Lower risk for cardiovascular mortality in oral 1alpha-hydroxy vitamin D3 users in a haemodialysis population.

BACKGROUND: Renal failure results in deficiency of active vitamin D3 that has diverse effects on metabolism and organ functions. Treatment with active forms of vitamin D(3) ameliorates abnormalities in bone and mineral metabolism, cardiac function, immune response and others. We hypothesized that treatment with vitamin D(3) may be beneficial for survival in patients with end-stage renal disease (ESRD). METHODS: We compared the risk of death between regular users (n = 162) and non-users (n = 80) of oral 1alpha-hydroxyvitamin D3 (alfacalcidol) in a cohort of ESRD patients undergoing haemodialysis for a follow-up of 61 +/- 23 months. The daily dose of alfacalcidol ranged from 0.25 to 1.5 microg, with a median of 0.5 microg. RESULTS: The alfacalcidol users showed a lower risk of death from cardiovascular disease than the non-users in a univariate Cox model [hazards ratio (HR) 0.287, 95% confidence interval (CI) 0.127-0.649, P = 0.003], whereas the risk for death from non-cardiovascular disease was not different between the two groups. Stepwise multivariate Cox analysis showed that cardiovascular mortality was significantly associated with age, presence of diabetes mellitus and treatment with alfacalcidol (HR 0.377, 95% CI 0.246-0.578, P = 0.022). CONCLUSIONS: These results indicate that use of oral alfacalcidol was associated with reduced risk for cardiovascular death in this cohort of ESRD patients. The result of this observational study warrants further randomized controlled trials with 1alpha-hydroxy vitamin D3 to confirm the possibility that such medication improves survival of ESRD patients.     

Calcium phosphate metabolism and cardiovascular disease in patients with chronic kidney disease

Traditional risk factors for atherosclerotic cardiovascular disease (CVD) do not adequately explain the considerable increase in cardiovascular mortality observed among patients with end-stage renal disease (ESRD): these patients experience mortality rates 10-100 times those without ESRD. Disorders of mineral metabolism, including abnormalities in calcium, phosphorus, parathyroid hormone, and vitamin D, represent cardiovascular risk factors unique to the ESRD population. These disturbances manifest clinically through the promotion of extraskeletal calcification and disorders of bone remodeling, two processes which appear to share a common pathogenesis. This article presents evidence describing the impact of calcification-induced arterial stiffness on cardiovascular outcomes of patients with ESRD, along with data relating altered mineral metabolism to all-cause and cardiovascular mortality. Specific management recommendations include 1) early intervention to prevent the development of overt secondary hyperparathyroidism, 2) a more judicious strategy for vitamin D therapy, and 3) a thoughtful approach to the use of calcium-containing phosphate binders, taking into account the underlying bone remodeling disorder and the presence or absence of extraskeletal calcium accumulation.     

Opinion: Which of the K/DOQI Guidelines for Bone Disease in Dialysis Patients Should be Changed?

The K‐DOQI guidelines for bone metabolism in chronic kidney disease recommend measuring 25(OH) vitamin D levels and correcting deficiencies in stages 3 and 4 but not in ESRD. Most nephrologists are not concerned with 25(OH) vitamin D deficiency, despite evidence in hemodialysis patients that deficient vitamin D status [as measured by 25(OH) vitamin D levels] plays a role in bone disease. PD patients are often deficient in 25(OH) vitamin D in part because of peritoneal effluent losses, and correction may decrease muscle and bone complaints. Data from other populations are indicative of the importance of vitamin D in cancer surveillance and immune functioning. Randomized controlled trials of correction of 25(OH) vitamin D deficiency in both hemodialysis and peritoneal dialysis patients are urgently needed. vitamin D).     

Vitamin D and its analogues: do they protect against cardiovascular disease in patients with kidney disease?

