Mineral metabolic abnormalities and mortality in dialysis patients

[Thoracoscopic resection of recurrent atypically located parathyroid adenoma of anterior mediastinum in a patient with hyperparathyroidism undergoing renal replacement therapy]

We present successful surgical treatment of a patient with chronic kidney disease (CKD) and hyperparathyroidism undergoing renal replacement therapy. At baseline, parathyroidectomy via cervical access was performed for parathyroid adenomas. After 6 years, clinical and laboratory relapse of disease required thoracoscopic resection of atypically located anterior mediastinal adenoma. This case demonstrates that this disease is one of the most difficult in modern medicine requiring a special approach in diagnosis and treatment. Patients with CKD and hyperparathyroidism need for follow-up, control of total and ionized serum calcium, inorganic phosphorus and parathormone, osteodensitometry, ultrasound and scintigraphy of thyroid and parathyroid glands, and, if necessary, CT or MRI of the neck and chest organs.

The Relationship Between C-Reactive Protein (CRP) Concentrations and Erythropoietin Resistance, Hospital Admission Rate, Control of Mineral Metabolism, and Comorbidity in Hemodialysis Patients

Background End-stage kidney disease patients undergoing hemodialysis are prone to develop inflammation detected by high serum C-reactive protein (CRP) levels. This study highlights the association between CRP and the erythropoietin resistance index, hospital admission rate, control of mineral metabolism, and comorbidities in a tertiary hospital and two dialysis centers in Saudi Arabia. Objectives The objective of the study is to assess the relationship between CRP levels and hemoglobin level, hospital admission rate, mineral metabolism, and comorbidity in hemodialysis patients. Materials and methods This was a cross-sectional study conducted at King Abdulaziz Medical City Dialysis Center and the South and North Dialysis Centers of King Abdullah Dialysis Program in Riyadh. All hemodialysis adult patients who have been on dialysis for over six months were included. Patients with acute illnesses and pediatric patients were excluded. The association between CRP and other variables was reported using the Pearson correlation test. The calculated sample size was 218 by using the Raosoft website; however, the final number we analyzed was 209 after exclusion. Results The prevalence of a high level of CRP was more common among patients with diabetes mellitus (p=0.008) and those who were using antihypertensives (p=0.044) while the prevalence of a high level of CRP was less common among underweight patients (p=0.031) and hepatitis C virus (HCV)-positive patients (p=<0.001). The mean value of Kt/V was significantly lower among patients with a high level of CRP (p=0.009). HCV negative was the only independent significant risk factor associated with high CRP concentration (p=0.006). Conclusions In conclusion, there was an association between CRP levels with BMI, diabetics, the use of antihypertensive medications, and negative or undetectable HCV test results with the latter being the only independent significant factor. These data suggest that patients meeting these characteristics are in an inflammatory state and more prone to develop complications; thus, implementing CPR testing in this population might be useful. Other reviews showing causations are needed to further elucidate.

Evaluation of laboratory values affecting mortality of end-stage renal disease patients: a competing risks approach

BACKGROUND

Chronic Kidney Disease (CKD) is a prevalent and life-threatening situation recognized as an emerging health issue. The present study aimed to evaluate the effect of demographic and laboratory parameters on the survival of patients with End-Stage Renal Disease (ESRD) in a hemodialysis (HD) center in Iran.

MATERIALS AND METHODS

This study was conducted on patients receiving chronic HD in Iran Helal Pharmaceutical and Clinical Complex between 2014 and 2018. The survival time was considered as the time interval between HD initiation and death. Receiving kidney transplantation was regarded as a competing risk, and an improper form of two-parameter Weibull distribution was utilized to simultaneously model the time to both death and renal transplantation. The Bayesian approach was conducted for parameters estimation.

RESULTS

Overall, 29 (26.6%) patients expired, and 19 (17.4%) received kidney transplants. The male gender was related to poor survival, having nearly 4.6 folds higher hazard of mortality (90% HPD region: 1.36-15.49). Moreover, Serum calcium levels [Formula: see text]9.5 mg/dL (adjusted Sub-hazard ratio (S-HR)=2.33, 90% HPD region: 1.05-5.32) and intact parathyroid hormone (iPTH) [Formula: see text]150 pg/mL (adjusted S-HR = 2.56, 90% HPD region: 1.09-6.15) were associated with an elevated hazard of mortality. The cumulative incidence function (CIF) for transplantation was greater than death in the first two years of the study. Subsequently, the CIF for death exceeded transplantation in the following two years. The 4-year cumulative incidence of death and kidney transplantation was 63.7% and 36.3%, respectively.

