Daniel W. Coyne

Selective vitamin D receptor activation with paricalcitol for reduction of albuminuria in patients with type 2 diabetes (VITAL study): a randomised controlled trial.

BACKGROUND Despite treatment with renin–angiotensin–aldosterone system (RAAS) inhibitors, patients with diabetes have increased risk of progressive renal failure that correlates with albuminuria. We aimed to assess whether paricalcitol could be used to reduce albuminuria in patients with diabetic nephropathy. METHODS In this multinational, placebo-controlled, double-blind trial, we enrolled patients with type 2 diabetes and albuminuria who were receiving angiotensin-converting enzyme inhibitors or angiotensin receptor blockers. Patients were assigned (1:1:1) by computer-generated randomisation sequence to receive 24 weeks’ treatment with placebo,1 μg/day paricalcitol, or 2 μg/day paricalcitol. The primary endpoint was the percentage change in geometric mean urinary albumin-to-creatinine ratio (UACR) from baseline to last measurement during treatment for the combined paricalcitol groups versus the placebo group. Analysis was by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT00421733. FINDINGS Between February, 2007, and October, 2008, 281 patients were enrolled and assigned to receive placebo(n=93), 1 μg paricalcitol (n=93), or 2 μg paricalcitol (n=95); 88 patients on placebo, 92 on 1 μg paricalcitol, and 92 on2 μg paricalcitol received at least one dose of study drug, and had UACR data at baseline and at least one timepoint during treatment, and so were included in the primary analysis. Change in UACR was: –3% (from 61 to 60 mg/mmol;95% CI –16 to 13) in the placebo group; –16% (from 62 to 51 mg/mmol; –24 to –9) in the combined paricalcitol groups, with a between-group difference versus placebo of –15% (95% CI –28 to 1; p=0.071); –14% (from 63 to 54 mg/mmol; –24 to –1) in the 1 μg paricalcitol group, with a between-group difference versus placebo of –11%(95% CI –27 to 8; p=0.23); and –20% (from 61 to 49 mg/mmol; –30 to –8) in the 2 μg paricalcitol group, with a between-group difference versus placebo of –18% (95% CI –32 to 0; p=0.053). Patients on 2 μg paricalcitol showed a nearly, sustained reduction in UACR, ranging from –18% to –28% (p=0.014 vs placebo). Incidence of hypercalcaemia,adverse events, and serious adverse events was similar between groups receiving paricalcitol versus placebo. INTERPRETATION Addition of 2 μg/day paricalcitol to RAAS inhibition safely lowers residual albuminuria in patients with diabetic nephropathy, and could be a novel approach to lower residual renal risk in diabetes. FUNDING Abbott.

Prevalence, treatment, and control of hypertension in chronic hemodialysis patients in the United States

BACKGROUND Hypertension is common in chronic hemodialysis patients, yet there are limited data on the epidemiology of hypertension in these patients in the United States. METHODS We assessed the prevalence, treatment, and control of hypertension in a cohort of 2535 clinically stable, adult hemodialysis patients who participated in a multicenter study of the safety and tolerability of an intravenous iron preparation. Hypertension was defined as an average predialysis systolic blood pressure >150 mm Hg or diastolic blood pressure >85 mm Hg, or the use of antihypertensive medications. RESULTS Hypertension was documented in 86% (n = 2173) of patients. The prevalence of hypertension, in contrast to that observed in the general population, did not increase linearly with age and was not affected by sex or ethnicity. Hypertension was controlled adequately in only 30% (n = 659) of the hypertensive patients. In the remaining patients, hypertension was either untreated (12% [252/2173]) or treated inadequately (58% [1262/2173]). CONCLUSION Control of hypertension, particularly systolic hypertension, in chronic hemodialysis patients in the United States is inadequate, despite recognition of its prevalence and the frequent use of antihypertensive drugs. Optimizing the use of medications and closer attention to nonpharmacologic interventions, such as adjustment of dry weight, a low-sodium diet, and exercise, may improve control.

