Propensity score matching and persistence correction to reduce bias in comparative effectiveness: the effect of cinacalcet use on all-cause mortality.

PURPOSE: The generalisability of randomised controlled trials (RCTs) may be limited by restrictive entry criteria or by their experimental nature. Observational research can provide complementary findings but is prone to bias. Employing propensity score matching, to reduce such bias, we compared the real-life effect of cinacalcet use on all-cause mortality (ACM) with findings from the Evaluation of Cinacalcet Therapy to Lower Cardiovascular Events (EVOLVE) RCT in chronic haemodialysis patients. METHODS: Incident adult haemodialysis patients receiving cinacalcet, recruited in a prospective observational cohort from 2007-2009 (AROii; n = 10,488), were matched to non-exposed patients regardless of future exposure status. The effect of treatment crossover was investigated with inverse probability of censoring weighted and lag-censored analyses. EVOLVE ACM data were analysed largely as described for the primary composite endpoint. RESULTS: AROii patients receiving cinacalcet (n = 532) were matched to 1790 non-exposed patients. The treatment effect of cinacalcet on ACM in the main AROii analysis (hazard ratio 1.03 [95% confidence interval (CI) 0.78-1.35]) was closer to the null than for the Intention to Treat (ITT) analysis of EVOLVE (0.94 [95%CI 0.85-1.04]). Adjusting for non-persistence by 0- and 6-month lag-censoring and by inverse probability of censoring weight, the hazard ratios in AROii (0.76 [95%CI 0.51-1.15], 0.84 [95%CI 0.60-1.18] and 0.79 [95%CI 0.56-1.11], respectively) were comparable with those of EVOLVE (0.82 [95%CI 0.67-1.01], 0.83 [95%CI 0.73-0.96] and 0.87 [95%CI 0.71-1.06], respectively). CONCLUSIONS: Correcting for treatment crossover, we observed results in the 'real-life' setting of the AROii observational cohort that closely mirrored the results of the EVOLVE RCT. Persistence-corrected analyses revealed a trend towards reduced ACM in haemodialysis patients receiving cinacalcet therapy.

Magnesium - its role in CKD.

Magnesium containing compounds present promising oral phosphate binders for the treatment of hyperphosphataemia in patients with chronic kidney disease (CKD). However, the impact of magnesium in CKD patients still remains unclear in clinical routine practice. Therefore, this publication provides a practicable overview of knowledge about the physiological role of magnesium in general and in particular in CKD patients. Prevalence of hypomagnesaemia is high in the general population and especially in intensive care unit patients, but often not being detected. Magnesium deficiency increases the risk for several diseases, like diabetes mellitus type 2, hypertension and atherosclerosis. Moderate hypermagnesaemia, however, seems to have beneficial effects on vascular calcification and mortality rates in CKD patients. On the other hand, higher serum magnesium levels are reported to be linked to lower PTH levels and results on the effects on bone are controversial. In addition, low magnesium levels are associated with low bone mass, osteoporosis and vascular calcification. In dialysis patients serum magnesium levels are dependent mainly on the dialysate magnesium concentration. To confirm the potential delay of arterial calcification and improved survival outcomes by long-term intervention with magnesium powered randomized studies are required in dialysis patients. Since a recent trial revealed that a phosphate binder containing a combination of magnesium carbonate and calcium acetate was as effective as the polymer-based agent sevelamer hydrochloride and had an equally good tolerability profile, it is time for a re-examination of the role of magnesium in CKD patients.

Characteristics of bone mineral metabolism in patients with stage 3-5 chronic kidney disease not on dialysis: results of the OSERCE study.

