Effect of parathyroid hormone on erythropoiesis

The clinical efficacy of combined ESA and Roxadustat treatment for renal anemia in hemodialysis patients with secondary hyperparathyroidism: A case series

RATIONALE

Pharmacological mechanism of Roxadustat in the treatment of renal anemia.

PATIENT CONCERNS

To investigate the efficacy and safety of combined Roxadustat and erythropoiesis stimulator (ESA) treatment of renal anemia in hemodialysis patients with secondary hyperparathyroidism.

DIAGNOSES

A retrospective analysis was conducted on hemodialysis patients with renal anemia and secondary hyperparathyroidism treated with ESAs alone, who were admitted to our hospital from March 2022 to December 2022.

INTERVENTIONS

The patients were treated with Roxadustat combined with ESAs for 3 months, during which oral iron supplementation was given, and the changes in Hb levels and laboratory-related indicators before and after the combined treatment were analyzed.

OUTCOMES

The results showed that a total of 13 patients received combination therapy, with a significant increase in Hb compared to ESAs alone (t = -3.955, P = .002). The Hb qualification rate was 38.46%, and the ∆Hb response rate was 76.92%. The parathyroid hormone significantly decreased with a statistically significant difference (Z = -2.062b, P = .039). Hemoglobin (RBC), total iron binding capacity, and serum ferritin (male) were significantly increased compared to ESAs alone. Total cholesterol and low-density lipoprotein were significantly lower than ESAs alone. The differences in the changes in the above indicators were statistically significant (P < .05). There was no statistically significant difference in changes in other laboratory-related indicators (P > .05). No adverse reactions were observed during the combined treatment of 13 patients.

LESSONS SUBSECTIONS

The combination of Roxadustat and ESAs can effectively improve renal anemia in hemodialysis patients with secondary hyperparathyroidism, as well as improve indicators of hyperparathyroidism and blood lipid levels with high levels of safety. This combined treatment thus provides a new and safe treatment method for these patients.

Comparative effectiveness and acceptability of HIF prolyl-hydroxylase inhibitors versus for anemia patients with chronic kidney disease undergoing dialysis: a systematic review and network meta-analysis

Background: The comparative benefits and acceptability of HIF-PHIs for treating anemia have not been well researched to date. We sought to compare the effectiveness of 6 HIF-PHIs and 3 ESAs for the treatment of renal anemia patients undergoing dialysis. Data sources: Cochrane Central Register of Controlled Trials, PubMed, Embase, Cochrane Library, MEDLINE, Web of Science, and clinicaltrials.gov databases. Results: Twenty-five RCTs (involving 17,204 participants) were included, all of which were designed to achieve target Hb levels by adjusting thee dose of HIF-PHIs. Regarding the efficacy in achieving target Hb levels, no significant differences were found between HIF-PHIs and ESAs in Hb response at the dose-adjusted designed RCTs selected for comparison. Intervention with roxadustat showed a significantly lower risk of RBC transfusion than rhEPO, with an OR and 95% CI of 0.76 (0.56-0.93). Roxadustat and vadadustat had higher risks of increasing the discontinuation rate than ESAs; the former had ORs and 95% CIs of 1.58 (95% CI: 1.21-2.06) for rhEPO, 1.66 (1.16-2.38) for DPO (darbepoetin alfa), and 1.76 (1.70-4.49) for MPG-EPO, and the latter had ORs and 95% CIs of 1.71 (1.09-2.67) for rhEPO, 1.79 (1.29-2.49) for DPO, and 2.97 (1.62-5.46) for MPG-EPO. No differences were observed in the AEs and SAEs among patients who received the studied drugs. Results of a meta-analysis of gastrointestinal disorders among AEs revealed that vadadustat was less effect on causing diarrea than DPO, with an OR of 0.97 (95% CI, 0.9-0.99). Included HIF-PHIs, were proven to be more effective than ESAs in reducing hepcidin levels and increasing TIBC and serum iron level with OR of -0.17 (95% CI, -0.21 to -0.12), OR of 0.79 (95% CI, 0.63-0.95), and OR of 0.39 (95% CI, 0.33-0.45), respectively. Conclusion: HIF-PHIs and ESAs have their characteristics and advantages in treating anemia undergoing dialysis. With the selected dose-adjusted mode, some HIF-PHIs appeared to be a potential treatment for DD-CKD patients when ompared with rhEPO, due to its effectiveness in decreasing the risk of RBC transfusion rate or regulating iron or lipid metabolism while achieving target Hb levels. Systematic Review Registration: https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=306511; Identifier: CRD42022306511.

Evaluation of malnutrition and inflammation after total parathyroidectomy in patients on maintenance dialysis

PURPOSE

To evaluate the effect of total parathyroidectomy (tPTx) on malnutrition and inflammation in patients on maintenance dialysis (MHD) having secondary hyperparathyroidism (SHPT).

METHODS

Twenty-five patients on MHD having SHPT who were being treated with tPTx were selected, and changes in their general condition (dry body mass), parathyroid hormone (PTH) and calcium levels, nutrition state (hemoglobin, hematocrit, serum albumin, and total iron binding capacity), and inflammatory status [serum C-reactive protein (CRP), interleukin-6 (IL-6), tumor necrosis factor (TNF-α), and the malnutrition-inflammation score (MIS)] were observed at 12, 24, and 36 months postoperatively.

RESULTS

Compared with the preoperative period, the dry body mass increased at 12, 24, and 36 months postoperatively (P < 0.01), hemoglobin, hematocrit, and serum albumin increased significantly (P < 0.01), whereas calcium, phosphorus, and PTH levels decreased significantly (P < 0.01). Serum CRP, IL-6, and TNF-α levels were significantly decreased at 12, 24, and 36 months after surgery (P < 0.01). Furthermore, MIS was reduced as well but to a lesser extent (P < 0.01).

CONCLUSION

tPTx effectively reduced MIS in maintenance dialysis patients, and the alleviated malnutrition and improved inflammatory status may contributed to improving the quality of life of patients on MHD with SHPT.

Association between Serum Magnesium and Hemoglobin in Patients with Primary Hyperparathyroidism

BACKGROUND

There is a positive association between serum magnesium and hemoglobin levels in the general population. However, no studies have evaluated the association between serum magnesium and hemoglobin levels in patients with primary hyperparathyroidism (PHPT). We aimed to investigate whether there is a relationship between serum magnesium and hemoglobin levels in the patient population with PHPT.

METHODS

This retrospective study included 307 hospitalized PHPT patients who were continuously admitted to the Second Xiangya Hospital of Central South University, from January 2010 to August 2020. Laboratory and demographic data of patients were collected. Hypomagnesemia was defined as serum magnesium <0.75 mmol/L. Patients with a hemoglobin level below 130 g/L in males and below 120 g/L in females were accepted as the anemic group.

