Incidence and risk factors for hip or other bone fractures among hemodialysis patients in the Dialysis Outcomes and Practice Patterns Study

Comparison between paricalcitol and active non-selective vitamin D receptor activator for secondary hyperparathyroidism in chronic kidney disease: a systematic review and meta-analysis of randomized controlled trials

PURPOSE

The goal of this systematic review is to evaluate the efficacy and safety of paricalcitol versus active non-selective vitamin D receptor activators (VDRAs) for secondary hyperparathyroidism (SHPT) management in chronic kidney disease (CKD) patients.

METHODS

PubMed, EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL), clinicaltrials.gov (inception to September 2015), and ASN Web site were searched for relevant studies. A meta-analysis of randomized controlled trials (RCTs) and quasi-RCTs that assessed the effects and adverse events of paricalcitol and active non-selective VDRA in adult CKD patients with SHPT was performed using Review Manager 5.2.

RESULTS

A total of 10 trials involving 734 patients were identified for this review. The quality of included trials was limited, and very few trials reported all-cause mortality or cardiovascular calcification without any differences between two groups. Compared with active non-selective VDRAs, paricalcitol showed no significant difference in both PTH reduction (MD -7.78, 95% CI -28.59-13.03, P = 0.46) and the proportion of patients who achieved the target reduction of PTH (OR 1.27, 95% CI 0.87-1.85, P = 0.22). In addition, no statistical differences were found in terms of serum calcium, episodes of hypercalcemia, serum phosphorus, calcium × phosphorus products, and bone metabolism index.

CONCLUSIONS

Current evidence is insufficient, showing paricalcitol is superior to active non-selective VDRAs in lowering PTH or reducing the burden of mineral loading. Further trials are required to prove the tissue-selective effect of paricalcitol and to overcome the limitation of current research.

Serum Parathyroid Hormone Concentrations and Clinical Outcomes in ESRD: A Call for Targeted Clinical Trials

Secondary hyperparathyroidism almost universally accompanies end-stage renal disease (ESRD). In some, but not all studies, elevated serum parathyroid hormone (PTH) concentrations are associated with increased fracture rates, cardiovascular disease, and mortality in ESRD. The serum concentration of PTH required for optimal bone health and reduced cardiovascular risk in such patients remains elusive. Recent clinical trials have failed to show substantial changes in morbidity and mortality following reductions of elevated serum PTH concentrations. In this review, we will assess some of the difficulties in evaluating elevated serum PTH concentrations, and their association with skeletal fractures and mortality in ESRD patients. We are of the opinion that in the context of ESRD, elevated PTH concentrations occur in conjunction with other comorbid conditions such as diabetes mellitus, malnutrition, hypertension, volume excess, preexisting heart disease, all of which have prevented establishing a precise association between elevated serum PTH concentrations and global or skeletal outcomes. Age, gender, and racial variability among groups make interpretation exceptionally difficult. Analysis of prevalent ESRD populations with secondary hyperparathyroidism should take all these factors into account. We suggest that future clinical trials which examine the usefulness of reductions in serum PTH concentrations be conducted in age, sex, and racially balanced groups, without or with minimal coexisting confounding disease. Furthermore, trials in such populations should have as their primary outcome a reduction in fractures rather than an alteration in mortality.

Altered material properties are responsible for bone fragility in rats with chronic kidney injury

Chronic kidney disease (CKD) is associated with an increased risk of fragility fractures, but the underlying pathophysiological mechanism remains obscure. We performed an in vivo experimental study to examine the roles of uremia and abnormal mineral/parathyroid metabolism in the development of bone metabolic abnormalities in uremic rats. Male Sprague-Dawley rats were divided into four groups, comprising sham operation (high turnover bone control=HTB-Cont), 5/6-nephrectomy (high turnover bone nephrectomized=HTB-Nx), thyroparathyroidectomy (low turnover bone control=LTB-Cont), and thyroparathyroidectomy plus 5/6 nephrectomy (low turnover bone nephrectomized=LTB-Nx), and maintained for 16 weeks. Uremia was successfully created in the LTB-Nx and HTB-Nx groups, while hyperparathyroidism was only found in the HTB-Nx group. Cancellous bone histomorphometry revealed significantly higher bone turnover in the HTB-Nx group than in the LTB-Nx group. Storage modulus at 1 Hz and tan delta in cortical bone of the femur, which represent the viscoelastic mechanical properties, were significantly lower in both Nx groups than in the Cont groups regardless of bone metabolism. Pentosidine-to-matrix ratio was increased and crystallinity was decreased in both Nx groups regardless of bone turnover. Mineral-to-matrix ratio was significantly decreased in the HTB-Nx group, but increased in the LTB-Nx group. Enzymatic collagen crosslinks were decreased in the HTB-Nx group. The degree of orientation of the c-axis in carbonated hydroxyapatite (biological apatite=BAp) crystallites was decreased in both Nx groups regardless of bone metabolism. Stepwise multivariate regression revealed that pentosodine-to-matrix ratio and BAp preferential c-axis orientation were significantly associated with storage modulus and tan delta. In conclusion, bone elastic mechanical properties deteriorated regardless of bone metabolism or bone mass in rats with chronic kidney injury. Various changes in bone mineral properties were associated with CKD, including abnormal parathyroid function, impaired bone turnover, and uremia associated with the accumulation of uremic toxins, were responsible for these changes. Pentosidine-to-matrix ratio and BAp orientation at position 5 were the two meaningful determinants of elastic bone mechanical strength, and both factors were associated with the severity of uremia, but not parathyroid function or bone metabolism. These two factors may account for the increased bone fragility among CKD patients.

Economic Evaluation of Cinacalcet in the United States: The EVOLVE Trial

BACKGROUND

Previous economic evaluations of cinacalcet in patients with secondary hyperparathyroidism (sHPT) relied on the combination of surrogate end points in clinical trials and epidemiologic studies.

OBJECTIVES

The objective was to conduct an economic evaluation of cinacalcet on the basis of the EValuation Of Cinacalcet HCl Therapy to Lower CardioVascular Events (EVOLVE) trial from a US payer perspective.

METHODS

We developed a semi-Markov model to assess the cost-effectiveness of cinacalcet in addition to conventional therapy, compared with conventional therapy alone, in patients with moderate-to-severe sHPT receiving hemodialysis. We used treatment effect estimates from the unadjusted intent-to-treat (ITT) analysis and prespecified covariate-adjusted ITT analysis as our main analyses. We assessed model sensitivity to variations in individual inputs and overall decision uncertainty through probabilistic sensitivity analyses.

RESULTS

The incremental cost-effectiveness ratio (ICER) for cinacalcet was $61,705 per life-year and $79,562 per quality-adjusted life-year (QALY) gained using the covariate-adjusted ITT analysis. Probabilistic sensitivity analysis suggested a 73.2% chance of the ICER being below a willingness-to-pay threshold of $100,000. Treatment effects from unadjusted ITT analysis yielded an ICER of $115,876 per QALY. The model was most sensitive to the treatment effect on mortality.

