AKI Associated with Acute Pancreatitis.

Acute pancreatitis is a common disorder of the pancreas. It is the most frequent gastrointestinal cause for hospitalization and one of the leading causes of in-hospital deaths. Its severity ranges from mild self-limited disease to severe acute necrotizing pancreatitis characterized by systemic complications and multiorgan failure. Severe acute pancreatitis develops in about 20% of patients with acute pancreatitis and may be associated with multiorgan failure (respiratory, cardiovascular, and kidney). AKI is a frequent complication of severe acute pancreatitis and develops late in the course of the disease, usually after the failure of other organs. It carries a very poor prognosis, particularly if kidney replacement therapy is required, with mortality rates exceeding 75%. The exact pathophysiology of AKI in acute pancreatitis remains unclear but appears to result from initial volume depletion followed by complex vascular and humoral factors. Here, we provide an overview of the epidemiology, pathogenesis, causes, and management of AKI in patients with severe acute pancreatitis.

Vascular access mortality and hospitalization among hemodialysis patients in Palestine.

Vascular access complications are common in patients with end-stage kidney disease who are receiving maintenance hemodialysis (HD) and are responsible for an enormous burden of morbidity and mortality among these patients. Differences in the all-cause mortality rate and hospitalization between dialysis catheter use and arteriovenous (AV) vascular access use have not been documented in our HD population. We performed a 12-month prospective analysis of our HD patients from four dialysis centers. We examined all-cause mortality and hospitalization in patients being dialyzed through HD catheters as compared to patients with AV access. A total of 382 patients were included in the study. Of these, 88 had catheters and 294 had AV accesses. Seventy-eight percent of all catheters were temporary nontunneled dialysis catheters. The overall gross mortality rate for all patients was 14.7%. Gross mortality was significantly lower among AV access group compared to the catheter group (12.2% vs. 22.7%; P = 0.015). Catheter use was associated with a relative hazard ratio (HR) of 1.85 [95% confidence interval (CI), 1.13-3.03] compared with use of an AV access. Hospitalization rate was also significantly lower among patients with AV access versus patients who used catheters (27.6% vs. 46.6%; P = 0.006). The risk of hospitalization was also higher in catheter users with a relative HR of 1.69 (95% CI, 1.26-2.26) compared with use of AV access. In our HD population where the majority of catheters were temporary nontunneled catheters, dialysis catheter use was associated with higher mortality and increased hospitalization rates compared with AV access. These results emphasize the urgent need to minimize the use of dialysis catheters, in order to reduce mortality and hospitalization rates among HD patients.

Dyslipidemia in Dialysis Patients.

Dyslipidemia is a well-established traditional risk factor for cardiovascular events in the general population, particularly those with preexisting cardiovascular disease (CVD). In this population, reductions in total and low density lipoprotein cholesterol (LDL-C) levels are effective in reducing coronary artery events and mortality. Dyslipidemia is more common in patients with chronic kidney disease (CKD) and is believed to contribute to the high prevalence of CVD in these patients. To date, the treatment of dyslipidemia in patients with CKD followed the guidelines recommended by the US National Cholesterol Education Program Adult Treatment Panel III (ATP III) for the treatment of lipid abnormalities. These guidelines recommend that initiation of lipid-lowering therapy be based on LDL-C level and the projected 10-year risk for coronary artery disease (CAD). However, we now recognize that the relationship between serum cholesterol and CVD is more complex in patients with CKD, particularly those receiving maintenance hemodialysis. This has been demonstrated by the failure of three large randomized clinical trials to show a beneficial effect of lipid-lowering therapy in reducing mortality in dialysis patients despite significant reduction in LDL-C levels. These results have caused uncertainty among nephrologists about how best to manage dyslipidemia in their patients. In this review, the role of dyslipidemia as a risk factor for atherosclerosis in ESRD patients and the results of the 3 clinical trials and other studies, including their limitations will be discussed, and a schema for treating dyslipidemia in dialysis patients will be proposed.

Treatment of vitamin D deficiency/insufficiency with ergocalciferol is associated with reduced vascular access dysfunction in chronic hemodialysis patients.

