Serum 25(OH)-cholecalciferol concentration is associated with hemoglobin level and erythropoietin resistance in patients on maintenance hemodialysis

Effect of vitamin D supplementation on management of anemia in hemodialysis patients with vitamin D deficiency: A double-blind, randomized, controlled trial

INTRODUCTION

Anemia and vitamin D deficiency are common problems among hemodialysis (HD) patients. This study aimed to assess the impact of correction of vitamin D deficiency with vitamin D supplementation on the improvement of anemia in patients with end-stage renal disease (ESRD) on maintenance HD.

METHODS

This double-blind, randomized, controlled study included 100 anemic HD patients with vitamin D deficiency who were randomly divided using the closed envelop method into two groups (1:1). The first group received vitamin D (50,000 IU) monthly for 6 months, and the other group received a placebo for the same period. 25-Hydroxyvitamin D (25(OH)D) levels were measured for both groups at the beginning of the study and after 6 months at the end of the study. Hemoglobin (Hb) concentrations were recorded monthly.

FINDINGS

Vitamin D supplementation during the period of the study increased 25(OH)D levels in the vitamin D group more than the placebo group (p > 0.001). Serum ferritin, serum iron, and transferrin saturation did not differ significantly between both groups during the period of the study. Hb concentration in the vitamin D group increased more than that in the other group over the period of the study, and there was a statistically significant difference between the two groups in all durations of follow-up. Erythropoietin (EPO) dosage requirements were found to be lower in the vitamin D group than in the placebo group, and this was statistically significant (p > 0.001).

DISCUSSION

Vitamin D supplementation in anemic ESRD patients on HD with vitamin D deficiency or insufficiency is safe and effective in improving anemia and decreasing EPO dosage.

Long-term cholecalciferol supplementation in hemodialysis patients: Effects on mineral metabolism, inflammation, and cardiac parameters

BACKGROUND

Low levels of 25-hydroxyvitamin D [25(OH)D] are frequent in chronic kidney disease and are associated with adverse outcomes. The aim of this 5-year prospective study was to evaluate the effects of cholecalciferol supplementation on mineral metabolism, inflammation and cardiac parameters in hemodialysis (HD) patients.

METHODS

The study included 97 patients. Cholecalciferol was given after HD according to 25(OH)D baseline levels measured twice (end of winter and of summer). The 25(OH)D levels, circulating bone metabolism, inflammation parameters, brain natriuretic peptide (BNP), pulse pressure (PP), and left ventricular mass index (LVMI) were evaluated before and after supplementation.

RESULTS

There was a significant increase in 25(OH)D levels after supplementation (p < 0.001); however, serum calcium (p = 0.02), phosphorus (p = 0.018), and iPTH (p = 0.03) were decreased. Magnesium levels increased during the study (p = 0.03). A reduction in the number of patients under active vitamin D (p < 0.001) and in the dose and number of patients treated with darbepoetin (p = 0.02) was observed. Serum albumin increased (p < 0.001), and C-reactive protein decreased (p = 0.01). BNP (p < 0.001), PP (p = 0.007), and LVMI (p = 0.02) were significantly reduced after supplementation.

CONCLUSIONS

Long-term cholecalciferol supplementation allowed correction of 25(OH)D deficiency, improved mineral metabolism with less use of active vitamin D, attenuated inflammation, reduced the dose of the erythropoiesis-stimulating agent, and improved cardiac dysfunction.

Low serum 1,25(OH)2D3 in end-stage renal disease: is reduced 1α-hydroxylase the only problem?

Low serum 1,25-dihydroxyvitamin D (1,25(OH)2D) in end-stage renal disease (ESRD) is considered a consequence of elevated fibroblast growth factor 23 (FGF23) and concomitant reduced activity of renal 1α-hydroxylase (CYP27B1). Current ESRD treatment strategies to increase serum calcium and suppress secondary hyperparathyroidism involve supplementation with vitamin D analogues that circumvent 1α-hydroxylase. This overlooks the potential importance of 25-hydroxyvitamin D (25(OH)D) deficiency as a contributor to low serum 1,25(OH)2D. We investigated the effects of vitamin D (cholecalciferol) supplementation (40,000 IU for 12 weeks and maintenance dose of 20,000 IU fortnightly), on multiple serum vitamin D metabolites (25(OH)D, 1,25(OH)2D3 and 24,25(OH)2D3) in 55 haemodialysis patients. Baseline and 12 month data were compared using related-samples Wilcoxon signed rank test. All patients remained on active vitamin D analogues as part of routine ESRD care. 1,25(OH)2D3 levels were low at baseline (normal range: 60-120 pmol/L). Cholecalciferol supplementation normalised both serum 25(OH)D and 1,25(OH)2D3. Median serum 25(OH)D increased from 35.1 nmol/L (IQR: 23.0-47.5 nmol/L) to 119.9 nmol/L (IQR: 99.5-143.3 nmol/L) (P < 0.001). Median serum 1,25(OH)2D3 and 24,25(OH)2D3 increased from 48.3 pmol/L (IQR: 35.9-57.9 pmol/L) and 3.8 nmol/L (IQR: 2.3-6.0 nmol/L) to 96.2 pmol/L (IQR: 77.1-130.6 pmol/L) and 12.3 nmol/L (IQR: 9-16.4 nmol/L), respectively (P < 0.001). A non-significant reduction in daily active vitamin D analogue dose occurred, 0.94 µmcg at baseline to 0.77 µmcg at 12 months (P = 0.73). The ability to synthesise 1,25(OH)2D3 in ESRD is maintained but is substrate dependent, and serum 25(OH)D was a limiting factor at baseline. Therefore, 1,25(OH)2D3 deficiency in ESRD is partly a consequence of 25(OH)D deficiency, rather than solely due to reduced 1α-hydroxylase activity as suggested by current treatment strategies.

Relationship between serum vitamin D3 concentration and anaemia in patients with chronic kidney disease in China

Objective

In the present study, we aimed to investigate the relationship between serum vitamin D3 concentration and anaemia in patients with chronic kidney disease (CKD) in China, to assist understanding of the effects of vitamin D treatment in such patients.

Methods

A total of 225 patients with CKD were enrolled and a range of laboratory parameters were measured. The participants were allocated to three groups, according to their serum 25-hydroxyvitamin D3 concentration: a severe deficiency group, a deficiency group, and a sufficiency group. The prevalences of anaemia in the three groups were assessed, and the factors associated with anaemia in patients with CKD were analysed using logistic regression.

Results

The prevalences of anaemia were 79.5% in the severe deficiency group, 63.5% in the deficiency group, and 48.0% in the sufficiency group. The prevalence of anaemia gradually increased with the severity of vitamin D3 deficiency. The prevalences of anaemia in participants with stages 1 to 5 CKD were 21.1%, 30.4%, 39.5%, 78.7%, and 94.6%, respectively.

Conclusion

Vitamin D3 deficiency may increase the risk of anaemia in patients with CKD.

Low vitamin D status is associated with anaemia in hospitalised cats

BACKGROUND

The major physiological role of vitamin D has traditionally been considered to be the regulation of calcium homeostasis and maintenance of skeletal health. However, there is increasing evidence that vitamin D influences a wider range of physiological processes including erythropoiesis. Vitamin D (25-hydroxyvitamin D, 25(OH)D) deficiency concentrations have been associated with anaemia in human beings. In contrast, the relationship between vitamin D status and erythropoiesis has not been investigated in cats.

METHODS

Clinical records of cats consecutively presenting between November 2013 and February 2015 were reviewed. For each cat, data including sex, age, breed, serum albumin and creatinine concentrations, and appetite scores were extracted. A multivariable linear regression model was constructed to examine the relationship between 25(OH)D concentrations and these variables.

RESULTS

Cats with anaemia had significantly lower 25(OH)D concentrations (median 49.5 nmol/l, n=31) than cats with packed cell volume above the lower limit of the reference range (median 109.0 nmol/l, n=130) (P<0.001). A binary logistic regression found that red blood cell count and mean corpuscular volume were negatively correlated with serum 25(OH)D concentrations (P<0.001 and P=0.007, respectively).

CONCLUSION

Vitamin D (25(OH)D) concentration is positively associated with red blood cell count and mean corpuscular volume in cats with a wide range of different illnesses.

Influence of Dialysis Modality on the Treatment of Anemia in Patients with End-Stage Kidney Disease

Anemia is a common complication among the patients with end-stage kidney disease. Management of anemia is influenced by several factors: iron deficiency, subtherapeutic dosage of erythropoietin, microinflammation, vitamin D deficiency, increased iPTH levels and inadequate hemodialysis.

The aim of the study was to examine impact of dialysis modality on blood hemoglobin level as well as status of iron, status of vitamin D, hemodialysis adequacy and erythropoietin dose.