CONCLUSION

Male gender, hypercalcemia, and hypoparathyroidism were associated with worse outcomes. Correcting mentioned laboratory parameters may improve patients' survival in the HD population.

Abnormal Calcium Metabolism Mediated Increased Risk of Cardiovascular Events Estimated by High Ankle-Brachial Index in Patients on Peritoneal Dialysis

Cardiovascular disease (CVD) is the leading cause of death in peritoneal dialysis (PD) patients. But the relationship between regular PD and the risk of major adverse cardiovascular events (MACE) remains controversial. The possible risk factors are not fully elucidated. This study aims to investigate the possible factors affecting the risk of MACE estimated by high ankle-brachial index (ABI) in PD patients. A total of 243 patients were enrolled and divided into chronic kidney diseases (CKD) stage 1, non-dialyzed CKD stages 2–5, and PD groups. The prevalence of high ABI, indicating increased MACE, was elevated with CKD progression but not further increased in PD patients. Systolic blood pressure was closely correlated with high ABI in non-dialyzed CKD patients (β = 0.059, P = 0.001). But in PD patients, serum calcium had a crucial effect on high ABI (β = −9.853, P < 0.001). Additionally, PD patients with high ABI tended to dialyze inadequately (Kt/V <1.7) compared to those with normal ABI (29.0 vs. 13.3%, P = 0.031). Further mediation analysis revealed that ~86.2% of the relationship between Kt/V and high ABI was mediated by serum calcium in PD patients (mediation effect = 86.2%, ab = −0.220, 95% CI: −0.381 to −0.059, P = 0.008), especially in those starting PD before 55 years of age and with normal body mass index. This present study indicated that improvement of PD adequacy by maintaining calcium balance might be a promising method to reduce the risk of MACE estimated by high ABI for PD patients.

The estimation of protein equivalents of total nitrogen in Chinese CAPD patients: an explanatory study

Objective

The protein equivalent of total nitrogen appearance (PNA) formula, based on the urea nitrogen appearance (UNA), is popularly used by stable continuous ambulatory peritoneal dialysis (CAPD) patients to estimate dietary daily protein intake (DPI). However, we found that the estimated DPI was higher than that directly evaluated from the dietary records of most of our CAPD patients. Therefore, in the present study, we tried to determine possible bias in PNA estimation by UNA with a nitrogen balance study of our CAPD patients.

Methods

Thirty-one CAPD patients with stable clinical conditions were included. Their 3-day dietary records were reviewed by a dedicated dietitian to calculate their energy, protein, and nitrogen intake (NI). The nitrogen removal (NR) from urine and dialysate was measured by the Kjeldahl technique. Then, we calculated the proportion of urea nitrogen appearance (UNA) in total nitrogen appearance (TNA) and analyzed the possible factors that could affect this proportion.

Results

Among these patients, 17 males and 14 females, the mean age was 64.19 ± 12.42, and the dialysate drainage volume was 6700 (2540) ml/day. The percentage of UNA in TNA was 63.22 ± 6.66%. Compared with the other classic nitrogen balance studies in the CAPD population, the protein nitrogen and other nonurea nitrogen losses in this study were all lower. Based on these 31 nitrogen balance studies, we proposed a pair of new equations to estimate PNA by UNA. (1) PNA = 9.3 + 7.73 UNA; (2) PNA = PNPNA + TPL = 6.7 + 7.28 UNA + TPL.

Conclusion

Our study suggested that the PNA formula generated from previous European studies overestimated DPI in our CAPD patients.

Adequate Management of Phosphorus in Patients Undergoing Hemodialysis Using a Dietary Smartphone App: Prospective Pilot Study

Background

The renal diet is complex and requires alterations of the diet and careful monitoring of various nutrients. Elevated serum phosphorus is common among patients undergoing hemodialysis, and it is associated with many complications. Smartphone technology could be used to support both dietitians and patients by providing a source of accessible and reliable information.

