New scenarios in secondary hyperparathyroidism: etelcalcetide. Position paper of working group on CKD-MBD of the Italian Society of Nephrology

Bone mineral abnormalities (defined as Chronic Kidney Disease Mineral Bone Disorder; CKD-MBD) are prevalent and associated with a substantial risk burden and poor prognosis in CKD population. Several lines of evidence support the notion that a large proportion of patients receiving maintenance dialysis experience a suboptimal biochemical control of CKD-MBD. Although no study has ever demonstrated conclusively that CKD-MBD control is associated with improved survival, an expanding therapeutic armamentarium is available to correct bone mineral abnormalities. In this position paper of Lombardy Nephrologists, a summary of the state of art of CKD-MBD as well as a summary of the unmet clinical needs will be provided. Furthermore, this position paper will focus on the potential and drawbacks of a new injectable calcimimetic, etelcalcetide, a drug available in Italy since few months ago.

Current and potential treatment options for hyperphosphatemia

INTRODUCTION

Hyperphosphatemia is common in late stages of chronic kidney disease and is often associated with elevated parathormone levels, abnormal bone mineralization, extra-osseous calcification, and increased risk of cardiovascular events and death. Several classes of oral phosphate binders are available to help control plasma phosphorus levels. Although effective at lowering serum phosphorus, they all have safety, tolerability, and compliance issues that need to be considered when selecting which one to use.

AREAS COVERED

This paper reviews the most established treatment options for hyperphosphatemia, in patients with chronic kidney disease, focusing on the new inhibitors of active phosphate absorption.

EXPERT OPINION

The prevention and the treatment of hyperphosphatemia is today far to be satisfactory. Nonetheless, an extending range of phosphate binders are now available. Aluminum has potentially serious toxic risks. Calcium-based binders are very effective but can lead to hypercalcemia and/or positive calcium balance and progression of cardiovascular calcification. No long-term data are available for the new calcium acetate/magnesium combination product. Lanthanum is an effective phosphate binder, and long-term effects of tissue deposition seem clinically irrelevant. Sevelamer, appear to have profiles that would lead to pleiotropic effects and reduced progression of vascular calcification, and the main adverse events seen with these agents are gastrointestinal. Iron has a powerful capability of binding phosphate, thus numerous preparations are available, both with and without significant systemic absorption of the iron component. The inhibitors of active intestinal phosphate transport, with their very selective mechanism of action and low pill burden seem the most interesting approach; however, do not seem at present to be effective alone, in reducing serum phosphorus levels.

[New scenarios in secondary hyperparathyroidism: etelcalcetide. Position paper of Nephrologists form Lombardy]

Bone mineral abnormalities (defined as Chronic Kidney Disease Mineral Bone Disorder; CKD-MBD) are prevalent and associated with a substantial risk burden and poor prognosis in CKD population. Several lines of evidence support the notion that a large proportion of patients receiving maintenance dialysis experience a suboptimal biochemical control of CKD-MBD. Although no study has ever demonstrated conclusively that CKD-MBD control is associated with improved survival, an expanding therapeutic armamentarium is available to correct bone mineral abnormalities. In this position paper of Lombardy Nephrologists, a summary of the state of art of CKD-MBD as well as a summary of the unmet clinical needs will be provided. Furthermore, this position paper will focus on the potential and drawbacks of a new injectable calcimimetic, etelcalcetide, a drug available in Italy since few months ago.

Predictors of first ischemic lower limb ulcer in dialysis patients: an observational cohort study

BACKGROUND

Lower limb ischemia affects the quality of life, physical activity and life expectancy of dialysis patients. The aim of this study was to investigate the risk factors associated with ischemic foot ulcers considering clinical, laboratory and therapeutic domains.

METHODS

This observational cohort study was based on data from the Nephrology and Dialysis Department database of Alessandro Manzoni Hospital, Lecco (Italy). All of the incident patients who started dialysis between 1 January 1999 and 29 February 2012 were enrolled, excluding temporary guests, patients with acute renal failure and patients with previous limb ischemia or amputation. Multivariate Cox regression analysis identified the predictors in each domain, which were matched in the final model. A time-dependent approach was used to take into account the evolution of some of the prognostic covariates.