Vitamin D deficiency or insufficiency is highly prevalent among patients with chronic kidney disease (CKD). This study aims to determine the relationship between vitamin D and frequency of vascular access dysfunction (VAD) in hemodialysis (HD) patients. We reviewed medical records of all HD patients who had serum 25-hydroxyvitamin D (25OHD) levels at 4 outpatient dialysis facilities between January 2011 and January 2012. Patients were included if they were ≥18 years of age, had been on maintenance dialysis for ≥3 months, and had native arteriovenous fistula or synthetic polytetrafluoroethylene grafts for dialysis access. Patients with catheters were excluded. 25-Hydroxyvitamin D levels <30 ng/mL were documented in 183 patients (86%). Median and interquartile range [Q1, Q3] of 25OHD level was 16 [11, 25] ng/mL. Among 213 dialysis patients, 102 had VAD. Median 25OHD level was significantly lower in patients who had VAD than in those without VAD (14.5 [10, 22] vs. 19 [12, 27.5] ng/mL; P = 0.003). There was significant association between VAD and the lowest quartile relative to the highest quartile of 25OHD level. A 25OHD level <12 ng/mL was associated with more than doubling of risk for VAD (OR 2.56; 95% CI [1.05-6.23], P < 0.05). Of 213 patients, 140 were treated with ergocalciferol and 73 were not treated. Treatment was associated with significant reduction in VAD (OR = 0.36; 95% CI [0.19-0.68], P = 0.002). Vitamin D deficiency or insufficiency is an independent risk factor for VAD in HD patients; its treatment with ergocalciferol is associated with decreased VAD.

Effect of sodium zirconium cyclosilicate on potassium lowering for 28 days among outpatients with hyperkalemia: the HARMONIZE randomized clinical trial.

IMPORTANCE: Hyperkalemia is a common electrolyte abnormality that may be difficult to manage because of a lack of effective therapies. Sodium zirconium cyclosilicate is a nonabsorbed cation exchanger that selectively binds potassium in the intestine. OBJECTIVE: To evaluate the efficacy and safety of zirconium cyclosilicate for 28 days in patients with hyperkalemia. DESIGN, SETTING, AND PARTICIPANTS: HARMONIZE was a phase 3, multicenter, randomized, double-blind, placebo-controlled trial evaluating zirconium cyclosilicate in outpatients with hyperkalemia (serum potassium ≥5.1 mEq/L) recruited from 44 sites in the United States, Australia, and South Africa (March-August 2014). INTERVENTIONS: Patients (n = 258) received 10 g of zirconium cyclosilicate 3 times daily in the initial 48-hour open-label phase. Patients (n = 237) achieving normokalemia (3.5-5.0 mEq/L) were then randomized to receive zirconium cyclosilicate, 5 g (n = 45 patients), 10 g (n = 51), or 15 g (n = 56), or placebo (n = 85) daily for 28 days. MAIN OUTCOMES AND MEASURES: The primary end point was mean serum potassium level in each zirconium cyclosilicate group vs placebo during days 8-29 of the randomized phase. RESULTS: In the open-label phase, serum potassium levels declined from 5.6 mEq/L at baseline to 4.5 mEq/L at 48 hours. Median time to normalization was 2.2 hours, with 84% of patients (95% CI, 79%-88%) achieving normokalemia by 24 hours and 98% (95% CI, 96%-99%) by 48 hours. In the randomized phase, serum potassium was significantly lower during days 8-29 with all 3 zirconium cyclosilicate doses vs placebo (4.8 mEq/L [95% CI, 4.6-4.9], 4.5 mEq/L [95% CI, 4.4-4.6], and 4.4 mEq/L [95% CI, 4.3-4.5] for 5 g, 10 g, and 15 g; 5.1 mEq/L [95% CI, 5.0-5.2] for placebo; P < .001 for all comparisons). The proportion of patients with mean potassium <5.1 mEq/L during days 8-29 was significantly higher in all zirconium cyclosilicate groups vs placebo (36/45 [80%], 45/50 [90%], and 51/54 [94%] for the 5-g, 10-g, and 15-g groups, vs 38/82 [46%] with placebo; P < .001 for each dose vs placebo). Adverse events were comparable between zirconium cyclosilicate and placebo, although edema was more common in the 15-g group (edema incidence: 2/85 [2%], 1/45 [2%], 3/51 [6%], and 8/56 [14%] patients in the placebo, 5-g, 10-g, and 15-g groups). Hypokalemia developed in 5/51 (10%) and 6/56 patients (11%) in the 10-g and 15-g zirconium cyclosilicate groups, vs none in the 5-g or placebo groups. CONCLUSIONS AND RELEVANCE: Among outpatients with hyperkalemia, open-label sodium zirconium cyclosilicate reduced serum potassium to normal levels within 48 hours; compared with placebo, all 3 doses of zirconium cyclosilicate resulted in lower potassium levels and a higher proportion of patients with normal potassium levels for up to 28 days. Further studies are needed to evaluate the efficacy and safety of zirconium cyclosilicate beyond 4 weeks and to assess long-term clinical outcomes. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT02088073.