RESULTS

Among the 307 patients with PHPT included in our study, 77 (25.1%) patients (33 (32.4%) males and 44 (21.5%) females) had hypomagnesemia. A total of 138 (45.0%) patients (49 males (48.0%) and 89 females (43.4%)) had anemia. Compared with the nonanemic group, the anemic group had lower average albumin, eGFR, and serum magnesium levels in both males and females. In contrast, average creatinine, PTH, and corrected calcium were significantly higher in the anemic group than in the nonanemic group in both males and females. Lower serum magnesium levels were associated with lower hemoglobin levels independent of serum calcium, albumin, eGFR, and PTH in PHPT patients.

CONCLUSIONS

Hypomagnesemia is a common electrolyte disorder in PHPT patients. Hypomagnesemia is independently associated with lower hemoglobin levels in patients with PHPT.

[Assessment of the prevalence of anemia in patients with primary hyperparathyroidism: a single-center observational study]

BACKGROUND

The combination of primary hyperparathyroidism (PHPT) with anemia was first described in 1931. It remains unclear whether PHPT is the direct cause of anemia, or it develops due to PHPT's complications. The frequency of PHPT--associated anemia in the Russian population is unknown.

AIM

To assess the prevalence of anemia in patients with PHPT admitted to the Department of Parathyroid Glands Pathology in the Endocrinology Research Centre from January 2017 to August 2020.

MATERIALS AND METHODS

The study included patients with PHPT over 18 years old. A single-center observational one-stage one-sample uncontrolled study was carried out. We analyzed laboratory and instrumental data obtained during inpatient examination in accordance with the standards of medical care. Statistical analysis was performed using Statistica 13 (StatSoft, USA) and SPSS (IBM, USA) software packages.

RESULTS

The study included 327 patients with PHPT, 28 (9%) men and 299 (91%) women. The median age was 59 years [51; 66]. 26 patients (8%) with anemia were identified. Statistically significant differences between patients with and without anemia were found only in the GFR. Comparison of patients with and without anemia didn't reveal any significant differences in the incidence of PHPT's complications.Significant differences in serum hemoglobin concentration and average hemoglobin concentration in erythrocytes were revealed between patients with and without vertebrae fractures. In the group of patients without compression fractures these parameters were higher.In the subgroup of patients with total calcium concentration above 3 mmol/L and PTH above 3 normal values, the incidence of anemia reached 21% (95% CI: 10%; 35%). Within this group we revealed tendencies to higher levels of PTH, ionized calcium and osteocalcin in patients with anemia.

CONCLUSION

In general, there was no correlation between hypercalcemia, the degree of PTH elevation and the presence of anemia in patients with PHPT. However, in the subgroup of patients with severe hypercalcemia, there was a relationship between the concentration of PTH, ionized calcium and the presence of anemia. In patients with PHPT and vertebral fractures, significantly lower concentrations of blood hemoglobin and hemoglobin in erythrocytes were observed.

Myelofibrosis and Pancytopenia Associated With Primary Hyperparathyroidism

Objective

Primary hyperparathyroidism (PHPT) has varied clinical presentations. Hematologic abnormalities secondary to PHPT have been described before. However, pancytopenia as the initial presentation has rarely been reported. We report a patient with PHPT who presented for evaluation of pancytopenia.

Methods

Histopathology of the bone marrow at presentation is described. Bone biochemistry results and the hematologic profile before and after curative parathyroidectomy are presented.

Results

A 48-year-old woman presented with pancytopenia (hemoglobin, 6.3 g/dL; total leucocyte count, 3000 cells/mm³; and platelet count, 60 000 cells/mm³), and her bone marrow study showed marrow fibrosis. Biochemical evaluation revealed hypercalcemia (15.5 mg/dL), hypophosphatemia (2.2 mg/dL), and elevated total alkaline phosphatase (4132 U/L). Bone mineral density assessment by dual-energy X-ray absorptiometry scan revealed osteoporosis at all 3 sites, which was more severe in the distal one third of the forearm. Further investigations confirmed the diagnosis of PHPT (serum parathyroid hormone, 2082 pg/mL). Following curative parathyroidectomy, in addition to normalization of calcium, there was restoration of all 3 hematologic cell lines at 3 months.

Conclusion

Pancytopenia may be a rare manifestation of PHPT. Thus, it may be prudent to evaluate the calcium profile in patients with chronic refractory anemia and pancytopenia.

Anemia in primary hyperparathyroidism

Introduction. Anaemia is a complication of primary hyperparathyroidism (PHPT). Pathogenesis of PHPT-induced anaemia involves inhibited erythroid cell proliferation associated with the underlying disease and non-specific factors (blood loss, chronic kidney disease). However, its specific mechanisms remain unclear.

Aim. Clinical description of a PHPT case with multifactorial complicating anaemia.

Main findings. With putative evidence existing on relationships between PHPT and anaemia, no large clinical trials substantiated suitable algorithms for such patients’ management. The genesis of anaemia reported in this case was multifactorial and not decisively excluding PHPT from putative causes.

Parathyroid Hormone: A Uremic Toxin

Parathyroid hormone (PTH) has an important role in the maintenance of serum calcium levels. It activates renal 1α-hydroxylase and increases the synthesis of the active form of vitamin D (1,25[OH]₂D₃). PTH promotes calcium release from the bone and enhances tubular calcium resorption through direct action on these sites. Hallmarks of secondary hyperparathyroidism associated with chronic kidney disease (CKD) include increase in serum fibroblast growth factor 23 (FGF-23), reduction in renal 1,25[OH]₂D₃ production with a decline in its serum levels, decrease in intestinal calcium absorption, and, at later stages, hyperphosphatemia and high levels of PTH. In this paper, we aim to critically discuss severe CKD-related hyperparathyroidism, in which PTH, through calcium-dependent and -independent mechanisms, leads to harmful effects and manifestations of the uremic syndrome, such as bone loss, skin and soft tissue calcification, cardiomyopathy, immunodeficiency, impairment of erythropoiesis, increase of energy expenditure, and muscle weakness.

Recurrence of Hyperparathyroidism after Total Parathyroidectomy and Autotransplantation in Peritoneal Dialysis Patients

Objective

To evaluate the effectiveness of total parathyroidectomy (PTX) with autotransplantation in the treatment of secondary hyperparathyroidism (HPT), and to assess recurrence rate of HPT in this peritoneal dialysis (PD) population.

Design

A retrospective study in a single home PD unit.

Patients

Between 1994 and 1998, 19 of 574 patients on PD underwent PTX for treatment of secondary HPT.

Main Outcome Measures

Clinical and biochemical improvement, recurrence of HPT, improvement in anemia post-PTX.