RESULTS

Of the 526 incident dialysis patients, 120 developed a lower limb ischemic lesion after a median of 13 months. The incidence of new ulcers was constant during the study period (6 per 100 person-years), but higher in the diabetics with a relative rate of 4.5. The variables significantly related to an increased risk of lower limb ulcers were age, male gender, diabetes, ischemic heart disease, treatment with proton pump inhibitors, iron, anticoagulants and calcium-based binders, and blood levels of phosphorus, triglycerides and C-reactive protein.

CONCLUSION

The incidence of lower limb ulcers was highest during the early dialysis follow-up and was associated with, in addition to diabetes, modifiable laboratory and therapeutic predictors such as anticoagulants, proton pump inhibitors, calcium-containing binders, calcimimetics and iron.

Sudden Death in End Stage Renal Disease: Comparing Hemodialysis versus Peritoneal Dialysis

BACKGROUND/AIMS

This study aimed to evaluate total and sudden death (SD) in a cohort of dialysis patients, comparing hemodialysis (HD) vs. peritoneal dialysis (PD).

METHODS

This is a multicenter retrospective cohort study.

RESULTS

Deaths were 626 out of 1,823 in HD and 62 of 249 in PD patients. HD patients had a greater number of comorbidities (p < 0.05). PD patients had a lower risk of death than HD patients (p < 0.001); however, the advantage decreased with time (p < 0.001). Mortality predictors were left ventricular ejection fraction (LVEF) ≤35%, older age, ischemic heart disease, diabetes mellitus, previous stroke, and atrial fibrillation (p < 0.03). SDs were 84:71 in HD and 13 in PD population (12.1 and 22.8% of all causes of death, respectively). A non-significant risk of SD among PD compared to HD patients was detected. SD predictors were older age, ischemic heart disease, and LVEF ≤35% (p < 0.05).

CONCLUSIONS

HD patients showed a greater presence of comorbidities and reduced survival compared to PD patients; however, the incidence of SD does not differ in the 2 populations. Video Journal Club "Cappuccino with Claudio Ronco" at http://www.karger.com/?doi=464347.

Assessment of intradialysis calcium mass balance by a single pool variable-volume calcium kinetic model

INTRODUCTION

A reliable method of intradialysis calcium mass balance quantification is far from been established. We herein investigated the use of a single-pool variable-volume Calcium kinetic model to assess calcium mass balance in chronic and stable dialysis patients.

METHODS

Thirty-four patients on thrice-weekly HD were studied during 240 dialysis sessions. All patients were dialyzed with a nominal total calcium concentration of 1.50 mmol/L. The main assumption of the model is that the calcium distribution volume is equal to the extracellular volume during dialysis. This hypothesis is assumed valid if measured and predicted end dialysis plasma water ionized calcium concentrations are equal. A difference between predicted and measured end-dialysis ionized plasma water calcium concentration is a deviation on our main hypothesis, meaning that a substantial amount of calcium is exchanged between the extracellular volume and a nonmodeled compartment.

FINDINGS

The difference between predicted and measured values was 0.02 mmol/L (range -0.08:0.16 mmol/L). With a mean ionized dialysate calcium concentration of 1.25 mmol/L, calcium mass balance was on average negative (mean ± SD -0.84 ± 1.33 mmol, range -5.42:2.75). Predialysis ionized plasma water concentration and total ultrafiltrate were the most important predictors of calcium mass balance. A significant mobilization of calcium from the extracellular pool to a nonmodeled pool was calculated in a group of patients.

DISCUSSION

The proposed single pool variable-volume Calcium kinetic model is adequate for prediction and quantification of intradialysis calcium mass balance, it can evaluate the eventual calcium transfer outside the extracellular pool in clinical practice.

The Agreement between Auscultation and Lung Ultrasound in Hemodialysis Patients: The LUST Study

BACKGROUND AND OBJECTIVES

Accumulation of fluid in the lung is the most concerning sequela of volume expansion in patients with ESRD. Lung auscultation is recommended to detect and monitor pulmonary congestion, but its reliability in ESRD is unknown.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In a subproject of the ongoing Lung Water by Ultra-Sound Guided Treatment to Prevent Death and Cardiovascular Complications in High Risk ESRD Patients with Cardiomyopathy Trial, we compared a lung ultrasound-guided ultrafiltration prescription policy versus standard care in high-risk patients on hemodialysis. The reliability of peripheral edema was tested as well. This study was on the basis of 1106 pre- and postdialysis lung ultrasound studies (in 79 patients) simultaneous with standardized lung auscultation (crackles at the lung bases) and quantification of peripheral edema.