Objective

The aim of this pilot is to assess the potential efficacy of an intervention using the educational and self-monitoring mobile app KELA.AE on the phosphorous management in hemodialysis patients. Results will be used to improve both the app and a planned, rigorous large-scale trial intended to assess app efficacy.

Methods

This is a prospective pilot study performed at the hemodialysis unit of Al Qassimi Hospital (Emirate of Sharjah, United Arab Emirates). All patients were assessed for eligibility and, based on inclusion criteria, considered for enrollment. Participants met with a dietitian once a week and used the mobile app regularly for 2 weeks. Outcomes (knowledge, self-reported nonadherence, dietary intake, anthropometry, and biochemical data) were measured. This pilot is reported as per guidelines for nonrandomized pilot and feasibility studies and in line with the CONSORT (Consolidated Standards of Reporting Trials) 2010 checklist for reporting pilot or feasibility trials.

Results

Of 26 subjects, 23 successfully completed the pilot. Patient dietary knowledge about phosphorous management improved from 51.4% (SD 13.9) to 68.1% (SD 13.3) after intervention with a large effect size (d=1.22, 95% CI 0.59 to 1.85). Dietary protein intake increased from a mean of 0.9 g/kg (SD 0.3) per day to a mean of 1.3 g/kg (SD 0.5) per day with a large effect size (d=1.07, 95% CI 0.45 to 1.69). Phosphorus to protein ratio dropped from a mean of 18.4 mg/g protein to 13.5 mg/g protein with a large effect size (d=0.83, 95% CI 0.22 to 1.43). There was no evidence of change in phosphorous intake, self-reported nonadherence, and serum phosphorus.

Conclusions

The findings of this prospective pilot reveal the potential efficacy of a smartphone app as a supportive nutrition education tool for phosphorus management in patients undergoing hemodialysis. This pilot study showed that the KELA.AE app has the potential to improve knowledge and dietary choices. A rigorous randomized controlled trial should be performed to evaluate the efficacy, assessing app use of a long-term intervention.

Effectiveness of phosphate binders in adult patients with end stage renal disease receiving hemodialysis: a systematic review

OBJECTIVES

The objective of the review was to evaluate the effectiveness of the use of phosphate binders on mortality and serum levels of phosphorus, calcium and parathyroid hormone in adult patients with end stage renal disease receiving hemodialysis compared to hemodialysis with no phosphate binder use.

INTRODUCTION

End stage renal disease leading to hemodialysis is a common global health issue. Effective management of this population is focused on balancing alterations in bone mineral markers such as phosphorus, calcium and parathyroid hormone. Chronic imbalances are associated with all-cause mortality. Phosphate binders are a crucial element to regulating these levels.

INCLUSION CRITERIA

The review considered studies including adult patients, age 18 and over, receiving hemodialysis. The intervention of interest was the use of any drug within the class of phosphate binders. Outcomes of interest were all-cause mortality and serum levels of phosphorus, calcium and parathyroid hormone. Experimental and quasi-experimental study designs were considered.

METHODS

A search for relevant published and unpublished literature was conducted through November 5, 2017. Databases searched included PubMed, CINAHL, Embase and Cochrane Central Register of Controlled Trials (CENTRAL), in addition to gray literature sources. Articles that met the inclusion criteria were further assessed for methodological validity by two independent reviewers using the standard critical appraisal instruments from Joanna Briggs Institute. Data were extracted from papers included in the review using the standardized data extraction tool from the Joanna Briggs Institute. Quantitative data were pooled for statistical meta-analysis to evaluate the impact of phosphate binders on phosphorus and calcium.

RESULTS

Seven studies were included in this review. A meta-analysis of four studies showed that the use of phosphate binders resulted in a statistically significant decrease in phosphorus levels compared to placebo (mean difference -1.89 mg/dL, 95% confidence interval -2.03 mg/dL, -1.75 mg/dL); three additional studies described narratively also showed a statistically significant decrease in phosphorus. A meta-analysis of three studies showed a statistically significant increase in calcium compared to placebo (mean difference 0.57 mg/dL, 95% confidence interval 0.50 mg/dL, 0.64 mg/dL); two additional studies described narratively showed no difference in effect on calcium. Of the three studies that measured parathyroid hormone, one showed a statistically significant improvement with the use of phosphate binders (mean difference -83.0 pg/mL, 95% confidence interval -154.63 pg/mL, -11.37 pg/mL) and two showed no difference in effect. No studies measured mortality.

