Relationship of associated secondary hyperparathyroidism to serum fibroblast growth factor-23 in end stage renal disease: a case-control study

Anemia of Chronic Kidney Disease-A Narrative Review of Its Pathophysiology, Diagnosis, and Management

Anemia is one of the most common chronic kidney disease (CKD) complications. It negatively affects patients' quality of life and clinical outcomes. The pathophysiology of anemia in CKD involves the interplay of various factors such as erythropoietin (EPO) deficiency, iron dysregulation, chronic inflammation, bone marrow dysfunction, and nutritional deficiencies. Despite recent advances in understanding this condition, anemia still remains a serious clinical challenge in population of patients with CKD. Several guidelines have been published with the aim to systematize the diagnostic approach and treatment of anemia; however, due to emerging data, many recommendations vary between publications. Recent studies indicate a potential of novel biomarkers to evaluate anemia and related conditions such as iron deficiency, which is often present in CKD patients. Our article aims to summarize the pathophysiology of anemia in CKD, as well as the diagnosis and management of this condition, including novel therapeutic approaches such as hypoxia-inducible factor-prolyl hydroxylase inhibitors (HIF-PHI). Understanding these complex subjects is crucial for a targeted approach to diagnose and treat patients with anemia in CKD effectively.

Association of Anemia with Parathyroid Hormone Levels and Other Factors in Patients with End-Stage Renal Disease Undergoing Hemodialysis: A Cross-Sectional, Real-World Data Study in Pakistan

End-stage renal disease (ESRD) patients are mostly managed with maintenance hemodialysis (MHD). ESRD patients on MHD also present with many complications, such as anemia, hyperparathyroidism, and hepatitis prevalence. This study depicts the real-world scenario of anemia among MHD and end-stage renal disease patients in the Pakistani population. A retrospective, multicentric, and real-world data analytical study was conducted at 4 dialysis centers in Pakistan. The study had a sample size of n = 342 patients on maintenance hemodialysis. The data were gathered from the medical records of patients. Data analysis was performed using STATA Version 16. Statistical significance was gauged at a 0.05 level of significance. According to our results, the mean age of the patients was 45 (±15) years. Most of the patients were male (n = 234, 68.4%), whereas 58.1% of the patients were maintained on twice-weekly hemodialysis. The most commonly reported comorbidities were hypertension and diabetes mellitus. The frequency of dialysis (P < 0.01) and comorbidities (P = 0.009) had a significant association with anemia in MHD patients. The majority of the patients had hyperparathyroidism (52%) with anemia. Upon performing binary logistic regression, multivariate analysis displayed a similar odds value for having anemia in patients with every additional month in the duration of hemodialysis (OR 1.01, P = 0.001), the odds of anemic patients having a positive antihepatitis-C antibody (OR 2.22, P = 0.013), and the odds of having anemia in patients in the age category below 45 years (OR 1.93, P = 0.013). In conclusion, the study results depict that every additional month in the duration of hemodialysis, age (<45 years), and positive anti-HCV antibody status, these variables were more likely to have anemia in our study MHD patients. While in our final multivariate model, no statistically significant association was observed between hyperparathyroidism and anemia.

Fibroblast Growth Factor 23 Level and Cardiovascular Parameters in Children with Chronic Kidney Disease

OBJECTIVE

To find out the serum fibroblast growth factor 23 (FGF-23) levels in different grades of CKD, and the prevalence of abnormal left ventricular mass index (LVMI), carotid intima-medial thickness (cIMT), and central pulse wave velocity (cPWV) and the risk factors including FGF-23 for these abnormalities.

METHODS

Fifty-nine patients of CKD with G2 to G5, aged 2-18 y were included. The LVMI, cIMT, and cPWV were measured using standard techniques, and serum intact FGF-23 levels were estimated at enrollment.

RESULTS

Median FGF-23 levels were significantly raised in all the grades of CKD than controls (p < 0.001), and also in G4 and G5 in comparison to G2&3 and in G5D than G5. Increased LVMI in 42 (71.2%), elevated cIMT in 30 (57.7%), and cPWV in 14 (26.9%) patients were found. The FGF-23 showed significant negative correlation with eGFRcr and positive with serum iPTH, phosphate and alkaline phosphatase levels, but had no correlations with LVMI, cIMT SDS, and cPWV SDS. Only systolic BP SDS (odds ratio 1.5, 95% CI 1.008-2.231, p = 0.046) was observed as a significant predictor for increased cIMT, while no variables had any association with abnormal LVMI and cPWV.