RESULTS

Lung congestion by crackles, edema, or a combination thereof poorly reflected the severity of congestion as detected by ultrasound B lines in various analyses, including standard regression analysis weighting for repeated measures in individual patients (shared variance of 12% and 4% for crackles and edema, respectively) and κ-statistics (κ ranging from 0.00 to 0.16). In general, auscultation had very low discriminatory power for the diagnosis of mild (area under the receiver operating curve =0.61), moderate (area under the receiver operating curve =0.65), and severe (area under the receiver operating curve =0.68) lung congestion, and the same was true for peripheral edema (receiver operating curve =0.56 or lower) and the combination of the two physical signs.

CONCLUSIONS

Lung crackles, either alone or combined with peripheral edema, very poorly reflect interstitial lung edema in patients with ESRD. These findings reinforce the rationale underlying the Lung Water by Ultra-Sound Guided Treatment to Prevent Death and Cardiovascular Complications in High Risk ESRD Patients with Cardiomyopathy Trial, a trial adopting ultrasound B lines as an instrument to guide interventions aimed at mitigating lung congestion in high-risk patients on hemodialysis.

Impact of European medicines agency recommendations for hypersensitivity reactions on intravenous iron prescription in haemodialysis centres of the Lombardy region

BACKGROUND

The European Medicines Agency (EMA) has recommended measures to minimize the risk of hypersensitivity reactions (HSRs) to intravenous iron (IVFe). We analysed the effects of these recommendations on IVFe clinical management among haemodialysis centres (HDCs) in Lombardy, Italy.

MATERIALS AND METHODS

A questionnaire was sent to all 117 HDCs to collect information on centre characteristics, e.g. HDC type [hospital centre (HC) vs. centre with limited assistance (CAL)], presence/absence of intensive care unit (ICU) and/or emergency trained staff, IVFe therapy regarding molecules, administration modalities, side effects, and percentage variations in iron prescription between 2014 and 2013 (outcome, Δ-IVFe%). A linear regression model was applied to evaluate the focus effect (β) of HDC type on the outcome, controlling for possible confounding effects of the other characteristics.

RESULTS

Response rate was 73.5 %. IVFe therapy was used in 69.1 % (HDC range 11-100) of patients. Following EMA recommendations, prescription was reduced by 12.6 %, with the largest reduction observed in CALs. No severe HSRs were reported. HCs had more frequently an ICU [97.2 vs. 20 %, odds ratio (OR) = 63.6 (95 % confidence interval 15.56; 537.47), p < 0.001], emergency trained staff [97.2 vs. 61.2 %, OR = 10.7 (2.68; 85.33), p < 0.001] and instrumental facilities (91.7 vs. 58 %, OR = 5.8 (2.03; 23.55), p < 0.001] than CALs. Linear regression demonstrated a significant raw effect of HDC type on Δ- IVFe% [β =  19.6 (9.82; 30.63), p < 0.001]. No association was found when HDC type was adjusted for ICU-presence [β = 6.7 (-2.32; 18.30), p = 0.199] or for all-confounding factors [β = 5.6 (-5.50; 17.08), p = 0.337].

CONCLUSIONS

This survey shows a disparity in IVFe therapy prescription following EMA recommendations, which is largely influenced by the presence/absence of ICUs in HD centres.

Ionic conductivity of peritoneal dialysate: a new, easy and fast method of assessing peritoneal membrane function in patients undergoing peritoneal dialysis

BACKGROUND

Peritoneal membrane function can be assessed using the peritoneal equilibration test (PET) and similar tests, but these are almost always complicated to use, require a considerable amount of working time and their results cannot always be easily interpreted. Ionic conductivity is a measure of the ability of an electrolyte solution to conduct electricity. We tested the hypothesis that the ionic conductivity of peritoneal dialysate can be used to evaluate peritoneal membrane function in peritoneal dialysis patients.