OSERCE is a multi-centre and cross-sectional study with the aim of analysing the biochemical, clinical, and management characteristics of bone mineral metabolism alterations and the level of compliance with K/DOQI guideline recommendations in patients with chronic kidney disease (CKD) not on dialysis. The study included a total of 634 patients from 32 different Spanish nephrology units, all with CKD, estimated glomerular filtration rates <60 ml/min/1.73 m(2), and not on dialysis (K/DOQI stage: 33% stage 3, 46% stage 4, and 21% stage 5). In 409 of these patients, laboratory parameters were also measured in a centralised laboratory, including creatinine, calcium, phosphorous, intact parathyroid hormone (PTH), 25-OH-vitamin D, and 1,25-OH2-Vitamin D levels. The rates of non-compliance with the K/DOQI objectives for calcium, phosphorous, intact PTH, and calcium x phosphate product among these patients were 45%, 22%, 70%, and 4%, respectively. Of the 70% of patients with intact PTH levels outside of the target range established by the K/DOQI guidelines, 55.5% had values above the upper limit and 14.5% had values below the lower limit. Of the 45% of patients with calcium levels outside of the target range, 40% had values above the upper limit and 5% had values below the lower limit. Of the 22% of patients with phosphorous levels outside of the target range, 19% had values above the upper limit, and 3% had values below the lower limit. Finally, 4% of patients also had values for the calcium x phosphate product that were outside of the recommended range. Only 1.8% of patients complied with all four K/DOQI objectives. The values detected in centralised laboratory analyses were not significantly different from those measured in the laboratories at each institution. In addition, 81.5% of patients had a deficiency of calcidiol (25-OH-D3) (<30 ng/ml); of these, 35% had moderate-severe deficiency (<15 ng/ml) and 47% had mild deficiency (15-30 ng/ml). Calcitriol (1,25-OH2-D3) levels were deficient in 64.7% of patients. Whereas the calcidiol deficiency was not correlated with the CKD stage, calcitriol deficit were more pronounced at more advanced stages of CKD. The results of the OSERCE study confirm the difficulty in reaching the target values recommended by the K/DOQI guidelines in patients with CKD not on dialysis, in particular in the form of poor control of secondary hyperparathyroidism and vitamin D deficiency. With this in mind, we must review strategies for treating bone mineral metabolism alterations in these patients, and perhaps revise the target parameters set by current guidelines.

Double treatment with paricalcitol-associated calcifediol and cardiovascular risk biomarkers in haemodialysis.

BACKGROUND: The deficit of 25-hydroxyvitamin D (25OHD) associated with secondary hyperparathyroidism (SHPT) is a frequent finding in chronic kidney disease (CKD) patients on haemodialysis (HD). These events are associated with increased morbidity and mortality rates of cardiovascular (CV) origin. Adequate 25OHD serum levels as well as the use of selective vitamin D receptor activators (VDRA) have been shown to have beneficial and independent effects on bone mineral metabolism and cardiovascular risk. Currently, there is still controversy regarding the type of supplementation needed by CKD patients on HD. OBJECTIVE: The aim of our study was to evaluate whether there is a benefit of combination therapy with 25OHD, calcifediol and a VDRA, oral paricalcitol, on bone-mineral metabolism and inflammatory markers, compared to single treatment with each of these in a group of patients on HD. MATERIAL AND METHOD: We performed a prospective study of 6 months, involving 26 patients in our HD unit. We randomised patients into two groups: group 1 (G1) received oral paricalcitol treatment at doses of 1 mcg/day. Group 2 (G2) was treated with 1 ampoule calcifediol/wk (0.266 mg/wk=16 000U) orally. After 3 months of treatment, calcifediol and paricalcitol were added to the G1 and G2 respectively at the same doses, keeping these treatments together for 3 months to complete the 6 months of follow-up. Laboratory tests were performed at months 0, 3 and 6, measuring in all patients serum markers of 25OHD, calcium (Ca), phosphorus (P) and PTH. Bone turnover markers measured were: alkaline phosphatase (AP), aminoterminal propeptide of procollagen type 1 (Pinp1) and carboxyl-terminal telopeptide of type I collagen (CrossLaps), and inflammatory markers: IL-8. We also collected data on levels of insulin, glucose, haemoglobin, erythropoiesis-stimulating agents (ESAs) and rates of resistance to EPO and HOMA (homeostasis model assessment). RESULTS: We detected a deficit of 25-hydroxyvitamin D in all patients studied, with a mean of 13.67 ± 4.81 ng/ml. Supplementation with oral calcifediol significantly corrects this deficit without evidence of toxicity (35.36 ± 33.68 ng/ml in G1 at 6 months and 59.21 ± 26.50 ng/ml in G2 at 3 months). Paricalcitol treatment significantly reduces PTH levels in G1 at 3 months (P<.039). We also noted a decrease in bone marker Pinp1 with paricalcitol, pointing to a possible direct effect on bone cells (P<.001). Both treatment with paricalcitol and with calcifediol produced a significant decrease in levels of IL-8 (P<.001), a known inflammatory marker, drawing attention to a trend towards better response to erythropoiesis-stimulating agents (ESAs), possibly related to the decrease in inflammation. The HOMA index did not change significantly. CONCLUSION: Based on our results, we cannot conclude that the association of calcifediol and paricalcitol produces advantages over the effect of each drug separately. In addition, Paricalcitol by itself appears to have a direct effect on cellular bone remodelling.