BACKGROUND: Patients with chronic kidney disease (CKD) are at high risk for cardiovascular disease, and despite recent advances in hypertension control, anemia management, and dialysis adequacy, mortality remains high. Improved understanding of nontraditional risk factors, including those present at early phases in CKD, may lead to novel therapeutic strategies. CKD has been demonstrated to be an independent risk factor for cardiovascular disease in the general population, but data are lacking as to the associated potential abnormalities that occur in association with reduced glomerular filtration rate (GFR), which may contribute to this increased risk. Data are accumulating regarding the role of abnormalities of calcium, phosphorus, vitamin D, and parathyroid hormone (PTH) in cardiovascular disease. Vitamin D deficiency is present even in the early stages of CKD. Vitamin D plays a central role in calcium-phosphorus homeostasis, regulation of PTH, and formation and maintenance of bone. However, until recently, vitamin D has not been considered to have a biologic role in CKD beyond mineral regulation, or has been considered as a negative factor contributing to soft tissue and cardiovascular calcification. In light of recent observational studies showing an association of vitamin D therapy and survival benefit in hemodialysis patients, the effects of vitamin D on cardiovascular system have become a heavily debated issue. METHODS: A Medline search was performed to identify relevant literature describing the role of vitamin D in the pathogenesis of cardiovascular disease. Both the experimental and clinical literatures in English were reviewed. RESULTS: The accumulating published data demonstrate both associative relationships and mechanisms for biologic plausibility. The following three potential mechanisms may be important for the protective effects of vitamin D against cardiovascular disease mortality: vitamin D can inhibit various aspects of inflammation, which have been established as a key pathogenic mechanism in atherosclerosis; vitamin D exerts an antiproliferative effect on myocardial cell hypertrophy and proliferation, which underlies the pathogenesis of congestive heart failure; and vitamin D acts as a negative endocrine regulator for the renin-angiotensin system, which itself plays an important independent role in hypertension and cardiovascular health. CONCLUSION: Vitamin D deficiency might be an underestimated nonclassical risk factor for cardiovascular disease in CKD. Based on a review of the evidence, from both basic science and clinical studies, this article supports the possible protective role of vitamin D beyond its effect on mineral metabolism, and suggests the need for ongoing evaluation of the role of vitamin D in cardiovascular health in the CKD population.     

Cardiac consequences of hypertension in hemodialysis patients

Hypertension in end-stage renal disease (ESRD) is an important risk factor for left ventricular hypertrophy (LVH), cardiac failure, coronary artery disease (CAD), and arrhythmia. LVH is generally considered an integrator of the long-term effects of hypertension and other cardiovascular (CV) risk factors and represents the strongest predictor of adverse CV outcomes in ESRD patients. The risk of heart failure is higher in patients with a history of hypertensive renal disease than in those with other diagnoses. Both coronary heart disease (CHD) and LVH predict congestive heart failure, which is often the ultimate cause of death in patients with cardiac ischemia or LVH. A history of long-standing hypertension is associated with ischemic heart disease both in cross-sectional and prospective studies in ESRD. Atrial fibrillation and ventricular arrhythmias are highly prevalent in dialysis patients and are implicated in mortality and sudden death in this population. Despite the lack of evidence from randomized controlled trials, it appears reasonable that interventions aimed at curbing the high CV mortality of ESRD should be targeted to both hypertension and LVH.     