Impact of Dialysis Dose and Membrane on Infection-Related Hospitalization and Death: Results of the HEMO Study

Infection is the second most common cause of death among hemodialysis patients. A predefined secondary aim of the HEMO study was to determine if dialysis dose or flux reduced infection-related deaths or hospitalizations. The effects of dialysis dose, dialysis membrane, and other clinical parameters on infection-related deaths and first infection-related hospitalizations were analyzed using Cox regression analysis. Among the 1846 randomized patients (mean age, 58 yr; 56% female; 63% black; 45% with diabetes), there were 871 deaths, of which 201 (23%) were due to infection. There were 1698 infection-related hospitalizations, yielding a 35% annual rate. The likelihood of infection-related death did not differ between patients randomized to a high or standard dose (relative risk [RR], 0.99 [0.75 to 1.31]) or between patients randomized to high-flux or low-flux membranes (RR, 0.85 [0.64 to 1.13]). The relative risk of infection-related death was associated (P < 0.001 for each variable) with age (RR, 1.47 [1.29 to 1.68] per 10 yr); co-morbidity score (RR, 1.46 [1.21 to 1.76]), and serum albumin (RR, 0.19 [0.09 to 0.41] per g/dl). The first infection-related hospitalization was related to the vascular access in 21% of the cases, and non-access-related in 79%. Catheters were present in 32% of all study patients admitted with access-related infection, even though catheters represented only 7.6% of vascular accesses in the study. In conclusion, infection accounted for almost one fourth of deaths. Infection-related deaths were not reduced by higher dose or by high flux dialyzers. In this prospective study, most infection-related hospitalizations were not attributed to vascular access. However, the frequency of access-related, infection-related hospitalizations was disproportionately higher among patients with catheters compared with grafts or fistulas.

Ferric Gluconate Reduces Epoetin Requirements in Hemodialysis Patients with Elevated Ferritin

The Dialysis Patients Response to IV Iron with Elevated Ferritin (DRIVE) study demonstrated the efficacy of intravenous ferric gluconate to improve hemoglobin levels in anemic hemodialysis patients who were receiving adequate epoetin doses and who had ferritin levels between 500 and 1200 ng/ml and transferrin saturation (TSAT) < or = 25%. The DRIVE-II study reported here was a 6-wk observational extension designed to investigate how ferric gluconate impacted epoetin dosage after DRIVE. During DRIVE-II, treating nephrologists and anemia managers adjusted doses of epoetin and intravenous iron as clinically indicated. By the end of observation, patients in the ferric gluconate group required significantly less epoetin than their DRIVE dose (mean change of -7527 +/- 18,021 IU/wk, P = 0.003), whereas the epoetin dose essentially did not change for patients in the control group (mean change of 649 +/- 19,987 IU/wk, P = 0.809). Mean hemoglobin, TSAT, and serum ferritin levels remained higher in the ferric gluconate group than in the control group (P = 0.062, P < 0.001, and P = 0.014, respectively). Over the entire 12-wk study period (DRIVE plus DRIVE-II), the control group experienced significantly more serious adverse events than the ferric gluconate group (incidence rate ratio = 1.73, P = 0.041). In conclusion, ferric gluconate maintains hemoglobin and allows lower epoetin doses in anemic hemodialysis patients with low TSAT and ferritin levels up to 1200 ng/ml.

Ferumoxytol as an Intravenous Iron Replacement Therapy in Hemodialysis Patients

BACKGROUND AND OBJECTIVES Intravenous iron is a key component of anemia management for chronic kidney disease (CKD). Ferumoxytol is a unique intravenous iron product that can be administered as a rapid injection in doses up to 510 mg. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS This was a randomized, open-label, controlled, multicenter Phase 3 trial to evaluate the safety and efficacy of intravenous ferumoxytol compared with oral iron. Anemic patients with CKD stage 5D on hemodialysis and on a stable erythropoiesis-stimulating agent regimen received either two injections of 510 mg of ferumoxytol within 7 d (n = 114) or 200 mg elemental oral iron daily for 21 d (n = 116). The primary efficacy endpoint was the change in hemoglobin from baseline to day 35. Safety was closely monitored. RESULTS Ferumoxytol resulted in a mean increase in hemoglobin of 1.02 +/- 1.13 g/dl at day 35 compared with 0.46 +/- 1.06 g/dl with oral iron (P = 0.0002). Twice as many ferumoxytol-treated patients than oral iron-treated patients achieved a > or =1 g/dl hemoglobin increase at day 35 (P = 0.0002). There was a greater mean increase in transferrin saturation (TSAT) with ferumoxytol compared with oral iron at day 35 (P < 0.0001). The larger hemoglobin increase after ferumoxytol compared with oral iron at day 35 persisted after adjustment for baseline hemoglobin, TSAT, and serum ferritin. Overall adverse event rates were comparable between groups. CONCLUSIONS In patients on hemodialysis, rapid intravenous injection of 510 mg of ferumoxytol led to significantly greater hemoglobin increases compared with oral iron, with comparable tolerability.