Ferric carboxymaltose in patients with iron-deficiency anemia and impaired renal function: the REPAIR-IDA trial.

BACKGROUND: Iron-deficiency anemia in non-dialysis-dependent chronic kidney disease (NDD-CKD) frequently requires parenteral iron replacement, but existing therapies often require multiple administrations. We evaluated the efficacy and cardiovascular safety of ferric carboxymaltose (FCM), a non-dextran parenteral iron permitting large single-dose infusions, versus iron sucrose in patients with iron-deficiency anemia and NDD-CKD. METHODS: A total of 2584 participants were randomized to two doses of FCM 750 mg in one week, or iron sucrose 200 mg administered in up to five infusions in 14 days. The primary efficacy endpoint was the mean change to highest hemoglobin from baseline to Day 56. The primary composite safety endpoint included all-cause mortality, nonfatal myocardial infarction, nonfatal stroke, unstable angina, congestive heart failure, arrhythmias and hyper- and hypotensive events. RESULTS: The mean hemoglobin increase was 1.13 g/dL in the FCM group and 0.92 g/dL in the iron sucrose group (95% CI, 0.13-0.28). Similar results were observed across all subgroups, except Stage 2 CKD. More subjects in the FCM group achieved a hemoglobin increase of ≥ 1.0 g/dL between baseline and Day 56 (48.6 versus 41.0%; 95% CI, 3.6-11.6%). There was no significant difference between FCM and iron sucrose recipients with respect to the primary composite safety endpoint, including the major adverse cardiac events of death, myocardial infarction, or stroke. A significant difference in the number of protocol-defined, predominantly transient hypertensive episodes was observed in the FCM group. CONCLUSIONS: Two 750-mg infusions of FCM are a safe and effective alternative to multiple lower dose iron sucrose infusions in NDD-CKD patients with iron-deficiency anemia.

A randomized controlled trial comparing intravenous ferric carboxymaltose with oral iron for treatment of iron deficiency anaemia of non-dialysis-dependent chronic kidney disease patients.

BACKGROUND: Iron deficiency is a common cause of anaemia and hyporesponsiveness to erythropoiesis-stimulating agents (ESAs) in non-dialysis-dependent chronic kidney disease (ND-CKD) patients. Current intravenous iron agents cannot be administered in a single high dose because of adverse effects. Ferric carboxymaltose, a non-dextran parenteral iron preparation, can be rapidly administered in high doses. METHODS: This open-label trial randomized 255 subjects with glomerular filtration rates ≤ 45 mL/min/1.73 m(2), haemoglobin ≤ 11 g/dL, transferrin saturation ≤ 25%, ferritin ≤ 300 ng/mL, and stable ESA dose to either intravenous ferric carboxymaltose 1000 mg over 15 min (with up to two additional doses of 500 mg at 2-week intervals) or oral ferrous sulphate 325 mg thrice daily for a total of 195 mg elemental iron daily for 56 days. RESULTS: In the modified intent-to-treat population, the proportion of subjects achieving a haemoglobin increase ≥ 1 g/dL at any time was 60.4% with ferric carboxymaltose and 34.7% with oral iron (P < 0.001). At Day 42, mean increase in haemoglobin was 0.95 ± 1.12 vs 0.50 ± 1.23 g/dL (P = 0.005), mean increase in ferritin was 432 ± 189 ng/mL vs 18 ± 45 ng/mL (P < 0.001) and mean increase in transferrin saturation was 13.6 ± 11.9% vs 6.1 ± 8.1% (P < 0.001). Treatment-related adverse events were significantly fewer with ferric carboxymaltose than with oral iron (2.7% and 26.2%, respectively; P < 0.0001). CONCLUSIONS: We conclude that 1000 mg ferric carboxymaltose can be rapidly administered, is more effective and is better tolerated than oral iron for treatment of iron deficiency in ND-CKD patients.