Bone mineral density in patients on maintenance dialysis

Disorders of bone and mineral metabolism affect almost all patients with advanced chronic kidney disease (CKD). High prevalence of decreased bone mineral density has been reported in this population; however, the role and diagnostic utility of bone density measurements are not well established. The incidence of bone fractures is high in patients with ESRD, but the association between fractures and bone density is not obvious. A recent meta-analysis suggested that decreased density at the radius might be associated with higher overall fracture risk. Changes in bone mineral density reflect several underlying pathological processes, such as vitamin D deficiency, estrogen deficiency and changes in bone turnover. The response of bone to these factors and processes is not uniform: it can vary in different compartments of the same bone or in different bones of the skeleton. Therefore, it is important to differentiate between the various types of bone. This may be possible by proper selection of the measurement site or using methods such as quantitative bone computed tomography. Previous studies used different methods and measured bone mineral density at diverse sites of the skeleton, which makes the comparison of their results very difficult. The association between changes in bone mineral metabolism and cardiovascular mortality is well known in ESRD patients. Studies also suggest that low bone density itself might be an indicator for high risk of cardiovascular events and poor overall outcome in this population. Some of the risk factors of low bone mineral density, such as vitamin D or estrogen deficiency, are potentially modifiable. Further studies are needed to elucidate if interventions modifying these risk factors will have an impact on clinical outcomes. In this review, we discuss the options for and problems of assessment of bone density and summarize the literature about factors associated with low bone density and its link to clinical outcomes in patients on maintenance dialysis.     

Cardiovascular events in chronic dialysis patients: emphasizing the importance of vascular disease prevention

Cardiovascular disease is the leading cause of death in both chronic kidney disease and peritoneal dialysis/hemodialysis patients. Vascular disease prevention in these patients is therefore important to reduce the incidence of cardiovascular events and the high morbidity and mortality. This Editorial discusses the traditional, (1) smoking, (2) dyslipidemia, (3) body mass index, (4) glycemic control and (5) blood pressure, and non-traditional, (1) anemia, (2) vitamin D/hyperparathyroidism, (3) calcium/phosphorus metabolism and (4) magnesium, risk factors in renal patients. Current evidence does not support routine statin use and antiplatelet medication to dialysis patients. Patient compliance and adherence to proposed measures could be essential to reduce cardiovascular events and mortality rates in this high-risk population.     

Arterial and cardiac disease in young adults with childhood-onset end-stage renal disease-impact of calcium and vitamin D therapy.

BACKGROUND: Studies in patients with childhood-onset end-stage renal disease (ESRD) provide a diagnostic window to the evolution of cardiovascular disease (CVD) in this population. Hyperphosphataemia and renal osteodystrophy are particularly difficult to treat in paediatric patients, but there is only limited information regarding the effect of calcium-containing phosphate binders and vitamin D preparations on the development of CVD in the young. METHODS: We studied 40 adult patients (mean age 23.6 years) who developed ESRD at the age of 11.5 +/- 4 years and 40 matched healthy control subjects. Nine patients were on dialysis and 31 had a functioning kidney transplant. Measurements included intima-media thickness (IMT) of the common carotid artery, electron beam computed tomography (EBCT) for the detection of coronary artery calcifications (CAC), echocardiography and post-ischaemic arterial blood flow by venous occlusion plethysmography. Patient characteristics, atherosclerotic risk factors and a complete account of prescribed medications were analysed for correlations with arterial and cardiac changes. RESULTS: The IMT was not significantly different in patients and controls; four patients (10%) had coronary calcifications on EBCT. Twenty-five patients (62.5%) had left ventricular hypertrophy. Patients had a 40% reduction of post-ischaemic arterial flow. Morphological alterations of the heart and arteries were significantly correlated with the duration of ESRD and dialysis time, and with the cumulative intake of calcium-containing phosphate binders and active vitamin D preparations. Functional changes (vascular reactivity) were correlated with duration of ESRD and non-traditional risk factors. CONCLUSIONS: Young adults with ESRD since childhood have systemic CVD characterized by a decrease in arterial elasticity, the occurrence of CAC and changes in left ventricular morphology. Treatment with calcium-containing phosphate binders and active vitamin D preparations is independently associated in a dose-dependent manner with surrogate markers for CVD.     

