

Simultaneous bilateral femoral neck fractures are extremely rare without obvious injury. Herein, we report the case of a patient on dialysis presenting with bilateral femoral neck fractures, which is a condition with high complication and mortality rates according to a review of the pertinent literature.

CASE PRESENTATION

We report the case a 47-year-old female with a history of 8 years of haemodialysis due to polycystic kidney disease who presented with bilateral hip pain during walking. The clinical history and results of physical and radiographic examinations of this patient are shown. Single-stage bilateral hemiarthroplasty was performed after a multidisciplinary team consultation. Three days after the operation, she could ambulate with a walker. The woman gradually regained her previous ability to walk over 6 months after surgery.

CONCLUSIONS

A multidisciplinary team consultation for perioperative management is necessary and effective in patients on dialysis. Early diagnosis with prompt surgical treatment could lead to favourable recovery.

Bone fragility in patients with chronic kidney disease

Mineral and bone diseases (MBD) are predominant in patients with chronic kidney disease (CKD) and lead to several bone manifestations, from pain to skeletal fractures. Cumulative traditional clinical risk factors, such as age and gender, in addition to those related to CKD, enhance the risk of comorbidity and mortality related to fractures. Despite great advances in understanding MBD in CKD, clinical and biological targets are lacking, which leads to under-management of fractures. Optimal PTH control results in a net improvement in defining the levels of bone remodeling. In addition, circulating biomarkers such as bone-specific alkaline phosphatase and cross-linked collagen type I peptide will also provide additional information about remodeling rate, bone mineralization and the evaluation of fracture risk. Imaging techniques identify patients at risk by measurement of bone mineral density by DEXA or by high peripheral QCT, which allow the discrimination of trabecular and cortical bone. Here, we have reviewed the literature related to epidemiology and the pathophysiological role of mineral and biochemical factors involved in CKD-MBD with a special focus on fracture risk. We also provide an algorithm that could be used for the management of bone diseases and to guide treatment decisions. Finally, the combined expertise of clinicians from various disciplines is crucial for the best prevention of fractures.

Hip fractures in patients with chronic kidney disease admitted to Victorian hospitals

There is a paucity of epidemiological data in Australia on fracture rates in patients with chronic kidney disease (CKD). Using data from the Victorian Admitted Episodes Dataset, we assessed the incidence of hip fractures requiring hospitalisation between 2006 and 2015, comparing those coded with and without the co-morbidity CKD. ICD-9 and ICD-10 codes were used to determine hip fractures and comorbidities. Overall, 7.4% of 77 076 Victorian hospital admissions for hip fractures had CKD as a co-morbidity, with an increasing proportion over the study period. Mortality was significantly higher in the CKD cohort compared to no CKD, perhaps in part due to increased associated comorbidities of diabetes and ischaemic heart disease.

Hospitalized fracture rates amongst patients with chronic kidney disease in Australia using data linkage

BACKGROUND

Renal osteodystrophy leading to fractures in chronic kidney disease (CKD) is associated with significant hospitalization, morbidity, mortality and health care costs. There is a paucity of data on fractures in the CKD population in Australia.

AIM

To describe the trends and impact of hospitalized fractures in an Australian population of non-dialysis CKD patients.

METHODS

Retrospective observational data derived using data linkage. Fracture rates, trends in hospital admissions, comorbidity burden and mortality were analysed in a non-dialysis CKD population between 2000 and 2010 in the Australian state of New South Wales. Hospitalized patients with CKD and fractures were compared with CKD patients without fracture.

RESULTS

A total of 149 839 hospitalized patients with CKD were included, of whom 9898 (6.6%) experienced one or more fractures. Patients with fracture were older, more likely to be female with a higher comorbidity burden than those without. Hospital admissions involving fracture were longer than non-fracture admissions (14.3 vs 5.9 days, P < .0001) and patients were less likely to be discharged home (28.3% vs 80.9%, P < .0001). The 12-month mortality rate was high at 41%.

CONCLUSION

Australian non-dialysis CKD patients with hospitalized fractures were older, had a greater burden of disease, and have similar rates of fracture and associated mortality compared to international CKD cohorts. Implications of fracture requiring hospitalization are considerable, with longer admissions, greater healthcare costs, lower likelihood of discharge home and significant mortality. As fracture prevention in the CKD population evolves, treatment algorithms should account for those at greatest risk.

Selective Serotonin Reuptake Inhibitor Use and Hip Fracture Risk Among Patients on Hemodialysis

RATIONALE & OBJECTIVE

Use of selective serotonin reuptake inhibitors (SSRIs) has been associated with hip fracture risk in the general population. This study examined this relationship among patients with kidney failure treated by hemodialysis, a unique high-risk subpopulation, within which the impact of SSRIs on hip fracture risk remains unexplored.

STUDY DESIGN

Case-control study.