Tratamiento doble con calcifediol asociado a paricalcitol y biomarcadores de riesgo cardiovascular en hemodiálisis / Double treatment with paricalcitol-associated calcifediol and cardiovascular risk biomarkers in haemodialysis

Introducción: El déficit de 25-hidroxivitamina D (25OHD) asociado a un hiperparatiroidismo secundario son hallazgos frecuentes en pacientes con enfermedad renal crónica (ERC) en hemodiálisis (HD). Estos hechos se asocian con un incremento de la morbimortalidad de origen cardiovascular (CV). Niveles séricos adecuados de 25OHD, así como el uso de activadores selectivos del receptor de vitamina D (AsRVD), han demostrado tener efectos beneficiosos sobre el metabolismo óseo-mineral y el riesgo CV de manera independiente. Actualmente aún existe controversia respecto al tipo de suplementación que precisan los pacientes con ERC en HD. Objetivo: El objetivo de nuestro estudio fue evaluar si existe beneficio alguno en el tratamiento combinado de 25OHD, calcifediol oral y AsRVD, paricalcitol oral sobre el metabolismo óseo-mineral y marcadores inflamatorios, respecto al tratamiento único con cada uno de ellos, en un grupo de pacientes de HD. Material y métodos: Realizamos un estudio prospectivo de 6 meses de duración sobre 26 pacientes de nuestra (..) (AU)

Background: The deficit of 25-hydroxyvitamin D (25OHD) associated with secondary hyperparathyroidism (SHPT) are frequent findings in patients with chronic kidney disease (CKD) on hemodialysis (HD). These events are associated with increased morbidity and mortality of cardiovascular (CV). 25OHD adequate serum levels as well as the use of selective activators of the vitamin D receptor (AsRVD) have been shown to have beneficial effects on bone metabolism and mineral and cardiovascular risk independently. Currently there is still controversy regarding the type of supplementation needed by patients with CKD on HD. Aims: The aim of our study was to evaluate whether there is benefit in combination therapy with 25OHD, calcifediol and a AsRVD, oral paricalcitol on bone-mineral metabolism and inflammatory markers, compared to single treatment with each of them in a group HD patients. Material and methods: A prospective study of 6 months, over 26 patients in our HD unit. We randomized patients into two groups: group 1 (G1) received oral paricalcitol treatment at doses of 1mcg/day. Group 2 (G2) was treated with 1 ampoule calcifediol/wk (0.266mg/wk=16.000U) orally. After 3 months of treatment, was added (..) (AU)

Beyond the cardiorenal anaemia syndrome: recognizing the role of iron deficiency.

Growing awareness that heart failure, renal impairment, and anaemia are frequent co-morbidities which can exacerbate one another in a vicious circle of clinical deterioration has led to the concept of the cardiorenal anaemia syndrome (CRAS). The role of iron deficiency within this complex interplay has been less well examined. Scrutiny of data from the recent FAIR-HF trial raises a new hypothesis: is it time for 'CRAS' to be supplemented with new acronyms such as CRIDS (cardiorenal-iron deficiency syndrome) or even CRAIDS (cardiorenal-anaemia-iron deficiency syndrome)? Iron deficiency occurs frequently in heart failure patients with or without anaemia. It not only impairs oxygen transport through reduced erythropoiesis, but adversely affects oxidative metabolism, cellular energetics, and immune mechanisms, and the synthesis and degradation of complex molecules such as DNA. One large observational study in patients with heart failure found iron deficiency to be an independent predictor of death or urgent heart transplantation (hazard ratio 1.58, 95% confidence interval 1.14-2.17, P = 0.005). In the FAIR-HF trial, i.v. iron therapy was associated with significant improvements in physical functioning in iron-deficient patients with heart failure, even in non-anaemic patients in whom haemoglobin levels did not change following i.v. iron administration. Key questions regarding the use of i.v. iron supplementation in the setting of heart failure merit exploration and could readily be answered by appropriately designed clinical trials. It is to be hoped that these important clinical trials are conducted, to permit a more subtle characterization of the patient's pathological condition and interventional requirements.