Detection and quantification of cardiovascular calcifications with electron beam tomography to estimate risk in hemodialysis patients

Cardiovascular disease is the leading cause of death in dialysis patients, accounting for nearly half of all deaths among end-stage renal disease (ESRD) patients. Even young dialysis patients are at risk. Cardiovascular disease in chronic renal failure patients has been associated with elevated serum phosphorus levels and elevated calcium-phosphorus (Ca x P) product, and mismanagement of calcium and phosphorus metabolism has been implicated as a major factor in the development of soft tissue calcification and cardiovascular disease. ESRD patients frequently face hyperphosphatemia as well as excess calcium load, which elevate the Ca x P product, thereby contributing to the development of calcific complications. Electron beam computed tomography (EBCT) can be used to detect different calcification stages in a variety of tissues, and is a sensitive tool for detecting calcified coronary artery plaques as well as cardiac and valvular calcifications. Hemodialysis patients have high calcium scores on EBCT imaging, and these are associated with elevations in Ca x P product. In a recent study, patients with calcification were found to have had twice the daily calcium intake from calcium-based phosphate binders than patients without calcification. Strategies to reduce cardiac risk in hemodialysis patients include use of a dialysate low in calcium, use of vitamin D analogs that are less calcemic, and use of calcium-free phosphate binders. EBCT can be a useful adjunct to these therapies, since it permits sensitive and quantitative initial assessment, as well as ongoing monitoring of disease progression.     

Cardiovascular disease in patients with end-stage renal disease on hemodialysis in a developing country

Cardiovascular disease is the main cause of death among patients with end-stage renal disease (ESRD). The present study was undertaken to identify the main cardiovascular diseases and their risk factors in 160 patients with ESRD on hemodialysis (HD) in Brazil. Their mean age was 47 ± 39 years. The main risk factors for cardiovascular diseases were arterial hypertension (89.4%), dyslipidemia (78.3%), low high-density lipoprotein levels (84.2%) and low physical activity (64.1%). Family history of coronary insufficiency and high low-density lipoprotein levels were significantly associated with coronary artery disease (P = 0.005 and P = 0.029, respectively). Sedentary life style, diabetes mellitus, secondary hyperparathyroidism and hyperglycemia also showed a significant association with the underlying vascular disease (P = 0.017, P = 0.039, P = 0.037 and P = 0.030, respectively). Hypercalcemia, hypertension and black race were factors significantly associated with left ventricular systolic dysfunction (P = 0.01, P = 0.0013 and P = 0.024, respectively). Our study shows that the most prevalent cardiovascular diseases in patients with ESRD were left ventricular hypertrophy, atherosclerotic disease, valvular disease and coronary artery disease. Hypertension and dyslipidemia were the common risk factors associated with cardiovascular diseases. The present study was undertaken to identify the main cardiovascular diseases and their risk factors in 160 patients with ESRD on HD in a single center in Brazil.     

Roles of metabolic and endocrinological alterations in atherosclerosis and cardiovascular disease in renal failure: another form of metabolic syndrome

Patients with end-stage renal disease have markedly increased risk for death from cardiovascular disease. Renal failure is associated with multiple metabolic and endocrinologic abnormalities, and these alterations are involved in advanced atherosclerosis and high cardiovascular risk. Increased insulin resistance index by homeostasis model assessment (HOMA-IR), a simple index of insulin resistance, was an independent predictor of cardiovascular mortality in nondiabetic patients on maintenance hemodialysis. Renal failure impairs lipoprotein metabolism leading to the atherogenic lipoprotein profile characterized by increased triglyceride-rich remnant lipoproteins such as intermediate-density lipoprotein, an independent factor of increased aortic stiffness. Non-high-density lipoprotein cholesterol, the sum of cholesterol of intermediate-density lipoprotein and other apoB-containing lipoproteins, is an independent factor associated with increased arterial thickness and a predictor of cardiovascular death in hemodialysis patients. The risk for cardiovascular death in hemodialysis patients is associated closely with hypertension and malnutrition, but not with obesity. The constellation of insulin resistance, dyslipidemia, hypertension, and malnutrition in renal failure suggests the presence of another type of metabolic syndrome promoting cardiovascular disease. In addition, vitamin D deficiency and abnormalities in calcium, phosphate, and parathyroid hormone levels increase the death risk from cardiovascular disease in renal failure. It is expected that treatment of these metabolic and endocrinologic alterations would improve the survival of patients with renal failure.     