SETTINGS & PARTICIPANTS

Eligible cases of hip fracture among maintenance hemodialysis patients between January 1, 2009, and September 30, 2015, were identified using the US Renal Data System. Each case was matched on index date with 10 eligible controls. To be eligible, study participants needed to have more than 1 year of Medicare Parts A and B coverage and more than 3 years of Part D coverage. For a separate examination of new short-term SSRI exposure, we selected cases and controls with more than 18 months of Part D coverage and no prior antidepressant use for 1 year.

EXPOSURE

During the 3-year Part D coverage period, use of SSRIs characterized as any (≥1 prescription filled), low, moderate, and high use (<20%, 20%-<80%, and≥80% of days covered by filled prescriptions, respectively).

OUTCOME

We selected cases using International Classification of Diseases, Ninth Revision codes 820.xx and 821.xx. In addition to 1 of these codes tied to a hospitalization, we required a corresponding surgical procedural code within 7 days of diagnosis.

ANALYTIC APPROACH

Conditional logistic regression to estimate unadjusted and multivariable-adjusted ORs and 95% CIs.

RESULTS

We identified 4,912 cases and 49,120 controls. SSRI use was associated with increased hip fracture risk (adjusted OR, 1.25; 95% CI, 1.17-1.35). Risk for fracture was estimated for any, low, moderate, and high SSRI use: adjusted conditional ORs were 1.25 (95% CI, 1.17-1.35), 1.20 (95% CI, 1.08-1.32), 1.31 (95% CI, 1.18-1.43), and 1.26 (95% CI, 1.12-1.41), respectively. The association between hip fracture events and SSRI use was also seen in the examination of new short-term use (adjusted OR, 1.43; 95% CI, 1.23-1.67).

LIMITATIONS

Biomarkers of mineral bone disorder were not captured and accounted for in this analysis.

CONCLUSIONS

We demonstrated an association between increased hip fracture risk and both long- and new short-term SSRI use. The stronger association with new short-term use may suggest an acute mechanism potentially related to falls.

A multi-imaging modality study of bone density, bone structure and the muscle - bone unit in end-stage renal disease

End stage renal disease (ESRD) is associated with sarcopenia and skeletal fragility. The objectives of this cross-sectional study were to (1) characterize body composition, bone mineral density (BMD) and bone structure in hemodialysis patients compared with controls, (2) assess whether DXA areal BMD (aBMD) correlates with peripheral quantitative CT (pQCT) measures of volumetric BMD (vBMD), cortical dimensions and MRI measures of trabecular microarchitecture, and (3) determine the magnitude of bone deficits in ESRD after adjustment for muscle mass. Thirty ESRD participants, ages 25 to 64 years, were compared with 403 controls for DXA and pQCT outcomes and 104 controls for MRI outcomes; results were expressed as race- and sex- specific Z-scores relative to age. DXA appendicular lean mass index (ALMI kg/m2) and total hip, femoral neck, ultradistal and 1/3rd radius aBMD were significantly lower in ESRD, vs. controls (all p < 0.01). pQCT trabecular vBMD (p < 0.01), cortical vBMD (p < 0.001) and cortical thickness (due to a greater endosteal circumference, p < 0.02) and MRI measures of trabecular number, trabecular thickness, and whole bone stiffness were lower (all p < 0.01) in ESRD, vs. controls. ALMI was positively associated with total hip, femoral neck, ultradistal radius and 1/3rd radius aBMD and with tibia cortical thickness (R = 0.46 to 0.64). Adjustment for ALMI significantly attenuated bone deficits at these sites: e.g. mean femoral neck aBMD was 0.79 SD lower in ESRD, compared with controls and this was attenuated to 0.33 with adjustment for ALMI. In multivariate models within the dialysis participants, pQCT trabecular vBMD and cortical area Z-scores were significant and independently (all p < 0.02) associated with DXA femoral neck, total hip, and ultradistal radius aBMD Z-scores. Cortical vBMD (p = 0.01) and cortical area (p < 0.001) Z-scores were significantly and independently associated with 1/3rd radius areal aBMD Z-scores (R2 = 0.62). These data demonstrate that DXA aBMD captures deficits in trabecular and cortical vBMD and cortical area. The strong associations with ALMI, as an index of skeletal muscle, highlight the importance of considering the role of sarcopenia in skeletal fragility in patients with ESRD.