Results

Nineteen (3.3%) patients required PTX between 1994 and 1998. These 5 men and 14 women ranged in age from 22 to 66 years; they had been on maintenance PD pre-PTX for 47.5 ± 38.1 months, and were followed for 26.1 ± 15.5 months post-PTX. Sixteen patients had temporary hypocalcemia that was managed by oral (n = 10) or intravenous (n = 6) calcium supplements and calcitriol, while 3 patients had severe “hungry bone” syndrome postoperatively. One patient had recurrent laryngeal nerve palsy post-PTX. Bone pain disappeared in all 12 patients. Pruritus improved in 12/13 patients; fatigue improved in 15/16 patients. Comparison showed significant differences between hemoglobin and hematocrit values 1 month pre-PTX and 12 months post-PTX ( p < 0.05). Parathyroid hormone (PTH) level in 15 (79%) patients returned to normal (≤€7.6 pmol/L) during the first month post-PTX. In 5/12 (42%) patients, PTH level was ≤ 7.6 pmol/L 2 years post-PTX, while in 2/12 (17%), PTH was > 22.8 pmol/L (three times normal) 2 years post-PTX, and 3/5 (60%) patients had a PTH > 22.8 pmol/L 3 years post-PTX.

Conclusions

Total PTX with autotransplantation is associated with a tendency for recurrence of HPT. Our findings suggest that total PTX with autotransplantation may be an ineffective procedure in controlling HPT over the long term.

Hyporesponsiveness to Anemia Therapy—What are we Doing Wrong?

Most patients receiving anemia therapy respond well, with a significant rise in hemoglobin concentration. However, approximately 5% – 10% of patients fail to show a satisfactory response despite high doses of erythropoietin. The definition of hyporesponsiveness to anemia therapy is somewhat arbitrary, but it is generally regarded as a failure to achieve a hemoglobin concentration of 10 – 11 g/dL despite a dose of erythropoietin in excess of 200 U/kg weekly.

The condition has many causes, the most important ones being iron deficiency, infection or inflammation, and underdialysis. Investigating a patient's poor response to erythropoietin should begin with a check for compliance, followed by screening for iron deficiency. If doubt exists about the presence of iron deficiency, then a trial of intravenous iron may be given.

A reticulocyte count may be helpful. A significantly elevated count suggests the presence of blood loss or hemolysis. The level of C-reactive protein (CRP) may be useful as an indicator of underlying inflammation, and underdialysis may be corrected by increasing the dialysis prescription. If other, minor causes of hyporesponsiveness to erythropoietin have been excluded, then a bone marrow biopsy should be performed. Some patients may require higher doses of erythropoietin, and it is not unreasonable to increase the dose to 10,000 U thrice weekly.

Some causes of hyporesponsiveness to erythropoietin, such as iron deficiency and underdialysis, are easily corrected; but others, such as primary bone marrow disorders and hemoglobinopathies, are not possible to overcome.

Anemia and iron deficiency among chronic kidney disease Stages 3-5ND patients in the Chronic Kidney Disease Outcomes and Practice Patterns Study: often unmeasured, variably treated

Background

International variation in anemia assessment and management practices in chronic kidney disease (CKD) is poorly understood.

Methods

We performed a cross-sectional analysis of anemia laboratory monitoring, prevalence and management in the prospective Chronic Kidney Disease Outcomes and Practice Patterns Study (CKDopps). A total of 6766 participants with CKD Stages 3a–5ND from nephrology clinics in Brazil, France, Germany and the USA were included.

Results

Among patients with anemia (hemoglobin <12 g/dL), 36–58% in Brazil, the USA and Germany had repeat hemoglobin measured and 40–61% had iron indices measured within 3 months of the index hemoglobin measurement. Anemia was more common in the USA and Brazil than in France and Germany across CKD stages. Higher ferritin and lower iron saturation (TSAT) levels were observed with lower hemoglobin levels, and higher ferritin with more advanced CKD. The proportion of anemic patients with ferritin <100 ng/mL or TSAT <20% ranged from 42% in Brazil to 53% in France and Germany, and of these patients, over 40% in Brazil, Germany and the USA, compared with 27% in France, were treated with oral or intravenous iron within 3 months after hemoglobin measurement. The proportion of patients with hemoglobin <10 g/dL treated with erythropoiesis-stimulating agents ranged from 28% in the USA to 57% in Germany.

Conclusions

Hemoglobin and iron stores are measured less frequently than per guidelines. Among all regions, there was a substantial proportion of anemic patients with iron deficiency who were not treated with iron, highlighting an area for practice improvement in CKD care.

Ethnic prevalence of anemia and predictors of anemia among chronic kidney disease patients at a tertiary hospital in Johannesburg, South Africa

INTRODUCTION

Anemia is a complication of chronic kidney disease (CKD) that can greatly impact on its prognosis. However, the risk factors for anemia, including the influence of ethnicity, are not well established among the CKD population in Johannesburg.

METHODS

This was a cross-sectional study of 353 adult CKD patients attending the renal outpatient clinic of the Charlotte Maxeke Johannesburg Academic Hospital (Johannesburg, South Africa) from June 1, 2016 to December 30, 2016. Sociodemographic and clinical characteristics were obtained using a proforma. Blood samples were collected for serum electrolytes and hematological parameters. Predictors of low hemoglobin and iron deficiency anemia (IDA) were evaluated using multivariable binary logistic regression.

RESULTS

The mean age and prevalence of anemia among the CKD participants were 55.3±15.0 years and 43.18% (95% CI: 38.1%-48.4%), respectively. Blacks had the highest prevalence of anemia (46.9%), while Indians/Asians had the lowest (18.2%). Although the odds of anemia was 3.8-fold higher (odds ratio =3.8, P-value =0.059) among CKD stage V participants as compared to CKD stage I, the relationship between anemia and stages of CKD was non-linear. Diabetes mellitus (odds ratio =2.31, P-value =0.005) had a strong association with anemia among the CKD participants.

CONCLUSION

Almost half of the CKD participants were anemic, and the odds of anemia did not increase linearly with increasing severity of CKD. There was a marked ethnic disparity in anemia prevalence. Our study highlights the need for risk-based management of anemia among CKD patients.

Emerging Association Between Parathyroid Hormone and Anemia in Hemodialysis Patients

Anemia is a common complication of chronic kidney disease (CKD). There are various causes of renal anemia such as decreased production of erythropoietin, resistance to erythropoietin, shortened survival of red blood cells, and bone marrow fibrosis. Secondary hyperparathyroidism (SHPT) is a less recognized, but potentially significant cause of renal anemia in CKD patients. Parathyroid hormone (PTH) has been regarded as a uremic toxin that has multiple adverse effects, and its elevated levels have been associated with renal anemia in hemodialysis patients. Moreover, recent clinical studies have shown that the treatment of SHPT using either vitamin D receptor activators, calcimimetics, or parathyroidectomy leads to improvement of anemia, supporting the role of PTH in renal anemia. Emerging data have also indicated the involvement of bone-derived fibroblast growth factor 23 in renal anemia. This review summarizes recent insights into the role of PTH in renal anemia and discusses the importance of treating SHPT in improving the control of renal anemia in hemodialysis patients.