Anemia trials in CKD and clinical practice: refining the approach to erythropoiesis-stimulating agents.

As our knowledge of managing renal anemia with recombinant human erythropoietin has grown, new clinical challenges have emerged. Although initial observational studies produced important favorable results, troubling observations later came from 4 randomized controlled trials that assigned CKD patients to intervention with an erythropoiesis-stimulating agent (ESA) to achieve high hemoglobin levels (Hb). The difference between the observational studies and these randomized controlled trials comes from the observation of higher cardiovascular events when targeting higher Hb, but lower events once patients had achieved these Hb targets. In all of the 4 RCTs, the primary intervention was 'targeting' a higher Hb, and using higher dosages of ESA as the means. Therefore, the question to be solved is: what is harmful with recombinant human erythropoietin--targeting higher hemoglobin or achieving higher hemoglobin? Evidence supporting a relationship between ESA exposure and worse outcomes is not universal, and these comorbidities would require the administration of high doses. However, increasing ESA doses in hyporesponsive patients to achieve a specific target is not reasonable. Managing anemia in CKD patients is complex. It is affected by the underlying disease, comorbid conditions, the environment and several other factors that differ among patients. Thus, anemia management in these patients needs an individualized approach. Each patient should be treated according to a Hb target with the lowest effective ESA dose, while avoiding large fluctuations in Hb levels or prolonged periods outside the target. This strategy may necessitate changes to the ESA dose, dosing frequency and iron supplementation over the course of a patient's treatment, and proactive management of conditions that can affect ESA responsiveness. While all ESAs effectively increase Hb levels, differences with respect to route of administration, pharmacokinetics, and dosing frequency and efficiency should be considered to maximize the benefits of ESA treatment for the individual patient.

Evaluation of calcium acetate/magnesium carbonate as a phosphate binder compared with sevelamer hydrochloride in haemodialysis patients: a controlled randomized study (CALMAG study) assessing efficacy and tolerability.

BACKGROUND: Phosphate binders are required to control serum phosphorus in dialysis patients. A phosphate binder combining calcium and magnesium offers an interesting therapeutic option. METHODS: This controlled randomized, investigator-masked, multicentre trial investigated the effect of calcium acetate/magnesium carbonate (CaMg) on serum phosphorus levels compared with sevelamer hydrochloride (HCl). The study aim was to show non-inferiority of CaMg in lowering serum phosphorus levels into Kidney Disease Outcome Quality Initiative (K/DOQI) target level range after 24 weeks. Three hundred and twenty-six patients from five European countries were included. After a phosphate binder washout period, 255 patients were randomized in a 1:1 fashion. Two hundred and four patients completed the study per protocol (CaMg, N = 105; dropouts N = 18; sevelamer-HCl, N = 99; dropouts N = 34). Patient baseline characteristics were similar in both groups. RESULTS: Serum phosphorus levels had decreased significantly with both drugs at week 25, and the study hypothesis of CaMg not being inferior to sevelamer-HCl was confirmed. The area under the curve for serum phosphorus (P = 0.0042) and the number of visits above K/DOQI (≤1.78 mmol/L, P = 0.0198) and Kidney disease: Improving global outcomes (KDIGO) targets (≤1.45 mmol/L, P = 0.0067) were significantly lower with CaMg. Ionized serum calcium did not differ between groups; total serum calcium increased in the CaMg group (treatment difference 0.0477 mmol/L; P = 0.0032) but was not associated with a higher risk of hypercalcaemia. An asymptomatic increase in serum magnesium occurred in CaMg-treated patients (treatment difference 0.2597 mmol/L, P < 0.0001). There was no difference in the number of patients with adverse events. CONCLUSION: CaMg was non-inferior to the comparator at controlling serum phosphorus levels at Week 25. There was no change in ionized calcium; there was minimal increase in total serum calcium and a small increase in serum magnesium. It had a good tolerability profile and thus may represent an effective treatment of hyperphosphataemia.