The efficacy and safety of current intravenous iron preparations for the management of iron-deficiency anaemia: a review.

Iron-deficiency anaemia (IDA) is a major health problem worldwide, but responds well to iron supplementation. New approaches are leading to more effective management of this condition. Iron deficiency (ID) is usually suspected in at-risk patients with declining haemoglobin (Hb) levels and then confirmed by measuring serum ferritin levels and transferrin saturation. However, regular monitoring of these iron indicators and other laboratory parameters in susceptible individuals may lead to early recognition of falling iron stores and facilitate pre-emptive therapeutic intervention before anaemia develops. Patients with ID are commonly prescribed oral iron preparations because of convenience and low cost. However, the efficacy of these agents is limited by their reduced absorption rate and gastrointestinal side-effects. Alternatively, treatment of IDA in patients requiring erythropoiesis-stimulating agents (ESAs) is more predictably achieved by use of intravenous (i.v.) iron. Unfortunately, the development of serious adverse events (SAEs) from high molecular-weight iron dextran has led to reluctance to use i.v. iron in the treatment of IDA. Similarly, but to a much lesser extent, low molecular-weight iron dextran is associated with a number of SAEs, including allergic or anaphylactic reactions. The introduction of second-generation i.v. iron formulations, including iron sucrose and ferric gluconate, was clearly an improvement over i.v. iron dextran. These formulations proved to be effective in the management of IDA and are not associated with the serious allergic reactions encountered with i.v. iron dextran. For these reasons, use of these preparations became more widespread in the treatment of IDA across a wide range of clinical conditions. An important advantage of i.v. iron over oral iron is that it may bypass hepcidin actions by directly loading transferrin and making iron available to macrophages. Despite a reduction in the short-term risks, there is still concern about the potential for long-term toxicity of i.v. iron use (e. g. atherosclerosis development, infection and increased mortality). The association of atherosclerosis with iron overload remains unclear. Alternatively, the relative risk for mortality or hospitalization from infection in patients undergoing haemodialysis (HD) who received i.v. iron was shown not to be higher than that observed in the overall HD population. Indeed, doses of i.v. iron up to 400 mg/month were associated with improved patient survival. Second-generation i.v. iron formulations are more frequently used for treating IDA than i.v. iron-dextran in patients with various chronic conditions including those with chronic kidney disease. In the latter, IDA should be corrected before initiation of ESA therapy, as iron deficiency can lead to hyporesponsiveness to ESA. However, a major limitation of the second-generation i.v. iron agents is that they cannot be administered in large doses and the typical 1000 mg therapy requires several clinic visits. Thus, there is a need for an i.v. iron agent that can be safely administered in a single dose of 1000 mg of iron and therefore requires less frequent clinic visits. This limitation has now been overcome with the introduction of newer i.v. iron preparations. Ferric carboxymaltose offers effective and rapid correction of IDA by overcoming the limitations observed with previous i.v. iron preparations. This agent has been shown to be effective and well tolerated in a number of randomized controlled trials in a variety of chronic conditions.

Cardiovascular calcification in nondialyzed patients with chronic kidney disease.