CONCLUSIONS

In the unadjusted ITT analysis, cinacalcet does not represent a cost- effective use of health care resources when applying a willingness-to-pay threshold of $100,000 per QALY. When using the covariate-adjusted ITT treatment effect, which represents the least biased estimate, however, cinacalcet is a cost-effective therapy for patients with moderate-to-severe sHPT on hemodialysis.

The FRAX ® as a predictor of mortality in Japanese incident hemodialysis patients: an observational, follow-up study

The World Health Organization Fracture Risk Assessment Tool (FRAX(®)) was recently developed to estimate the 10-year absolute risk of osteoporotic fracture among the general population. However, the evidence for its use in chronic kidney disease patients has been lacking, and the association between the FRAX(®) and mortality is unknown. Therefore, a hospital-based, prospective, cohort study was conducted to evaluate the predictive ability of the FRAX(®) for mortality in hemodialysis patients. A total of 252 patients who had been started on maintenance hemodialysis, 171 men and 81 women, with a mean age of 67 ± 14 years, was studied. The endpoint was defined as all-cause death. The Cox proportional hazards model was used to calculate hazard ratios and 95 % confidence intervals. During the mean follow-up period of 3.4 ± 2.7 years, 61 deaths occurred. The median (interquartile range) of the FRAX(®) for major osteoporotic fracture was 6.9 (4.6-12.0) % in men and 19.0 (7.6-33.0) % in women. Cumulative survival rates at 5 years after starting dialysis, with the FRAX(®) levels above and below the median, were 51.9 and 87.9 %, respectively, in men and 67.4 and 83.7 %, respectively, in women. Overall, in men, the multivariate Cox regression analyses revealed that the log-transformed FRAX(®) remained an independent predictor of death after adjusting by confounding variables. However, in women, the significant association between the FRAX(®) value and the outcome was eliminated if age was put into these models. Among Japanese hemodialysis patients, the FRAX(®) seems to be useful for predicting death, especially in men.

Should chronic metabolic acidosis be treated in older people with chronic kidney disease?

Metabolic acidosis is common in advanced chronic kidney disease and has been associated with a range of physiological derangements of importance to the health of older people. These include associations with skeletal muscle weakness, cardiovascular risk factors, and bone and mineral disorders that may lead to fragility fractures. Although metabolic acidosis is associated with accelerated decline in kidney function, end-stage renal failure is a much less common outcome in older, frail patients than cardiovascular death. Correction of metabolic acidosis using bicarbonate therapy is commonly employed, but the existing evidence is insufficient to know whether such therapy is of net benefit to older people. Bicarbonate is bulky and awkward to take, may impose additional sodium load with effects on fluid retention and blood pressure, and may cause gastrointestinal side effects. Trial data to date suggest potential benefits of bicarbonate therapy on progression of renal disease and nutrition, but trials have not as yet been published examining the effect of bicarbonate therapy across a range of domains relevant to the health of older people. Fortunately, a number of trials are now underway that should allow us to ascertain whether bicarbonate therapy can improve physical function, quality of life, and vascular, bone and kidney health in older people, and hence decide whether any benefits seen outweigh adverse effects and additional treatment burden in this vulnerable group of patients.

Kidney Function and Fracture Risk: The Atherosclerosis Risk in Communities (ARIC) Study

BACKGROUND

People with end-stage renal disease are at high risk for bone fracture. Less is known about fracture risk in milder chronic kidney disease and whether chronic kidney disease-associated fracture risk varies by sex or assessment with alternative kidney markers.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

10,955 participants from the Atherosclerosis Risk in Communities (ARIC) Study followed up from 1996 to 2011.

PREDICTOR

Kidney function as assessed by creatinine-based estimated glomerular filtration rate (eGFRcr), urine albumin-creatinine ratio, and alternative filtration markers.

OUTCOMES

Fracture-related hospitalizations determined by diagnostic code.

MEASUREMENTS

Baseline kidney markers; hospitalizations identified by self-report during annual telephone contact and active surveillance of local hospital discharge lists.

RESULTS

Mean age of participants was 63 years, 56% were women, and 22% were black. During a median follow-up of 13 years, there were 722 incident fracture-related hospitalizations. Older age, female sex, and white race were associated with higher risk for fracture (P<0.001). The relationship between eGFRcr and fracture risk was nonlinear: <60mL/min/1.73m(2), lower eGFRcr was associated with higher fracture risk (adjusted HR per 10mL/min/1.73m(2) lower, 1.24; 95% CI, 1.05-1.47); there was no statistically significant association for ≥60mL/min/1.73m(2) in the primary analysis. In contrast, there was a graded association between other markers of kidney function and subsequent fracture, including albumin-creatinine ratio (HR per doubling, 1.10; 95% CI, 1.06-1.14), cystatin C-based eGFR (HR per 1-SD decrease, 1.15; 95% CI, 1.06-1.25), and 1/β2-microglobulin (HR per 1-SD decrease, 1.26, 95% CI, 1.15-1.37).

LIMITATIONS

No bone mineral density assessment; one-time measurement of kidney function.

CONCLUSIONS

Both low eGFR and higher albuminuria were significant risk factors for fracture in this community-based population. The shape of the association in the upper ranges of eGFR varied by the filtration marker used in estimation.

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.

Fracture Burden and Risk Factors in Childhood CKD: Results from the CKiD Cohort Study

Childhood chronic kidney disease (CHD) poses multiple threats to bone accrual; however, the associated fracture risk is not well characterized. This prospective cohort study included 537 CKD in Children (CKiD) participants. Fracture histories were obtained at baseline, at years 1, 3, and 5 through November 1, 2009, and annually thereafter. We used Cox regression analysis of first incident fracture to evaluate potential correlates of fracture risk. At enrollment, median age was 11 years, and 16% of patients reported a prior fracture. Over a median of 3.9 years, 43 males and 24 females sustained incident fractures, corresponding to 395 (95% confidence interval [95% CI], 293-533) and 323 (95% CI, 216-481) fractures per 10,000 person-years, respectively. These rates were 2- to 3-fold higher than published general population rates. The only gender difference in fracture risk was a 2.6-fold higher risk in males aged ≥15 years (570/10,000 person-years, adjusted P=0.04). In multivariable analysis, advanced pubertal stage, greater height Z-score, difficulty walking, and higher average log-transformed parathyroid hormone level were independently associated with greater fracture risk (all P≤0.04). Phosphate binder treatment (predominantly calcium-based) was associated with lower fracture risk (hazard ratio, 0.37; 95% CI, 0.15-0.91; P=0.03). Participation in more than one team sport was associated with higher risk (hazard ratio, 4.87; 95% CI, 2.21-10.75; P<0.001). In conclusion, children with CKD have a high burden of fracture. Regarding modifiable factors, higher average parathyroid hormone level was associated with greater risk of fracture, whereas phosphate binder use was protective in this cohort.