A randomized, double-blind, placebo-controlled study to assess the efficacy and safety of cinacalcet HCl in participants with CKD not receiving dialysis.

BACKGROUND: Secondary hyperparathyroidism is observed in patients with early chronic kidney disease (CKD). This study investigated the safety and efficacy of cinacalcet for secondary hyperparathyroidism in participants with CKD not receiving dialysis. STUDY DESIGN: Double-blind, randomized, 32-week, phase 3 study. SETTING & PARTICIPANTS: 404 participants with stage 3 or 4 CKD from 73 centers in 9 countries. INTERVENTIONS: Cinacalcet:placebo (3:1 ratio). OUTCOMES & MEASUREMENTS: Proportion of participants with a mean decrease of 30% or greater in intact parathyroid hormone (iPTH) level, proportion with iPTH level of 70 or less or 110 or less pg/mL (stage 3 and 4 CKD, respectively), and mean percentage of iPTH change from baseline, all during the efficacy-assessment phase. RESULTS: A greater proportion of cinacalcet than placebo participants achieved a 30% or greater decrease in iPTH level (74% versus 28%; P < 0.001), corresponding to a 43.1% decrease in iPTH level from baseline (cinacalcet) compared with a 1.1% increase (placebo). At week 32, serum calcium levels were 8.9 +/- 0.8 mg/dL (-8.9%; cinacalcet) and 9.9 +/- 0.6 mg/dL (+0.8%; placebo), phosphorus levels were 4.5 +/- 1.0 mg/dL (+21.4%) and 4.0 +/- 0.7 mg/dL (+6.8%), and calcium-phosphorus product values were 40.1 +/- 8.3 mg(2)/dL(2) (+18.9%) and 38.9 +/- 6.9 mg(2)/dL(2) (+17.1%), respectively. During the study course, 62% (cinacalcet) and 1% (placebo) of participants experienced 2 consecutive serum calcium concentrations less than 8.4 mg/dL. They generally were asymptomatic and without significant clinical consequences. Treatment generally was well tolerated, and most adverse events were mild to moderate in severity. LIMITATIONS: The study was not designed to assess the effects of cinacalcet on vascular calcification, bone histomorphometric parameters, or other clinical outcomes. It is not known whether the observed differences in changes in iPTH levels are clinically more important than observed differences in changes in serum calcium or phosphorus levels or dosages of vitamin D sterols and phosphate binders. CONCLUSIONS: These data show that cinacalcet treatment in patients with CKD not receiving dialysis can decrease plasma iPTH levels, but with frequent (albeit generally asymptomatic) serum calcium levels less than 8.4 mg/dL and increases in serum phosphorus levels.

New strategies for the treatment of hyperparathyroidism incorporating calcimimetics.

BACKGROUND: Hyperparathyroidism (HPT), characterised by increased parathyroid hormone (PTH) secretion and parathyroid hyperplasia, can be caused by physiologic defects in the parathyroid gland (primary HPT [PHPT]) or as a consequence of declining renal function (secondary HPT [SHPT]). OBJECTIVE: To review the safety and efficacy of cinacalcet in the treatment of SHPT and PHPT. METHODS: Studies indexed in NLM/PubMed investigating the safety, efficacy, and pharmacokinetics of cinacalcet for PHPT and SHPT and supporting preclinical evidence. RESULTS/CONCLUSION: Recent evidence has demonstrated the efficacy of the calcimimetic cinacalcet in the treatment of PHPT and SHPT. Compared with traditional therapies such as vitamin D sterols and phosphate binders, cinacalcet treatment can allow an increased proportion of patients with SHPT to improve Kidney Disease Outcomes Quality Initiative (KDOQI) Bone Metabolism and Disease laboratory parameter target attainment. Recent evidence suggests that improvements in these biochemical parameters with cinacalcet can translate into improved morbidity and mortality. Cinacalcet lowers PTH and calcium in patients following renal transplantation, and also normalises serum calcium in patients with PHPT. Ongoing studies are focusing and future studies are likely to focus on the effect of cinacalcet on clinical outcomes and on novel strategies for the integration of cinacalcet with traditional therapies to improve serum PTH and mineral metabolism control.