Labile iron in parenteral iron formulations: a quantitative and comparative study

Sir, The recent paper by Van Wyck et al. [1] examined in vitro transfer of iron from iron products to transferrin. The discussion appears to have missed several relevant points. First, the wide concentration range examined appears not to be clinically relevant for all products. As mentioned in the Methods section, ferric gluconate has a far lower peak concentration (1900mcg/dl after 125mg) than iron dextrans (3080–3396mcg/dl after 100mg) or iron sucrose (3000mcg/dl after 100mg). Similarly, the peak concentration for 62.5mg of ferric gluconate is significantly lower than the peak concentration after 50mg of iron dextran or iron sucrose, yet these lower doses when given once every week or two to haemodialysis patients, are most likely to match ongoing iron losses [2]. When these concentrations are analysed in the authors’ Figure 1 (see attached Figure 1) it becomes apparent that one would predict little clinical difference between these products even though 25% more ferric gluconate is being administered. In figure 2 of their paper the authors excluded from their analysis the 865mcg/dl results, yet this is very close to the peak concentration obtained after 62.5mg of ferric gluconate (965mcg/dl), and would likely be close to the peak serum concentration of 25mg of iron sucrose or iron dextran. Additionally, the discussion does notmention or discuss the wide variation in serum half-life of the iron products ( 1 h for ferric gluconate, 6 h for iron sucrose and 48–60 h for iron dextran). A long serum half-life would influence the time for continued iron donation, the peak drug concentration achieved, and have serious implications for administration of higher than approved doses of these products. In spite of the risk of anaphylaxis, iron dextran is still used in the US for total dose infusions ( 1000mg given over 2–3 h) for convenience reasons. Van Wyck et al. have stated that 500mg of iron sucrose can be administered safely over 4 h. While others and I have found 250–500mg of ferric gluconate infused over 1 h well tolerated in haemodialysis patients, we recommended only the 250mg dose [3]. Based on the present study results alone, perhaps higher dose infusions should not be recommended at all, or if necessary the agent with the shortest half-life and lowest peak concentration should be used. On a more clinically pertinent note, the authors state that the Scandinavian Hemoglobin Normalization Trial results support the safety of iron sucrose because the high

Iron supplementation to treat anemia in patients with chronic kidney disease.

Iron deficiency is prevalent in patients with chronic kidney disease (CKD), and use of oral and intravenous iron in patients with CKD who do not require dialysis might obviate or delay the need for treatment with eythropoiesis-stimulating agents (ESAs). Patients on hemodialysis have lower intestinal iron absorption, greater iron losses, and require greater iron turnover to maintain the ESA-driven red cell mass than do healthy individuals. In these patients, intravenous iron reduces ESA dose requirements and increases the likelihood of maintaining levels of hemoglobin within the desired range. Oral iron is inferior to intravenous iron in patients on hemodialysis, in part because elevated serum levels of hepcidin prevent intestinal absorption of iron. Increased levels of hepcidin also impair the normal recycling of iron through the reticuloendothelial system. Levels of serum ferritin and transferrin saturation below 450 pmol/l and 20%, respectively are indicative of iron deficiency, but values above the normal range lack diagnostic value in patients with CKD on dialysis. The availability of various iron preparations and new developments in delivering iron should enable adequate provision of iron to patients with CKD. This Review examines the efficacy, safety and use of iron supplementation therapy for the treatment of anemia in patients with CKD.