The study included 120 patients which were divided into two groups: the group of patients treated with hemodiafiltration and the group of patients treated with standard hemo-dialysis. For statistical analysis Kolmogorov-Smirnov test, Student’s t-test and Mann-Whitney U-test were used.

Blood hemoglobin level and parameters of hemodialysis adequacy (Kt/V index, spKt/V index, URR index), hematocrit ad protein catabolic rate (nPCR) were statisticaly significant lower in patients treated with regular hemodialysis compared to patients treated with regular hemodiafiltration. Serum ferritin level, C-reactive protein level and average monthly dose of intravenous iron were higher in the patients treated with regular hemodialysis compared to patients treated with hemodiafiltration.

Patients treated with hemodiafiltration have lower grade of microinflammation, better iron status and better control of anemia compared to the patients treated with regular hemodialysis. Dialysis modality is an important factor that influences management of anemia in the patients with end-stage kidney disease.

Effect of cholecalciferol on serum hepcidin and parameters of anaemia and CKD-MBD among haemodialysis patients: a randomized clinical trial

In this multicentre double-blind randomized clinical trial, we investigated the effects of oral cholecalciferol supplementation on serum hepcidin and parameters related to anaemia and CKD-MBD among haemodialysis patients. Participants were assigned in a 2:2:1:1 ratio to either (1) thrice-weekly 3,000-IU cholecalciferol, (2) once-monthly cholecalciferol (equivalent to 9,000 IU/week), (3) thrice-weekly placebo, or (4) once-monthly placebo. We also examined the effect modifications by selected single nucleotide polymorphisms in vitamin D-related genes. Out of 96 participants, 94 were available at Month 3, and 88 completed the 6-month study. After adjustment for baseline values, serum hepcidin levels were higher at Day 3 in the combined cholecalciferol (vs. placebo) group, but were lower at Month 6 with increased erythropoietin resistance. Cholecalciferol increased serum 1,25(OH)₂D levels, resulting in a greater proportion of patients who reduced the dose of active vitamin D at Month 6 (31% vs. 10% in the placebo group). Cholecalciferol also suppressed intact PTH only among patients with severe vitamin D deficiency. In conclusion, cholecalciferol supplementation increases serum hepcidin-25 levels in the short term and may increase erythropoietin resistance in the long term among haemodialysis patients. Both thrice-weekly and once-monthly supplementation effectively increases serum 1,25(OH)₂D levels, and hence, reduces active vitamin D drugs.

Clinical Trial Registry: This study was registered at ClinicalTrials.gov and University Hospital Medical Information Network Clinical Trials Registry (UMIN-CTR) as NCT02214563 (registration date: 12/08/2014) and UMIN000011786 (registration date: 15/08/2014), respectively (please refer to the links below). ClinicalTrials.gov: https://clinicaltrials.gov/ct2/show/record/NCT02214563. UMIN-CTR: https://upload.umin.ac.jp/cgi-open-bin/ctr/ctr.cgi?function=brows&action=brows&type=summary&recptno=R000017152&language=E.

Activation of the vitamin D receptor transcription factor stimulates the growth of definitive erythroid progenitors

The pathways that regulate the growth of erythroid progenitors are incompletely understood. In a computational analysis of gene expression changes during erythroid ontogeny, the vitamin D receptor (Vdr) nuclear hormone receptor transcription factor gene was identified in fetal and adult stages, but not at the embryonic stage of development. Vdr was expressed in definitive erythroid (EryD) progenitors and was downregulated during their maturation. Activation of Vdr signaling by the vitamin D3 agonist calcitriol increased the outgrowth of EryD colonies from fetal liver and adult bone marrow, maintained progenitor potential, and delayed erythroid maturation, as revealed by clonogenic assays, suspension culture, cell surface phenotype, and gene expression analyses. The early (cKit⁺CD71^lo/neg), but not the late (cKit⁺CD71^hi), EryD progenitor subset of Lin^negcKit⁺ cells was responsive to calcitriol. Culture of cKit⁺CD71^lo/neg progenitors in the presence of both vitamin D3 and glucocorticoid receptor ligands resulted in an increase in proliferation that was at least additive compared with either ligand alone. Lentivirus shRNA-mediated knockdown of Vdr expression abrogated the stimulation of early erythroid progenitor growth by calcitriol. These findings suggest that Vdr has a cell-intrinsic function in early erythroid progenitors. Targeting of downstream components of the Vdr signaling pathway may lead to new approaches for the expansion of erythroid progenitors ex vivo.

Vitamin D insufficiency, hemoglobin, and anemia in children with chronic kidney disease

BACKGROUND

25-Hydroxyvitamin D (25OHD) deficiency is common in children with chronic kidney disease (CKD). It has been associated with an increased risk for anemia in both healthy US children and in adults with CKD. This association has not been explored in children with CKD.

METHODS

Children aged 1-16 enrolled in the Chronic Kidney Disease in Children (CKiD) study with mild to moderate kidney dysfunction, and with 25OHD measured at baseline (n = 580), were included in the analysis. The cross-sectional associations between 25OHD and hemoglobin (g/dL) and anemia were assessed. Anemia was defined as hemoglobin < 5th percentile for age and sex.

RESULTS

Overall 334 (57.59%) children were vitamin D insufficient/deficient and 137 (23.62%) were anemic. Of those who were vitamin D insufficient/deficient, 95 (28.44%) were anemic. In the overall cohort, the odds of being anemic was 1.9 times higher (95% CI, 1.22-3.04, p < 0.01) in vitamin D insufficient/deficient vs sufficient children, when adjusting for covariates (age, sex, race [black, white, or other], body mass index (BMI), iohexol GFR (iGFR), erythropoietin stimulation agent (ESA) use, iron supplementation use, and underlying cause of CKD). Stratified by race, the odds of being anemic was 2.39 times higher (95% CI, 1.41-4.05, p = 0.001) in vitamin D insufficient/deficient vs vitamin D sufficient white children. The association between vitamin D status and anemia was not significant in black children.

CONCLUSIONS

The data support our hypothesis that vitamin D insufficiency/deficiency increases the odds of anemia in children with CKD. The effect was strong and significant among white, but not black, children.

Low 1,25-dihydroxyvitamin D level is associated with erythropoietin deficiency and endogenous erythropoietin resistance in patients with chronic kidney disease

PURPOSE

Erythropoietin (EPO) deficiency and resistance to endogenous EPO is an important pathophysiological feature in anemia of chronic kidney disease (CKD). Low 1,25 dihydroxyvitamin D [1,25(OH)₂D] level is known to contribute to anemia of CKD. We aimed to investigate the associations between serum 1,25(OH)₂D and anemia, EPO deficiency, and endogenous EPO resistance in patients with CKD.

METHODS

This study included 409 patients with CKD [glomerular filtration rate (GFR) < 60 ml/min/1.73 m²] who were not on dialysis therapy. Patients on exogenous EPO therapy and patients with iron deficiencies were excluded. Endogenous EPO resistance was assessed by calculating the ratio of endogenous EPO to hemoglobin (Hb) (endogenous EPO/Hb ratio). The associations of Hb level, endogenous EPO level, and the endogenous EPO/Hb ratio with clinical and laboratory variables were investigated by univariate and multivariate analyses.

RESULTS

In univariate analysis, serum 1,25(OH)₂D level was correlated with the Hb level, endogenous EPO level, and the endogenous EPO/Hb ratio. Multiple regression analysis revealed that the serum 1,25(OH)₂D level remained significantly associated with the Hb level (β = 0.532, P < 0.001), endogenous EPO level (β = 0.149, P = 0.010), and the endogenous EPO/Hb ratio (β = - 0.187, P = 0.002), even after adjusting for other confounding factors, including the levels of parathyroid hormone and the inflammatory marker C-reactive protein.

CONCLUSION

The serum 1,25(OH)₂D level exhibited significant associations with anemia, EPO deficiency, and endogenous EPO resistance in CKD patients. These associations were independent of secondary hyperparathyroidism and inflammation status.

Erythrocyte P2X1 receptor expression is correlated with change in haematocrit in patients admitted to the ICU with blood pathogen-positive sepsis

Background

Pore-forming proteins released from bacteria or formed as result of complement activation are known to produce severe cell damage. Inhibition of purinergic P2X receptors markedly reduces damage inflicted by cytolytic bacterial toxin and after complement activation in both erythrocytes and monocytes. P2X expression generally shows variation throughout the population. Here, we investigate correlation between P2X receptor abundance in blood cell plasma membranes and haematocrit during sepsis, in patients admitted to the emergency department (ED) or intensive care unit (ICU).

Method

Patients admitted to the ED and successively transferred to ICU with the diagnosis sepsis (< 2 systemic inflammatory response syndrome (SIRS) criteria and suspected infection), were grouped as either blood pathogen-positive (14 patients) or blood pathogen-negative (20 patients). Blood samples drawn at ICU admission were analysed for P2X₁ and P2X₇ receptor abundance using indirect flow cytometry.