Health state utilities associated with major clinical events in the context of secondary hyperparathyroidism and chronic kidney disease requiring dialysis

BACKGROUND

Patients with chronic kidney disease (CKD) and secondary hyperparathyroidism (SHPT) who require dialysis are at increased risk for cardiovascular events and bone fractures. To assist in economic evaluations, this study aimed to estimate the disutility of these events beyond the impact of CKD and SHPT.

METHODS

A basic one-year health state was developed describing CKD and SHPT requiring dialysis. Further health states added acute events (cardiovascular events, fractures, and surgical procedures) or chronic post-event effects. Acute health states described a year including an event, and chronic health states described a year subsequent to an event. General population participants in Canada completed time trade-off interviews from which utilities were derived. Pairwise comparisons were made between the basic state and event, and between comparable health states.

RESULTS

A total of 199 participants (54.8% female; mean age = 46.3 years) completed interviews. Each health state had ≥130 valuations. The mean (SD) utility of the basic health state was 0.60 (0.34). For acute events, mean utility differences versus the basic state were: myocardial infarction, -0.06; unstable angina, -0.05; peripheral vascular disease (PVD) with amputation, -0.33; PVD without amputation, -0.11; heart failure, -0.14; stroke, -0.30; hip fracture, -0.14; arm fracture, -0.04; parathyroidectomy, +0.02; kidney transplant, +0.06. Disutilities for chronic health states were: stable angina, -0.09; stroke, -0.27; PVD with amputation, -0.30; PVD without amputation, -0.12; heart failure, -0.14.

CONCLUSIONS

Cardiovascular events and fractures were associated with lower utility scores, suggesting a perceived decrease in quality of life beyond the impact of CKD and SHPT.

Sclerostin and DKK1: new players in renal bone and vascular disease

For more than a decade, the Wnt-β-catenin pathway has been the focus of intense basic and clinical research in the bone field because of its importance in skeletal development and maintenance of bone mass. Wnt activation increases bone formation and decreases bone resorption. The Wnt-β-catenin signaling pathway is tightly regulated by several inhibitors, among which Dickkopf-related protein 1 (DKK1) and sclerostin have been most comprehensively studied. Mounting evidence indicates that a disturbed Wnt-β-catenin signaling is also implicated in the pathogenesis of the chronic kidney disease-associated bone and mineral disorder (CKD-MBD) and affects its various components. DKK1 and sclerostin, more specifically, may be involved in the intense cross-talk between the kidneys, vasculature, and bone. Studies exploring clinical correlates of circulating sclerostin and DKK1 levels so far yielded conflicting results. Biological variability and analytical issues account at least partly for this inconsistency. Antibodies neutralizing Wnt inhibitors may be an appealing strategy to prevent or treat CKD-MBD. Caution is however warranted as sclerostin not only opposes mineralization in the bone but possibly also in the vasculature. Additional studies are required to define determinants of Wnt inhibitors in CKD and to evaluate the efficacy and safety of recently introduced pharmaceuticals targeting these inhibitors.

Fibromyalgia and its clinical relevance in renal transplant recipients

OBJECTIVE

Recent evidence suggests that fibromyalgia syndrome (FS) is associated with inflammation and endothelial dysfunction. Our aim was to determine the prevalence of FS in renal transplant recipients and to identify possible links between FS and clinical and laboratory parameters.

METHODS

Ninety-nine kidney transplant recipients with normal graft functions (37.15 ± 10.83 years old, 67 male) were enrolled in the study. All subjects completed the Fibromyalgia Impact Questionnaire (FIQ). The biochemical and clinical parameters in the 1st post-transplantation year were retrospectively recorded. Cardiovascular parameters, including body composition analyses (Tanita), ambulatory blood pressure monitoring data, and pulse-wave velocity, were cross-sectionally analyzed.

RESULTS

Mean FIQ score for the whole group was 21.4 ± 14.7. Eight patients had FIQ score >50, and these patients had significantly higher left ventricular mass index than patients with lower FIQ score (P = .048). Patients were divided according to their physical impairment score (PIS): PIS ≥5 (n = 50) and PIS <5 (n = 49). Patients with higher PIS had significantly higher serum creatinine (P = .047) and lower eGFR values (P = .008) than patients with lower PIS. Patients were also evaluated with the use of the stiffness score (SS): patients with (n = 41) and without (n = 58) stiffness. Patients with stiffness had significantly higher office systolic (P = .027) and diastolic (P = .044) blood pressure, body mass index (P = .033), and sagittal abdominal diameter (P = .05) than patients without stiffness. Decline in estimated glomerular filtration rate levels were significantly higher in patients with higher FIQ (7.6% vs 9.4%; P = .0001) than in other patients.

CONCLUSIONS

FS in renal transplant recipients was strongly associated with hypertension, arterial stiffness, obesity, and renal allograft dysfunction.

Effects of Cinacalcet on Fracture Events in Patients Receiving Hemodialysis: The EVOLVE Trial

Fractures are frequent in patients receiving hemodialysis. We tested the hypothesis that cinacalcet would reduce the rate of clinical fractures in patients receiving hemodialysis using data from the Evaluation of Cinacalcet HCl Therapy to Lower Cardiovascular Events trial, a placebo-controlled trial that randomized 3883 hemodialysis patients with secondary hyperparathyroidism to receive cinacalcet or placebo for ≤64 months. This study was a prespecified secondary analysis of the trial whose primary end point was all-cause mortality and non-fatal cardiovascular events, and one of the secondary end points was first clinical fracture event. Clinical fractures were observed in 255 of 1935 (13.2%) patients randomized to placebo and 238 of 1948 (12.2%) patients randomized to cinacalcet. In an unadjusted intention-to-treat analysis, the relative hazard for fracture (cinacalcet versus placebo) was 0.89 (95% confidence interval [95% CI], 0.75 to 1.07). After adjustment for baseline characteristics and multiple fractures, the relative hazard was 0.83 (95% CI, 0.72 to 0.98). Using a prespecified lag-censoring analysis (a measure of actual drug exposure), the relative hazard for fracture was 0.72 (95% CI, 0.58 to 0.90). When participants were censored at the time of cointerventions (parathyroidectomy, transplant, or provision of commercial cinacalcet), the relative hazard was 0.71 (95% CI, 0.58 to 0.87). Fracture rates were higher in older compared with younger patients and the effect of cinacalcet appeared more pronounced in older patients. In conclusion, using an unadjusted intention-to-treat analysis, cinacalcet did not reduce the rate of clinical fracture. However, when accounting for differences in baseline characteristics, multiple fractures, and/or events prompting discontinuation of study drug, cinacalcet reduced the rate of clinical fracture by 16%-29%.