Vitamin D deficiency and anemia in early chronic kidney disease

Vitamin D has a number of pleiotropic effects in a variety of tissues, in addition to its well-known effects on mineral metabolism. To determine whether it has an effect on erythropoiesis, we studied the association of the components of the vitamin D axis with the prevalence and severity of anemia in chronic kidney disease. We measured the concentrations of 25-hydroxyvitamin D (25D), 1,25-dihydroxyvitamin D (1,25D), and hemoglobin in a cross-sectional study of 1661 subjects in SEEK, a multi-center cohort study of chronic kidney disease patients in the United States, of whom 41% met the criteria for anemia. The mean hemoglobin concentrations significantly decreased with decreasing tertiles of 25D and 1,25D. These linear trends remained significant after adjustment for age, gender, ethnicity, eGFR, diabetes, and parathyroid hormone. In similarly adjusted models, the lowest tertiles of 25D and 1,25D were independently associated with 2.8- and 2.0-fold increased prevalence of anemia compared with their respective highest tertiles. Patients with severe dual deficiency of 25D and 1,25D had a 5.4-fold prevalence of anemia compared with those replete in both. Our study shows that 25D and 1,25D deficiency are independently associated with decreased hemoglobin levels and anemia in chronic kidney disease. Whether this association is causal requires further study.

Iron management in chronic kidney disease: conclusions from a “Kidney Disease: Improving Global Outcomes” (KDIGO) Controversies Conference

Before the introduction of erythropoiesis-stimulating agents (ESAs) in 1989, repeated transfusions given to patients with end-stage renal disease caused iron overload, and the need for supplemental iron was rare. However, with the widespread introduction of ESAs, it was recognized that supplemental iron was necessary to optimize hemoglobin response and allow reduction of the ESA dose for economic reasons and recent concerns about ESA safety. Iron supplementation was also found to be more efficacious via intravenous compared to oral administration, and the use of intravenous iron has escalated in recent years. The safety of various iron compounds has been of theoretical concern due to their potential to induce iron overload, oxidative stress, hypersensitivity reactions, and a permissive environment for infectious processes. Therefore, an expert group was convened to assess the benefits and risks of parenteral iron, and to provide strategies for its optimal use while mitigating the risk for acute reactions and other adverse effects.

A Randomized, Double-Blind, Placebo-Controlled Trial of Niacinamide for Reduction of Phosphorus in Hemodialysis Patients

BACKGROUND AND OBJECTIVES Niacinamide inhibits intestinal sodium/phosphorus transporters and reduces serum phosphorus in open-label studies. A prospective, randomized, double-blind, placebo-controlled crossover trial was performed for assessment of the safety and efficacy of niacinamide. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Hemodialysis patients with phosphorus levels > or =5.0 mg/dl were randomly assigned to 8 wk of niacinamide or placebo, titrated from 500 to 1500 mg/d. After a 2-wk washout period, patients switched to 8 wk of the alternative therapy. Vitamin D analogs and calcimimetics were held constant; phosphorus binders were not changed unless safety criteria were met. RESULTS Thirty-three patients successfully completed the trial. Serum phosphorus fell significantly from 6.26 to 5.47 mg/dl with niacinamide but not with placebo (5.85 to 5.98 mg/dl). A concurrent fall in calcium-phosphorus product was seen with niacinamide, whereas serum calcium, intact parathyroid hormone, uric acid, platelet, triglyceride, LDL, and total cholesterol levels remained stable in both arms. Serum HDL levels rose with niacinamide (50 to 61 mg/dl but not with placebo. Adverse effects were similar between both groups. Among patients who were > or =80% compliant, results were similar, although the decrease in serum phosphorus with niacinamide was more pronounced (6.45 to 5.28 mg/dl) and the increase in HDL approached significance (49 to 58 mg/dl). CONCLUSIONS In hemodialysis patients, niacinamide effectively reduces serum phosphorus when co-administered with binders and results in a potentially advantageous increase in HDL cholesterol. Further study in larger randomized trials and other chronic kidney disease populations is indicated.