METHODS

We measured the ionic conductivity and classic biochemical parameters of peritoneal dialysate in 69 patients during a modified PET and compared their ability to evaluate peritoneal membrane function and to diagnose ultrafiltration failure (UFF).

RESULTS

Ionic conductivity was correlated well with classical parameters of peritoneal transport as glucose reabsorption of glucose (D/D0: r(2) = 0.62, P < 0.0001) and creatinine transport (D/PCreat: r(2) = 0.72, P < 0.0001). Twelve patients (17%) experienced UFF and, in them, the ionic conductivity area under the receiver-operating characteristic curve was 0.91 (95% confidence interval: 0.81-0.96) with sensitivity of 1.00 and specificity of 0.84 at a cut-off value of 12.75 mS/cm.

CONCLUSIONS

These findings indicate that the ionic conductivity of peritoneal dialysate can be used as a new screening tool to evaluate peritoneal membrane function.

Phosphate binders for the treatment of hyperphosphatemia in chronic kidney disease patients on dialysis: a comparison of safety profiles

INTRODUCTION

Hyperphosphatemia is common in the late stages of chronic kidney disease (CKD) and is associated with elevated parathormone levels, abnormal bone mineralization, extraosseous calcification and increased risk of cardiovascular events and death. Several classes of oral phosphate binders are available to help control phosphorus levels. Although effective at lowering serum phosphorus, they all have safety issues that need to be considered when selecting which one to use.

AREAS COVERED

This paper reviews the use of phosphate binders in patients with CKD on dialysis, with a focus on safety and tolerability. In addition to the more established agents, a new resin-based phosphate binder, colestilan, is discussed.

EXPERT OPINION

Optimal phosphate control is still an unmet need in CKD. Nonetheless, we now have an extending range of phosphate binders available. Aluminium has potentially serious toxic risks. Calcium-based binders are still very useful but can lead to hypercalcemia and/or positive calcium balance and cardiovascular calcification. No long-term data are available for the new calcium acetate/magnesium combination product. Lanthanum is an effective phosphate binder, but there is insufficient evidence about possible long-term effects of tissue deposition. The resin-based binders, colestilan and sevelamer, appear to have profiles that would lead to less vascular calcification, and the main adverse events seen with these agents are gastrointestinal effects.

The effects of colestilan versus placebo and sevelamer in patients with CKD 5D and hyperphosphataemia: a 1-year prospective randomized study

BACKGROUND

This study compared the effects of short-term titrated colestilan (a novel non-absorbable, non-calcium, phosphate binder) with placebo, and evaluated the safety and efficacy of colestilan over 1 year compared with sevelamer, in patients with chronic kidney disease (CKD) 5D.

METHODS

This prospective multicentre study comprised a 4-week phosphate binder washout period, a 16-week short-term, flexible-dose, treatment period (including a 4-week placebo-controlled withdrawal period) and a 40-week extension treatment phase.

RESULTS

At Week 16 (the end of the 4-week placebo-controlled withdrawal period), serum phosphorus level was 0.43 mmol/L (1.32 mg/dL) lower with colestilan than placebo (P < 0.001; primary end point). Serum LDL-C level was also lower with colestilan than with placebo (P < 0.001). Both colestilan and sevelamer produced significant reductions from baseline in serum phosphorus levels (P < 0.001), maintained for 1 year, and the proportion of patients achieving target levels of ≤1.78 mmol/L (5.5 mg/dL) or ≤1.95 mmol/L (6.0 mg/dL) at study end were similar (65.3 and 73.3%, respectively, for colestilan, and 66.9 and 77.4%, respectively, for sevelamer). Serum calcium level remained stable in the colestilan group but tended to increase slightly in the sevelamer group (end-of-study increase of 0.035 mmol/L over baseline). Both binders produced similar reductions from baseline in LDL-C level (P < 0.001), and responder rates after 1 year, using a target of <1.83 mmol/L (70 mg/dL) or <2.59 mmol/L (100 mg/dL) were similar in both groups (50.7 and 85.3% for colestilan and 54.0 and 80.6% for sevelamer). Colestilan was generally well tolerated.