Chronic kidney disease and bone metabolism

Chronic kidney disease-related mineral and bone disease (CKD-MBD) is a syndrome defined as a systemic mineral metabolic disorder associated with CKD, and the term renal osteodystrophy indicates a pathomorphological concept of bone lesions associated with CKD-MBD. Cortical bone thinning, abnormalities in bone turnover and primary/secondary mineralization, elevated levels of circulating sclerostin, increased apoptosis in osteoblasts and osteocytes, disturbance of the coupling phenomenon, iatrogenic factors, accumulated micro-crackles, crystal/collagen disorientation, and chemical modification of collagen crosslinks are all possible candidates found in CKD that could promote osteopenia and/or bone fragility. Some of above factors are the consequences of abnormal systemic mineral metabolism but for others it seem unlikely. We have used the term uremic osteoporosis to describe the uremia-induced bone fragility which is not derived from abnormal systemic mineral metabolism. Interestingly, the disease aspect of uremic osteoporosis appears to be similar to that of senile osteoporosis.

Use of renin-angiotensin system inhibitors is associated with reduction of fracture risk in hemodialysis patients

Background

Patients with chronic kidney disease, especially those undergoing dialysis treatment and having secondary hyperparathyroidism, have a high risk of bone fracture. The renin-angiotensin system (RAS) is associated with osteoclastic bone resorption. We aimed to examine whether the use of RAS inhibitors reduces the incidence of fracture in hemodialysis patients.

Methods and Findings

This was a multicenter, 3-year, prospective, observational study. From 2008 to 2011, maintenance hemodialysis patients with secondary hyperparathyroidism (N = 3,276) treated with angiotensin converting enzyme inhibitor (ACEI)/angiotensin II receptor blocker (ARB) at baseline were followed for a mean of 2.7 years. The association between the use of ACEI/ARB and hospitalization rate owing to fracture was examined by using Cox regression models. Effect modifications by the severity of secondary hyperparathyroidism (intact parathyroid hormone [iPTH] level), sex, and systolic blood pressure were also examined. The incidence proportion of fracture-related hospitalization was 5.42% throughout the observation period. ACEI/ARB use was associated with a lower rate of fracture-related hospitalization (adjusted hazard ratio, 0.65; 95% confidence interval [CI], 0.45–0.92). This association was not significantly affected by sex (P = 0.56) or systolic blood pressure levels (P = 0.87). The hazard ratios adjusted by iPTH levels were qualitatively different, but not statistically significant (P = 0.11): 0.77 (95% CI, 0.42–1.39), 0.38 (95% CI, 0.20–0.73), 0.59 (95% CI, 0.29–1.21), and 1.29 (95% CI, 0.58–2.42) for the first, second, third and fourth quartiles of iPTH, respectively.

Conclusions

Use of RAS inhibitors is associated with a lower rate of fracture-related hospitalization in hemodialysis patients with secondary hyperparathyroidism.

Trial Registration

ClinicalTrials.gov NCT00995163

Increased hip fracture and mortality in chronic kidney disease individuals: the importance of competing risks

BACKGROUND

Many studies have shown a correlation between chronic kidney disease (CKD) and fracture. However, increased mortality in CKD patients is a competing risk scenario not accounted for in previous studies. Our aim was to investigate the true impact of CKD on hip fracture after accounting for a competing risk with death.

METHODS

We conducted a population-based cohort study to determine the impact of CKD on hip fractures in individuals aged ≥50years old registered in the SIDIAP(Q) database (representative of 1.9 million people in Catalonia, Spain). Cox regression was used to estimate hazard ratio (HR) for death and hip fracture according to CKD status. A competing risk (Fine and Gray) model was fitted to estimate sub-HR for hip fracture in CKD or CKD-free patients accounting for differential mortality.

RESULTS

A total of 873,073 (32,934 (3.8%) CKD) patients were observed for 3 years. During follow-up, 4,823 (14.6%) CKD and 36,328 (4.3%) CKD-free participants died (HR, 1.83 [95% CI, 1.78-1.89]), whilst 522 (1.59%) and 6,292 (0.75%) sustained hip fractures, respectively. Adjusted Cox models showed a significantly increased risk of hip fractures for the CKD group (HR, 1.16 [1.06-1.27]), but this association was attenuated in competing risk models accounting for mortality (SHR, 1.14 [1.03-1.27]).

CONCLUSIONS

Both death and hip fracture rates are increased (by 83% and 16%, respectively) in CKD patients. However, the association between CKD and hip fractures is attenuated when an excess of mortality is taken into account. A competing risk with death must be considered in future analyses of association between CKD and any health outcomes.

Perioperative Implications of End-stage Renal Disease in Orthopaedic Surgery

End-stage renal disease is a prevalent condition that substantially impacts a patient's quality of life. As medical advancements improve function and rates of survival, the number of persons with end-stage renal disease will grow, with orthopaedic surgeons increasingly encountering patients with the disease in their practice. End-stage renal disease is a complex medical condition that is often associated with multiple medical comorbidities. Orthopaedic surgery in patients with this disease is associated with at least a twofold risk of complications and mortality compared with a population without end-stage renal disease. Patients are at an increased risk for cardiovascular, metabolic, hematologic, and infectious complications. Orthopaedic surgeons should be familiar with pertinent issues in the preoperative evaluation and the postoperative management of these patients and should understand the risks of surgery to better inform patients and family. Careful coordination with consulting specialists is necessary to minimize morbidity and improve outcome.

Chronic kidney disease and the skeleton

Fractures across the stages of chronic kidney disease (CKD) could be due to osteoporosis, some form of renal osteodystrophy defined by specific quantitative histomorphometry or chronic kidney disease-mineral and bone disorder (CKD-MBD). CKD-MBD is a systemic disease that links disorders of mineral and bone metabolism due to CKD to either one or all of the following: abnormalities of calcium, phosphorus, parathyroid hormone or vitamin D metabolism; abnormalities in bone turnover, mineralization, volume, linear growth or strength; or vascular or other soft-tissue calcification. Osteoporosis, as defined by the National Institutes of Health, may coexist with renal osteodystrophy or CKD-MBD. Differentiation among these disorders is required to manage correctly the correct disorder to reduce the risk of fractures. While the World Health Organization (WHO) bone mineral density (BMD) criteria for osteoporosis can be used in patients with stages 1-3 CKD, the disorders of bone turnover become so aberrant by stages 4 and 5 CKD that neither the WHO criteria nor the occurrence of a fragility fracture can be used for the diagnosis of osteoporosis. The diagnosis of osteoporosis in stages 4 and 5 CKD is one of the exclusion-excluding either renal osteodystrophy or CKD-MBD as the cause of low BMD or fragility fractures. Differentiations among the disorders of renal osteodystrophy, CKD-MBD or osteoporosis are dependent on the measurement of specific biochemical markers, including serum parathyroid hormone (PTH) and/or quantitative bone histomorphometry. Management of fractures in stages 1-3 CKD does not differ in persons with or without CKD with osteoporosis assuming that there is no evidence for CKD-MBD, clinically suspected by elevated PTH, hyperphosphatemia or fibroblast growth factor 23 due to CKD. Treatment of fractures in persons with osteoporosis and stages 4 and 5 CKD is not evidence-based, with the exception of post-hoc analysis suggesting efficacy and safety of specific osteoporosis therapies (alendronate, risedronate and denosumab) in stage 4 CKD. This review also discusses how to diagnose and manage fragility fractures across the five stages of CKD.