Clinical Effect of Recombinant Human Erythropoietin on Anemia Associated with Chronic Renal Failure. A Multiinstitutional Study in Japan

Clinical effect and safety of recombinant human erythropoietin (r-HuEPO) were evaluated in 66 hemodialysis patients with intractable anemia. Initially, 50U/kg dry weight (DW) of r-HuEPO was administered intravenously at the end of every hemodialysis procedure for 4 weeks, then the dosage was increased to 100 and 200U/kg DW for poor responders. The patients’ hematocrits rose from 19.8 ± 2.3% (pretreatment) to 30.2 ± 4.9% after 12 weeks. From 206 U of blood transfusion requirement in the 3-month period before the study, only 34 U were needed after treatment. Serum iron and ferritin levels fell significantly during the study, and iron storage was considered to be one of the decisive factors in the response to r-HuEPO. Blood pressure rose in the course of r-HuEPO administration, but uncontrollable hypertension was rarely observed. There was no significant adverse effect of r-HuEPO except for this mild hypertension. These results indicate that r-HuEPO is an excellent therapeutic aid for the anemia associated with chronic renal failure.

Effect of peritoneal dialysis versus hemodialysis on renal anemia in renal in end-stage disease patients: a meta-analysis

The aim of this meta-analysis was to evaluate the effect of peritoneal dialysis (PD) and hemodialysis (HD) on renal anemia (RA) in renal disease patients by a meta-analysis. Relevant studies published before June 2015 were searched. Pooled odds ratio (OR) with 95% confidence interval (CI) was used to evaluate the effect of HD and PD on RA based on five indexes: hemoglobin, ferritin, transferrin saturation index, serum albumin, and parathyroid hormone. Sensitivity analysis and publication bias assessment were conducted to evaluate the stability and reliability of our results. A total of fourteen eligible studies with 1103 cases underwent HD and 625 cases underwent PD were used for this meta-analysis. There were no significant difference for levels of hemoglobin (SMD = -0.23, 95% CI: -0.74 to 0.28), ferritin (SMD = 0.01, 95% CI: -0.59 to 0.62), parathyroid hormone (SMD = 0.11, 95% CI: -1.53 to 1.75) and transferrin saturation index (SMD = -0.06, 95% CI: -0.67 to 0.56) between HD and PD group. However, the content of serum albumin in HD group was much more than that in PD group (SMD = 1.58, 95% CI: 0.35 to 2.81). Neither of the included studies could reverse the pooled side effect and Egger's test demonstrated no publication bias. Both of the two dialysis strategies have a similar effect on RA in renal disease patients.

Altered Expression Pattern of CD55 and CD59 on Red Blood Cells in Anemia of Chronic Kidney Disease

OBJECTIVE

The aim of this study was to investigate the expression pattern of CD55 and CD59 on red blood cells (RBCs) in anemic chronic kidney disease (CKD) patients, and factors that might influence their expression.

SUBJECTS AND METHODS

Nighty-one adult anemic CKD patients and 80 healthy controls (HCs) were enrolled. Anemic CKD patients were divided into 3 subgroups based on receiving erythropoietin and renal replacement therapies. Flow cytometric analysis of CD55 and CD59 expression was performed on RBCs from blood samples obtained from CKD patients and HCs.

RESULTS

CD59 deficiency was significantly higher among CKD patients than HCs (n = 68, 74.7%, vs. n = 13, 16.3%, respectively; p < 0.001). The median proportions of CD55- and CD59-deficient RBCs in CKD patients were significantly higher compared to HCs (0.34 vs. 0.15, and 4.3 vs. 2.0, p < 0.001 and p < 0.001, respectively). The mean fluorescence intensity (MFI) of CD55 and CD59 expression was significantly lower in CKD patients compared to HCs (1.2 vs. 2.8, and 17.0 vs. 20.3, p < 0.04 and p < 0. 001, respectively). The hemoglobin level was inversely correlated with the proportions of CD55- and CD59-deficient RBCs (r = -0.37, p < 0.001, and r = -0.22, p < 0.02, respectively). The number of CD59-deficient patients was significantly different between the 3 subgroups of CKD patients (p = 0.001), and a significant difference was present in the MFI of CD55 and CD59 expression among the 3 subgroups (p = 0.04 and p = 0.03, respectively).

CONCLUSION

The expression pattern of CD55 and CD59 on RBCs is altered in anemic CKD patients, which could play a role in the pathogenesis of anemia in CKD.

Effects of Secondary Hyperparathyroidism Treatment on Improvement in Anemia: Results from the MBD-5D Study

OBJECTIVES

Anemia is an important prognostic factor in hemodialysis patients. It has been reported that parathyroidectomy ameliorates anemia and reduces the requirement of postoperative erythropoiesis-stimulating agents. The objective of this study was to assess the effect of cinacalcet, which is considered as a pharmacological parathyroidectomy, on anemia in hemodialysis patients.

METHODS

We used data from a prospective cohort of Japanese hemodialysis patients with secondary hyperparathyroidism; the criteria were: intact parathyroid hormone concentrations ≥ 180 pg/mL or use of an intravenous or oral vitamin D receptor activator. All patients were cinacalcet-naïve at study enrollment. The main outcome measure was achievement of the target hemoglobin level (≥10.0 g/dL), which was measured repeatedly every 6 months. Cinacalcet exposure was defined as cumulative time since initiation. Both conventional longitudinal models and marginal structural models were adjusted for confounding factors.

RESULTS

Among 3,201 cinacalcet-naïve individuals at baseline, cinacalcet was initiated in 1,337 individuals during the follow up. Cinacalcet users were slightly younger; included more patients with chronic glomerulonephritis and fewer with diabetes; were more likely to have a history of parathyroidectomy; and were more often on activated vitamin D agents, phosphate binders, and iron supplements. After adjusting for both time-invariant and time-varying potential confounders, including demographics, comorbidities, comedications, and laboratory values, each additional 6-month duration on cinacalcet was associated with a 1.1-fold increase in the odds of achieving the target hemoglobin level.

CONCLUSIONS

Cinacalcet may improve anemia in chronic hemodialysis patients with secondary hyperparathyroidism, possibly through pathways both within and outside the parathyroid hormone pathways. Further investigations are warranted to delineate the roles of cinacalcet not only in the management of chronic kidney disease-mineral and bone disorder but also in anemia control.

High Dose ESAs Are Associated with High iPTH Levels in Hemodialysis Patients with End-Stage Kidney Disease: A Retrospective Analysis

Objective

Anemia and secondary hyperparathyroidism are the two most common complications associated with chronic kidney disease. Erythropoiesis-stimulating agents (ESAs) are widely used in the management of anemia in hemodialysis patients. A reverse correlation has been established between hyperparathyroidism and hemoglobin levels. The aim of this retrospective study is to evaluate the relationship of high-dose ESAs and hyperparathyroidism in hemodialysis patients with anemia.

Methods

A total of 240 uremic patients maintained on regular hemodialysis were enrolled in this study. Among them, 142 patients were treated with Epiao^® (epoetin-alfa) and 98 patients were treated with Recormon^® (epoetin-beta). The target hemoglobin concentration was 110–130 g/L. Laboratory measurements including hemoglobin, calcium, phosphorus, albumin, intact-parathyroid hormone (iPTH), serum ferritin, and transferrin saturation were collected.