Cardiovascular complications in pediatric end-stage renal disease

Mortality from end-stage renal disease (ESRD) is often due to cardiac causes. Although cardiovascular complications of ESRD have long been recognized, only recently has the presence of traditional cardiovascular risk factors been associated with late cardiovascular complications. This review presents a history of cardiac involvement in ESRD, the pathophysiology of accelerated atherosclerosis and left ventricular hypertrophy, and a summary of the literature on cardiovascular risk assessment in children. Techniques for non-invasive assessment of cardiac end-organ injury are also discussed. Recommendations for monitoring of risk factors and treatment in the pediatric ESRD population are presented.     

What would we like to know, and what do we not know about fibroblast growth factor 23?

Recently, a new view of the molecular mechanisms of phosphate homeostasis and secondary hyperparathyroidism pathogenesis has been proposed, with fibroblast growth factor 23 (FGF23) as a novel player in the field. FGF23 is a 32-kDa peptide secreted by the osteocytes involved in the control of phosphate homeostasis and calcitriol metabolism. FG23 is constantly elevated in advanced chronic kidney disease (CKD) patients, and recent studies have indicated that high levels are associated with the progression of CKD and with higher mortality rates in hemodialysis patients. In the CKD population, high serum FGF23 concentration seems to predict the occurrence of refractory secondary hyperparathyroidism, by inducing a resistance of the parathyroid glands to FGF23, and to be associated with higher mortality risk in incident hemodialysis patients. FGF23 appears to be involved in bone metabolism, but a direct effect of FGF23 on bone disease in humans has not yet been elucidated, even if the inhibitory effect of FGF23 on osteoblast activity that has been described in animal models and hereditary rickets is clearly connected with FGF23 deficiency. The association between altered levels of FGF23 and bone disease could be mainly due to the dysregulation of phosphate-handling and vitamin D metabolism, more than to a direct antiosteoblastic activity of FGF23. FGF23 appears to be a new biomarker, which is independently associated with several cardiovascular risk factors such as endothelial dysfunction, arterial stiffness and left ventricular hypertrophy, in the general population as well as in early CKD. All of the above have been related to cardiovascular and general mortality. Until now, we know that elevated FGF23 levels in dialysis patient are associated with several cardiovascular adverse outcomes mentioned above; the clinical relevance of high FGF23 values in dialysis patients remains unclear, because therapy with active vitamin D sterols further increases FGF23 levels but, on the other hand, is associated with a survival benefit in dialysis patients. This paradox highlights the need for future prospective randomized trials to evaluate the correlation between vitamin D therapy and FGF23 levels in dialysis patients. In the clinical setting, there are still different FGF23 actions that need investigation. In this sense, increased knowledge of mineral metabolism disorder alterations in CKD may be used to improve diagnostics and select future treatments.     

Vitamin D status and mortality risk in patients with chronic kidney disease

Several studies have shown that mineral metabolism disorders play a major role in determining a higher mortality rate for end-stage renal disease patients. Vitamin D deficiency is associated with cardiovascular events in hemodialysis patients. Recently, an association between vitamin D insufficiency and cardiovascular or renal events has been found, in patients with chronic renal failure who have not started renal replacement therapy yet. To further investigate this issue, we evaluated the relationship between blood levels of 25-hydroxyvitamin D (25-OH D; > or ≤30 ng/mL) and mortality or dialysis dependence in 104 incident consecutive patients with chronic kidney disease stages 3-5, over a period of 17 months, with a follow-up of 2 years in a cross-sectional analysis. The correlation between different levels of vitamin D and the risk of events has been estimated by using a probit model. Explanatory variables employed concerned age, sex, blood pressure, BMI, and number of co-morbid factors. The average 25-OH D concentration was of 30.13 ng/mL. During follow-up (>16 months), each patient experienced an average of 1.28 events. Vitamin D has been shown to reduce the probability of cardiovascular or renal events. Vitamin D intake for more than 12 months can reduce the probability of such events by 11.42%. Each co-morbid factor, instead, raises the probability of events by 29%. Lower probabilities of experiencing an adverse cardiovascular event might depend on higher levels of vitamin D. The influence of 25-OH D on survival in chronic kidney disease patients may be related to unrecognized factors that need to be further explored.     