Effects of raloxifene on bone metabolism in postmenopausal women on chronic hemodialysis

BACKGROUND

Postmenopausal women with end-stage renal failure are at an increased risk of fracture because of the effects of secondary hyperparathyroidism and postmenopausal osteoporosis. In the present study, we investigated the feasibility of using raloxifene to prevent fractures in postmenopausal women with end-stage renal failure on hemodialysis.

METHODS

This study was conducted using a multicenter, single-arm, prospective design. Raloxifene was administered to postmenopausal women aged ≥50 years who were on maintenance hemodialysis and met any of the following criteria after a 24-week run-in period: an alkaline phosphatase level (bone formation marker) of ≥6.18 µkat/L (≥370 U/L), a bone-specific alkaline phosphatase (BAP; bone formation marker) level of ≥0.59 µkat/L (≥35.4 U/L), or a bone-derived tartrate-resistant acid phosphatase (TRACP-5b; bone resorption marker) level of ≥4.2 U/L.

RESULTS

A total of 48 individuals were eligible for study inclusion. Of them, 30 individuals participated in this study. The BAP levels were significantly decreased at week 4, but returned to the baseline levels at week 24. Similarly, the TRACP-5b levels were significantly decreased at week 4, but returned to the baseline levels at week 24. The serum calcium value decreased consistently after the start of raloxifene therapy. The intact parathyroid hormone (iPTH) levels were likely increased at week 4. The ratio of BAP to iPTH levels and the ratio of TRACP-5b to iPTH levels both showed significant decreases over time. During the raloxifene therapy, no thrombosis or other drug-related adverse events developed.

CONCLUSION

The study results indicated that raloxifene can transiently reduce the levels of bone metabolism markers and might be useful for preventing fractures in postmenopausal women with end-stage renal failure, although raloxifene use over the long term may not have adequate efficacy in the absence of appropriate concomitant active vitamin D therapy.

Association of serum bicarbonate with bone fractures in hemodialysis patients: the mineral and bone disorder outcomes study for Japanese CKD stage 5D patients (MBD-5D)

BACKGROUND/AIMS

Bone fracture is often complicated in hemodialysis (HD) patients. Metabolic acidosis is related to bone disease and muscle wasting, but it is not known whether acid-base disturbance is associated with the risk of bone fractures. The aim of this study was to clarify the association of serum bicarbonate level with bone fracture in HD patients.

METHODS

Using a subcohort of the Mineral and Bone Disorder Outcomes Study for Japanese CKD Stage 5D Patients (MBD-5D), 890 prevalent HD patients (age: 62 years old, male: 62.8%, duration of dialysis: 8.3 years) with secondary hyperparathyroidism were studied. After measuring predialysis serum bicarbonate at a 2-day interdialytic interval, we prospectively followed them every 3 months, and examined the occurrence of any type of bone fracture or hospitalization due to fracture over a 3-year observation period.

RESULTS

Seventy-four bone fractures and 47 hospitalizations due to fracture were observed during the follow-up period. HD patients with serum bicarbonate <20 mmol/l had a 1.93 (95% CI 1.01-3.71)-fold higher risk for all-cause fractures than those with serum bicarbonate of 20.0-21.9 mmol/l. A higher bicarbonate level (≥22 mmol/l) was also related to an increased risk of bone fracture. A restricted cubic regression spline disclosed that the higher or the lower than 21.0 mmol/l of serum bicarbonate, the greater the risk for bone fracture.

CONCLUSION

Both a lower level and a higher level of predialysis bicarbonate concentration were associated with risk of bone fracture in HD patients with secondary hyperparathyroidism.

Epidemiology and mortality of hip fracture among patients on dialysis: Taiwan National Cohort Study

Chronic kidney disease increases the risk for hip fractures. Hip fractures are associated with increased mortality, decreased quality of life, and higher economic burden. To determine whether dialysis modality is associated with a higher incidence of hip fractures in patients with end-stage renal disease (ESRD), we used the Taiwan National Health Insurance Research Database to examine the records of 51,473 patients who began dialysis between 1999 and 2005. The patients were followed until death, transplantation, dialysis cessation, or 31 December 2008. The follow-up period was (mean±SD) 4.14±2.48 years. The cumulative incidence rate of hip fracture was calculated using Kaplan-Meier methods. Predictors of hip fracture were determined using Cox models. During the study period, 1903 patients had a hip fracture. The overall incidence rate of hip fracture was 89.21/10,000 patient-years. Patients on hemodialysis (HD) had a 31% higher incidence of hip fracture than those on peritoneal dialysis (PD) (HR 1.31, 95% CI: 1.01-1.70). Patients ≥65 years old had more than 13 times the risk of a hip fracture than did those 18-44 years old (HR: 13.65; 95% CI: 10.12-18.40). Other factors that increased the risk of a hip fracture were a prior hip fracture (HR: 1.44; 95% CI: 1.15-1.80), osteoporosis (HR: 1.24; 95% CI: 1.07-1.45), DM (HR: 1.66; 95% CI: 1.51-1.83), and liver cirrhosis (HR: 1.37, 95% CI: 1.15-1.64). The overall in-hospital mortality rate was 3.2%. The cumulative survival rates after a hip fracture were 74.6% at one year and only 29.6% at seven years. Our findings supported the notion that being on HD is a risk for hip fracture. Additionally, old age, female gender, a prior hip fracture, osteoporosis, DM and liver cirrhosis were also risk factors for hip fracture in patients with ESRD and undergoing dialysis.

Fragility fractures and osteoporosis in CKD: pathophysiology and diagnostic methods

Both chronic kidney disease (CKD) and osteoporosis are major public health problems associated with an aging population. Osteoporosis is characterized by reduced bone mineral density, while CKD results in qualitative changes in bone structure; both conditions increase the predisposition to fragility fractures. There is a significant coprevalence of osteoporotic fractures and CKD, particularly in the elderly population. Not only is the risk of fracture higher in the CKD population, but clinical outcomes are significantly worse, with substantial health care costs. Management of osteoporosis in the CKD population is particularly complex given the impact of renal osteodystrophy on bone quality and the limited safety and hard outcome data for current therapy in patients with severe CKD or on dialysis therapy. In this review, we discuss the pathophysiology of osteoporosis, the impact of CKD on bone strength, and the role of novel imaging techniques and biomarkers in predicting underlying renal osteodystrophy on bone histomorphometry in the context of CKD.