CONCLUSIONS

Serum FGF-23 showed higher levels with increasing grades of CKD, but no significant association with cardiovascular parameters. Systolic BP SDS was found as a significant risk factor for increased cIMT in children with CKD.

Gut Microbiota Correlates With Clinical Responsiveness to Erythropoietin in Hemodialysis Patients With Anemia

The main treatment for renal anemia in end-stage renal disease (ESRD) patients on hemodialysis is erythropoiesis (EPO). EPO hyporesponsiveness (EH) in dialysis patients is a common clinical problem, which is poorly understood. Recent searches reported that gut microbiota was closely related to the occurrence and development of ESRD. This study aims to explore the changes in gut microbiota between ESRD patients with different responsiveness to EPO treatment. We compared the gut microbiota from 44 poor-response (PR) and 48 good-response (GR) hemodialysis patients treated with EPO using 16S rDNA sequencing analysis. The results showed that PR patients displayed a characteristic composition of the gut microbiome that clearly differed from that of GR patients. Nine genera (Neisseria, Streptococcus, Porphyromonas, Fusobacterium, Prevotella_7, Rothia, Leptotrichia, Prevotella, Actinomyces) we identified by Lasso regression and ROC curves could excellently predict EH. In contrast, five genera (Faecalibacterium, Citrobacter, Bifidobacterium, Escherichia–Shigella, Bacteroides) identified by the same means presented a protective effect against EH. Analyzing the correlation between these biomarkers and clinical indicators, we found that gut microbiota may affect response to EPO through nutritional status and parathyroid function. These findings suggest that gut microbiota is altered in hemodialysis patients with EH, giving new clues to the pathogenesis of renal anemia.

Managing Anemia across the Stages of Kidney Disease in Those Hyporesponsive to Erythropoiesis-Stimulating Agents

BACKGROUND

Patients with CKD frequently have anemia that results from iron-restricted erythropoiesis and inflammation. Anemia of CKD is currently managed with iron supplements and erythropoiesis-stimulating agents (ESAs) to promote erythropoiesis and with RBC transfusion in severe cases. Hyporesponse to ESAs, or the need for larger than usual doses to attain a given hemoglobin (Hb) level, is associated with increased morbidity and mortality and presents a pressing clinical challenge, particularly for patients on dialysis. This paper reviews ESA hyporesponse and potential new therapeutic options in the management of anemia of CKD.

SUMMARY

The most common causes of ESA hyporesponse include iron deficiency and inflammation, and to a lesser degree, secondary hyperparathyroidism, inadequate dialysis, malnutrition, and concomitant medications. Management of ESA hyporesponse is multipronged and involves treating low level infections, ensuring adequate nutrition, and optimizing iron status and dialysis modality, although some patients can remain refractory. Inflammation directly increases production and secretion of hepcidin, contributes to an impaired response to hypoxia, and suppresses proliferation of erythroid progenitors. Coordination of renal and hepatic erythropoietin (EPO) production and iron metabolism is under the control of hypoxia-inducible factors (HIF), which are in turn regulated by HIF-prolyl hydroxylases (HIF-PHs). HIF-PHs and hepcidin are therefore attractive potential drug targets particularly in patients with ESA hyporesponse. Several oral HIF-PH inhibitors have been evaluated in patients with anemia of CKD and have been shown to increase Hb and reduce hepcidin regardless of inflammation, iron status, or dialysis modality. These sustained effects are achieved through more modest increases in endogenous EPO compared with ESAs. Key Messages: Treatments that address ESA hyporesponse remain a significant unmet clinical need in patients with anemia of CKD. New therapies such as HIF-PH inhibitors have the potential to address fundamental aspects of ESA hyporesponse and provide a new therapeutic option in these patients.