CONCLUSIONS

Colestilan is effective and safe for the treatment of hyperphosphataemia in patients with CKD 5D, and affords similar long-term phosphorus and cholesterol reductions/responder rates to sevelamer.

CKD patients: the dilemma of serum PTH levels

Recent observational studies of patients with stage 3-5 chronic kidney disease (CKD) not undergoing dialysis have shown that even slight increases in parathyroid hormone (PTH) levels are associated with an increased cardiovascular risk, regardless of the serum levels of calcium and phosphorus and vitamin D therapy. These studies suggest paying particular attention to monitoring PTH levels from the early stages of CKD, and preventing any mineral metabolism disorders that may trigger the excessive synthesis and secretion of PTH. However, it is not easy to determine when an appropriate response becomes maladaptive and requires the pharmacological suppression of the parathyroid gland because the gland's adaptive response can vary widely from one person to another. Furthermore, PTH levels are not always a good predictor of bone turnover and current PTH assays have various methodological limitations. Treating the early mineral metabolism abnormalities of CKD may help prevent the cardiovascular complications whose frequency, costs and mortality have a profound effect on society as a whole. For this reason, there is great interest in establishing adequate target ranges for PTH at different stages of CKD, and determining the most appropriate strategies for reaching them.

Economic evaluation of cinacalcet in the treatment of secondary hyperparathyroidism in Italy

BACKGROUND

Imbalanced levels of parathyroid hormone (PTH), serum calcium (Ca) and phosphorous (P) are associated with an increased risk of cardiovascular (CV) death and fracture in dialysis patients with secondary hyperparathyroidism (SHPT). The calcimimetic agent cinacalcet can attenuate the mineral and hormonal imbalances characteristic of SHPT and may improve outcomes in such patients. Here we describe a cost-utility analysis of cinacalcet for SHPT in dialysis patients in Italy.

METHODS

We developed a probabilistic Markov model to simulate the effect of cinacalcet on Ca, P and PTH levels in dialysis patients with SHPT, based on data from a European, multicentre, open-label study. The model then correlated these levels with mortality and morbidity (CV events, fractures and parathyroidectomies) using data from the literature, and incorporated Italian data for dialysis, drugs and management of events according to the national cost structure. The simulation horizon was patient lifetime; simulated treatment alternatives were standard treatment (mainly vitamin D sterols and phosphate binders) and cinacalcet + standard treatment. A 3.5% discount rate was applied to life expectancy (LE), quality-adjusted life-expectancy (QALE), costs and times below the upper ranges (time in range [TiR]) recommended by the National Kidney Foundation - Kidney Disease Outcomes Quality initiative for PTH, Ca, P and Ca × P. Utilities were derived from the published literature and took into account dialysis and the impairment of quality of life due to the occurrence of CV events and fractures. Costs were evaluated in year 2009 values from the perspective of the Italian National Healthcare System.

RESULTS

Baseline results were calculated with 10,000 iterations. Compared with standard treatment alone, addition of cinacalcet was associated with a mean (SD) increase in TiR of 5.26 (6.59), 3.63 (6.87), 1.70 (6.66) and 2.68 (5.55) discounted patient-years for PTH, Ca and P, respectively, and combined PTH, Ca, P and Ca × P. Cinacalcet increased LE by 1.20 (3.75) life-years (LYs) and QALE by 0.89 (2.59) QALYs. When including the cost for dialysis, the incremental cost-effectiveness ratio (ICER) was €50,012 per LY and €67,361 per QALY, while, if dialysis costs were not included, the ICER was €23,473 per LY and €31,616 per QALY.

CONCLUSIONS

The results suggest that cinacalcet treatment could be considered cost effective for treatment of SHPT in the Italian healthcare setting, but further investigations are needed to confirm these findings.

Effect of MCI-196 on serum phosphate and cholesterol levels in haemodialysis patients with hyperphosphataemia: a double-blind, randomized, placebo-controlled study

BACKGROUND

Hyperphosphataemia in patients on haemodialysis (HD) can lead to, or worsen, secondary hyperparathyroidism (with associated bone disease) and extra-skeletal calcifications associated with increased cardiovascular morbidity and mortality. MCI-196 is a new, non-absorbed, non-calcium-based phosphate binder. The aim of this study was to determine the effect of three fixed doses of MCI-196, on serum phosphorus level and other parameters relevant to HD patients.