Is the dialysate calcium concentration of 1.75 mmol/L suitable for Chinese patients on maintenance hemodialysis?

We studied the effects of increasing the dialysate calcium concentration (DCa) to 1.75 mmol/L on controlling chronic kidney disease-mineral and bone disorder in Chinese patients on maintenance hemodialysis (MHD). We reviewed the data of MHD patients in one center (cohort 1) during prior 10 years and analyzed the risk factors of mortality and transference calcification (TC) in120 MHD patients surviving in 2003 (cohort 2). A multicenter, prospective, parallel-group, controlled trial (cohort 3) was also conducted from January 2011 to December 2012. The DCa at one center was increased from 1.5 to 1.75 mmol/L but was not changed at the other two centers. The clinical outcomes, biochemical parameters, medicine treatments, and TC markers [aortic arch calcification score (AoACS)] were compared between groups. In cohort 1, the annual mean serum iPTH increased significantly over 10 years. In cohort 1, 72 patients survived for 10 years, whose doses of calcium salts and active vitamin D3 and AoACs increased progressively. In cohort 2, the main cause of death was cardiocerebrovascular disease (CCVD) (n = 18, 48.6 %). Male sex and lower serum calcium concentrations were independent risk factors for CCVD mortality. In cohort 3, serum phosphorus, iPTH, and 25(OH)D decreased and serum calcium increased significantly; also, the doses of calcium and vitamin D3 decreased from 2011 to 2012 in the DCa 1.75 group. There were no significant differences in clinical outcomes either between groups or between the two calendar years. Our results indicate that increasing DCa to 1.75 mmol/L can decrease the elevated levels of serum iPTH and phosphorus, reduce the doses of calcium and vitamin D3, and be safe for short periods of time.

Vitamin D and chronic kidney disease-mineral bone disease (CKD-MBD)

Chronic kidney disease (CKD) is a modern day epidemic and has significant morbidity and mortality implications. Mineral and bone disorders are common in CKD and are now collectively referred to as CKD- mineral and bone disorder (MBD). These abnormalities begin to appear even in early stages of CKD and contribute to the pathogenesis of renal osteodystrophy. Alteration in vitamin D metabolism is one of the key features of CKD-MBD that has major clinical and research implications. This review focuses on biology, epidemiology and management aspects of these alterations in vitamin D metabolism as they relate to skeletal aspects of CKD-MBD in adult humans.

Increasing dietary phosphorus intake from food additives: potential for negative impact on bone health

It is important to consider whether habitual high phosphorus intake adversely affects bone health, because phosphorus intake has been increasing, whereas calcium intake has been decreasing in dietary patterns. A higher total habitual dietary phosphorus intake has been associated with higher serum parathyroid hormone (PTH) and lower serum calcium concentrations in healthy individuals. Higher serum PTH concentrations have been shown in those who consume foods with phosphorus additives. These findings suggest that long-term dietary phosphorus loads and long-term hyperphosphatemia may have important negative effects on bone health. In contrast, PTH concentrations did not increase as a result of high dietary phosphorus intake when phosphorus was provided with adequate amounts of calcium. Intake of foods with a ratio of calcium to phosphorus close to that found in dairy products led to positive effects on bone health. Several randomized controlled trials have shown positive relations between dairy intake and bone mineral density. In our loading test with a low-calcium, high-phosphorus lunch provided to healthy young men, serum PTH concentrations showed peaks at 1 and 6 h, and serum fibroblast growth factor 23 (FGF23) concentrations increased significantly at 8 h after the meal. In contrast, the high-calcium, high-phosphorus meal suppressed the second PTH and FGF23 elevations until 8 h after the meal. This implies that adequate dietary calcium intake is needed to overcome the interfering effects of high phosphorus intake on PTH and FGF23 secretion. FGF23 acts on the parathyroid gland to decrease PTH mRNA and PTH secretion in rats with normal kidney function. However, increased serum FGF23 is an early alteration of mineral metabolism in chronic kidney disease, causing secondary hyperthyroidism, and implying resistance of the parathyroid gland to the action of FGF23 in chronic kidney disease. These findings suggest that long-term high-phosphorus diets may impair bone health mediated by FGF23 resistance both in chronic kidney disease patients and in the healthy population.

Incidence and risk factors for hip fractures in dialysis patients

This study described the incidence of hip fractures, associated diseases, and related costs generated in dialysis versus non-dialysis patients.

INTRODUCTION

Skeletal fractures are a great concern in chronic kidney disease patients and, in particular, hip fractures that enhance the mortality. We aimed to accurately determine the incidence of hip fractures and associated diseases and to calculate the costs generated in dialysis patients.

METHODS

We obtained data from the 2010 French National Hospital Database. We first extracted the hospital stays related to hip fractures as a primary diagnosis according to the ICD-10 codes and then the hospitalizations for dialysis. We compared the frequency of comorbidities in both populations.

RESULTS

Among the 88,962 patients who suffered from hip fractures, 362 were on dialysis. The incidence was significantly higher in dialysis patients (x4) compared to non-dialysis patients. Women on dialysis experienced hip fractures at an earlier age than non-dialysis women. Dementia was identified as a major risk factor in the dialysis patients (72 vs. 26%, p < 0.0001). Moreover, diabetes and cardiovascular diseases were comorbidities strongly associated with hip fractures in both gender, but hypertension and malnutrition were observed exclusively in men on dialysis. Mortality rate and length of hospital stay were increased (5 days) in both genders.

CONCLUSION

The incidence of hip fractures is increased in dialysis patients, affecting a larger percentage of men and women on dialysis than in the non-dialysis population and enhancing the financial burden and mortality. Dementia is a major risk factor for hip fractures in dialysis patients in addition to diabetes and cardiovascular diseases.