Fracture Risk in Dialysis and Kidney Transplanted Patients: A Systematic Review

Chronic kidney disease is associated with an increased risk of fracture and cardiovascular mortality. The risk of fracture in hemodialysis (HD), peritoneal dialysis (PD) and kidney transplant (KT) patients is higher when compared with the general population. However, there exists a knowledge gap concerning which group has the highest risk of fracture. We aimed to compare the risk of fracture in HD, PD, and KT populations. We conducted a systematic review of observational studies evaluating the risk of fracture in HD, PD, or KT patients. Eligible studies were searched using MEDLINE, Embase, Web of Science, and Cochrane Library from their inception to January 2016, and in grey literature. Incidences (cumulative and rate) of fracture were described together using the median, according to fracture sites, the data source (administrative database or cohort and clinical registry), and fracture diagnosis method. Prevalence estimates were described separately. We included 47 studies evaluating the risk of fracture in HD, PD, and KT populations. In administrative database studies, incidence of hip fracture in HD (median 11.45 per 1000 person-years [p-y]), range: 9.3 to 13.6 was higher than in KT (median 2.6 per 1000 p-y; range 1.5 to 3.8) or in PD (median 5.2 per 1000 p-y; range 4.1 to 6.3). In dialysis (HD+PD), three studies reported a higher incidence of hip fracture than in KT. Prevalent vertebral fracture (assessed by X-rays or questionnaire) reported in HD was in a similar range as that reported in KT. Incidence of overall fracture was similar in HD and KT, from administrative databases studies, but lower in HD compared with KT, from cohorts or clinical registry studies. This systematic review suggests an important difference in fracture risk between HD, PD, and KT population, which vary according to the diagnosis method for fracture identification. © 2018 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.

Rethinking Bone Disease in Kidney Disease

Renal osteodystrophy (ROD) is the bone component of chronic kidney disease mineral and bone disorder (CKD-MBD). ROD affects bone quality and strength through the numerous hormonal and metabolic disturbances that occur in patients with kidney disease. Collectively these disorders in bone quality increase fracture risk in CKD patients compared with the general population. Fractures are a serious complication of kidney disease and are associated with higher morbidity and mortality compared with the general population. Furthermore, at a population level, fractures are at historically high levels in patients with end-stage kidney disease (ESKD), whereas in contrast the general population has experienced a steady decline in fracture incidence rates. Based on these findings, it is clear that a paradigm shift is needed in our approach to diagnosing and managing ROD. In clinical practice, our ability to diagnose ROD and initiate antifracture treatments is impeded by the lack of accurate noninvasive methods that identify ROD type. The past decade has seen advances in the noninvasive measurement of bone quality and strength that have been studied in kidney disease patients. Below we review the current literature pertaining to the epidemiology, pathology, diagnosis, and management of ROD. We aim to highlight the pressing need for a greater awareness of this condition and the need for the implementation of strategies that prevent fractures in kidney disease patients. Research is needed for more accurate noninvasive assessment of ROD type, clinical studies of existing osteoporosis therapies in patients across the spectrum of kidney disease, and the development of CKD-specific treatments. © 2018 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of the American Society for Bone and Mineral Research.

Proton Pump Inhibitors, Histamine-2 Receptor Antagonists, and Hip Fracture Risk among Patients on Hemodialysis

BACKGROUND AND OBJECTIVES

An association between proton pump inhibitor (PPI) use and hip fracture risk has been described in the general population, where the primary causative hypothesis focuses on impaired gastrointestinal calcium absorption. The impact of acid suppressor use on hip fracture risk in a high-risk subset, patients with ESKD requiring hemodialysis, is unknown and could help further distinguish the reason for higher susceptibility among PPI users.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Using the US Renal Data System, we identified all hip fracture events recorded between 2009 and 2014 among patients dependent on hemodialysis. Eligible cases were matched on index date with ten controls. We identified PPI and histamine-2 receptor antagonist use from Medicare Part D claims covering 3 years before the index date and stratified according to proportion of days covered by filled prescriptions. Using logistic regression with multiple imputation for missing data, we estimated unadjusted and multivariable-adjusted odds ratios (ORs) and 95% confidence intervals (95% CIs).

RESULTS

We studied 4551 cases and 45,510 controls. Patients were older, more likely to be female and white, and had shorter dialysis vintage; fewer were obese. A larger proportion of patients had any prior PPI (70% versus 63%) or histamine-2 receptor antagonist (25% versus 23%) use. Use of PPI was associated with higher risk of hip fracture (adjusted OR, 1.19; 95% CI, 1.11 to 1.28). This association remained within subgroups of low, moderate, and high PPI use, yielding adjusted ORs of 1.16 (95% CI, 1.06 to 1.27), 1.21 (95% CI, 1.11 to 1.31), and 1.19 (95% CI, 1.08 to 1.31), respectively.

CONCLUSIONS

Among patients with ESKD on hemodialysis, PPIs and not histamine-2 receptor antagonists were associated with hip fracture events.

Risk of hip fracture in patients on dialysis or kidney transplant: a meta-analysis of 14 cohort studies

Purpose

We aimed to conduct a meta-analysis of published cohort studies to evaluate the risk of hip fracture in patients undergoing dialysis or kidney transplantation (KT).

Methods

We identified relevant studies by searching PubMed, EMBASE and Google Scholar databases from their inception to December 31, 2017. Cohort studies evaluating risk of hip fractures in patients undergoing dialysis or KT were considered included. The methodological quality of the cohort studies was assessed using the modified Newcastle-Ottawa scale.