Prevalence, clinical correlates and therapy cost of mineral abnormalities among haemodialysis patients: a cross-sectional multicentre study.

BACKGROUND: This study evaluated the proportion of patients who met National Kidney Foundation Kidney Disease Outcomes Quality Initiative (NKF-K/DOQI) guidelines for mineral status, and assessed the cost of therapy for mineral management of patients under haemodialysis treatment in Spain. METHODS: Demographic and biochemical data were collected for 1312 patients undergoing standard three-times weekly maintenance haemodialysis at six Spanish centres during December 2003. Age, gender, diabetic nephropathy, haemodialysis duration, serum calcium, phosphorus, calcium-phosphorus product (Ca x P), and intact parathyroid hormone (iPTH) levels were monitored. Exploratory analyses of associations between demographic and biochemical parameters, were undertaken using bivariate and multivariate regression techniques. RESULTS: Mean age of patients was 62 years. 97% were Caucasian, 23% were diabetic. In total, 51% of patients received calcium binders, 21% sevelamer, 16% aluminium hydroxide, and 29% received no binders; 33% of patients received calcitriol. Prevalence of patients outside K/DOQI targets was: calcium 50%, phosphorus 46%; Ca x P 33%; iPTH 77%. Elevated phosphorus (>5.5 mg/dl) was independently associated with younger age [OR 0.972 (95% CI 0.963-0.980), P<0.001] and higher iPTH [OR 1.0005 (95% CI 1.0002-1.0008), P<0.001]. Elevated Ca x P (>or=55 mg(2) x dl(2)) showed a similar relationship. High iPTH levels (>300 pmol/l) were associated with female gender [OR 1.574 (95% CI 1.213-2.041), P<0.001], high serum phosphorus [OR 1.230 (95% CI 1.130-1.338), P<0.001], and longer duration of dialysis [OR 1.003 (95% CI 1.001-1.005), P<0.01]. Poorly controlled serum phosphorus, Ca x P and iPTH were associated with more expensive therapy for mineral management. CONCLUSIONS: One in three haemodialysis patients in Spain remains above the upper target range defined in current mineral metabolism guidelines. This abnormal profile is more common in younger patients and females and therapy is more expensive in younger patients.

Cinacalcet HCl: a novel therapeutic for hyperparathyroidism.

Hyperparathyroidism (HPT) is a significant clinical concern for patients with a variety of diseases, notably the secondary HPT associated with chronic kidney disease requiring dialysis. Secondary HPT is associated with elevated para-thyroid hormone (PTH) levels, decreased levels of 1,25 dihydroxyvitamin D, and disordered mineral levels (usually high calcium and phosphorus). If not controlled, secondary HPT can result in bone disease, vascular calcification, and ultimately, patient mortality. Established, conventional therapies, such as 1,25dihydroxyvitamin D analogues (vitamin D analogues) and phosphate binders, have proven to be inadequate in enabling patients to meet the National Kidney Foundation's-Kidney Disease Outcomes Quality Initiative (NKF-K/DOQI) treatment goals for PTH, calcium and phosphorus levels. A novel therapeutic, cinacalcet HCl (formerly AMG 073; Sensipar in the US and Mimpara in Europe; Amgen, Inc.), binds directly to the calcium-sensing receptor (CaR) on the cells of the parathyroid gland, increasing the receptor's sensitivity to calcium and reducing PTH, serum calcium and phosphorus levels. Treatment with cinacalcet in clinical trials has safely and effectively improved achievement of the NKF-K/DOQI goals. Cinacalcet has also reduced serum calcium levels in patients with primary HPT, including parathyroid carcinoma, in the clinical trial setting. Evidence suggesting the utility of cinacalcet in these diseases and the potential for additional therapeutic applications will be discussed.

Cinacalcet for secondary hyperparathyroidism in patients receiving hemodialysis.