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

Altered bone structure and function contribute to the high rates of fractures in dialysis patients compared to the general population. Fracture events may increase the risk of subsequent adverse clinical outcomes. Here we assessed the incidence of post-fracture morbidity and mortality in an international cohort of 34,579 in-center hemodialysis patients in the Dialysis Outcomes and Practice Patterns Study (DOPPS). We estimated country-specific rates of fractures requiring a hospital admission and associated length of stay in the hospital. Incidence rates of death and of a composite event of death/rehospitalization were estimated for 1 year after fracture. Overall, 3% of participants experienced a fracture. Fracture incidence varied across countries, from 12 events/1000 patient-years (PY) in Japan to 45/1000 PY in Belgium. In all countries, fracture rates were higher in the hemodialysis group compared to those reported for the general population. Median length of stay ranged from 7 to 37 days in the United States and Japan, respectively. In most countries, postfracture mortality rates exceeded 500/1000 PY and death/rehospitalization rates exceeded 1500/1000 PY. Fracture patients had higher unadjusted rates of death (3.7-fold) and death/rehospitalization (4.0-fold) compared to the overall DOPPS population. Mortality and hospitalization rates were highest in the first month after the fracture and declined thereafter. Thus, the high frequency of fractures and increased adverse outcomes following a fracture pose a significant health burden for dialysis patients. Fracture prevention strategies should be identified and applied broadly in nephrology practices.

Accumulated uremic toxins attenuate bone mechanical properties in rats with chronic kidney disease

The prevalence of hip fracture is very high among patients with chronic kidney disease (CKD); however, the reason for this is unclear. We examined the effects of accumulated uremic toxins on bone chemical composition and elastic mechanical properties. Rats underwent thyroparathyroidectomy and progressive partial nephrectomy (TPTx-Nx), and were administered with vehicle or AST-120 to reduce serum indoxyl sulfate (IS) levels. Bone mechanical properties, bone mineral density (BMD), cortical bone chemical composition, and histomorphometry were determined. Storage modulus was reduced in TPTx-Nx rats compared with rats that underwent TPTx alone. BMD and histomorphometric parameters did not differ between the groups. In terms of cortical bone chemical composition, the mineral/matrix ratio and carbonate substitution was increased, whereas crystallinity was decreased in TPTx-Nx rats. The enzymatic crosslink ratio and pentosidine:matrix ratio were increased in TPTx-Nx rats. AST-120 abolished the effects of TPTx-Nx and decreased the serum IS concentration. Stepwise multiple regression analysis revealed that the pentosidine:matrix and mineral:matrix ratios were independent contributors to the storage modulus. In conclusion, the accumulated uremic toxins, including IS, seem to play an important role in deteriorating bone mechanical properties by altering the chemical composition of bone. This mechanism may account for the increased prevalence of hip fracture among patients with CKD.

Uremic osteoporosis

Abnormalities in bone turnover, mineralization, and volume represent one of the three components of chronic kidney disease–related mineral and bone disorder (CKD-MBD). The risk of hip fracture is considerably high, while the risk of spinal compression fracture may not be more elevated among CKD patients than in general population. The relationship between bone fracture and bone mineral density in CKD patients is more complex than in those without kidney disease. An increase in the rate of falls has been reported to be a major cause of high hip fracture risk among CKD patients; however, it certainly is not the only underlying mechanism. Abnormal parathyroid function is not likely to be a major cause of hip fracture among CKD patients. In experimental CKD animals, mechanical elasticity properties of long bones showed an inverse correlation with kidney function. The deterioration of bone elasticity showed a significant correlation with bone biochemical changes. Of note, administration of the oral absorbent AST-120 was capable of preventing both changes. These findings suggest that uremic toxins cause a deterioration of bone material properties, and changes in material properties disturb bone elasticity. This disease concept cannot be considered to be a direct consequence of CKD-MBD. We therefore would like to call it ‘uremic osteoporosis'. This entity may be a major cause of increased hip fracture risk among CKD patients.

Charlson co-morbidity index and albumin significantly associated with fracture risk in peritoneal dialysis patients

Published literature on fracture in dialysis patients seldom addressed the effect of co-morbidity and malnutrition. In this study, we reported the incidence and risk factors for fracture in peritoneal dialysis patients. Peritoneal dialysis patients who had fractures between 2006 and 2011 were recruited. Demographic data, details of fracture, Charlson Co-morbidity Index (CCI) and biochemical parameters were also collected. Non-fracture controls, matched for age, gender and duration of dialysis, were also recruited at ratio 1:1 for fracture risk analysis. The incidence of fracture was 1 in 37 patient-years. The commonest site of fracture was neck of femur (n = 16, 55.2%). Twenty-four patients (82.8%) developed fracture after slip and fall injury. Eight out of 17 self-ambulatory patients (47.1%) became non-ambulatory after fracture. Infection was the commonest complication during hospitalization. Univariant analysis demonstrated high CCI (P = 0.001), hypoalbuminaemia (P < 0.001), loss of self autonomy (P = 0.006) and non-ambulatory state (P = 0.011) significantly associated with increased fracture risk. However, only CCI (odds ratio (OR) 1.373, P = 0.028) and albumin (OR 0.893, P = 0.025) increased fracture risk significantly on multivariant analysis. Bone profile and parathyroid hormone were not significant risk factors. To conclude, fracture associated with adverse outcome in peritoneal dialysis patients. High CCI score and hypoalbuminaemia significantly increase risk of fracture.

Vitamin K status in chronic kidney disease

The purpose of this review is to summarize the research to date on vitamin K status in chronic kidney disease (CKD). This review includes a summary of the data available on vitamin K status in patients across the spectrum of CKD as well as the link between vitamin K deficiency in CKD and bone dynamics, including mineralization and demineralization, as well as ectopic mineralization. It also describes two current clinical trials that are underway evaluating vitamin K treatment in CKD patients. These data may inform future clinical practice in this population.

Persistent hyperparathyroidism is a major risk factor for fractures in the five years after kidney transplantation

The risk of fractures after kidney transplantation is high. Hyperparathyroidism frequently persists after successful kidney transplantation and contributes to bone loss, but its impact on fracture has not been demonstrated. This longitudinal study was designed to evaluate hyperparathyroidism and its associations with mineral disorders and fractures in the 5 posttransplant years. We retrospectively analyzed 143 consecutive patients who underwent kidney transplantation between August 2004 and April 2006. The biochemical parameters were determined at transplantation and at 3, 12 and 60 months posttransplantation, and fractures were recorded. The median intact parathyroid hormone (PTH) level was 334 ng/L (interquartile 151-642) at the time of transplantation and 123 ng/L (interquartile 75-224) at 3 months. Thirty fractures occurred in 22 patients. The receiver operating characteristic (ROC) curve analysis for PTH at 3 months (area under the ROC curve = 0.711, p = 0.002) showed that a good threshold for predicting fractures was 130 ng/L (sensitivity = 81%, specificity = 57%). In a multivariable analysis, independent risk factors for fracture were PTH >130 ng/L at 3 months (adjusted hazard ratio [AHR] = 7.5, 95% CI 2.18-25.50), and pretransplant osteopenia (AHR = 2.7, 95% CI 1.07-7.26). In summary, this study demonstrates for the first time that persistent hyperparathyroidism is an independent risk factor for fractures after kidney transplantation.