Vitamin D Status and Mortality Risk in Patients with Chronic Kidney Disease

Several studies have shown that mineral metabolism disorders play a major role in determining a higher mortality rate for end-stage renal disease patients. Vitamin D deficiency is associated with cardiovascular events in hemodialysis patients. Recently, an association between vitamin D insufficiency and cardiovascular or renal events has been found, in patients with chronic renal failure who have not started renal replacement therapy yet. To further investigate this issue, we evaluated the relationship between blood levels of 25-hydroxyvitamin D (25-OH D; > or ≤30 ng/mL) and mortality or dialysis dependence in 104 incident consecutive patients with chronic kidney disease stages 3–5, over a period of 17 months, with a follow-up of 2 years in a cross-sectional analysis. The correlation between different levels of vitamin D and the risk of events has been estimated by using a probit model. Explanatory variables employed concerned age, sex, blood pressure, BMI, and number of co-morbid factors. The average 25-OH D concentration was of 30.13 ng/mL. During follow-up (>16 months), each patient experienced an average of 1.28 events. Vitamin D has been shown to reduce the probability of cardiovascular or renal events. Vitamin D intake for more than 12 months can reduce the probability of such events by 11.42%. Each co-morbid factor, instead, raises the probability of events by 29%. Lower probabilities of experiencing an adverse cardiovascular event might depend on higher levels of vitamin D. The influence of 25-OH D on survival in chronic kidney disease patients may be related to unrecognized factors that need to be further explored.     

Use of cardiac biomarkers in end-stage renal disease

Mortality among patients with ESRD remains high because of an excessive cardiovascular risk related to a very high incidence of cardiac hypertrophy, cardiomyopathy, heart failure, and coronary artery disease. Identifying serum biomarkers that are useful in profiling cardiovascular risk and enabling stratification of early mortality and cardiovascular risk is an important goal in the treatment of these patients. This review examines current evidence pertaining to the role and utility of two emerging cardiac biomarkers, B-type natriuretic peptide and cardiac troponin T, in patients with ESRD. Together, these data demonstrate how these two cardiac biomarkers may play an adjunctive role to echocardiography in assessing cardiovascular risk and how they may aid in the clinical treatment of these patients.     

Traditional and emerging cardiovascular and renal risk factors: an epidemiologic perspective

Patients with chronic kidney disease (CKD) represent an important segment of the population (7-10%) and, mostly because of the high risk of cardiovascular complications associated with renal insufficiency, detection and treatment of CKD is now a public health priority. Traditional risk factors can incite renal dysfunction and cardiovascular damage as well. As renal function deteriorates, non-traditional risk factors play an increasing role both in glomerular filtration rate (GFR) loss and cardiovascular damage. Secondary analyses of controlled clinical trials suggest that inflammation may be a modifiable risk factor both for cardiac ischemia and renal disease progression in patients with or at risk of coronary heart disease. Homocysteine predicts renal function loss in the general population and cardiovascular events in end-stage renal disease (ESRD), but evidence that this sulfur amino acid is directly implicated in the progression of renal disease and in the high cardiovascular mortality of uremic patients is still lacking. High sympathetic activity and raised plasma concentration of asymmetric dimethylarginine (ADMA) have been associated to reduced GFR in patients with CKD and to cardiovascular complications in those with ESRD but again we still lack clinical trials targeting these risk factors. Presently, the clinical management of CKD patients remains largely unsatisfactory because only a minority of these attain the treatment goals recommended by current guidelines. Thus, in addition to research into new and established risk factors, it is important that nephrologists make the best use of knowledge already available to optimize the follow-up of these patients.     