Chronic kidney disease (CKD) has become a major health-care problem of global proportions. Progression to end-stage renal disease (ESRD), the need for renal replacement therapy, and the high annual death rate of dialysis patients are the most noticeable outcomes of CKD. Less appreciated, however, is the fact that most patients with CKD actually die mainly from cardiovascular disease, rather than progress to ESRD. Coronary artery calcification (CAC), a surrogate marker of atherosclerosis, is common in dialysis and CKD patients. Coronary artery calcium scores, as measured by ultrafast computed tomography, is an independent predictor of future cardiac events. Using this technique, several studies have documented extensive calcification in dialysis patients, a subject of several exhaustive reviews. Unfortunately, much less attention has been paid to calcification in nondialyzed patients with CKD. In this review, I will emphasize the fact that CVC is common in patients with CKD not yet on dialysis, develops early in the course of CKD, and worsens with the decline in renal function particularly among diabetics who progressed to ESRD. I will also discuss the pathogenesis of CVC in CKD patients and highlight the lack of a major role for abnormalities of mineral metabolism in the pathogenesis of calcification in CKD patients. In addition to the high prevalence of traditional risk factors for CAD, the presence of proteinuria, reduced renal function, diabetic nephropathy, and the rate of progression to ESRD may represent the main uremia-related factors that increase the risk for calcification in CKD. Finally, I will review the protective role of inhibitors of calcification in CKD.

The CARE study and cardiovascular calcification.

Cardiovascular disease (CVD) remains the major mortality risk in dialysis patients, accounting for almost 50 percent of deaths. Risk is related to the increased prevalence of traditional risk factors for CVD and to the contribution of abnormalities in mineral metabolism as well as cardiovascular calcification. Hyperphosphatemia invariably is present among patients with end-stage renal disease and is becoming an increasingly important clinical entity. In addition to its role in the pathogenesis of secondary hyperparathyroidism, elevated serum phosphorus increases the mortality risk among these patients. The pathophysiologic mechanisms by which persistent hyperphosphatemia enhances mortality risk in dialysis patients are not yet completely understood. Given that inadequate control of serum phosphorus contributes to elevated calcium-phosphorus (Ca x P) product, hyperphosphatemia may play a key role in cardiovascular calcification. The National Kidney Foundation's Kidney Disease Outcomes Quality Initiative (K/DOQI) "Clinical Practice Guidelines for Bone Metabolism and Disease in Chronic Kidney Disease" recommends more stringent levels for controlling serum phosphorus and Ca x P product to improve patients' quality of life and longevity. Several studies, including the CARE study, have shown that calcium acetate is more cost-effective than sevelamer as a phosphate binder. Although concern has been raised about its purported link to cardiovascular calcification, the author demonstrates in this review that calcium acetate can be used effectively with doses of elemental calcium that meet the K/DOQI guidelines.

Reducing the burden of cardiovascular calcification in patients with chronic kidney disease.

Patients with chronic kidney disease (CKD) have a higher burden of atherosclerotic coronary artery disease compared with age- and gender-matched individuals with normal renal function. Cardiovascular calcification (CVC), a marker of atherosclerosis, is also more prevalent in these patients and is associated with serious clinical consequences. The pathogenesis of CVC is complex and includes factors that promote calcification and others that inhibit calcification. Thus, multiple therapeutic interventions should be used simultaneously to reduce the burden of calcification in patients with CKD. Thus far, interventional attempts have focused on curtailing the effects of factors that promote calcification such as management of known traditional factors for atherosclerotic coronary artery disease and on adopting specific approaches to normalize mineral metabolism, deliver adequate dialysis, and control serum cholesterol level. By contrast, interventions that may bolster the effects of inhibitors of calcification have not yet been studied well but are beginning to attract attention. Ideally, the goal of interventions is not only to slow or halt progression of calcification but also to reverse pre-existing calcification. Whether this goal is achievable is not currently known. This review examines the potential of various therapeutic interventions in reducing the CVC burden in patients with CKD. Moreover, the review is intended to stimulate more research in this area because the efficacy of these interventions has not been examined in controlled clinical trials.