Cost per responder analysis in patients with secondary hyperparathyroidism on dialysis treated with cinacalcet

BACKGROUND

Growing financial pressure on US dialysis providers requires economic efficiency considerations. The objective of this study was to examine short-term economic efficiencies of a cinacalcet-based treatment approach for secondary hyperparathyroidism.

METHODS

This study retrospectively assessed cost per biochemical response of the OPTIMA trial. OPTIMA was conducted in end-stage renal disease patients to compare biochemical control in patients receiving cinacalcet in addition to vitamin D sterols and phosphate binders vs patients receiving vitamin D sterol and phosphate binders alone. It explored three laboratory measurement response definitions from baseline to week 23: (1) decreases in parathyroid hormone (PTH) ≥30%; (2) PTH ≤ 300 pg/ml; and (3) PTH ≤ 300 pg/mL, calcium <9.5 mg/dL and phosphorus <5.5 mg/dL. Medication use and costs were measured to calculate average costs and incremental cost per responder. Stratification by lower and higher baseline PTH assessed cost per response by disease severity.

RESULTS

There were 38-77% more responders with cinacalcet vs control, depending on response definition. Mean (SD) per patient total medication costs were $5423 ($3698) for cinacalcet and $2633 ($2334) for control, leading to a mean difference of $2790 over 23 weeks. When response was defined as a decrease in PTH ≥ 30% from baseline, the average cost per responder was $11,266 for control vs $7027 for cinacalcet. The incremental cost per incremental responder ranged from $5186-$9168. Across all response measures, cost per responder was lower in patients with lower baseline PTH.

CONCLUSIONS

Representing a more efficient allocation of economic resources over the short-term, cinacalcet-based treatment algorithm led to a lower cost per biochemical response, particularly in patients with lower disease severity, vs vitamin D sterols and phosphate binders alone. These findings should be interpreted alongside the study limitation of converting international trial-based medication utilization into US costs.

High prevalence of vertebral fractures assessed by quantitative morphometry in hemodialysis patients, strongly associated with vascular calcifications

Few studies have provided information on the prevalence of vertebral fractures (VFs) and their risk factors in hemodialysis patients. A multicenter, cross-sectional, observational study was carried out to assess the prevalence of VFs and vascular calcifications (VCs) in 387 hemodialysis patients (mean age 64.2 ± 14.1 years, 63 % males) and in a control group of 51 osteoporotic subjects. Biochemical tests included 25(OH) vitamin D, bone Gla protein (total and undercarboxylated), and total matrix Gla protein. Vertebral quantitative morphometry was carried out centrally for the detection of VF, defined as reduction by ≥20 % of one of the vertebral body dimensions. In the same radiograph, aortic and iliac VC scores were calculated. Prevalence of VF was 55.3 % in hemodialysis patients and 51.0 % in the control group. Multivariate analysis disclosed that male gender (59.8 vs. 47.6 %, p = 0.02; OR = 1.78, 95 % CI 1.15-2.75) and age (mean ± SD 66.7 ± 13.1 vs. 61.0 ± 14.7 years, p < 0.001; OR = 1.03, 95 % CI 1.01-1.05) were significantly associated with VF. The prevalence of aortic VC was significantly higher in hemodialysis patients than in controls (80.6 vs. 68.4 %, p = 0.001). The factors with the strongest association with VC, apart from atrial fibrillation, were serum 25(OH)vitamin D levels below 29 ng/mL for aortic VC (OR = 1.85, 95 % CI 1.04-3.29) and VF both for aortic (OR = 1.77, 95 % CI 1.00-3.14) and iliac (OR = 1.96, 95 % CI 1.27-3.04) VC. In conclusion, the prevalence of VF, especially in males, and VC, in both genders, is high in hemodialysis patients. VF is associated with VC. Vitamin D deficiency is also associated with VC. Further longitudinal studies are warranted to investigate fractures in renal patients.

Temporal trends in fracture rates and postdischarge outcomes among hemodialysis patients

Patients with ESRD have a substantially increased risk of bone fractures, but the burden of fractures has not been sufficiently characterized in this population. Here, we analyzed fracture rates and postdischarge outcomes using Medicare data from hemodialysis patients in the United States between 2000 and 2009. We assessed adjusted quarterly fracture rates (inpatient and outpatient) and consequences of postfracture hospitalization for seven categories of fracture location. Pelvis/hip, vertebral, and lower leg fractures were the most prevalent fracture types. Pelvis/hip fractures declined slightly from 29.6 to 20.6 per 1000 patient-years between early 2000 and late 2009, but the incidence rates for all other fracture types remained relatively constant. Median lengths of stay for the primary fracture hospitalization ranged from 5 days (interquartile range [IQR], 3-9 days) for forearm/wrist fractures to 8 days (IQR, 5-12 days) for femur fractures. The proportion of patients discharged from the primary hospitalization to a skilled-nursing facility ranged from 28% (ribs/sternum) to 47% (pelvis/hip). A negative binomial regression model suggested that patients had an adjusted mean of 3.8-5.2 additional hospitalizations during the year after discharge from the index hospitalization, varying by fracture type, comprising a mean of 33-52 inpatient days. Case-mix-adjusted mortality rates after discharge ranged from 0.43 to 0.91 per patient-year and were highest for vertebral, pelvis/hip, and femur fractures. In conclusion, fractures in the dialysis population are common and are associated with a substantially increased risk for death and hospitalization.

Temporal trends in fracture rates and postdischarge outcomes among hemodialysis patients

Patients with ESRD have a substantially increased risk of bone fractures, but the burden of fractures has not been sufficiently characterized in this population. Here, we analyzed fracture rates and postdischarge outcomes using Medicare data from hemodialysis patients in the United States between 2000 and 2009. We assessed adjusted quarterly fracture rates (inpatient and outpatient) and consequences of postfracture hospitalization for seven categories of fracture location. Pelvis/hip, vertebral, and lower leg fractures were the most prevalent fracture types. Pelvis/hip fractures declined slightly from 29.6 to 20.6 per 1000 patient-years between early 2000 and late 2009, but the incidence rates for all other fracture types remained relatively constant. Median lengths of stay for the primary fracture hospitalization ranged from 5 days (interquartile range [IQR], 3-9 days) for forearm/wrist fractures to 8 days (IQR, 5-12 days) for femur fractures. The proportion of patients discharged from the primary hospitalization to a skilled-nursing facility ranged from 28% (ribs/sternum) to 47% (pelvis/hip). A negative binomial regression model suggested that patients had an adjusted mean of 3.8-5.2 additional hospitalizations during the year after discharge from the index hospitalization, varying by fracture type, comprising a mean of 33-52 inpatient days. Case-mix-adjusted mortality rates after discharge ranged from 0.43 to 0.91 per patient-year and were highest for vertebral, pelvis/hip, and femur fractures. In conclusion, fractures in the dialysis population are common and are associated with a substantially increased risk for death and hospitalization.