Results

In our meta-analysis of 14 retrospective cohort studies, a total of more than 1.5 million patients undergoing dialysis or KT were included, of whom more than 30,000 had hip fractures. After the merger, the proportion of hip fractures was 1.92% (95% CI, 1.38%−2.46%) with significant heterogeneity (I²=99.9%, P=0.000) in all patients, and the incidence rate of hip fractures (per 1,000 person-years) was 8.95 (95% CI, 4.05–13.85) with significant heterogeneity (I²=99.9%, P=0.000). The pooled relative risks (RR) value for dialysis patients compared with the general population were 6.35 (95% CI, 4.53–8.88) for male and 5.57 (95% CI, 4.44–6.99) for female. The pooled RR value for hemodialysis (HD) patients compared with peritoneal dialysis (PD) patients was 1.39 (95% CI, 1.13–1.70) with no heterogeneity (I²=0.0%, P=0.763).

Conclusion

In conclusion, the present meta-analysis reveals that about 2% of dialysis or KT patients go on to sustain a hip fracture during follow-up, with the overall hip fracture incidence rates being 8.95 per 1,000 person-years. The overall risk of hip fracture was more than 5-fold higher in dialysis patients than in the general population. Among patients on PD, HD, and KT, HD and KT patients had the highest and the lowest risk of hip fractures, respectively.

Magnetic resonance imaging based assessment of bone microstructure as a non-invasive alternative to histomorphometry in patients with chronic kidney disease

BACKGROUND

Chronic kidney disease (CKD) adversely affects bone microarchitecture and increases fracture risk. Historically, bone biopsy has been the 'gold standard' for evaluating renal bone disease but is invasive and infrequently performed. High-resolution magnetic resonance imaging (MRI) quantifies bone microarchitecture noninvasively. In patients with CKD, it has not been compared with results derived from bone biopsy or with imaging using dual energy X-ray absorptiometry (DXA).

METHODS

Fourteen patients with end-stage kidney disease (ESKD) underwent MRI at the distal tibia, bone mineral density (BMD) by dual energy X-ray absorptiometry (DXA; hip and spine) and transiliac bone biopsies with histomorphometry and microcomputed tomography (micro-CT). All patients had biomarkers of mineral metabolism. Associations were determined by Spearman's or Pearson's rank correlation coefficients.

RESULTS

MRI indices of trabecular network integrity, surface to curve ratio (S/C) and erosion index (EI), correlated to histomorphometric trabecular bone volume (S/C r = 0.85, p = 0.0003; EI r = -0.82, p = 0.001), separation (S/C r = -0.58, p = 0.039; EI r = 0.79, p = 0.0012) and thickness (S/C, r = 0.65, p = 0.017). MRI EI and trabecular thickness (TbTh) also correlated to micro-CT trabecular separation (EI r = 0.63, p = 0.02; TbTh r = -0.60, p = 0.02). Significant correlations were observed between histomorphometric mineralization and turnover indices and various MRI parameters. MRI-derived trabecular parameters were also significantly related to femoral neck BMD.

CONCLUSIONS

This study highlights the heterogeneity of bone microarchitecture at differing skeletal sites. MRI demonstrates significant, relevant associations to important bone biopsy and DXA indices and warrants further investigation to assess its potential to non-invasively evaluate changes in bone structure and quality over time.

Management of Osteoporosis in CKD

CKD mineral and bone disease is a common complication of kidney disease, and it affects the majority of patients with moderate to severe CKD. Recently, prospective studies have shown that measurement of bone mineral density by dual energy x-ray absorptiometry predicts incident fracture, providing nephrologists the ability to risk classify patients for skeletal fragility and targeted antifracture strategies for the first time. Furthermore, an expanding body of literature and anecdotal evidence suggest that pharmacologic agents used to treat osteoporosis in the general population can be safely used in patients with CKD. This review highlights the effects of the Kidney Disease Improving Global Outcomes updates on the management of CKD-associated osteoporosis, discusses recent investigations on the effects of antiosteoporotic agents in patients with CKD, and provides an overview of novel antiosteoporosis agents and the potential challenges related to their use in CKD.

Declining Rates of Hip Fracture in End-Stage Renal Disease: Analysis From the 2003-2011 Nationwide Inpatient Sample

The incidence of hip fracture in patients with end-stage renal disease (ESRD) is considerably higher than that in the general age- and sex-matched population. Although medical therapy for chronic kidney disease mineral bone disorder (CKD-MBD) has changed considerably over the last decade, rates of hip fracture in the entire ESRD population have not been well-characterized. Herein, we evaluated temporal trends in rates of hip fracture, in-hospital mortality, and costs of associated hospital stay in ESRD. We identified hospitalizations for hip fracture from 2003 to 2011 using the Nationwide Inpatient Sample, a representative national database inclusive of all ages and payers. We incorporated data from the United States Renal Data System and the US Census to calculate population-specific rates. Between 2003 and 2011, we identified 47,510 hip fractures in the ESRD population. The overall rate of hip fracture was 10.04/1000 person-years. The rate was 3.73/1000 person-years in patients aged less than 65 years, and 20.97/1000 person-years in patients aged 65 or older. Age- and sex-standardized rates decreased by 12.6% from 2003 (10.23/1000 person-years; 95% confidence interval [CI], 7.99/1000 to 12.47/1000) to 2011 (8.94/1000 person-years; 95% CI, 7.12/1000 to 10.75/1000). Hip fracture rates over time were virtually identical in patients aged less than 65 years; however, rates decreased by 15.3% among patients aged 65 years or older; rates declined more rapidly in older women compared with older men (p for interaction = 0.047). In-hospital mortality rate after hip fracture operation declined by 26.7% from 2003 (8.6%; 95% CI, 6.8 to 10.4) to 2011 (6.3%; 95% CI, 4.9 to 7.7). In ESRD, age- and sex-standardized hip fracture rates and associated in-hospital mortality have declined substantially over the last decade. © 2017 American Society for Bone and Mineral Research.