Results

Hemoglobin concentration increased as iPTH level decreased by stratification. However, no significant association between anemia and calcium or phosphorus level was found. Patients with iPTH levels within 150–300 pg/mL had the highest levels of hemoglobin, serum ferritin, and transferrin saturation. Patients treated with Recormon and Epiao had similar hemoglobin concentrations. However, the dose of Recormon for anemia treatment was significantly less than that the dose of Epiao (P < 0.05). The level of iPTH in the Recormon group was significantly lower than in the Epiao group. In patients with hemoglobin levels between 110 and 130 g/L (P < 0.05), iPTH level was found to be significantly lower in patients treated with lower doses of ESAs than in patients treated with higher doses of ESAs, no matter which ESA was used (Recormon or Epiao, P < 0.05).

Conclusion

The dose of ESAs might be positively associated with iPTH level, suggesting that a reasonable hemoglobin target can be achieved by using the lowest possible ESA dose.

Serum phosphorus and association with anemia among a large diverse population with and without chronic kidney disease

BACKGROUND

We hypothesized that phosphorus has an effect on anemia in both normal kidney function and early chronic kidney disease (CKD). We sought to determine whether higher phosphorus levels are associated with anemia in a large diverse population without CKD and early CKD.

METHODS

This study is a historical population-based study within the Kaiser Permanente Southern California health system (1 January 1998 to 31 December 2013) among individuals aged 18 years and older with estimated glomerular filtration rate >30 mL/min/1.73 m(2) and measurements of serum phosphorus, creatinine and hemoglobin. Individuals were excluded if they had secondary causes of anemia. Odds ratio (OR) estimated for moderate anemia defined as hemoglobin <11 g/dL for both sexes. Mild anemia was defined as <12 g/dL (females) and <13 g/dL (males).

RESULTS

Among 155 974 individuals, 4.1% had moderate anemia and 12.9% had mild anemia. Serum phosphorus levels ≥3.5 mg/dL were associated with both mild and moderate anemia. Moderate anemia OR (95% confidence interval) was 1.16 (1.04-1.29) for every 0.5 mg/dL phosphorus increase and 1.26 (1.07-1.48) in the highest versus middle phosphorus tertile. Additional independent anemia risk factors, including female sex, Asian race, diabetes, low albumin and low iron saturation, were observed, but did not alter the anemia-phosphorus association.

CONCLUSIONS

Higher phosphorus levels were associated with a greater likelihood for anemia in a population with early CKD and normal kidney function. Phosphorus may be a biomarker for anemia and may affect aspects of hematopoiesis.

Young age, male sex, and end-stage renal disease with secondary hyperparathyroidism as risk factors for intraoperative hyperkalemia during parathyroidectomy

STUDY OBJECTIVE

The aim of this study was to investigate the risk factors of intraoperative hyperkalemia in end-stage renal disease patients undergoing parathyroidectomy (PTx) with autotransplantation (AT).

DESIGN

Prospective observational study.

SETTING

Operating room of a tertiary care medical center.

PATIENTS

Thirty-two adult, American Society of Anesthesiologists physical status 2 and 3 patients with secondary hyperparathyroidism aged between 31 and 72 years scheduled for PTx with AT.

MEASUREMENTS

Laboratory chemistries (intact parathyroid hormone, Na, K, Ca, P, arterial blood gas) were obtained before surgery and at 2 time points during surgery. The first chemistry levels during surgery were checked after the first 2 parathyroid glands had been removed, and the second levels were checked after wound closure. Statistical analysis was performed using t test, Fisher exact test, the receiver operating characteristic curve method, as appropriate.

MAIN RESULTS

Eight patients (25%) developed hyperkalemia during surgery. The hyperkalemia patients had younger age (42±11.44 years vs 52.58±11.83 years, P=.044) and a male dominance (odds ratio, 11.4; P=.01; 95% confidence interval, 1.74-74.65). The cutoff for age was 40.5 years, according to the highest value for sensitivity plus specificity of the receiver operating characteristic curve. There was a higher incidence of intraoperative hyperkalemia in younger patients than in older patients (odds ratio, 8.33; P=.023; 95% confidence interval, 1.39-49.87) as well as a significant increase in potassium level during surgery in younger male patients (P=.005 and .002, respectively).

CONCLUSIONS

The anesthesiologist should be aware of the complications of intraoperative hyperkalemia during PTx with AT, especially in male end-stage renal disease patients younger than 40 years.

The role of parathyroidectomy in JAK2 mutation negative polycythemia vera

The relationship between polycythemia vera (PV) and primary hyperparathyroidism is not well understood. Remission or improvement of PV following parathyroidectomy in the setting of primary hyperparathyroidism has previously been described; however, long-term outcomes are not well characterized. We describe a patient with JAK2 mutation negative PV and primary hyperparathyroidism, with a dramatic, but ultimately transient, improvement in hemoglobin following resection of a parathyroid adenoma. While screening for hyperparathyroidism may be useful in the setting of PV, indications for parathyroidectomy should be driven by symptomatology or established criteria, not the desire to affect the clinical course of PV.

Parathyroid hormone may be an early predictor of low serum hemoglobin concentration in patients with not advanced stages of chronic kidney disease

Background

Parathyroid hormone (PTH) has been associated with anemia only in dialysis patients with severe hyperparathyroidism. Whether an association between PTH and hemoglobin also exists in patients with chronic kidney disease not on dialysis (CKD-patients) is still unclear. In this study we evaluated the association between PTH and hemoglobin in CKD-patients without severe secondary hyperparathyroidism.

Methods

Hospitalized patients and outpatients (N = 979) were retrospectively evaluated and categorized according to PTH quartile and serum hemoglobin (<12.0, <11.0, <10.0 g/dl). Gender, diabetes, glomerular filtration rate (GFR), hemoglobin, PTH, markers of mineral metabolism, inflammation, iron status and nutrition were variables of adjustment in univariate and multivariate analysis.

Results

An inverse association (p = 0.001) was observed between PTH and hemoglobin in patients as a whole, in diabetics, and in patients with GFR ≤60 ml/min. PTH was the single predictor of low hemoglobin in patients as a whole (unstandardized beta −2.12; p = 0.005), in diabetics (unstandardized beta −8.86; p = 0.007) and in patients with GFR ≤60 ml/min (unstandardized beta −2.52; p = 0.006). For each increase of quartile of PTH the risk of having hemoglobin level <10.0 mg/dl was more than doubled [hazard ratio (HR) 2.79, 95 % confidence interval (CI) 2.00–3.88; p = 0.001]. The receiver operating characteristic curve showed that PTH ≥122 pg/ml had 67 % sensitivity and 75 % specificity in predicting hemoglobin level <10.0 g/dl with area under the curve of 0.758 (95 % CI 0.73–0.78).