CONCLUSION

Phosphate binders are effective in reducing serum phosphorus. The findings on parathyroid hormone and calcium did not provide adequate support for phosphate binder use. The impact on mortality was not directly measured in any of the included studies.

A comparison between the combined effect of calcium carbonate with sucroferric oxyhydroxide and other phosphate binders: an in vitro and in vivo experimental study

Background

Approximately 30% of patients on dialysis received combination therapy for their phosphate binder prescription; however, few studies for combined effects of phosphate binders are reported. For the purpose of evaluating the efficacy of combination therapy, we compared the efficacy of sucroferric oxyhydroxide (PA21) combined with calcium carbonate with that of lanthanum carbonate hydrate, sevelamer hydrochloride, and ferric citrate hydrate combined with calcium carbonate.

Methods

For in vitro studies, calcium carbonate and the other phosphate binders alone or in combination were stirred in phosphate solution at pH 2–8 for 2 h. After centrifuging the suspension, the phosphorus level in the supernatant was determined. For in vivo studies, rats were orally administered calcium carbonate and the other phosphate binders (except for sevelamer hydrochloride) alone or in combination, followed by oral administration of phosphate solution adjusted to pH 2 or 7. Serum samples were collected from the rats at predetermined timepoints and the serum phosphorus levels were determined and analyzed using a two-way analysis of variance.

Results

In the in vitro study, the measured phosphate-binding capacity of combining sevelamer hydrochloride, PA21, and lanthanum carbonate hydrate with calcium carbonate was approximately equal to or greater than the theoretical values under most conditions. Furthermore, these combined effects were insensitive to pH in that order. The measured phosphate-binding capacity of ferric citrate hydrate combined with calcium carbonate was smaller than the theoretical values, and the combination did not exhibit efficacy under any of the tested conditions. In the in vivo study, the combined effect of PA21 and calcium carbonate at both pH values and that of lanthanum carbonate hydrate and calcium carbonate at pH 2 were additive. In contrast, the combined effect of lanthanum carbonate hydrate and calcium carbonate at pH 7 and that of ferric citrate hydrate and calcium carbonate at pH 2 were antagonistic.

Conclusions

These results suggest that coadministration of PA21 and calcium carbonate showed good and relatively stable efficacy throughout the range of the gastrointestinal pH and that combining lanthanum carbonate hydrate and ferric citrate hydrate with calcium carbonate may not produce the expected efficacy under certain conditions.

Markers of mineral metabolism and vascular access complications: The Choices for Healthy Outcomes in Caring for ESRD (CHOICE) study

INTRODUCTION

Vascular access dysfunction is a major cause of morbidity in patients with end-stage renal disease (ESRD) on chronic hemodialysis. The effects of abnormalities in mineral metabolism on vascular access are unclear. In this study, we evaluated the association of mineral metabolites, including 25-hydroxy vitamin D (25(OH)D) and fibroblast growth factor-23 (FGF-23), with vascular access complications.

METHODS

We included participants from the Choices for Healthy Outcomes in Caring for ESRD (CHOICE) Study who were using an arteriovenous fistula (AVF; n = 103) or arteriovenous graft (AVG; n = 116). Serum levels of 25(OH)D, FGF-23, parathyroid hormone (PTH), calcium, phosphorus, C-reactive protein (CRP) and interleukin-6 (IL-6) were assessed from stored samples. Participants were followed for up to 1 year or until a vascular access intervention or replacement.

FINDINGS

A total of 24 participants using an AVF and 43 participants using an AVG experienced access intervention. Those with 25(OH)D level in the lowest tertile (<11 ng/mL) had an increased risk of AVF intervention compared to those with higher 25(OH)D levels (adjusted relative hazard [aHR] = 3.28; 95% confidence interval [CI]: 1.31, 8.20). The highest tertile of FGF-23 (>3750 RU/mL) was associated with greater risk of AVF intervention (aHR = 2.56; 95% CI: 1.06, 6.18). Higher PTH was associated with higher risk of AVF intervention (aHR = 1.64 per SD of log(PTH); 95% CI: 1.02, 2.62). These associations were not observed in participants using an AVG. None of the other analytes were significantly associated with AVF or AVG intervention.