Associations of Glycemic Control With Cardiovascular Outcomes Among US Hemodialysis Patients With Diabetes Mellitus

Background

There is a lack of data on the relationship between glycemic control and cardiovascular end points in hemodialysis patients with diabetes mellitus.

Methods and Results

We included adult Medicare‐insured patients with diabetes mellitus who initiated in‐center hemodialysis treatment from 2006 to 2008 and survived for >90 days. Quarterly mean time‐averaged glycated hemoglobin (HbA_1c) values were categorized into <48 mmol/mol (<6.5%) (reference), 48 to <58 mmol/mol (6.5% to <7.5%), 58 to <69 mmol/mol (7.5% to <8.5%), and ≥69 mmol/mol (≥8.5%). Medicare claims were used to identify outcomes of cardiovascular mortality, nonfatal myocardial infarction (MI), fatal or nonfatal MI, stroke, and peripheral arterial disease. We used Cox models as a function of time‐varying exposure to estimate multivariable adjusted hazard ratios and 95%CI for the associations between HbA_1c and time to study outcomes in a cohort of 16 387 eligible patients. Patients with HbA_1c 58 to <69 mmol/mol (7.5% to <8.5%) and ≥69 mmol/mol (≥8.5%) had 16% (CI, 2%, 32%) and 18% (CI, 1%, 37%) higher rates of cardiovascular mortality (P‐trend=0.01) and 16% (CI, 1%, 33%) and 15% (CI, 1%, 32%) higher rates of nonfatal MI (P‐trend=0.05), respectively, compared with those in the reference group. Patients with HbA_1c ≥69 mmol/mol (≥8.5%) had a 20% (CI, 2%, 41%) higher rate of fatal or nonfatal MI (P‐trend=0.02), compared with those in the reference group. HbA_1c was not associated with stroke, peripheral arterial disease, or all‐cause mortality.

Conclusions

Higher HbA_1c levels were significantly associated with higher rates of cardiovascular mortality and MI but not with stroke, peripheral arterial disease, or all‐cause mortality in this large cohort of hemodialysis patients with diabetes mellitus.

Bone Quality in Chronic Kidney Disease: Definitions and Diagnostics

PURPOSE OF REVIEW

In this paper, we review the epidemiology, diagnosis, and pathogenesis of fractures and renal osteodystrophy.

RECENT FINDINGS

The role of bone quality in the pathogenesis of fracture susceptibility in chronic kidney disease (CKD) is beginning to be elucidated. Bone quality refers to bone material properties, such as cortical and trabecular microarchitecture, mineralization, turnover, microdamage, and collagen content and structure. Recent data has added to our understanding of the effects of CKD on alterations to bone quality, emerging data on the role of abnormal collagen structure on bone strength, the potential of non-invasive methods to inform our knowledge of bone quality, and how we can use these methods to inform strategies that protect against bone loss and fractures. However, more prospective data is required. CKD is associated with abnormal bone quality and strength which results in high fracture incidence.

Changing bone patterns with progression of chronic kidney disease

It is commonly held that osteitis fibrosa and mixed uremic osteodystrophy are the predominant forms of renal osteodystrophy in patients with chronic kidney disease. Osteitis fibrosa is a high-turnover bone disease resulting mainly from secondary hyperparathyroidism, and mixed uremic osteodystrophy is in addition characterized by a mineralization defect most often attributed to vitamin D deficiency. However, there is ancient and more recent evidence that in early chronic kidney disease stages adynamic bone disease characterized by low bone turnover occurs first, at least in a significant proportion of patients. This could be due to the initial predominance of bone turnover-inhibitory conditions such as resistance to the action of parathyroid hormone (PTH), reduced calcitriol levels, sex hormone deficiency, diabetes, and, last but not least, uremic toxins leading to repression of osteocyte Wnt/β-catenin signaling and increased expression of Wnt antagonists such as sclerostin, Dickkopf-1, and sFRP4. The development of high-turnover bone disease would occur only later on, when serum PTH levels are able to overcome peripheral PTH resistance and the other inhibitory factors of bone formation. Whether FGF23 and Klotho play a direct role in the transition from low- to high-turnover bone disease or participate only indirectly via regulating PTH secretion remains to be seen.