Conclusions

This study shows a significant inverse association between PTH and hemoglobin levels across the whole spectrum of non-dialysis CKD and a doubled risk of having serum hemoglobin <10.0 mg/dl in the absence of severely deranged PTH concentration. These findings may have clinical relevance in ascertaining the cause of unexplained low hemoglobin levels in CKD-patients.

Clinical pharmacokinetics and pharmacodynamics of erythropoiesis-stimulating agents

The cloning of the EPO gene in the early 1980s allowed for the development of recombinant erythropoietins and analogues [erythropoiesis-stimulating agents (ESAs)], offering an alternative to transfusion as a method of raising haemoglobin (Hb) levels, which have been used for more than 20 years to treat anaemia in millions of anaemic patients. There are now a number of ESAs available worldwide for the treatment of anaemia, approved for different routes of administration (intravenous and subcutaneous) and dosing intervals (three times weekly, weekly, biweekly and monthly). In this review, we discuss the pharmacokinetic characteristics, including absorption, distribution and elimination processes, across the different ESAs. Incomplete and slow lymphatic absorption, with limited extravascular distribution, and minor contributions of the target-mediated drug disposition to the overall elimination are the common characteristics across the marketed ESA. Additionally, we assess the similarities and differences of ESAs related to pharmacodynamics in the context of the different biomarkers used to monitor the magnitude and duration of the effect, and introduce the concept of the minimum effective concentration of the ESA. The relationship between the minimum effective concentration and the half-life suggests that the time during which drug concentrations are above the minimum effective concentration is the main determinant of ESA efficacy in increasing Hb levels. The tolerance phenomenon and its physiological mechanism and implications for ESA dosing are discussed. Finally, the areas of future clinical pharmacology research are envisioned.

The Association between Parathyroid Hormone Levels and Hemoglobin in Diabetic and Nondiabetic Participants in the National Kidney Foundation's Kidney Early Evaluation Program

BACKGROUND

Both anemia and secondary hyperparathyroidism are reflections of hormonal failure in chronic kidney disease (CKD). While the association of elevated levels of parathyroid hormone (PTH) and anemia has been studied among those with advanced CKD, less is known about this association in mild-to-moderate CKD.

METHODS

In a cross-sectional analysis, the relationship between PTH and hemoglobin levels was investigated in 10,750 participants in the National Kidney Foundation's Kidney Early Evaluation Program with an estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m².

RESULTS

In the unadjusted analysis, higher PTH levels were associated with lower hemoglobin levels. However, after multivariable adjustment for age, race, gender, smoking status, education, cardiovascular disease, diabetes, hypertension, cancer, albuminuria, BMI, baseline eGFR, calcium, and phosphorus, the direction of association changed. As compared to the first PTH quintile, hemoglobin levels were 0.09 g/dl (95% CI: 0.01-0.18), 0.15 g/dl (95% CI: 0.07-0.24), 0.18 g/dl (95% CI: 0.09-0.26), and 0.13 g/dl (95% CI: 0.07-0.25) higher for the second, third, fourth, and fifth quintiles, respectively. Similarly, each standard deviation increase in natural log transformed PTH was associated with a 0.06 g/dl (95% CI: 0.03-0.09, p = 0.0003) increase in hemoglobin. However, a significant effect modification was seen for diabetes (p = 0.0003). Each standard deviation increase in natural log transformed PTH was associated with a 0.10 g/dl (95% CI: 0.054-0.138, p < 0.0001) increase in hemoglobin, while no association was seen among those without diabetes mellitus.

CONCLUSION

After multivariable adjustment, there was a small positive association between PTH and hemoglobin among diabetics but not among nondiabetics.

The case for routine parathyroid hormone monitoring

Parathyroid hormone (PTH) is a uremic toxin with multiple systemic effects including bone disorders (renal osteodystrophy), myopathy, neurologic abnormalities, anemia, pruritus, and cardiomyopathy. Hyperparathyroidism is common in CKD and results in significant morbidity and mortality if left untreated. Clinical practice guidelines from the Kidney Disease Improving Global Outcomes initiative broadened the optimal PTH range to >2 and <9 times the upper limit of normal for the assay measured. Furthermore, the guidelines recommend following trends in PTH to determine the appropriate therapy. These guidelines overcome issues with the assay variability and help clinicians make judgments when treating individual patients. They also require frequent measurement in order to determine trends and implement appropriate treatments.

Mice lacking the sodium-dependent phosphate import protein, PiT1 (SLC20A1), have a severe defect in terminal erythroid differentiation and early B cell development

Phosphate is critical in multiple biological processes (phosphorylation reactions, ATP production, and DNA structure and synthesis). It remains unclear how individual cells initially sense changes in phosphate availability and the cellular consequences of these changes. PiT1 (or SLC20A1) is a constitutively expressed, high-affinity sodium-dependent phosphate import protein. In vitro data suggest that PiT1 serves a direct role in mediating cellular proliferation; its role in vivo is unclear. We have discovered that mice lacking PiT1 develop a profound underproduction anemia characterized by mild macrocytosis, dyserythropoiesis, increased apoptosis, and a near complete block in terminal erythroid differentiation. In addition, the animals are severely B cell lymphopenic because of a defect in pro-B cell development and mildly neutropenic. The phenotype is intrinsic to the hematopoietic system, is associated with a defect in cell cycle progression, and occurs in the absence of changes in serum phosphate or calcium concentrations and independently of a change in cellular phosphate uptake. The severity of the anemia and block in terminal erythroid differentiation and B cell lymphopenia are striking and suggest that PiT1 serves a fundamental and nonredundant role in murine terminal erythroid differentiation and B cell development. Intriguingly, as the anemia mimics the ineffective erythropoiesis in some low-grade human myelodysplastic syndromes, this murine model might also provide pathologic insight into these disorders.

Predictors of acquired perforating dermatosis in uremic patients on hemodialysis: a case-control study

OBJECTIVES

The purpose of this study was to identify the predictors of acquired perforating dermatosis (APD) in patients on maintenance hemodialysis (HD).

METHODS

A case-control study was performed at our outpatient HD center between January 1, 2000 and March 31, 2011. Patients on HD with APD were matched (1 : 2) for gender and age with controls on HD. Conditional logistic regression was used to identify factors associated with APD.

RESULTS

A total of 19 patients with APD and 38 age and gender matched patients were enrolled in the study. Univariate logistic regression showed that APD was significantly associated with diabetes mellitus (DM), reduced levels of intact parathyroid hormone (iPTH) and albumin (Alb), reduced dialysis adequacy (Kt/V) and urea reduction rate (URR), and elevated levels of high-sensitivity C-reactive protein (hsCRP). Multivariate logistic regression identified reduced iPTH (hazard ratio (HR): 0.983; P = 0.026) and Alb (HR: 0.099; P = 0.047) and elevated hsCRP (HR: 1.210, P = 0.024) as risk factors for APD.

CONCLUSIONS

iPTH, hsCRP, and Alb are predictors for APD in HD patients.