Cardiovascular calcification in Hispanic Americans (HA) with chronic kidney disease (CKD) due to type 2 diabetes.

BACKGROUND: Cardiovascular calcification (CVC) is common and severe in patients with end-stage renal disease on dialysis. However, the prevalence and severity of CVC is less well documented in patients with chronic kidney disease (CKD) not yet on dialysis. METHODS: Fifty-eight nondialyzed HA with type 2 diabetes and CKD were enrolled. They comprise 29 patients with stages 1 and 2 CKD (early CKD group) and 26 patients with stages 4 and 5 CKD (advanced CKD group). Coronary artery calcification (CAC) was measured by ultrafast spiral computed tomography, while peripheral artery calcification (PAC) was evaluated by plain x-ray of the chest, pelvis, thighs, and lower extremities. RESULTS: The prevalence of CAC and PAC were significantly higher in the advanced CKD group compared to the early CKD group (73% vs. 38%; P < 0.01 and 85% vs. 35%; P < 0.0001, respectively). The median CAC scores were 18-fold greater in the advanced CKD group (138.9 vs. 7.8, respectively). By linear regression analysis, a strong association was found between the level of renal function and ln total volume of CAC. CONCLUSION: Our data indicate that CAC and PAC are common and severe in HA diabetic patients with CKD not previously treated with dialysis, calcium-based phosphate binders, or vitamin D analogues. Lower level of renal function is associated with increased burden of vascular calcification in predialysis patients with CKD.

Treatment of hyperphosphatemia in patients with chronic kidney disease on maintenance hemodialysis.

Treatment of hyperphosphatemia in patients with chronic kidney disease on maintenance hemodialysis. Hyperphosphatemia in patients with ESRD leads to secondary hyperparathyroidism, renal osteodystrophy, and is independently associated with mortality risk. The exact mechanism by which hyperphosphatemia increases mortality risk is unknown, but it may relate to enhanced cardiovascular calcification. National Kidney Foundation K/DOQI bone metabolism and disease guidelines recommend maintenance of serum phosphorus (P) below 5.5 mg/dL, and Ca x P product less than 55 mg(2)/dL(2). Although calcium-based phosphate binders (CBPB) are cost effective, long-term safety concerns relate to their postulated role in progression of cardiovascular calcification. Sevelamer hydrochloride has been recommended as an alternative noncalcium phosphate binder. Results from the Calcium Acetate Renagel Evaluation (CARE study) indicate that calcium acetate is more effective than sevelamer in controlling serum phosphorous and Ca x P product in hemodialysis patients. In the Treat-to-Goal study, dialysis patients treated with sevelamer had slower progression of coronary and aortic calcification than patients treated with CBPB. The mechanism underlying the beneficial effect of sevelamer is unknown, but may relate to decreased calcium loading or to dramatic reductions in LDL cholesterol in sevelamer-treated patients. At present, evidence incriminating CBPB in the progression of cardiovascular calcification in ESRD remains largely circumstantial. As calcium acetate is more efficacious and cost effective than sevelamer, it remains an accepted first-line phosphate binder. In this review, we will examine these issues and provide rational guidelines for the use of calcium-based phosphate binders in patients on maintenance hemodialysis.

Dyslipidemia and progression of cardiovascular calcification (CVC) in patients with end-stage renal disease (ESRD).