METHODS

A total of 120 chronic kidney disease (CKD) stage 5 patients on HD and with the serum phosphorus level >2.1 mmol/l were randomized to receive double-blind treatment with either 3, 6 and 9 g/day MCI-196 or placebo for 3 weeks.

RESULTS

Serum phosphorous decreased in all three treatment groups (-0.038, -0.268 and -0.257 mmol/l in the 3, 6 and 9 g/day groups, respectively). The difference between treatment and placebo groups was significant for the 6 and 9 g/day groups (P < 0.05 in both cases). Changes in the mean serum calcium were minimal and without relevant differences between groups. However, calcium-phosphorus product (Ca x P) was significantly reduced in the 6 and 9 g/day groups P < 0.05). MCI-196 at all doses decreased serum intact PTH between baseline and endpoint, and differences between treatment groups and placebo were statistically significant for the 3 and 9 g/day groups (P < 0.02 in both cases). Both serum total and LDL cholesterol decreased significantly in all treatment groups compared to placebo (by 0.71-1.05 mmol/l, for total cholesterol and 0.68-0.94 mmol/l for LDL cholesterol P < 0.001 in all cases). There was minimal change in serum HDL cholesterol. MCI-196 at all doses decreased significantly serum uric acid between baseline and endpoint compared to placebo (P < 0.005 in all cases). The drug was well tolerated.

CONCLUSION

MCI-196 significantly reduced serum phosphorus, Ca x P and PTH, without effecting serum calcium levels. The additional reduction in total cholesterol and LDL cholesterol indicates a possible dual mechanism of action of MCI-196 that has the potential to reduce cardiovascular morbidity in CKD stage 5 patients.

[Do convective treatments significantly reduce morbidity and mortality?]

Standard hemodialysis is a far from ideal treatment for uremia since the morbidity and mortality of patients on hemodialysis are still significantly higher than those of non-hemodialyzed subjects with similar demographic characteristics. Because it has been suggested that the cause could lie in the inadequate removal of ''middle molecules'' by standard hemodialyis, two alternative treatments have been proposed: high-efficiency hemodialyis and high-flux hemodialyis. The 2002 results of the HEMO study showed that both these treatments are associated with a non-significant reduction in the relative risk of death (4% and 8%, respectively). The MPO study, which - unlike the HEMO study - enrolled only incident cases and not did not allow reuse of dialyzers, evaluated the mortality rate with high-flux and low-flux hemodialysis in a sicker population, i.e., patients with hypoalbuminemia, and showed a significant reduction in the relative risk of death especially in patients with diabetes. In an attempt to define the clinical impact of hemodiafiltration, some of the efficacy data from clinical studies are reviewed in light of a number of factors that may be related to the high mortality among hemodialysis patients. The current state of affairs suggests it is reasonable to prefer high-flux hemodialysis in sicker patients, especially diabetics. Moreover, the use of ultrapure dialysis fluid is recommended to reduce chronic inflammation and its consequences.

New approaches to treatment of secondary hyperparathyroidism

A large number of patients with chronic kidney disease are affected by secondary hyperparathyroidism. The related mineral metabolism abnormalities are associated with an increased relative risk of morbidity and mortality. The management of secondary hyperparathyroidism is made more complex by the fact that the disease progresses over time. Recent approaches to its management include vitamin D analogs, non-calcium/non-aluminum containing phosphate binders and calcimimetics.

International Study of Health Care Organization and Financing for renal replacement therapy in Italy: an evolving reality

The Italian national health system funds universal health care through general taxation, but health services are provided by local institutions. This study examines the epidemiology, provision, and funding of renal replacement therapy (RRT) in Italy. In 2001, prevalence and incidence of RRT in Italy were 0.083% and 0.014%, respectively. A 1999 donation law markedly increased renal transplantation rates. Italy spends 8.3% of its GDP on health care; 1.8% is for end-stage renal disease (ESRD) patients, who represent 0.083% of the general population. The reorganization of the NHS requires attention from the health community so that economic and geographic health disparities are not exacerbated.