Results

Here, we find inverse correlation between P2X₁ receptor expression and change in haematocrit (r_s − 0.80) and haemoglobin (r_s − 0.78) levels from admission to ED to arrival at ICU in patients with pathogen-positive sepsis. This correlation was not found in patients without confirmed bacteraemia. Patients with high P2X₁ expression had a significantly greater change in both haematocrit (− 0.59 ± 0.36) and haemoglobin levels (− 0.182 ± 0.038 mg/dl) per hour, during the first hours after hospital admission compared to patients with low P2X₁ expression (0.007 ± 0.182 and − 0.020 ± 0.058 mg/dl, respectively).

Conclusion

High levels of P2X₁ are correlated with more pronounced reduction in haematocrit and haemoglobin in patients with confirmed bacteraemia. This supports previous in vitro findings of P2X activation as a significant component in cell damage caused by pore-forming bacterial toxins and complement-dependent major attack complex. These data suggest a new potential target for future therapeutics in initial stages of sepsis.

Electronic supplementary material

The online version of this article (10.1186/s13054-018-2100-3) contains supplementary material, which is available to authorized users.

Vitamin D deficiency and mild to moderate anemia in young North Indian children: A secondary data analysis

OBJECTIVES

The aim of this study was to examine the association between vitamin D deficiency and anemia status among young children in the resource-poor setting of northern urban India.

METHODS

We used data from a randomized controlled trial of daily supplementation with folic acid, vitamin B₁₂, or both for 6 mo in children 6 to 30 mo of age conducted in Delhi, India. We measured serum vitamin D status, hemoglobin, plasma vitamin B₁₂, folate, soluble transferrin receptor, and homocysteine levels at baseline. Children with severe anemia (hemoglobin [Hgb] <7 g/dL) were excluded from enrollment. Multivariable logistic and multinomial logistic regressions were used to examine the association between vitamin D and anemia status at baseline.

RESULTS

25-Hydroxyvitamin-D (25 OHD) concentration was measured for 960 (96%) children. Of the children, 331 (34.5%) were vitamin-D deficient (<10 ng/mL). Approximately 70% of the enrolled children were anemic, with ∼46% having moderate (Hgb 7-9.9 g/dL) and 24% mild (Hgb 10-10.9 g/dL) anemia. There was no association between vitamin D and anemia status after adjusting for confounders; however, the risk for moderate anemia was significantly higher among vitamin D-deficient children than those who were vitamin-D replete (relative risk, 1.58; 95% confidence interval, 1.09-2.31).

CONCLUSIONS

Vitamin D deficiency was associated with moderate anemia among young children and the effect was independent of iron deficiency. The causal association of vitamin D deficiency with anemia risk remains debatable. The role of vitamin D in risk for anemia needs to be examined in further studies.

Anemia in the Elderly

Anemia affects a substantial fraction of the elderly population, representing a public health problem that is predicted to further increase in coming years because of the demographic drive. Being typically mild, it is falsely perceived as a minor problem, particularly in the elderly with multimorbidity, so that it often remains unrecognized and untreated. Indeed, mounting evidence indicates that anemia in the elderly (AE) is independently associated with disability and other major negative outcomes, including mortality. AE is generally multifactorial, but initial studies suggested that etiology remains unexplained in near one-third of cases. This proportion is consistently declining due to recent advances highlighting the role of several conditions including clonal hematopoiesis, "inflammaging," correctable androgen deficiency in men, and under-recognized iron deficiency. Starting from a real-world case vignette illustrating a paradigmatic example of anemia in an elderly patient with multimorbidity, we review the main clinical and pathophysiological aspect of AE, giving some practical insights into how to manage similar cases.

Vitamin D deficiency and anemia risk in children: a review of emerging evidence

There has been renewed scientific interest in the sequelae of vitamin D deficiency, given the emerging evidence on the diverse biologic functions of vitamin D, besides its fundamental role in bone and mineral metabolism. For the past decade, the evidence in the medical literature pointing to a relationship between anemia risk and vitamin D deficiency has been accumulating. This paper critically reviews the current evidence linking vitamin D deficiency to anemia risk in children. The synthesized evidence indicates that the studies, which were preponderantly conducted among the adult population, not only reported a bidirectional relationship between vitamin D deficiency and anemia but also showed a racial effect. In studies conducted among children, similar results were reported. Although the causal association of vitamin D deficiency with anemia risk (especially iron-deficiency anemia) remains debatable, the noncalcemic actions of the vitamin and its analogs hold prospects for several novel clinical applications. There is, however, unanimity in many reports suggesting that vitamin D deficiency is directly associated with anemia of chronic disease or inflammation. Despite the advances in unraveling the role of vitamin D in iron homeostasis, further research is still required to validate causality in the relationship between vitamin D deficiency and anemia, as well as to determine its optimal dosing, the ideal recipients for therapeutic intervention, and the preferred analogs to administer.

Pilot study of the effect of cholecalciferol supplementation on hepcidin in children with chronic kidney disease: Results of the D-fense Trial

BACKGROUND

Hepcidin is a key mediator of the anemia of chronic kidney disease (CKD). There is emerging evidence that 25-hydroxyvitamin D (25D) regulates hepcidin production.

METHODS

A randomized controlled trial of daily vitamin D supplementation for 12 weeks was performed with the aim to test the effects of 4000 versus 400 IU of cholecalciferol on serum hepcidin levels in children with non-dialysis CKD recruited at a tertiary care children's hospital. Hepcidin was quantified using a validated competitive enzyme-linked immunosorbent assay. 25D levels were measured using the chemiluminescence Liaison 25(OH)D assay system. Co-variables included hemoglobin, C-reactive protein, ferritin, and serum calcium and phosphorus for safety monitoring.

RESULTS

A total of 34 subjects were randomized to either the intervention or control group, of whom 26.5% were female and 23.5% were African American. The mean age of the study cohort was 10.9 [standard deviation (SD) 5.8] years, the mean baseline glomerular filtration rate was 60 (SD 17.6) ml/min/1.73 m², and mean baseline 25D level was 29.7 (SD 11.5) ng/ml. At baseline, 50% of subjects were 25D deficient. There were no significant differences in baseline characteristics between the intervention and control groups. Treatment with 4000 IU cholecalciferol was not associated with significant change in hepcidin level at 4 or 12 weeks, and multivariable generalized estimating equation regression demonstrated no significant difference in change in hepcidin over the treatment period in either arm. The median C-reactive protein level decreased significantly at 12 weeks in the intervention group.

CONCLUSIONS

These results do not suggest that daily nutritional vitamin D supplementation modifies serum hepcidin levels in children with CKD. Further study will be required to determine whether supplementation may be effective in children with more advanced CKD or those on dialysis.

Prevalence and treatment of hypovitaminosis D in the haemodialysis population of Coventry

Low serum 25(OH)D and associated bone and non-bone related problems are not well appreciated in end stage renal disease (ESRD). Vitamin D treatment strategies in the UK currently focus almost exclusively on calcitriol [1,25(OH)₂D], alfacalcidol or paricalcitol. In ESRD hypovitaminosis D is associated with bone loss, muscle weakness, falls, fractures and increased inflammation. National guidelines changed in 2014 and now recommend the diagnosis and treatment of low serum 25(OH)D in all patients with glomerular filtration rate (GFR) less than 30ml/min/1.73m². However as yet there are no standardized guidelines for dosage, frequency and monitoring in ESRD patients. Following a systematic review of the literature we developed a clinical guideline for cholecalciferol supplementation at University Hospitals of Coventry and Warwickshire, UK. The guideline recommends 40,000IU cholecalciferol weekly for patients with 25(OH)D <50nmol/L and 20,000IU weekly for patients with 25(OH)D 50-75nmol/L; to be continued long term unless levels increase to ≥150nmol/L. To date we have measured 25(OH)D levels in 385 in-center haemodialysis patients. Virtually all patients (95%) had serum 25(OH)D levels <75nmol/L (65% deficient, <30nmol/L; 30% insufficient, 30-74nmol/L). Only 5% of patients had optimal levels (≥75nmol/L). Our data indicates that hypovitaminosis D is prevalent in the haemodialysis population in Coventry and Warwickshire and this is likely to reflect UK haemodialysis patients, highlighting the need for a national supplementation guideline.

Ergocalciferol treatment does Not improve erythropoietin utilization and hospitalization rate in hemodialysis patients

Background

Vitamin D (25-hydroxyvitamin D; 25[OH]D) deficiency (VDD) is highly prevalent in chronic kidney disease. The aim of this study was to evaluate the effect of oral ergocalciferol supplementation on requirement of erythropoietin (EPO) and active vitamin D analogues, and hospitalization rate in maintenance hemodialysis (HD) patients.