Shortened red blood cell lifespan is related to the dose of erythropoiesis-stimulating agents requirement in patients on hemodialysis

Renal anemia is an important complication of chronic kidney disease (CKD). One of the most important complications of renal anemia is reduced red blood cell (RBC) lifespan, but there has been little research conducted into the causes of and treatments for this anemia. We measured alveolar carbon monoxide (CO) and then estimated RBC lifespan in patients on hemodialysis (HD). We also examined their requirement for erythropoiesis-stimulating agents (ESA), HD dose, nutrition factors, iron metabolism factor, reticulocyte counts and % reticulocytes. We enrolled 140 patients undergoing intermittent HD; among this group, 31 were not administered ESA and the others were on ESA therapy. Twelve healthy volunteers served as controls. The RBC lifespans in the healthy volunteers and in the HD patients were 128 ± 28 and 89 ± 28 days (mean ± SD), respectively. The RBC lifespan significantly and negatively correlated with ESA requirement (r = -0.489, P < 0.0001) in the HD patients. Other factors suspected to influence the RBC lifespan did not significantly correlate with the RBC lifespan in HD patients, in contrast to the correlation observed for S-Cr, BUN, S-ALB and total cholesterol vs. RBC lifespan. A shortened RBC lifespan seems to rather significantly affect the ESA requirement. Better nutritional status or active HD patients also seem to have longer RBC lifespans and lower ESA requirement.

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.

Landmark advances in the development of erythropoietin

This is a Minireview covering landmarks or milestones in the development of erythropoietin (EPO). Thirty-nine landmark advances have been identified, which cover the period 1863-2003. Several reports are included that directly support these original landmark advances. This Minireview also updates some of the advances in EPO research since my last Minireview update on EPO published in this journal in 2003. The areas of EPO research updated are: sites of production; purification, assay and standardization; regulation; action; use in anemias; extraerythropoietic actions; adverse effects; and blood doping. The new reports on the use of EPO in the therapy of myocardial infarction; stroke and other neurological diseases; diabetic retinopathy and other retinal diseases are also covered.

Effects of parathyroid hormone on immune function

Parathyroid hormone (PTH) function as immunologic mediator has become interesting with the recent usage of PTH analogue (teriparatide) in the management of osteoporosis. Since the early 1980s, PTH receptors were found on most immunologic cells (neutrophils, B and T cells). The in vitro evaluations for a possible role of PTH as immunomodulator have shown inconsistent results mainly due to methodological heterogeneity of these studies: it used different PTH formulations (rat, bovine, and human), at different dosages and different incubating periods. In some of these studies, the lymphocytes were collected from uremic patients or animals, which renders the interpretation of the results problematic due to the effect of uremic toxins. Parathyroidectomy has been found to reverse the immunologic defect in patients with high PTH levels. Nonetheless, the clinical significance of these findings is unclear. Further studies are needed to define if PTH does have immunomodulatory effects.

Normochromic normocytic anemia in a postmenopausal woman with severe osteoporosis treated with intermittent parathyroid hormone

Intermittent exogenous parathyroid hormone (PTH) is a potent osteoanabolic agent used for the treatment of severe osteoporosis. Two molecules of recombinant PTH are commercially available: the full-length PTH (PTH 1-84) and teriparatide (PTH 1-34). We present the first report of PTH-induced mild, asymptomatic, normochromic normocytic anemia in a postmenopausal woman treated sequentially with PTH 1-84 and PTH 1-34. Anemia was more pronounced with PTH 1-84 compared to PTH 1-34 and was reversed with each regimen discontinuation. We suggest monitoring of hematocrit and hemoglobin in PTH-treated patients, especially when PTH 1-84 is used.

Anaemia and mineral bone disorder in chronic kidney disease: a review of the current literature and implications for clinical nursing practice

Secondary hyperparathyroidism (SHPT) is one of the factors reported to have a negative impact on anaemia of chronic kidney disease (ACKD) and its treatment. SHPT is one of the abnormalities resulting from altered bone mineral metabolism. Five possible mechanisms have been proposed as to how SHPT impacts on anaemia in this paper. Each of these mechanisms will be considered and the treatment options reviewed including the implications for erythropoietic stimulating agents (ESA) prescribing. Anaemia and SHPT are both strongly predictive of complications and death from cardiovascular events in patients with chronic kidney disease (CKD). Nursing care of this group of patients should, therefore, be holistic in order to ensure optimum management. Ways in which we can practice to enhance quality of life and outcomes in this patient population will be discussed.

The association between parathyroid hormone and mortality in dialysis patients is modified by wasting

BACKGROUND

The association between parathyroid hormone (PTH) level and mortality in dialysis patients is controversial. We hypothesized that wasting, a common condition potentially related to adynamic bone disease, modifies the association of PTH with mortality and cardiovascular events (CVE), respectively.

METHODS

We analysed data from 1255 diabetic haemodialysis patients, participating in the German Diabetes and Dialysis Study between 1998 and 2004. The patients were stratified by the presence or absence of wasting (albumin <or=3.8 versus albumin >3.8 g/dL; BMI <or=23 versus BMI >23 kg/m(2)). Using Cox regression analyses, we calculated the risks of (1) all-cause mortality and (2) CVE according to baseline PTH levels. All analyses were adjusted for age, sex, atorvastatin treatment, duration of dialysis, comorbidity, HbA1c, phosphate, calcium, blood pressure, haemoglobin and C-reactive protein.

RESULTS

Patients had a mean age of 66 +/- 8 years, and 54% were male. Among patients without wasting (albumin >3.8 g/dL, n = 586), the risks of death and CVE during 4 years of follow-up significantly increased by 23% and 20% per unit increase in logPTH. Patients in the highest PTH tertile had a 74% higher risk of death (HR(adj) 1.74, 95% CI 1.27-2.40) and a 49% higher risk of CVE (HR(adj) 1.49, 95% CI 1.05-2.11) compared to patients in the lowest PTH tertile. In contrast, no effect was found in patients with wasting. Accordingly, additional analyses in strata of BMI showed that PTH significantly impacted on death and CVE [HR(logPTH)(adj) 1.15 and 1.14, respectively] only in patients without, but not in patients with, wasting.

CONCLUSIONS

Wasting modifies the association of PTH with adverse outcomes in diabetic dialysis patients. High PTH levels are of concern in the patients without wasting, while the effect of PTH on mortality is nullified in the patients with wasting.