Association of Vitamin D and secondary hyperparathyroidism with anemia in diabetic kidney disease

Introduction:

Anemia is common in Chronic Kidney Disease (CKD) and diabetes is a major leading risk factor for it. In Diabetic Kidney Disease (DKD), it worsens more, which further increases cardiovascular morbidity and mortality. Despite of adequate iron stores anemia persist, which may be due to impaired iron release from body stores that is unable to meet the demand for erythropoiesis (also called reticuloendothelial cell iron blockade). High parathyroid hormone (PTH) along with vitamin D, may be attributable for anemia.

Methods:

A cross-sectional study of 150 advanced (Stage 4 & 5) pre dialyzed DKD patients (GFR <30ml/min/1.73 m2), aged 40-70 years were included over a period of 1 year. Any other concomitant illness/ drugs leading to anemia were excluded. Serum samples were collected and urea, creatinine, hemoglobin, iron profile, vitamin D, iPTH, uric acid, calcium, phosphorous and albumin levels were measured. A data base was constructed on Microsoft Excel 2007 and statistical analyses were performed using the SPSS software version 20.0 (IBM, NY, USA).

Results:

Stage 5 DKD had more pronounced anemia compared to stage 4 DKD (P < 0.001). Hemoglobin (Hb) was inversely correlated with iPTH (r = -0.74, P < 0.001) and was associated with vitamin D deficiency (r = 0.51, P < 0.001) but not with serum ferritin. DKD patients with low eGFR (r = -0.6, P < 0.001), vitamin D (r = -0.43, P < 0.001) and serum calcium (r = -0.37, P < 0.001) had higher iPTH. Secondary hyperparathyroidism (beta=-0.005; P < 0.001) and Vitamin D (beta=0.053; P < 0.01) were strong predictor for Hb while parameters of iron profile was not statistically significant.

Conclusion:

An efficient control of PTH hypersecretion is therefore required to achieve a better management of anemia as well as mineral metabolism in DKD patients.

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.

Impacts of parathyroidectomy on renal anemia and nutritional status of hemodialysis patients with secondary hyperparathyroidism

The aim of this study was to investigate the impacts of parathyroidectomy (PTX) towards the renal anemia and nutritional status of hemodialysis patients with secondary hyperparathyroidism (SHPT). 32 patients, enrolled into the blood purification center of our hospital for the hemodialysis treatment, were collected and divided into the PTX group and the non-PTX group, with 16 patients in each group. The changes of relevant indicators such as immunoreactive parathyroid hormone (iPTH), anemia and nutrition were observed before, 1-, 3-, 6-month after the treatment. The contents of iPTH, Ca, P and Ca × P of the PTX group decreased rapidly 1 month after the surgery; while Hb and Hct increased significantly from the 1st postoperative month; the dosage of EPO was significantly reduced 3-month after the surgery; the content of Alb gradually increased from the 3(rd) postoperative month; the content of TG decreased significantly from the 6(th) postoperative month; while the contents of BMI and TSF increased significantly from the 6(th) postoperative month, which exhibited the statistically significant differences when compared with the preoperative and the non-PTX group (P < 0.05). PTX could quickly reduce the iPTH level and significantly improve the renal anemia and nutritional status; SHPT was the important factor that would affect the renal anemia and malnutrition; PTX could reduce the amount of EPO, and reduce the economic burden of patients.

The effect of renin-angiotensin system inhibitors on intact parathyroid hormone levels in peritoneal dialysis patients

HYPOTHESIS/INTRODUCTION

The objective of this article is to investigate the effect of renin-angiotensin system inhibitors (RASIs) on intact parathyroid hormone (iPTH) levels in continuous ambulatory peritoneal dialysis (CAPD) patients.

MATERIALS AND METHODS

All patients were divided into RASI-treated and non-treated groups. The relationships between the iPTH levels in CAPD patients and the clinical parameters and medication use were analyzed via linear regression.

RESULTS

A total of 149 CAPD patients were included in this study. The average iPTH level of the entire group was 189.4 pg/ml (range, 102.8-373.4 pg/ml). There were 79 (53.0%) and 70 (47.0%) cases in the RASI-treated and non-treated groups, respectively, with average iPTH levels of 139.0 pg/ml (range, 91.6-258.4 pg/ml) and 253.0 pg/ml (range, 134.3-467.2 pg/ml), respectively; this difference was statistically significant (p = 0.001). Multilinear regression analysis showed that age, dialysis vintage, serum phosphatemia, ALP, Hb and RASI use were independent factors that were associated with iPTH level.