Hip Fracture in Patients With Non-Dialysis-Requiring Chronic Kidney Disease

Patients with end-stage renal disease (ESRD) are at a high risk for hip fracture. Little is known about the risk for, and consequences of, hip fracture among patients with non-dialysis-requiring chronic kidney disease (CKD). We examined the incidence of hip fracture, in-hospital mortality, length of stay, and costs among patients with ESRD, non-dialysis-requiring CKD, and normal or near normal kidney function. Using the Healthcare Cost and Utilization Project's Nationwide Inpatient Sample, a nationally representative database, we identified hospitalizations for hip fracture in 2010. We incorporated data from the United States Renal Data System (USRDS) and the US census to calculate population-specific rates. Age-standardized incidence of hip fracture was highest among patients with ESRD (3.89/1000 person-years), followed by non-dialysis-requiring CKD (1.81/1000 persons) and patients with normal or near normal kidney function (1.18/1000 persons). In-hospital mo rtality (odds ratio [OR] = 1.69, 95% confidence interval [CI] 1.46 to 1.96), lengths of stay (median [10th, 90th percentiles] 5 [3 to 11] versus 5 [3 to 10] days) and costs (median $14,807 versus $13,314) were significantly higher in patients with non-dialysis-requiring CKD relative to patients with normal or near normal kidney function. In summary, non-dialysis-requiring CKD is associated with higher age-standardized rates of hip fracture and post-hip fracture mortality and higher resource utilization. © 2016 American Society for Bone and Mineral Research.

Chronic Kidney Disease-Mineral Bone Disorder in the Elderly Peritoneal Dialysis Patient

PURPOSE

The purpose of this paper was to review the literature concerning the treatment of chronic kidney disease-mineral bone disorder (CKD-MBD) in the elderly peritoneal dialysis (PD) patient.

RESULTS

Chronic kidney disease-mineral bone disorder is a major problem in the elderly PD patient, with its associated increased fracture risk, vascular calcification, and accelerated mortality fracture risk. Peritoneal dialysis, however, bears a lower risk than hemodialysis (HD). The approach to CKD-MBD prophylaxis and treatment in the elderly PD patient is similar to other CKD patients, with some important differences. Avoidance of hypercalcemia, hyperphosphatemia, and hyperparathyroidism is important, as in other CKD groups, and is generally easier to attain. Calcium-free phosphate binders are recommended for normocalcemic and hypercalcemic patients. Normalization of vitamin D levels to > 75 nmol/L (> 30 pg/L) and low-dose active vitamin D therapy is recommended for all patients. Hyperparathryoidism is to be avoided by using active vitamin D and cinacalcet. Particular attention should be paid to treating protein malnutrition. Fracture prophylaxis (exercise, use of walkers, dwelling modifications) are important. Hypomagnesemia is common in PD and can be treated with magnesium supplements. Vitamin K deficiency is also common and has been identified as a cause of vascular calcification. Accordingly, warfarin treatment for this age group is problematic.

CONCLUSION

While treatment principles are similar to other dialysis patient groups, physicians should be aware of the special problems of the elderly group.

Bone Parameters and Risk of Hip and Femur Fractures in Patients on Hemodialysis

BACKGROUND AND OBJECTIVES

Patients on hemodialysis have a high rate of hip fractures. In this study, we performed a contemporary analysis of mineral and bone parameters and their relationship to hip and femur fracture risk.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Patients on hemodialysis treated between 2000 and 2013 in Fresenius Medical Care North America facilities were included. Predictors were on the basis of data as of December 31 of each baseline year and time-averaged values of selected laboratory parameters and medication doses throughout the year. Four period cohorts were constructed from baseline years: 2000, 2003, 2006, and 2009. Follow-up for each cohort was ≤3 years.

RESULTS

The incidence of hip and femur fractures remained generally unchanged (P=0.40), except among patients who were white and >65 years of age, in whom the rate decreased significantly over the 14-year period (P<0.01). Results from combined multivariable models indicated that the lowest quartiles of time-averaged intact parathyroid hormone were independently associated with higher hip fracture risk (intact parathyroid hormone =181-272 pg/ml: hazard ratio, 1.20; 95% confidence interval [95% CI], 1.03 to 1.41 and intact parathyroid hormone <181 pg/ml: hazard ratio, 1.20; 95% CI, 1.01 to 1.44; referent third quartile, 273 to <433 pg/ml). The lowest quartile of time-averaged serum calcium was also associated with higher risk (calcium <8.7 mg/dl; hazard ratio, 1.17; 95% CI, 1.00 to 1.37) compared with the referent third quartile of 9.1 to <9.5 mg/dl.

CONCLUSIONS

We found an association between lower levels of intact parathyroid hormone and serum calcium and greater risk for hip and femur fractures among patients on hemodialysis. These findings support additional research toward elucidating long-term safety of treatment approaches for hyperparathyroidism in patients with ESRD.