Methods

This retrospective cohort study included 186 patients who were on HD for 3 months and had 25(OH)D levels < 30 ng/ml. Over 1-year period, 107 patients were supplemented with protocol-based ergocalciferol (D₂ group) and 79 were not (control). Parameters of erythropoiesis and bone-mineral metabolism, and monthly doses of EPO and paricalcitol were assessed at 6- and 12- months of ergocalciferol supplementation. Total hospitalizations were recorded for the same year.

Results

Baseline characteristics were similar across two arms except higher serum ferritin, transferrin saturation and prevalence of stroke in D2 and higher coronary artery disease in control group with overall mean ± SD 25(OH)D level of 16.8 ± 7 ng/ml. At 12 months, 25(OH)D levels increased significantly in D₂ group compared to control (30.5 ± 11.7 vs. 14.2 ± 9.3 ng/ml; p < 0.001). The EPO dose remained same with no difference in hemoglobin values between the two groups during the intervention period. On multivariate regression which included above variables there was no effect of ergocalciferol treatment on EPO dose (p = ns). Hospitalization rate was similar in two arms; however, ergocalciferol treatment inversely associated with paricalcitol dose (β ± SE = −10.4 ± 2.8; p < 0.001).

Conclusions

One-year of ergocalciferol supplementation was not associated with reduction in EPO requirement or hospitalization rate in HD patients with VDD. Further studies are warranted to determine definitive role of nutritional vitamin D in these patients.

Association of hematology profile with serum 25-hydroxy vitamin D and Bsml polimorphism in community-dwelling older adults

ABSTRACT Objective: To investigate the association between serum level of 25-hydroxy vitamin D and the Vitamin D Receptos gene BsmI polymorphism in the blood profile of community-dwelling older adults. Methods: This cross-sectional study included 142 older males and females. A questionnaire collected socio demographic information, medical history, and factors associated with sun exposure. Weight, height, and waist circumference were measured. Biological material was collected to analyze biochemical parameters 25-hydroxy vitamin D, parathormone, serum calcium, urea, creatinine, liver enzymes, and blood profile) and to verify the presence of the vitamin D receptos gene BsmI polymorphism. Results: Most participants were female (80.3%). The mean levels of 25-hydroxy vitamin D, hemoglobin, and hematocrit were 32.1±7.3 ng/dL, 13.5±1.5 d/dL, and 40.0±4.4%, respectively. Fifty-eight (40.8%) participants had vitamin D insufficiency/deficiency (25.7±3.3 ng/mL), and 18 (12.6%) had anemia. Serum vitamin D was associated with hemoglobin (p=0.030) and hematocrit (p=0.032). However, when subjects were categorized as anemic or not anemic, said association was not maintained (p=0.270). Moreover, the BsmI polymorphism was not associated with hemoglobin and hematocrit levels, regardless of vitamin D status. Conclusion: The serum level of vitamin D is associated with hematocrit and hemoglobin levels in older adults. However, these blood parameters were not associated with the vitamin D receptor gene BsmI polymorphism.

Spectrum and Burden of Erythropoiesis-Stimulating Agent Hyporesponsiveness Among Contemporary Hemodialysis Patients

BACKGROUND

Hemodialysis patients with erythropoiesis-stimulating agent (ESA) hyporesponsiveness have been a topic of active research. However, there have been no studies of ESA hyporesponsiveness among US patients following the dramatic change in anemia management that resulted from the 2011 changes in ESA product labeling and bundling of dialysis remuneration.

STUDY DESIGN

Retrospective observational study.

SETTING & PARTICIPANTS

We studied prevalent hemodialysis patients treated at a large dialysis organization in calendar years 2012 to 2013 (N=98,972).

PREDICTOR

ESA hyporesponsiveness, defined as 2 consecutive hemoglobin measurements < 10g/dL (every other week) with contemporaneous ESA dose > 7,700U/treatment. Patients with ESA hyporesponsiveness were identified during the first quarter of 2012 and followed up through 2013 using intention-to-treat principles.

OUTCOMES

Associations between the study exposure (ESA hyporesponsiveness) and mortality, missed hemodialysis treatments, ESA and iron use, and hemoglobin levels were determined using generalized estimating equations adjusting for imbalanced baseline covariates.

RESULTS

At baseline, 12,361 (12.5%) patients were identified as having ESA hyporesponsiveness. The mean hemoglobin level among patients with ESA hyporesponsiveness was ∼1g/dL lower than in patients without ESA hyporesponsiveness at baseline, narrowing over follow-up to 0.4g/dL. Initially, mean ESA use was approximately 3-fold greater for patients with ESA hyporesponsiveness than for those without ESA hyporesponsiveness, decreasing to 2-fold greater at study end; iron use and missed hemodialysis treatment rates were also greater among patients with ESA hyporesponsiveness throughout. ESA hyporesponsiveness was associated with enhanced mortality risk versus non-ESA hyporesponsiveness: adjusted incidence rate ratios were estimated at 2.24 (95% CI, 1.93-2.60) in the second quarter, gradually decreasing to 1.48 (95% CI, 1.18-1.84) by study end.

LIMITATIONS

It is possible that an alternative ESA hyporesponsiveness definition may be optimal. As such, the associations we observed may be conservative estimates of true relationships.

CONCLUSIONS

When using a contemporary definition at one point in time, ESA hyporesponsiveness was potently and persistently associated with greater mortality, greater iron and ESA use, and lower hemoglobin levels compared to non-ESA hyporesponsiveness.

Vitamin D in patients with chronic kidney disease: a position statement of the Working Group "Trace Elements and Mineral Metabolism" of the Italian Society of Nephrology

In the late 1970s, calcitriol was introduced into clinical practice for the management of secondary renal hyperparathyroidism in chronic kidney disease (CKD). Since then, the use of calcifediol or other native forms of vitamin D was largely ignored until the publication of the 2009 Kidney Disease Improving Global Outcomes (KDIGO) recommendations. The guidelines suggested that measurement of circulating levels of 25(OH)D (calcifediol) and its supplementation were to be performed on the same basis as for the general population. This indication was based on the fact that the precursors of active vitamin D had provided to CKD patients considerable benefits in survival, mainly due to their pleiotropic effects on the cardiovascular system. However, despite the long-term use of various classes of vitamin D in CKD, a clear definition is still lacking concerning the most appropriate time for initiation of therapy, the best compound to prescribe (active metabolites or analogs), the proper dosage, and the most suitable duration of therapy. The aim of this position statement is to provide and critically appraise the current plentiful evidence on vitamin D in different clinical settings related to CKD, particularly focusing on outcomes, monitoring and treatment-associated risks. However, it should be taken in account that position statements are meant to provide guidance; therefore, they are not to be considered prescriptive for all patients and, importantly, they cannot replace the judgment of clinicians.

ESA Hyporesponsiveness Is Associated with Adverse Events in Maintenance Hemodialysis (MHD) Patients, But Not with Iron Storage

Objective

It has been reported that hyporesponsiveness to erythropoiesis-stimulating agent (ESA) is associated with adverse events in patients on maintenance hemodialysis (MHD). However, it has not been determined whether higher iron storage is associated with an improved response, including better survival, to ESA.

Design and Method

We measured serum ferritin, hemoglobin (Hb), and transferrin saturation (TSAT) levels every three months for two years in 1,095 MHD patients. The weekly dose of ESA to Hb ratio was also calculated as an index of ESA responsiveness (ERI).

Results

A significant correlation (p<0.001, R = 0.89) between ferritin and Hb was only observed in the patients with ferritin levels <50 ng/mL. High-dose (≥50 mg/week) intravenous iron administration, female sex, low serum albumin, and angiotensin-converting enzyme inhibitor/angiotensin receptor blocker use were significant predictors of a high ERI value (>280); however, serum ferritin and TSAT levels did not predict a higher ERI. In the time-dependent Cox hazard model, the risk for a composite event in the patients with a high ERI (≥280) and a high ferritin level (≥100 ng/mL) was significantly greater (hazard ratio [HR], 2.09, P = 0.033) than that for patients with a high ERI and a low ferritin (<100 ng/mL) level.

Conclusion

Hb was dependent upon ferritin levels in patients with ferritin levels <50 ng/mL but not in patients with ferritin levels ≥50 ng/mL. Patients with hyporesponsiveness to ESA had a greater risk of composite events, but ERI was unrelated to iron storage.