The impact of short daily and nocturnal hemodialysis on quality of life, cardiovascular risk and survival

End-stage renal disease (ESRD) is a significant global health problem that places a considerable burden on health care resources. The leading cause of death in ESRD patients is cardiovascular disease, which is often preceded by changes in cardiac geometry, including left ventricular hypertrophy (LVH). Treatments that result in regression of LVH have been shown to lead to better clinical outcomes. Globally, most ESRD patients receive conventional hemodialysis (CHD) 3 times per week, but mortality rates remain high and quality of life (QoL) is poor. Increasing the frequency of HD to 5 or 6 times per week, either as short daily HD (SDHD) or nocturnal HD (NHD), can improve QoL, reduce cardiovascular risk and prolong survival, compared with CHD. Improvements in these end points are likely driven by enhancements in fluid management, blood pressure control, mineral metabolism and left ventricular mass regression. From a practical standpoint, SDHD and NHD are best delivered at home. Barriers to adoption of home HD are chiefly modifiable, and may include lack of a care partner or family support, fear of cannulation and access disconnection, and uncertainty in one's ability to learn the procedures required to perform self-HD. On a positive note, substantial progress has been made to overcome these and other perceived barriers.     

Cardiovascular calcification in patients with end-stage renal disease: a century-old phenomenon

The mortality risk from cardiovascular disease is increased in patients with end-stage renal disease (ESRD). This is due to both traditional and dialysis-specific factors. Recently, a number of the dialysis-specific risk factors have been implicated in the pathogenesis of cardiovascular calcification. These include: hyperphosphatemia, high calcium-phosphate (Ca x P) product, elevated parathyroid hormone levels, duration of dialysis, and treatment with calcium-containing phosphate binders and vitamin D analogs. The recent availability of electron beam computed tomography (EBCT) has triggered increased awareness of the occurrence of cardiovascular calcification in ESRD patients. Given the development of transient hypercalcemia with calcium-containing binders, a link between calcium load from use of calcium-containing phosphate binders and development coronary calcification has been proposed. However, a causal relationship between use of these agents and cardiovascular calcification has not been established. Moreover, this phenomenon had been recognized over a century ago, long before these phosphate binders became available. Although its pathogenesis is likely to be multifactorial, available data strongly implicate elevated serum phosphorus as the primary culprit. Furthermore, the risk of calcification may be aggravated by vitamin D therapy, particularly in patients with severe secondary hyperparathyroidism. Therefore, achieving vigorous control of serum phosphorus, Ca x P product and parathyroid hormone level might decrease cardiovascular calcification and improve survival of patients on maintenance hemodialysis. Since calcium acetate is the most cost-effective phosphate binder available, we recommend that it should remain the first line treatment of hyperphosphatemia in patients with ESRD.     

Fibroblast growth factor 23: associations with cardiovascular disease and mortality in chronic kidney disease

Fibroblast growth factor-23 (FGF-23) has emerged as an important hormone involved in phosphorus and vitamin D homeostasis. Chronic kidney disease (CKD) is the most common clinical condition in which FGF-23 levels are persistently and markedly elevated. Abnormal phosphate homeostasis and high circulating levels of FGF-23 are early complications of CKD. Although increases in FGF-23 levels may help maintain serum phosphate levels in the normal range in CKD, the long-term effects of its sustained elevated levels are unclear. Patients with CKD have high risks of developing end-stage renal disease (ESRD), cardiovascular disease, and premature death. Recent prospective studies in populations with predialysis CKD, ESRD on hemodialysis, and kidney transplant recipients demonstrate that elevated FGF-23 levels are independently associated with cardiovascular events and mortality. It was originally thought that FGF-23 was only a biomarker of disturbed phosphate balance; however, recent studies have shown that FGF-23 can have a direct effect on the heart, inducing left ventricular hypertrophy. This suggests that elevated FGF-23 levels may be a novel mechanism that explains the poor cardiovascular outcomes in CKD patients. Interventional studies are required in order to clarify the relation of causality between FGF-23 and cardiovascular mortality in this population.