Emerging role of high-resolution imaging in the detection of renal osteodystrophy

The term renal osteodystrophy refers to changes in bone morphology induced by chronic kidney disease (CKD) and represents the skeletal component of the entity 'chronic kidney disease - mineral and bone disorder'. Changes in turnover, mineralization, mass and microarchitecture impair bone quality, compromising strength and increasing susceptibility to fractures. Fractures are more common in CKD compared with the general population and result in increased morbidity and mortality. Screening for fracture risk and management of renal osteodystrophy are hindered by the complex, and still only partially understood, pathophysiology and the inadequacy of currently available diagnostic methods. Bone densitometry and bone turnover markers, although potentially helpful, have significant limitations in patients with CKD, and the 'gold standard' test of bone biopsy is infrequently performed in routine clinical practice. However, recent advances in high-resolution bone microarchitecture imaging may offer greater potential for quantification and assessment of bone structure and strength and, when used in conjunction with serum biomarkers, may allow non-invasive testing for a diagnostic virtual bone biopsy.

Fractures in chronic kidney disease: pursuing the best screening and management

PURPOSE OF REVIEW

Osteoporotic fractures are common and cause increased sickness and death. Men and women with chronic kidney disease (CKD) are at particularly high risk of osteoporotic fractures. Currently, however, there are no guidelines concerning noninvasive methods to assess fracture risk in CKD. Further, approved treatments to prevent fractures in otherwise healthy men and women are only recommended for use with caution in those with CKD. This review focuses on the recent data that support the use of noninvasive methods to assess fracture risk in CKD and highlights new therapies that could be used in fracture prevention in CKD.

RECENT FINDINGS

Data from prospective studies demonstrate that low bone mineral density predicts fracture in CKD patients. Post-hoc analyses demonstrate that agents approved for the treatment of postmenopausal osteoporosis (bisphosphonates, denosumab and teriparatide) when given to those with CKD are well tolerated and potentially efficacious with respect to fracture risk reduction.

SUMMARY

To date, patients, and nephrologists taking care of them, have largely ignored fracture risk assessment and treatment in CKD. This should change given recent data. Further studies are needed, specifically bone histomorphometric studies, which will increase our understanding of CKD-mineral bone disease (MBD) pathophysiology, and randomized clinical trials of therapy in patients with CKD.

Comparative health services research across populations: the unused opportunities in big data

Large population registries present opportunities to understand the epidemiology of disease, study patters of care, and compare the effectiveness of different care practices. While these 'big data' tempt investigators to examine all available individuals, a targeted approach that restricts the study to an optimal sub-population may yield more relevant insights. We discuss how researchers might adapt their studies existing literature to generate additional insights.

Association of Self-Reported Frailty with Falls and Fractures among Patients New to Dialysis

BACKGROUND

Although frailty has been linked to higher risk of falls and fracture in the general population, only few studies have examined the extent to which frailty is associated with these outcomes among patients with end-stage renal disease, who are at particularly high risk for these events.

METHODS

A total of 1,646 patients who were beginning maintenance hemodialysis in 297 dialysis units throughout the United States from September 2005 to June 2007 were enrolled in the Comprehensive Dialysis Study, and 1,053 Medicare beneficiaries were included in this study. Self-reported frailty was defined by the patients endorsing 2 or more of the following: poor physical functioning, exhaustion or low physical activity. Falls and fractures requiring medical attention were identified through Medicare claims data. We examined the association between frailty and the time to first fall or fracture using the Fine-Gray modification of Cox proportional hazards regression, adjusted for demographics, Quételet's body mass index, diabetes mellitus, heart failure and atherosclerosis.

RESULTS

Seventy-seven percent of patients were frail by self-report. The median length of follow-up was 2.5 (1.0-3.9) years. Crude rates of first medically urgent falls or fractures were 66 and 126 per 1,000 person-years in non-frail and self-reported frail participants, respectively. After accounting for demographic factors, comorbidities and the competing risk of death, self-reported frailty was associated with a higher risk of falls or fractures requiring medical attention (hazards ratio 1.60, 95% CI 1.16-2.20).

CONCLUSION

Participants reporting frailty experienced nearly twice the risk of medically urgent falls or fractures compared to those who did not report frailty.

The uses and abuses of Vitamin D compounds in chronic kidney disease-mineral bone disease (CKD-MBD)

Vitamin D is of paramount importance to skeletal development, integrity and health. Vitamin D homeostatis is typically deranged in a number of chronic conditions, of which chronic kidney disease is one of the most important. The use of vitamin D based therapy to target secondary hyperparathyroidism is now several decades old, and there is a large body of clinical practice, experience, guidelines and research to underpin this. However, there are many unknowns, of significant clinical relevance. Amongst which is what "species" of vitamin D we should be using, in what patient, and, under what conditions. Sadly, there has been a real dearth of randomised controlled trials, and trials with outputs of clinical relevance, which means our clinical practice has not developed and refined adequately ove the last 4 decades. This article will discuss the vexed but critical questions of which vitamin D therapies might suit which kidney patients, and will high-light the many important clinical questions which urgently require answering.