Vitamin D Supplementation and Hemoglobin Levels in Hypertensive Patients: A Randomized Controlled Trial

Epidemiological evidence suggests that circulating 25-hydroxyvitamin D (25OHD) levels are inversely associated with hemoglobin (Hb) levels and anemia risk. We evaluated whether vitamin D supplementation improves Hb levels and reduces anemia risk in hypertensive patients. Two hundred patients with 25OHD levels <75 nmol/L who attended the Styrian Vitamin D Hypertension Trial were included, of whom 188 completed the trial. Patients randomly received 2800 IU vitamin D3 daily or a matching placebo for eight weeks. Initially, the prevalence of anemic status (Hb levels <12.5 g/dL) and deficient 25OHD levels (<30 nmol/L) was 6.5% and 7.5%, respectively. All anemic patients had 25OHD levels >50 nmol/L. The mean (95% confidence interval) vitamin D effect on Hb levels was 0.04 (-0.14 to 0.22) g/dL (P = 0.661). Moreover, vitamin D treatment did not influence anemic status significantly (P > 0.999). Likewise, vitamin D had no significant effect on Hb levels in the subgroups of anemic patients or in patients with initial 25OHD levels <30 nmol/L. In conclusion, a daily vitamin D supplement of 2800 IU for eight weeks did not improve Hb levels or anemic status in hypertensive patients. Future trials should focus on anemic patients with deficient 25OHD levels (e.g., <30 nmol/L). This trial is registered with clinicaltrials.gov [NCT02136771].

Ergocalciferol Supplementation in Hemodialysis Patients With Vitamin D Deficiency: A Randomized Clinical Trial

Locally produced 1,25-dihydroxyvitamin D3 may have pleiotropic effects outside of bone. Experimental and observational studies suggest that nutritional vitamin D may enhance erythropoiesis in settings of 25-hydroxy vitamin D (25(OH)D) deficiency. We conducted a double-blind, placebo-controlled, randomized clinical trial to assess the effects of supplementation with ergocalciferol on epoetin utilization and other secondary outcomes in patients on hemodialysis with serum 25(OH)D <30 ng/ml. In all, 276 patients were randomized to 6 months of ergocalciferol or placebo. Mean±SD serum 25(OH)D increased from 16.0±5.9 ng/ml at baseline to 39.2±14.9 ng/ml in the ergocalciferol arm and did not change (16.9±6.4 ng/ml and 17.5±7.4 ng/ml, respectively) in the placebo arm. There was no significant change in epoetin dose over 6 months in the ergocalciferol or placebo arms (geometric mean rate 0.98 [95% confidence interval (95% CI), 0.94 to 1.02] versus 0.99 [95% CI, 0.95 to 1.03], respectively) and no difference across arms (P=0.78). No change occurred in serum calcium, phosphorus, intact parathyroid hormone, or C-reactive protein levels, cinacalcet use, or phosphate binder or calcitriol dose in either study arm. Rates of all-cause, cardiovascular, and infection-related hospitalizations did not differ by study arm, although statistical power was limited for these outcomes. In conclusion, 6 months of supplementation with ergocalciferol increased serum 25(OH)D levels in patients on hemodialysis with vitamin D insufficiency or deficiency, but had no effect on epoetin utilization or secondary biochemical and clinical outcomes.

The effect of Vitamin D administration on treatment of anemia in end-stage renal disease patients with Vitamin D deficiency on hemodialysis: A placebo-controlled, double-blind clinical trial

Background:

Chronic kidney disease is a progressive and irreversible loss of renal function. Anemia is one of the main complications of end-stage renal disease (ESRD) which is linked closely with other complications of the disease. The primary therapy for anemia in these patients is erythropoietin (EPO). The goal of this study was to find the effect of Vitamin D administration in addition to the appropriate dose of EPO in ESRD patients with Vitamin D deficiency.

Materials and Methods:

This was a double-blind clinical trial on 64 ESRD patients undergoing hemodialysis in Amin and Noor Hospitals of Isfahan, Iran. The patients were divided into two groups of control and intervention. The intervention group was given Vitamin D supplements and the control group received placebo. The required dose of EPO to reach the target hemoglobin (Hb) was measured and statistically analyzed.

Results:

A total number of 32 females and 32 males were included in this study. All the patients in the treatment group were aged between 18 and 76 and the patients in the control group were aged between 21 and 76 years old. There was a significant statistical relationship between Vitamin D administration and the required dose of EPO in both groups (P = 0.013). However, there was no correlation between the concentration of Hb and serum Vitamin D levels.

Conclusion:

Based on the main finding of this study, the relationship between Vitamin D administration and required dose of EPO seems that the predicted dose of Vitamin D prescribing strategy in Kidney Disease Outcomes Quality Initiative guidelines is not adequate to achieve normal serum Vitamin D in ESRD patients.

Vitamin D and anemia: insights into an emerging association

PURPOSE OF REVIEW

The current review highlights recent findings in the emerging association between vitamin D and anemia through discussion of mechanistic studies, epidemiologic studies, and clinical trials.

RECENT FINDINGS

Vitamin D has previously been found to be associated with anemia in various healthy and diseased populations. Recent studies indicate that the association may differ between race and ethnic groups and is likely specific to anemia of inflammation. The mechanism underlying this association involves the reduction of proinflammatory cytokines by vitamin D and the direct suppression of hepcidin mRNA transcription. There is also evidence that vitamin D may be protective against anemia by supporting erythropoiesis. Other calciotropic hormones including fibroblast growth factor 23, and parathyroid hormone have also been found to be associated with iron homeostasis and erythropoiesis.

SUMMARY

Recent advances in our understanding of the association between vitamin D and anemia suggest that maintenance of sufficient vitamin D status may be important in preventing anemia, particularly in diseases characterized by inflammation. Early clinical trials have been promising, but further research is needed to define the efficacy of vitamin D as a future approach for the treatment of anemia.

Vitamin D Status and the Risk of Anemia in Community-Dwelling Adults: Results from the National Health and Nutrition Examination Survey 2001-2006

Low vitamin D status has been implicated in several chronic medical conditions and unfavorable health outcomes. Our goal was to investigate whether serum 25-hydroxyvitamin D (25OHD) levels are a potentially modifiable risk factor for anemia in a nationally representative cohort of community-dwelling individuals in the United States. We performed a cross-sectional study of 5456 individuals (≥17 years) from the National Health and Nutrition Examination Survey from 2001 to 2006. Locally weighted scatterplot smoothing (LOWESS) was used to graphically depict the relationship between serum 25OHD levels and the cumulative frequency of anemia. Multivariable logistic regression models were then used to assess the independent association of 25OHD levels with anemia, while controlling for age, sex, race, body mass index, chronic kidney disease, as well as serum levels of C-reactive protein, ferritin, iron, vitamin B12, and folic acid. The mean (standard error) 25OHD and hemoglobin levels in the analytic group were 23.5 (0.4) ng/mL and 14.4 (0.1) g/dL, respectively. Prevalence of anemia was 3.9%. Locally weighted scatterplot smoothing analysis demonstrated a near-linear relationship between vitamin D status and cumulative frequency of anemia up to 25OHD levels of approximately 20  ng/mL. With increasing 25OHD levels, the curve flattened out progressively. Multivariable regression analysis demonstrated an inverse association of 25OHD levels with the risk of anemia (adjusted odds ratio 0.97; 95% confidence interval 0.95-0.99 per 1  ng/mL change in 25OHD). Compared to individuals with ≥20  ng/mL, individuals with 25OHD levels <20  ng/mL were more likely to be anemic (adjusted odds ratio 1.64; 95% confidence interval 1.08-2.49). In a nationally representative sample of community-dwelling individuals in the United States, low 25OHD levels were associated with increased risk of anemia. Randomized controlled trials are needed to determine whether optimizing vitamin D status can reduce the burden of anemia in the general population.

Association between serum alkaline phosphatase and primary resistance to erythropoiesis stimulating agents in chronic kidney disease: a secondary analysis of the HERO trial

BACKGROUND

Erythropoiesis stimulating agent (ESA)-resistant anemia is common in chronic kidney disease (CKD).

OBJECTIVES

To evaluate the determinants of severity of ESA resistance in patients with CKD and primary ESA-resistance.

DESIGN

Secondary analysis of a randomized controlled trial (the Handling Erythropoietin Resistance with Oxpentifylline, HERO).

SETTING AND PATIENTS

53 adult patients with CKD stage 4 or 5 and primary ESA-resistant anemia (hemoglobin ≤120 g/L, ESA resistance index [ERI] ≥1.0 IU/kg/week/gHb for erythropoietin or ≥0.005 μg/kg/week/gHb for darbepoeitin, no cause for ESA-resistance identified).

MEASUREMENTS

Iron studies, parathyroid hormone, albumin, liver enzymes, phosphate or markers of oxidative stress and inflammation.

METHODS

Participants were divided into tertiles of ERI. Multinomial logistic regression was used to analyse the determinants of ERI tertiles.