CONCLUSION

RASI use may be associated with a lower iPTH level in CAPD patients, although the underlying mechanism requires further study.

Prognostic importance of fibroblast growth factor-23 in dialysis patients

Introduction. In this study, we aimed to demonstrate the correlation of FGF-23 levels with bone-mineral metabolism, anemia, and the treatment in dialysis patients. Methods. Eighty-nine patients with similar age, gender, dialysis duration, and dialysis adequacy who were receiving hemodialysis replacement therapy for at least 6 months were included in the study. Serum iron, iron binding capacity, ferritin, hemoglobin (Hb), hematocrit (Htc), calcium (Ca), phosphorus (P), intact parathormone (iPTH), and FGF-23 levels were studied. In addition, active vitamin D and phosphate binders calcimimetic therapies that patients have received in the last 6 months were recorded. Results. It was determined that there was a positive correlation between serum FGF-23 values and PTH values (P < 0, 01) and Ca∗P values (P < 0, 01). A positive correlation was found between serum FGF-23 values and Ca values at a rate of 24,6% (P < 0, 05) and between P values at a rate of 59,1% (P < 0, 01). A positive correlation was determined between serum FGF-23 values and hemoglobin (Hb) values (P < 0, 05) and hematocrit (Htc) values (P < 0, 05). In multivariate analysis, no significant correlation was found between serum FGF-23 levels and Hb and Htc. Conclusion. The effects of high serum FGF-23 levels on different parameters may be correlated with the development of refractory secondary hyperparathyroidism.

Optimal use of phosphate binders in chronic kidney disease

INTRODUCTION

Hyperphosphatemia is one of the major factors associated with the development of vascular calcification in patients with chronic kidney disease (CKD). Since phosphate is retained in such patients, pharmacological treatment and other measures are necessary to control hyperphosphatemia. Several phosphate binders (calcium salts, magnesium salts, non-calcium-based binders and aluminium) are available for the treatment of hyperphosphatemia. Nevertheless, none of the above mentioned agents has shown an overall superiority over others, while potency and side effects are quite variable among them creating difficulties in choosing the optimal drug for each patient.

AREAS COVERED

The authors discuss the disturbed phosphate metabolism, the available phosphate binders, as well as the general therapeutic principles of treating hyperphosphatemia in CKD patients. The literature used for this review had been retrieved from PubMed and covers a large number of original and retrospective studies as well as prospective cohort studies, meta-analyses and international clinical guidelines.

EXPERT OPINION

Lowering serum phosphate levels in CKD patients may potentially have a positive impact on cardiovascular morbidity and mortality. Factors that should be taken into consideration when selecting a specific drug include CKD stage, cardiovascular disease, severity of secondary hyperparathyroidism, concomitant medications, life expectancy and patient compliance. Therefore, when selecting a specific phosphate binder, individualisation is mandatory.

Association of secondary hyperparathyroidism with hemoglobin level in patients with chronic kidney disease

PURPOSE

Secondary hyperparathyroidism (SHPT) is one of the less recognized reasons of anemia in chronic kidney disease (CKD). In this study, we evaluated the role of SHPT as a cause of anemia and correlation of intact parathyroid hormone (iPTH) and hemoglobin (Hb) level in hemodialysis (HD) patients.

METHODS

This cross-sectional study was carried out in 63 individuals admitted in HD unit of the institute. Serum samples were collected and urea, creatinine, Hb, ferritin and iPTH levels were measured. Statistical analysis was carried out using the SPSS software (IBM, NY, USA).

RESULTS

Mean ± standard deviation for serum urea, creatinine, Hb, ferritin and intact PTH were 177 ± 15.52, 15.16 ± 2.28 mg/dl, 7.03 ± 2.26 g/dl, 654.7 ± 563.4 ng/ml, 539.18 ± 493.59 pg/ml respectively. A reverse correlation was found between intact PTH and Hb level.

CONCLUSIONS

A variety of postulated pathophysiological mechanisms linking SHPT and anemia in CKD are discussed. An efficient control of parathyroid hormone hypersecretion may be required to achieve a better management of anemia in HD patients.