Mortality and complications after hip fracture among elderly patients undergoing hemodialysis

BACKGROUND

Osteoporotic hip fractures cause high mortality and morbidity in elderly adults. Compared to the general population, subjects with end-stage renal disease and hemodialysis often develop mineral bone disorders and have a higher risk for hip fractures.

METHODS

We conducted a matched cohort study design and used competing risk analysis to estimate the cumulative incidence of the complication rate. Subjects aged greater than 60 years with hip fracture were selected from Taiwan's National Health Insurance Research Database covering a period from 1997 to 2007, and these subjects were followed up until 2009. We used the Kaplan-Meier method to estimate the overall survival and used the log-rank test and multiple Cox proportional hazards model to explore the risk factors for survival. The cumulative incidence of the first complication was estimated using competing risk analysis.

RESULTS

Among hemodialysis subjects, the three-month, one-year, two-year and five-year mortality rates were 17.3 %, 37.2 %, 51.5 %, and 80.5 %, respectively; the one-year and five-year cumulative incidences of the first surgical complication were 14.2 % and 20.6 %, respectively; and the three-month cumulative incidence of the first medical complication was 24.1 %. Hemodialysis subjects presented a 2.32 times (95 % CI: 2.16-2.49) higher hazard ratio of overall death, 1.15 times (95 % CI: 1.01-1.30) higher sub-hazard ratio (sub-HR) of surgical complications, and 1.35 times (95 % CI: 1.21-1.52) higher sub-HR of the first medical complication than non-hemodialysis controls.

CONCLUSIONS

The overall mortality and complication rates of hemodialysis subjects after surgery for hip fracture were significantly higher than those of non-hemodialysis subjects. Further prospective studies which include important risk factors are necessary to more precisely quantify the adjusted effect of hemodialysis.

Bone marrow fat is increased in chronic kidney disease by magnetic resonance spectroscopy

In aging, the bone marrow fills with fat and this may lead to higher fracture risk. We show that a bone marrow fat measurement by magnetic resonance spectroscopy (MRS), a newer technique not previously studied in chronic kidney disease (CKD), is useful and reproducible. CKD patients have significantly higher bone marrow fat than healthy adults.

INTRODUCTION

Renal osteodystrophy leads to increased morbidity and mortality in patients with CKD. Traditional bone biopsy histomorphometry is used to study abnormalities in CKD, but the bone marrow, the source of osteoblasts, has not been well characterized in patients with CKD.

METHODS

To determine the repeatability of bone marrow fat fraction assessment by MRS and water-fat imaging (WFI) at four sites in patients with CKD, testing was performed to determine the coefficients of reproducibility and intraclass coefficients (ICCs). We further determined if this noninvasive technique could be used to determine if there are differences in the percent bone marrow fat in patients with CKD compared to matched controls using paired t tests.

RESULTS

The mean age of subjects with CKD was 59.8 ± 7.2 years, and the mean eGFR was 24 ± 8 ml/min. MRS showed good reproducibility at all sites in subjects with CKD and controls, with a coefficient of reproducibilities ranging from 2.4 to 13 %. MRS and WFI assessment of bone marrow fat showed moderate to strong agreement (ICC 0.6-0.7) at the lumbar spine, with poorer agreement at the iliac crest and no agreement at the tibia. The mean percent bone marrow fat at L2-L4 was 13.8 % (95 % CI 8.3-19.7) higher in CKD versus controls (p < 0.05).

CONCLUSIONS

MRS is a useful and reproducible technique to study bone marrow fat in CKD. Patients with CKD have significantly higher bone marrow fat than healthy adults; the relationship with bone changes requires further analyses.

Bone imaging and fracture risk assessment in kidney disease

Fractures are more common and are associated with greater morbidity and morality in patients with kidney disease than in members of the general population. Thus, it is troubling that in chronic kidney disease (CKD) patients there has been a paradoxical increase in fracture rates over the past 20 years compared to the general population. Increased fracture incidence in CKD patients may be driven in part by the lack of screening for fracture risk. In the general population, dual energy X-ray absorptiometry (DXA) is the clinical standard to stratify fracture risk, and its use has contributed to decreases in fracture incidence. In contrast, in CKD, fracture risk screening with DXA has been uncommon due to its unclear efficacy in predicting fracture and its inability to predict type of renal osteodystrophy. Recently, several prospective studies conducted in patients across the spectrum of kidney disease have demonstrated that bone mineral density measured by DXA predicts future fracture risk and that clinically relevant information regarding fracture risk is provided by application of the World Health Organization cutoffs for osteopenia and osteoporosis to DXA measures. Furthermore, novel high-resolution imaging tools, such as high-resolution peripheral quantitative computed tomography (HR-pQCT), have been used to elucidate the effects of kidney disease on cortical and trabecular microarchitecture and bone strength and to identify potential targets for strategies that protect against fractures. This review will discuss the updated epidemiology of fractures in CKD, fracture risk screening by DXA, and the utility of state-of-the art imaging methods to uncover the effects of kidney disease on the skeleton.