Hyporesponsiveness to erythropoietin: causes and management

In patients with chronic kidney disease, erythropoietin resistance is common, costly, and has implications beyond the management of anemia because the presence of erythropoietin resistance portends mortal outcomes. Exploring the provenance of erythropoietin resistance may be facilitated by the consideration of the pathogenetic triad of iron-restricted erythropoiesis, inflammation, and bone marrow suppression. Challenging to diagnose because of difficulty in interpreting tests of iron deficiency, iron-restricted erythropoiesis should be considered in patients who require high doses of erythropoietin, have low transferrin saturation (eg, <20%-25%), and do not have very high ferritin (eg, <1,200 ng/mL); a therapeutic trial of intravenous iron may be worthwhile. Aluminum intoxication is a rare cause of iron-restricted erythropoiesis that may manifest as microcytic hypochromic anemia. A decrease in serum albumin concentration may signal the presence of inflammation, which may be manifest (such as because of a recent illness or infection) or occult; the latter include clotted synthetic angioaccess, failed renal allograft, dialysis catheter, periodontal disease, underlying malignancy, or uremia per se. Marrow hyporesponsiveness may be improved by increasing the delivered dialysis dose, using ultrapure dialysate, maintaining adequate vitamin B12 and folate stores, or by treating hyperparathyroidism. In summary, improving the outcomes of erythropoietin-resistant patients will require complete patient assessment that goes beyond considerations of iron and erythropoietin dose alone. Given that erythropoietin dose is associated with mortality, mitigating erythropoietin resistance has the potential to improve patient outcomes.

Bone and mineral disorders in pre-dialysis CKD

Disorders in calcium, phosphorus, and parathyroid hormone (PTH) are common in chronic kidney disease (CKD) and may be associated with poor outcomes including a higher rate of CKD progression and increased death risk. Although these abnormalities have been examined extensively in patients with CKD stage 5 who are receiving chronic maintenance dialysis, they have not been studied to the same extent at earlier stages of CKD, in spite of the much larger numbers of patients in the early CKD population. We summarize the available literature on outcomes associated with bone and mineral disorders in patients with CKD not yet receiving maintenance dialysis. We have reviewed novel data linking fibroblast growth factor 23 (FGF-23) to phosphorus and vitamin D homeostasis. More rapid CKD progression is linked to hyperphosphatemia and its associated hyperparathyroidism and vitamin D deficiency. Hence, hyperphosphatemia may play a central role in the diverse disorders characterizing CKD. We provide a brief overview of the available treatment recommendations for bone and mineral disorders, with an emphasis on areas needing further research.

Secondary hyperparathyroidism is associated with higher mortality in men with moderate to severe chronic kidney disease

Secondary hyperparathyroidism is associated with mortality in patients undergoing maintenance dialysis treatment. We studied 515 male US veterans with chronic kidney disease, who were not yet on dialysis, to see what outcomes were associated with secondary hyperparathyroidism in this population. Relationships between intact parathyroid hormone levels and all-cause mortality along with the composite of mortality or incidence of dialysis were measured in unadjusted and adjusted Cox models for case-mix and laboratory variables. Elevated parathyroid hormone levels above the upper limit compared to the lower limit of the normal range were significantly associated with mortality after adjustments. Higher intact parathyroid hormone levels in the upper limit of normal were significantly associated with higher mortality overall and showed similar trends in subgroups of patients with stage 3 and stage 4-5 chronic kidney disease and with higher and lower serum calcium and phosphorus levels. Similar associations were found with the composite outcome of mortality or dialysis. Our study shows that secondary hyperparathyroidism is independently associated with higher mortality in patients with chronic kidney disease but not yet on dialysis.

Vitamin D receptor activation and survival in chronic kidney disease

Replacement of activated vitamin D has been the cornerstone of therapy for secondary hyperparathyroidism (SHPT). Recent findings from several large observational studies have suggested that the benefits of vitamin D receptor activators (VDRA) may extend beyond the traditional parathyroid hormone (PTH)-lowering effect, and could result in direct cardiovascular and metabolic benefits. The advent of several new analogs of the activated vitamin D molecule has widened our therapeutic armamentarium, but has also made therapeutic decisions more complicated. Treatment of SHPT has become even more complex with the arrival of the first calcium-sensing receptor (CSR) agonist (cinacalcet hydrochloride) and with the uncovering of novel mechanisms responsible for SHPT. We provide a brief overview of the physiology and pathophysiology of SHPT, with a focus on vitamin D metabolism, and discuss various practical aspects of VDRA therapy and its reported association with survival in recent observational studies. A detailed discussion of the available agents is aimed at providing the practicing physician with a clear understanding of the advantages or disadvantages of the individual medications. A number of open questions are also analyzed, including the present and future roles of CSR agonists and 25(OH) vitamin D replacement.

Benign parathyroid adenoma presenting with unusual parathyroid crisis, anemia and myelofibrosis

Although the clinical symptoms of patients with benign parathyroid adenoma are usually nonspecific and benign, a malignant presentation of the benign disease may sometimes occur. Here, we report a case of a 58-year-old woman who presented with aggravated sacrum pain, general malaise, and polydipsia. Initial laboratory findings revealed hypercalcemia, normocytic anemia, and impaired renal function. Acute hypercalcemic crisis manifested and primary hyperparathyroidism was diagnosed together with myelofibrosis on account of the result of bone marrow biopsy. Excision of a parathyroid adenoma was performed, and the anemia and bone marker regressed later. These findings suggested that benign parathyroid adenoma may mimic the clinical presentation of parathyroid carcinoma, releasing excess parathyroid hormone and resulting in hyperparathyroid crisis. In addition, primary hyperparathyroidism can be associated with anemia and myelofibrosis.

Does parathyroid hormone affect erythropoietin therapy in dialysis patients?

OBJECTIVE

The objective of this study was to assess the response to recombinant human erythropoietin (rHuEPO) during treatment of anemia in dialysis patients with hyperparathyroidism.

SUBJECTS AND METHODS

A total of 118 patients with stage 5 renal failure on dialysis therapy were selected for this study. Anemia was treated with rHuEPO. Laboratory data for each patient included intact parathyroid hormone (iPTH), hemoglobin (Hb), hematocrit (Hct), blood urea nitrogen, serum creatinine, calcium, phosphate, and alkaline phosphatase. Patients with iPTH >32 pmol/l were considered hyperparathyroid. Erythropoietin resistance index (ERI) was expressed as the ratio of weekly rHuEPO dose/Hct level.

RESULTS

Of the 118 patients, 83 (70.3%) were on hemodialysis (HD) and 35 (29.7%) were on continuous ambulatory peritoneal dialysis (CAPD). Sixty-three patients (64.3%) with iPTH >32 pmol/l had Hb <11 g/dl, while 34 (54.8%) with iPTH <32 had Hb >11 g/dl (p = 04). Thirty-three (56%) patients with iPTH >32 pmol/l had hemocrit <33%, while 38 (61.3%) with iPTH <32 had hemocrit <33% (p = 0.4). The median value of weekly rHuEPO dose in HD patients (12,000 units) was significantly higher in comparison with CAPD patients (6,000 units; p < 0.0001). ERI was significantly higher in HD than CAPD patients with iPTH <16 pmol/l (p = 0002) as well as with patients with 16-32 pmol/l (p = 0.012).

CONCLUSIONS

CAPD patients showed a reduced requirement for rHuEPO and better control of anemia compared with HD patients. ERI was also lower in CAPD than in HD patients. Hyperparathyroidism is a parameter predictive of rHuEPO hyporesponsiveness in dialysis patients.