RESULTS

All patients, except one, were receiving dialysis for end-stage kidney disease. The mean ± SD ERI values in the low (n = 18), medium (n = 18) and high (n = 17) ERI tertiles were 1.4 ± 0.3, 2.3 ± 0.2 and 3.5 ± 0.8 IU/kg/week/gHb, respectively (P < 0.001). There were no significant differences observed in age, gender, ethnicity, cause of kidney disease, diabetes, iron studies, parathyroid hormone, albumin, liver enzymes, phosphate or markers of oxidative stress and inflammation between the ERI tertiles. The median [inter-quartile range] serum alkaline phosphatase concentrations in the low, medium and high ERI tertiles were 89 [64,121], 99 [76,134 and 148 [87,175] U/L, respectively (P = 0.054). There was a weak but statistically significant association between ERI and serum alkaline phosphatase (R(2) = 0.06, P = 0.03). Using multinomial logistic regression, the risk of being in the high ERI tertile relative to the low ERI tertile increased with increasing serum alkaline phosphatase levels (P = 0.02). No other variables were significantly associated with ERI.

LIMITATIONS

Small sample size; bone-specific alkaline phosphatase, other markers of bone turnover and bone biopsies not evaluated.

CONCLUSIONS

Serum alkaline phosphatase was associated with severity of ESA resistance in ESA-resistant patients with CKD. Large prospective studies are required to confirm this association. (

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry 12608000199314).

Cardiorenal Syndrome and the Role of the Bone-Mineral Axis and Anemia

The association between chronic kidney disease (CKD) and cardiovascular disease (CVD) is well established, and there is mounting evidence of interorgan cross talk that may accelerate pathologic processes and the progression of organ dysfunction in both systems. This process, termed cardiorenal syndrome (CRS) by the Acute Dialysis Quality Initiative, is considered a major health problem: patients with CKD and CVD are at much higher risk of mortality than patients with either condition alone. To date, the majority of CRS research has focused on neurohormonal mechanisms and hemodynamic alterations. However, mounting evidence suggests that abnormalities in the normal pathophysiology of the bone-mineral axis, iron, and erythropoietin play a role in accelerating CKD and CVD. The goal of this article is to review the role and interrelated effects of the bone-mineral axis and anemia in the pathogenesis of chronic CRS.

Comparison of erythropoietin resistance in hemodialysis patients using calcitriol, cinacalcet, or paricalcitol

The erythropoiesis-stimulating agent (ESA) hyporesponsiveness index (EHRI) calculated as the weekly dose of EPO divided by weight (kg) divided by hemoglobin level (g/dL) has been considered useful to assess ESA resistance. Recent evidence suggests that active vitamin D, cinacalcet, and paricalcitol use may be related with lower ESA resistance. We conducted this observational cross-sectional study to investigate ESA resistance calculated by the EHRI among patients using calcitriol, cinacalcet, and paricalcitol. Participants underwent a medical history taken, physical examination, measurement of biochemical analysis, calculation of dialysis adequacy, and EHRI. Sixty-five patients did not receive any treatment regarding vitamin D, paricalcitol, and cinacalcet (group 1), 41 were taking only vitamin D (group 2), 50 were taking only paricalcitol (group 3), 19 were taking only cinacalcet (group 4), and 21 were taking paricalcitol + cinacalcet (group 5). The EHRI values for groups 1, 2, 3, 4, and 5 were 11.36 ± 8.72, 11.58 ± 5.72, 8.29 ± 5.54, 9.49 ± 4.61, and 8.91 ± 4.44 respectively (P =.034). Post hoc analysis showed that the EHRI differed between group 1 and group 3 (P =.017) and between group 2 and group 3 (P =.006). In linear regression analysis, use of paricalcitol was independently associated with EHRI. In conclusion, paricalcitol use was associated with lower EHRI levels as a measure of ESA resistance.

Independent association of circulating vitamin D metabolites with anemia risk in patients scheduled for cardiac surgery

BACKGROUND

Preoperative anemia is considered an independent risk factor of poor clinical outcome in cardiac surgical patients. Low vitamin D status may increase anemia risk.

METHODS

We investigated 3,615 consecutive patients scheduled for cardiac surgery to determine the association between preoperative anemia (hemoglobin [Hb] <12.5 g/dL) and circulating levels of the vitamin D metabolites 25-hydroxyvitamin D (25OHD) and 1,25-dihydroxyvitamin D (1,25[OH]2D).

RESULTS

Of the study cohort, 27.8 % met the criteria for anemia. In patients with deficient 25OHD levels (<30 nmol/l) mean Hb concentrations were 0.5 g/dL lower than in patients with adequate 25OHD levels (50.0-125 nmol/l; P<0.001). Regarding 1,25(OH)2D, mean Hb concentrations were 1.2 g/dL lower in the lowest 1,25(OH)2D category (<40 pmol/l) than in the highest 1,25(OH)2D category (>70 pmol/l; P<0.001). In multivariable-adjusted logistic regression analyses, the odds ratios for anemia of the lowest categories of 25OHD and 1,25(OH)2D were 1.48 (95%CI:1.19-1.83) and 2.35 (95%CI:1.86-2.97), compared with patients who had adequate 25OHD levels and 1,25(OH)2D values in the highest category, respectively. Anemia risk was greatest in patients with dual deficiency of 25OHD and 1,25(OH)2D (multivariable-adjusted OR = 3.60 (95%CI:2.40-5.40). Prevalence of deficient 25OHD levels was highest in anemia of nutrient deficiency, whereas low 1,25(OH)2D levels were most frequent in anemia of chronic kidney disease.

CONCLUSION

This cross-sectional study demonstrates an independent inverse association between vitamin D status and anemia risk. If confirmed in clinical trials, preoperative administration of vitamin D or activated vitamin D (in case of chronic kidney disease) would be a promising strategy to prevent anemia in patients scheduled for cardiac surgery.

Cross-sectional and longitudinal associations between the active vitamin D metabolite (1,25 dihydroxyvitamin D) and haemoglobin levels in older Australian men: the Concord Health and Ageing in Men Project

Anaemia and low 25 hydroxyvitamin D (25D) and 1,25 dihydroxyvitamin D (1,25D) levels are common in older people and may adversely affect morbidity and mortality. While there is some evidence for an association between low serum 25D levels and anaemia, there are limited studies among community-dwelling older people. In addition, the relationship between anaemia and the active vitamin D metabolite, 1,25D, has not been investigated. The aim of this study was to examine the associations between serum 25D and 1,25D with anaemia in community-living men aged ≥70 years. Population-based, cross-sectional analysis of the baseline phase and longitudinal analysis of the Concord Health and Ageing in Men Project (CHAMP), a large epidemiological study conducted in Sydney among men aged 70 years and older, were performed; 1666 men were seen at baseline (2005-2007), 1314 men at a 2-year follow-up (2007-2009) and 917 at a 5-year follow-up (2012-2013). The main outcome measurement was haemoglobin levels as a continuous measure. Covariates included 25D and 1,25D, estimated glomerular filtration rate, demographic information, lifestyle measures, health conditions and medication information. The prevalence of anaemia (Hb < 13.0 g/dL, WHO definition) was 14.6 %. In cross-sectional analysis, serum 25D concentrations were positively associated with haemoglobin levels in unadjusted analysis (β value 0.004; 95 % confidence interval (CI) 0.0009, 0.007; p = 0.01), but the associations were no longer significant after multivariate adjustment. The association between 1,25D levels and haemoglobin levels was significant in unadjusted analysis (β value 0.003; 95 % CI 0.002, 0.004; p < 0.0001) and remained significant in adjusted analysis (β value 0.001; 95 % CI 0.004, 0.003; p = 0.01). Serum 1,25D (but not 25D) levels at baseline were significantly associated with changes in haemoglobin over 2 and 5 years in unadjusted (β value 0.002; 95 % CI 0.0009, 0.003; p < 0.0001) and in fully adjusted analyses (β value 0.001; 95 % CI 0.0004, 0.002; p = 0.001). Serum 1,25D, but not 25D, concentrations are independently associated with haemoglobin levels in older men in both cross-sectional and longitudinal analyses. This raises the question whether vitamin D metabolites may influence anaemia states, mediated through different biological pathways, or represent a time-dependent biomarker of chronic ill health.

Longitudinal assessments of erythropoietin-stimulating agent responsiveness and the association with specific clinical outcomes in dialysis patients

BACKGROUND

Dose requirements of erythropoietin-stimulating agents (ESAs) can vary considerably over time and may be associated with cardiovascular outcomes. We aimed to longitudinally assess ESA responsiveness over time and to investigate its association with specific clinical end points in a time-dependent approach.

METHODS

The German Diabetes and Dialysis study (4D study) included 1,255 diabetic dialysis patients, of whom 1,161 were receiving ESA treatment. In those patients, the erythropoietin resistance index (ERI) was assessed every 6 months during a median follow-up of 4 years. The association between the ERI and cardiovascular end points was analyzed by time-dependent Cox regression analyses with repeated ERI measures.