BACKGROUND: Treatment of secondary hyperparathyroidism with vitamin D and calcium in patients receiving dialysis is often complicated by hypercalcemia and hyperphosphatemia, which may contribute to cardiovascular disease and adverse clinical outcomes. Calcimimetics target the calcium-sensing receptor and lower parathyroid hormone levels without increasing calcium and phosphorus levels. We report the results of two identical randomized, double-blind, placebo-controlled trials evaluating the safety and effectiveness of the calcimimetic agent cinacalcet hydrochloride. METHODS: Patients who were receiving hemodialysis and who had inadequately controlled secondary hyperparathyroidism despite standard treatment were randomly assigned to receive cinacalcet (371 patients) or placebo (370 patients) for 26 weeks. Once-daily doses were increased from 30 mg to 180 mg to achieve intact parathyroid hormone levels of 250 pg per milliliter or less. The primary end point was the percentage of patients with values in this range during a 14-week efficacy-assessment phase. RESULTS: Forty-three percent of the cinacalcet group reached the primary end point, as compared with 5 percent of the placebo group (P<0.001). Overall, mean parathyroid hormone values decreased 43 percent in those receiving cinacalcet but increased 9 percent in the placebo group (P<0.001). The serum calcium-phosphorus product declined by 15 percent in the cinacalcet group and remained unchanged in the placebo group (P<0.001). Cinacalcet effectively reduced parathyroid hormone levels independently of disease severity or changes in vitamin D sterol dose. CONCLUSIONS: Cinacalcet lowers parathyroid hormone levels and improves calcium-phosphorus homeostasis in patients receiving hemodialysis who have uncontrolled secondary hyperparathyroidism.

Secondary hyperparathyroidism: review of the disease and its treatment.

BACKGROUND: Most patients with chronic kidney disease (CKD) stage 5 develop secondary hyperparathyroidism (SHPT). SHPT is an adaptive response to CKD and its associated disruptions in the homeostatic control of serum phosphorus, calcium, and vitamin D. The poor control of mineral and parathyroid hormone (PTH) levels characteristic of SHPT is associated with serious clinical consequences. OBJECTIVE: This review discusses the pathophysiology and consequences of SHPT, as well as the efficacy and limitations of current treatment modalities. METHODS: Literature searches were conducted using the MEDLINE, EMBASE, and BIOSIS databases. Additional information was obtained from Internet web sites, textbooks, and nephrology congress abstracts. RESULTS: Patients with uncontrolled SHPT are at higher risk for cardiovascular morbidity and mortality, hospitalization, bone disease, vascular and soft-tissue calcification, and vascular access failure than patients whose mineral and PTH levels are well managed. New National Kidney Foundation Kidney Disease Outcomes Quality Initiative (K/DOQI) targets for calcium, phosphorus, calcium-phosphorus product, and PTH control have recently been published with the aim of improving the management of mineral metabolism in CKD patients. Data from observational studies suggest that the majority of patients currently have PTH and mineral levels outside these target ranges. CONCLUSIONS: Given the inadequacies of current therapies, novel agents are being developed that may help improve the management of SHPT.

Once-weekly compared with three-times-weekly subcutaneous epoetin beta: results from a randomized, multicenter, therapeutic-equivalence study.

BACKGROUND: The ability to reduce the administration frequency of subcutaneous (SC) epoetin could provide benefits. This multicenter open-label study investigated the therapeutic equivalence of SC epoetin beta once-weekly and thrice-weekly administration regimens in maintaining anemia correction in stable hemodialysis (HD) patients. METHODS: One hundred seventy-three patients were randomly assigned to either once-weekly epoetin beta (n = 84) or their original thrice-weekly regimen (n = 89) for 24 weeks. All patients were administered intravenous iron supplementation, as required. RESULTS: The per-protocol analysis included 134 patients (69 patients, once-weekly group; 65 patients, thrice-weekly group). Mean hematocrits in both groups remained stable throughout the study. The difference in mean time-adjusted area under the curve for hematocrits between the once-weekly and thrice-weekly groups (-0.54 vol%) and 90% confidence intervals (-1.27 to 0.19) were within the prespecified equivalence range (-2 to +2 vol%). There was no significant change in epoetin beta dose during the study. The ratio of mean weekly epoetin beta doses in the once-weekly and thrice-weekly groups (1.11) and 90% confidence interval (0.99 to 1.23) also remained within the prespecified range (0.8 to 1.25). Intention-to-treat analysis results were similar to per-protocol analysis results. Both regimens were well tolerated. CONCLUSION: Once-weekly and thrice-weekly SC epoetin beta administrations are statistically equivalent in terms of maintaining both stable hematocrits and epoetin beta dose requirements in HD patients. These findings may improve compliance among patients.