[Recent advances in the prevention of cardiovascular morbidity and mortality in end-stage renal disease: role of anemia, hyperparathyroidism and calcifications]

The mortality rate in patients with end-stage renal disease (ESRD) is extremely high, mainly because of the high prevalence of cardiovascular disease. In addition to traditional cardiovascular risk factors, other factors peculiar to chronic kidney disease play a role. Anemia and calcium-phosphate disorders are of particular interest, not only because they have been related to an increased risk of death but, more importantly, because they can be reversed by treatment, thereby providing the opportunity to prevent or delay the onset of cardiovascular disease. Despite a clear association between higher hemoglobin levels and better survival, data from interventional trials do not seem to show a significant positive effect of hemoglobin normalization with erythropoiesis-stimulating agents on survival and left ventricular mass in ESRD patients. Nevertheless, partial correction of anemia is still an important goal to be reached, as is also suggested by international guidelines. Disorders of calcium-phosphate metabolism have also been clearly related to increased mortality. Unlike anemia, which can be easily corrected by treatment in most cases, mineral metabolism is much less effectively treated. New agents, such as phosphate binders not containing calcium and aluminum, vitamin D analogs with lower calcemic activity, and calcimimetics, are becoming increasingly available in everyday clinical practice and are likely to allow a higher percentage of patients to achieve the recommended targets for calcium-phosphate and parathyroid hormone. Given that these molecules have only been introduced recently, clear data from interventional studies showing improved survival after adequate correction of mineral metabolism parameters are still lacking.

New Perspectives in the Management of Secondary Hyperparathyroidism

The traditional treatment of secondary hyperparathyroidism, which affects many patients with chronic kidney disease and is associated with an increased risk of morbidity and mortality, is not very effective. Recent approaches to its management include the use of vitamin D analogues, non-calcium non-aluminium containing phosphate binders, and calcimimetics.

[DOPPS estimate of guideline impact on survival in hemodialysis in Italy]

Knowing the relative risk (RR) of mortality associated with being outside the guideline targets and the percentage of patients in this situation, it is possible to estimate the number of patient life years that could be gained from adhering to guideline recommendations. We used a prevalent cross-sectional sample of 576 Italian patients from the Dialysis Outcomes and Practices Patterns Study (DOPPS) phase II (2002-2004) to determine the percentage of patients who failed to meet the Italian Society of Nephrology's targets for dialysis dose (spKt/V ≥ 1.3), anemia management (hemoglobin ≥ 11 g/dL), and mineral metabolism (serum calcium and phosphorus: ≤ 2.6 and ≤ 1.8 mmol/L, respectively), and the National Kidney Foundation's Kidney Disease Outcomes Quality Initiative (K/DOQI) targets for nutritional status (serum albumin ≥ 4 g/dL) and vascular access (facility catheter use ≤ 10%). We used a larger random sample of DOPPS patients to establish the adjusted RRs of mortality associated with the 6 examined targets. The percentage of patients outside the targets and the adjusted RRs were 34% and 1.12 for dialysis dose, 37.7% and 1.20 for anemia management, 40.8% and 1.14 for phosphorus, 14.4% and 1.22 for calcium, 62.5% and 1.46 for albumin, and 40.1% and 1.20 for facility catheter use. The adjusted sum of life years potentially gained by complete adherence to all 6 guidelines was 25,156 over a period of 5 years (2006-2010); a more conservative estimate, modeling life years potentially gained by bringing half of all patients outside targets within them, was 13,382. In conclusion, this analysis suggests opportunities to improve hemodialysis patient care in Italy. The magnitude of potential savings in life years should encourage greater adherence to guidelines and practices that are significantly associated with better survival.

Effectiveness of sodium and conductivity kinetic models in predicting end-dialysis plasma water sodium concentration: Preliminary results of a single-center experience