RESULTS

Patients had a mean age of 66 ± 8.2 years; 53% were male. During follow-up, a total of 495 patients died, of whom 136 died of sudden death and 102 of infectious death. The adjusted and time-dependent risk for sudden death was increased by 19% per 5-unit increase in the ERI (hazard ratio, HR = 1.19, 95% confidence interval, CI = 1.07-1.33). Similarly, mortality increased by 25% (HR = 1.25, 95% CI = 1.18-1.32) and infectious death increased by 27% (HR = 1.27, 95% CI = 1.13-1.42). Further analysis revealed that lower 25-hydroxyvitamin D levels were associated with lower ESA responsiveness (p = 0.046).

CONCLUSIONS

In diabetic dialysis patients, we observed that time-varying erythropoietin resistance is associated with sudden death, infectious complications and all-cause mortality. Low 25-hydroxyvitamin D levels may contribute to a lower ESA responsiveness.

Impact of vitamin D on immune function: lessons learned from genome-wide analysis

Immunomodulatory responses to the active form of vitamin D (1,25-dihydroxyvitamin D, 1,25D) have been recognized for many years, but it is only in the last 5 years that the potential role of this in normal human immune function has been recognized. Genome-wide analyses have played a pivotal role in redefining our perspective on vitamin D and immunity. The description of increased vitamin D receptor (VDR) and 1α-hydroxylase (CYP27B1) expression in macrophages following a pathogen challenge, has underlined the importance of intracrine vitamin D as key mediator of innate immune function. It is now clear that both macrophages and dendritic cells (DCs) are able to respond to 25-hydroxyvitamin D (25D), the major circulating vitamin D metabolite, thereby providing a link between the function of these cells and the variations in vitamin D status common to many humans. The identification of hundreds of primary 1,25D target genes in immune cells has also provided new insight into the role of vitamin D in the adaptive immune system, such as the modulation of antigen-presentation and T cells proliferation and phenotype, with the over-arching effects being to suppress inflammation and promote immune tolerance. In macrophages 1,25D promotes antimicrobial responses through the induction of antibacterial proteins, and stimulation of autophagy and autophagosome activity. In this way variations in 25D levels have the potential to influence both innate and adaptive immune responses. More recent genome-wide analyses have highlighted how cytokine signaling pathways can influence the intracrine vitamin D system and either enhance or abrogate responses to 25D. The current review will discuss the impact of intracrine vitamin D metabolism on both innate and adaptive immunity, whilst introducing the concept of disease-specific corruption of vitamin D metabolism and how this may alter the requirements for vitamin D in maintaining a healthy immune system in humans.

Vitamin D, race, and risk for anemia in children

OBJECTIVE

To examine the association between 25-hydroxyvitamin D [25(OH)D] deficiency and anemia in a cohort of otherwise-healthy children and to determine whether race modifies the association between 25(OH)D status and hemoglobin (Hgb).

STUDY DESIGN

Cross-sectional study of 10,410 children and adolescents ages 1-21 years from the 2001-2006 National Health and Nutrition Examination Survey. Anemia was defined as Hgb less than the 5th percentile for age and sex based on National Health and Nutrition Examination Survey III (1988-1994) data.

RESULTS

Lower 25(OH)D levels were associated with increased risk for anemia; <30 ng/mL, adjusted OR 1.93, 95% CI 1.21-3.08, P = .006, and <20 ng/mL, OR 1.47, 95% CI 1.14-1.89, P = .004. In linear regression, small but significant increases in Hgb were noted in the upper quartiles of 25(OH)D compared with the lowest quartile (<20 ng/mL) in the full cohort. Results of race-stratified linear regression by 25(OH)D quartile in white children were similar to those observed in the full cohort, but in black children, an increase in Hgb in the upper 25(OH)D quartiles was only apparent compared with the lowest black race-specific quartile (<12 ng/mL).

CONCLUSION

25(OH)D deficiency is associated with increased risk of anemia in healthy US children, but the 25(OH)D threshold levels for lower Hgb are lower in black children in comparison with white children.

Suppression of iron-regulatory hepcidin by vitamin D

The antibacterial protein hepcidin regulates the absorption, tissue distribution, and extracellular concentration of iron by suppressing ferroportin-mediated export of cellular iron. In CKD, elevated hepcidin and vitamin D deficiency are associated with anemia. Therefore, we explored a possible role for vitamin D in iron homeostasis. Treatment of cultured hepatocytes or monocytes with prohormone 25-hydroxyvitamin D or active 1,25-dihydroxyvitamin D decreased expression of hepcidin mRNA by 0.5-fold, contrasting the stimulatory effect of 25-hydroxyvitamin D or 1,25-dihydroxyvitamin D on related antibacterial proteins such as cathelicidin. Promoter-reporter and chromatin immunoprecipitation analyses indicated that direct transcriptional suppression of hepcidin gene (HAMP) expression mediated by 1,25-dihydroxyvitamin D binding to the vitamin D receptor caused the decrease in hepcidin mRNA levels. Suppression of HAMP expression was associated with a concomitant increase in expression of the cellular target for hepcidin, ferroportin protein, and decreased expression of the intracellular iron marker ferritin. In a pilot study with healthy volunteers, supplementation with a single oral dose of vitamin D (100,000 IU vitamin D2) increased serum levels of 25D-hydroxyvitamin D from 27±2 ng/ml before supplementation to 44±3 ng/ml after supplementation (P<0.001). This response was associated with a 34% decrease in circulating levels of hepcidin within 24 hours of vitamin D supplementation (P<0.05). These data show that vitamin D is a potent regulator of the hepcidin-ferroportin axis in humans and highlight a potential new strategy for the management of anemia in patients with low vitamin D and/or CKD.

Non-linear relationship between serum 25-hydroxyvitamin D and hemoglobin in Korean females: the Korean National Health and Nutrition Examination Survey 2010-2011

BACKGROUND

Anemia and vitamin D deficiency are both important health issues; however, the nature of the association between vitamin D and either hemoglobin or anemia remains unresolved in the general population.

METHODS

Data on 11,206 adults were obtained from the fifth Korean National Health and Nutritional Examination Survey. A generalized additive model was used to examine the threshold level for relationship between serum 25-hydroxyvitamin D [25(OH)D] and hemoglobin levels. A multivariate logistic regression for anemia was conducted according to 25(OH)D quintiles. All analyses were stratified according to sex and menstrual status.

RESULTS

The generalized additive model confirmed a threshold 25(OH)D level of 26.4 ng/mL (male, 27.4 ng/mL; premenopausal females, 11.8 ng/mL; postmenopausal females, 13.4 ng/mL). The threshold level affected the pattern of association between 25(OH)D and anemia risk: the odds ratio of the 1(st) quintile but not the 2(nd), 3(rd), and 4(th) quintiles were significantly different from the 5(th) quintile in both premenopausal and postmenopausal females, however there was no obvious trend in males.

CONCLUSIONS

This population-based study demonstrated a non-linear relationship with a threshold effect between serum 25(OH)D and hemoglobin levels in females. Further interventional studies are warranted to determine whether the appropriate level of hemoglobin can be achieved by the correction of vitamin D deficiency.

Ergocalciferol decreases erythropoietin resistance in children with chronic kidney disease stage 5

BACKGROUND

Vitamin D insufficiency is related to erythropoietin resistance in chronic kidney disease (CKD). This study was conducted to evaluate the effect of ergocalciferol on the dose of erythrocyte-stimulating agent (ESA) administered to children with CKD stage 5 and vitamin D insufficiency.

METHODS

Twenty patients aged <18 years with CKD stages 5 or 5D and vitamin D insufficiency were divided into two groups. During the 12-week study, ten patients received oral ergocalciferol (treatment) whereas the other ten patients did not (control). The ESA dosage was recorded monthly.

RESULTS

There were no significant differences in demographic data, ESA dosages, and laboratory data, including corrected calcium, phosphorus, parathyroid hormone, hemoglobin, ferritin, 25-hydroxyvitamin D (25D), and transferrin saturation levels, between the two groups at baseline. At the completion of the study, serum 25D levels in the treatment group were significantly increased from baseline (p = 0.02) and were significantly higher than the serum 25D levels in the controls (p < 0.005). The ESA dosage in the treatment group was significantly decreased when compared to baseline (p = 0.04).

CONCLUSIONS

Vitamin D deficiency should be routinely detected and treated. Our results show that the administration of ergocalciferol in conjunction with 1,25-dihydroxyvitamin D3 reduced the dose of ESA required to treat children with CKD stages 5 and 5D and may decrease erythropoietin resistance.