Dyslipidemia and progression of cardiovascular calcification (CVC) in patients with end-stage renal disease (ESRD). Cardiovascular calcification (CVC) is commonly encountered both in the general population as well as in patients with end-stage renal disease (ESRD). The etiology of CVC in patients with ESRD is multifactorial. Despite that, current debate remains narrowly focused on the role of calcium loading from calcium-based phosphate binders (CBPB) in the pathogenesis and progression of CVC. Yet, the alleged link between these binders and CVC has not been substantiated in well-designed controlled trials. In contrast, the purported role of sevelamer, a non-calcium-based phosphate binder, in slowing the progression of CVC in dialysis patients has attracted widespread attention. The beneficial effect of sevelamer on progression of calcification was thought to be due to lower calcium loading during its use. However, an alternative and possibly more likely mechanism involves sevelamer-induced lowering of LDL cholesterol. In this context, previous studies in individuals with normal renal function have documented amelioration of coronary artery calcification (CAC) with reduction of LDL-cholesterol by treatment with HMG-CoA reductase inhibitors (statins). Given that CAC is a well-accepted marker of atherosclerosis, and that high plasma cholesterol concentration is one of the main risk factors for atherosclerosis, then it is not unreasonable to suspect that CAC may be halted or even reversed by lowering of LDL cholesterol level with statin therapy. Unfortunately, the effect of lowering the LDL-cholesterol level on CAC has not been studied in patients with ESRD. Therefore, conclusions about this important topic should await the results of well-designed clinical studies that control for all factors potentially implicated in the CVC burden of patients with ESRD. In this review, I will discuss the role of various potential mechanisms involved in the pathogenesis of CVC in patients with ESRD, and emphasize the role of dyslipidemia and its treatment in this important clinical entity.

Consequences of hyperphosphatemia in patients with end-stage renal disease (ESRD).

Hyperphosphatemia is invariably present among patients with end-stage renal disease (ESRD) and is becoming an increasingly important clinical entity. Despite concerted efforts by patients, dietitians, and nephrologists to control serum phosphorus, a recent study by Block et al found that more than 60% of patients on hemodialysis in the United States have serum phosphorus levels above the recommended goal of 5.5 mg/dL. Historically, nephrologists have been concerned about the central role of elevated serum phosphorus in the pathogenesis of secondary hyperparathyroidism and extraosseous calcification. However, the consequences of untreated hyperphosphatemia have assumed more importance in the last few years, largely due to recent clinical studies that revealed a more sinister role of elevated serum phosphorus in increasing the mortality risk among patients with ESRD. Hemodialysis patients with serum phosphorus greater than 6.5 mg/dL were reported to have a 27% higher mortality risk than patients with serum phosphorus between 2.4 and 6.5 mg/dL. The pathophysiologic mechanisms by which persistent hyperphosphatemia enhances the mortality risk in dialysis patients are not yet completely understood. However, given that inadequate control of serum phosphorus contributes to elevated calcium-phosphorus product (Ca x P), untreated hyperphosphatemia may play a key role in cardiovascular calcification. In response to these findings, the National Kidney Foundation Kidney Disease Outcome Quality Initiative (K/DOQI) Clinical Practice Guidelines for Bone Metabolism and Disease in Chronic Kidney Disease have recently recommended more stringent levels for controlling serum phosphorus and Ca x P product in order to improve patients' quality of life and longevity.

Treatment of hyperphosphatemia in patients with chronic kidney disease on maintenance hemodialysis: results of the CARE study.

Most patients with end-stage renal disease develop hyperphosphatemia because their dietary intake exceeds phosphorus elimination by intermittent thrice-weekly dialysis. Inadequately treated hyperphosphatemia plays a central role in the pathogenesis of secondary hyperparathyroidism and extraosseous calcification. Moreover, in the last 15 years, this biochemical abnormality has become increasingly important following the publication of two epidemiologic studies that demonstrated an association between elevated serum phosphorus and increased mortality risk in patients with end-stage renal disease. As a result, the National Kidney Foundation Kidney Disease Outcome and Quality Initiative (K/DOQI) Bone Metabolism and Chronic Kidney Disease Guidelines recommend that serum phosphorus levels be maintained between 3.5 and 5.5 mg/dL. Unfortunately, cross-sectional studies have shown a mean serum phosphorus of 6.2 mg/dL in the maintenance hemodialysis population in the United States. An alarming 60% of patients have serum phosphorus in excess of the 5.5 mg/dL level recommended by K/DOQI guidelines. In order to achieve this new target for serum phosphorus, the most efficacious and cost-effective phosphate binders currently available should be utilized. In this review, we discuss the results of the Calcium Acetate Renagel Evaluation (CARE study), which clearly demonstrated the superiority of calcium acetate over sevelamer hydrochloride for controlling serum phosphorus and calcium-phosphate product to the levels recommended by the K/DOQI guidelines.