The attainment of a neutral sodium balance represents a major objective in hemodialysis patients. It requires that at the end of each dialysis session, total body water volume (V(f)) and total plasma water sodium concentration (Na(pwf)) are constant. Whereas to achieve a constant V(f) it is sufficient that ultrafiltration equals the interdialytic increase in body weight, it is impossible to predict the value of Na(pwf) and calculate the dialysate sodium concentration needed to obtain it without making use of kinetic mathematical models. The effectiveness of both sodium and conductivity kinetic models in predicting Na(pwf) has already been validated in previous clinical studies. However, applying the sodium kinetic model appears to be poorly feasible in the everyday clinical practice, due to the need for blood samples at the start of each dialysis session for the determination of predialysis plasma water sodium concentration. The conductivity kinetic model appears to be more easily applicable, because no blood samples or laboratory tests are needed to determine plasma water conductivity (C(pw)) and ionic dialysance (ID), used in place of plasma water sodium concentration and sodium dialysance, respectively. We applied the 2 models in 69 chronic hemodialysis patients using the Diascan Module for the automatic determination of C(pw) and ID, and using the latter as an estimate of sodium dialysance in the sodium kinetic model. The conductivity kinetic model was shown to be more accurate and precise in predicting Na(pwf) as compared with the sodium kinetic model. Both accuracy and imprecision of the 2 models were not significantly affected by the method used to estimate total body water volume. These findings confirm the conductivity kinetic model as being an effective and easily applicable instrument for the achievement of a neutral sodium balance in chronic hemodialysis patients.

Cinacalcet hydrochloride: calcimimetic for the treatment of hyperparathyroidism

Mineral metabolism disorders, including those related to secondary hyperparathyroidism, affect a large number of patients with chronic kidney disease and are associated with increased relative risk of morbidity and mortality in hemodialysis patients. The traditional therapy of secondary hyperparathyroidism based on vitamin D compounds and calcium-based phosphate binders is often limited by the increase of serum calcium and phosphorus levels limiting the dose that can be given safely, and thus, preventing the attainment of treatment targets. Cinacalcet hydrochloride (Sensipar^®, Mimpara^®, Parareg^®) is the first in a new class of therapeutic agents, the calcimimetics, that increase the sensitivity of calcium-sensing receptors to the extracellular calcium ions, thus lowering parathyroid hormone production and release, decreasing serum calcium and phosphorous concentrations simultaneously. Different randomized, double-blind, placebo-controlled trials evaluated the safety and ability of cinacalcet hydrochloride treatment to improve achievement of target levels of parathyroid hormone, calcium, phosphorus and calcium phosphorus product in dialysis patients. Cinacalcet hydrochloride has also demonstrated to be effective in reducing parathyroid hormone and serum calcium concentrations in patients with primary hyperparathyroidism. On the basis of available data, calcimimetics represent an important innovation and will change the management of mineral metabolism disorders in patients with chronic kidney disease and primary hyperparathyroidism.

Relationship between urea clearance and ionic dialysance determined using a single-step conductivity profile

BACKGROUND

On-line determination of ionic dialysance (ID) has been used to measure the clearance of small solutes like urea. However, attempts to determine the in vivo relationship between ID and urea clearance have led to discordant findings. The aim of this study was to determine the relationship between the mean values of repeated instantaneous determinations of ID throughout a dialysis session ((m)ID), obtained using a single-step inlet dialysate conductivity profile, and the mean values of urea clearance corrected for access recirculation (K(eu1)), total recirculation (access plus cardiopulmonary recirculation, K(eu2)), and the entire postdialysis urea rebound (K(wb)).

METHODS

Eighty-two anuric patients on chronic thrice-weekly hemodialysis were studied using an Integra machine equipped with the Diascan module for the automatic determination of ID. The mean values of repeated ID measurements made at 30-minute intervals were compared with K(eu1) (available for only 31 patients), K(eu2), and K(wb).

RESULTS

The results in all 82 patients were: (m)ID = 176 +/- 23 mL/min; K(eu2) = 181 +/- 25 mL/min; K(wb) = 159 +/- 22 mL/min. The mean (m)ID/K(wb) and (m)ID/K(eu2) ratios were, respectively, 1.11 +/- 0.06 and 0.98 +/- 0.06. The results in the 31 patients for whom K(eu1) values were available were: (m)ID = 179 +/- 24 mL/min and K(eu1) = 200 +/- 27 mL/min; the mean (m)ID/K(eu1) ratio was 0.90 +/- 0.05.

CONCLUSION

The mean value of repeated ID determinations obtained using a single-step conductivity profile underestimates urea clearance corrected for access recirculation, and may be considered an adequate estimate of urea clearance corrected for total recirculation.