Predicting erythropoietin resistance in hemodialysis patients with type 2 diabetes

Background

Resistance to ESAs (erythropoietin stimulating agents) is highly prevalent in hemodialysis patients with diabetes and associated with an increased mortality. The aim of this study was to identify predictors for ESA resistance and to develop a prediction model for the risk stratification in these patients.

Methods

A post-hoc analysis was conducted of the 4D study, including 1015 patients with type 2 diabetes undergoing hemodialysis. Determinants of ESA resistance were identified by univariate logistic regression analyses. Subsequently, multivariate models were performed with stepwise inclusion of significant predictors from clinical parameters, routine laboratory and specific biomarkers.

Results

In the model restricted to clinical parameters, male sex, shorter dialysis vintage, lower BMI, history of CHF, use of ACE-inhibitors and a higher heart rate were identified as independent predictors of ESA resistance. In regard to routine laboratory markers, lower albumin, lower iron saturation, higher creatinine and higher potassium levels were independently associated with ESA resistance. With respect to specific biomarkers, higher ADMA and CRP levels as well as lower Osteocalcin levels were predictors of ESA resistance.

Conclusions

Easily obtainable clinical parameters and routine laboratory parameters can predict ESA resistance in diabetic hemodialysis patients with good discrimination. Specific biomarkers did not meaningfully further improve the risk prediction of ESA resistance. Routinely assessed data can be used in clinical practice to stratify patients according to the risk of ESA resistance, which may help to assign appropriate treatment strategies.

Clinical trial registration

The study was registered at the German medical authority (BfArM; registration number 401 3206). The sponsor protocol ID and clinical trial unique identified number was CT-981-423-239. The results of the study are published and available at http://www.ncbi.nlm.nih.gov/pubmed/16034009.

Renal anaemia and EPO hyporesponsiveness associated with vitamin D deficiency: the potential role of inflammation

Resistance to erythropoiesis-stimulating agents (ESAs) has been observed in a considerable proportion of patients with chronic kidney disease (CKD) and it is reportedly associated with adverse outcomes, such as increased cardiovascular morbidity, faster progression to end-stage renal disease (ESRD) and all-cause mortality. The major causes of ESA resistance include chronic inflammation producing suppressive cytokines of early erythroid progenitor proliferation. In addition, pro-inflammatory cytokines stimulate hepcidin synthesis thus reducing iron availability for late erythropoiesis. Recent studies showing an association in deficiencies of the vitamin D axis with low haemoglobin (Hb) levels and ESA resistance suggest a new pathophysiological co-factor of renal anaemia. The administration of either native or active vitamin D has been associated with an improvement of anaemia and reduction in ESA requirements. Notably, these effects are not related to parathyroid hormone (PTH) values and seem to be independent on PTH suppression. Another possible explanation may be that calcitriol directly stimulates erythroid progenitors; however, this proliferative effect by extra-renal activation of 1α-hydroxylase enzyme is only a hypothesis. The majority of studies concerning vitamin D deficiency or supplementation, and degree of renal anaemia, point out the prevalent role of inflammation in the mechanism underlying these associations. Immune cells express the vitamin D receptor (VDR) which in turn is involved in the modulation of innate and adaptive immunity. VDR activation inhibits the expression of inflammatory cytokines in stromal and accessory cells and up-regulates the lymphocytic release of interleukin-10 (IL-10) exerting both anti-inflammatory activity and proliferative effects on erythroid progenitors. In CKD patients, vitamin D deficiency may stimulate immune cells within the bone marrow micro-environment to produce cytokines, inducing impaired erythropoiesis. Immune activation involves the reticuloendothelial system, increasing hepcidin synthesis and functional iron deficiency. Consequences of this inflammatory cascade are erythropoietin (EPO) resistance and anaemia. Given the key role of inflammation in the response to EPO, the therapeutic use of agents with anti-cytokines properties, such as vitamin D and paricalcitol, may provide benefit in the prevention/treatment of ESA hyporesponsiveness.

Hb level in relation to vitamin D status in healthy infants and toddlers

Objective

To assess the presence of an association between vitamin D deficiency and anaemia in Jordanian infants and toddlers, in whom both vitamin D deficiency and anaemia have previously been proved to be common separately.

Design

Cross-sectional prospective study.

Setting

Department of Paediatrics, Princess Rahma Teaching Hospital, Jordan.

Subjects

Healthy infants and children aged 6–36 months who were seen for primary care.

Results

Out of 203 infants and toddlers included in the study, the anaemia prevalence was 40·4 %. The prevalence of anaemia among infants (n 110) was 51·8 %, whereas it was 26·9 % among toddlers (n 93). No association between vitamin D status and anaemia was found.

Conclusions

Vitamin D deficiency is not a risk for anaemia in infants and toddlers.

Classical and emerging roles of vitamin D in hepatitis C virus infection

According to the Institute of Medicine, the risk of clinically significant vitamin D deficiency increases at 25-hydroxyvitamin D levels below 20 ng/mL. By this standard, most cirrhotic hepatitis C virus- (HCV-) positive patients and many noncirrhotic patients are vitamin D-deficient. The high prevalence of vitamin D deficiency among HCV patients is a cause for concern for several specific reasons. Classic studies established the importance of vitamin D and calcium in maintaining bone. Vitamin D's beneficial effects on bone are likely to be vital for HCV-infected patients because these individuals have a high prevalence of low bone mineral density. Many pharmaceutical agents reduce bone density and exposure to these drugs may increase bone disease in HCV-positive patients. Bone loss occurs following liver transplantation and bone density is often low in patients with HIV/HCV co-infection who are on combination antiretroviral therapy. Some evidence suggests that ribavirin reduces bone density, underscoring the special need to monitor vitamin D in patients receiving HCV treatment and to prescribe supplements, as appropriate. In addition to its role in calcium metabolism, vitamin D is also an immune modulator that reduces inflammation while enhancing protective immune responses. Higher vitamin D levels are associated with less liver fibrosis and less inflammation in HCV patients. Recent studies show that low vitamin D levels are associated with treatment failure among HCV-infected patients receiving pegylated-interferon and ribavirin. If confirmed, these findings will provide an additional reason to ensure adequate levels of vitamin D. Information about how to monitor vitamin D status and how to use vitamin D supplements most effectively in HCV-infected patients is provided.

Association of serum phosphorus level with anemia in kidney transplant recipients

BACKGROUND

Anemia and mineral and bone disorders (MBD) are both important and common complications in kidney transplant recipients. Studies in patients with chronic kidney disease indicated a possible independent association of higher serum phosphorus with anemia, but similar associations have not been examined in kidney transplant recipients. We hypothesized that higher serum phosphorus is associated with anemia independent of other components of MBD.

METHODS

We examined the association of serum phosphorus with hemoglobin level and the prevalence of anemia in a prevalent cohort of 992 kidney transplant recipients in a single outpatient transplant center. Associations were examined in linear and logistic regression models with adjustment for demographic and comorbid conditions for various known risk factors of anemia, including measures of iron deficiency, inflammation, and components of MBD including serum levels of 25(OH) vitamin D, parathyroid hormone, and fibroblast growth factor 23.

RESULTS

In multivariable adjusted regression models, a 1 standard deviation (0.8 mg/dL) higher serum phosphorus level was associated with 0.26 g/dL lower blood hemoglobin concentration (95% confidence intervals -0.36 to -0.15, P<0.001) and with an odds ratio for anemia of 1.77 (95% confidence intervals 1.33-2.37, P<0.001). These associations were consistent across the entire spectrum of the physiologic serum phosphorus concentration and were more accentuated in patients with lower estimated glomerular filtration rate.

CONCLUSIONS

Higher serum phosphorus is independently associated with anemia in kidney transplant recipients.

Plasma 25-hydroxyvitamin d is independently associated with hemoglobin concentration in male subjects with type 2 diabetes mellitus

Introduction. It was reported that 25-hydroxyvitamin D level was independently associated with anemia in chronic kidney diseases, but the relation between vitamin D and anemia in diabetes mellitus is not still certain. We analyzed the relation between plasma 25-hydroxyvitamin D level and hemoglobin concentration. Materials and Methods. A cross-sectional study in male patients with type 2 diabetes was performed. Correlation coefficients and standardized partial regression coefficient for the hemoglobin concentration were evaluated. Results. Hemoglobin concentration was positively correlated with body mass index, HbA1c, estimated glomerular filtration rate, cholinesterase, and 25-hydroxyvitamin D level and negatively correlated with age, duration of diabetes mellitus, serum creatinine, and urinary albumin creatinine ratio. Multiple regression analysis revealed the independent relation of 25-hydroxyvitamin D to hemoglobin concentration. Conclusions. Plasma circulating form of vitamin D is significantly associated with hemoglobin concentration in diabetes mellitus independent of the clinical markers for kidney function or nutrition.