DISCUSSION

Low levels of 25(OH)D and high levels of FGF-23 and PTH are associated with increased risk of AVF intervention. Abnormalities in mineral metabolism are risk factors for vascular access dysfunction and potential therapeutic targets to improve outcomes.

Dietary Application for the Management of Patients with Hemodialysis: A Formative Development Study

Objectives

To describe the step-by-step person-centered, theory-based development of the KELA.AE app for Arabic speaking hemodialysis patients.

Methods

A step-by-step person-driven theory-based approach was conducted to develop a self-monitoring and educational dietary app for hemodialysis patients. The development follows the Integration, Design, Assessment, and Sharing (IDEAS) framework. Qualitative, semi-structured interviews with 6 hemodialysis patients and 6 healthcare practitioners (dietitians and nephrologists) were performed to assess the need for an app, the willingness to use an app, and features desired in an app.

Results

The KELA.AE app, which includes a self-monitoring feature, CKD-friendly recipes, and a theory-based, evidence-based educational feature was developed. Qualitative analysis of interviews revealed two predominant themes from patient interviews ‘Experience with the diet’, ‘App evaluation’, and one theme from interviews with healthcare practitioners ‘App evaluation’. Patients expressed frustration with current accessibility of dietary information along with the need for educational materials in the app. The review of the KELA.AE prototype was positive overall, and patients reported a willingness to use the app. Healthcare practitioners considered the app accurate, simple, and culturally sensitive but expressed concerns about app misuse and the replacement of healthcare practitioners.

Conclusions

The KELA.AE app was found to be satisfactory and supportive of the participants' needs. Changes were made to the app as suggested during the interviews.

A Survey of Drug Burden in Patients Undergoing Maintenance Hemodialysis in Japan

Objective This report presents a part of a survey pertaining to drug burden in maintenance hemodialysis patients in Japan. Methods A patient-reported questionnaire-based survey was conducted from September to November 2016 in six regions in Japan. Patients A total of 700 patients (50-79 years old) on maintenance hemodialysis for >3 years and members of the Japan Association of Kidney Disease Patients (JAKDP) were provided with the questionnaire. They were randomly selected using stratified sampling according to patient distribution observed from the Japanese Society for Dialysis Therapy Renal Data Registry (JSDT JRDR). Results A total of 524 (74.9%) patient questionnaires were evaluated [mean (standard deviation; SD) age, 66.6 (7.2) years; males, 63.4%; dialysis vintage, 16.9 (9.1) years]. Patients' age, gender, and regional distribution were similar to the JSDT JRDR. They were taking an average (SD) of 16.4 (8.34) and 16.3 (8.55) oral medications/day on dialysis and nondialysis days, respectively. A majority of the patients were taking ≥10 oral medications/day on dialysis (75.1%) and nondialysis (74.4%) days, with phosphate binders being the most taken (7.0 tablets/day). A similar proportion (74.4%, 72.9%, respectively) was taking ≥6 different types of oral medications/day. Most patients were taking oral medications 3 (31%, 33%), 4 (24%, 22%), and ≥5 times (31%, 30%) a day, respectively. The drug burden was similar on dialysis and nondialysis days and did not vary with dialysis vintage. Conclusion The number, type, and frequency of oral medications in maintenance hemodialysis patients are high in Japan. The proportion of phosphate binders was highest among the prescription medications.

Prognostic value of bone- and vascular-derived molecular biomarkers in hemodialysis and renal transplant patients: a systematic review and meta-analysis

Background

Patients undergoing hemodialysis and kidney graft recipients are high-risk populations for cardiovascular and all-cause mortality. Fibroblast growth factor 23 (FGF23), osteoprotegerin (OPG), RANK ligand, osteopontin (OPN), Klotho protein and bone morphogenetic protein-7 (BMP-7) are bone- and vascular-derived molecular biomarkers that have been shown to be associated with cardiovascular surrogate end points; however, currently available data on the prognostic value of these biomarkers is inconsistent. The aim of the present study was to conduct a systematic review and meta-analysis in order to summarize the available evidence on the association of molecular biomarkers with mortality in individuals undergoing hemodialysis and renal transplant patients.

Methods

Two databases (MEDLINE and Embase) were systematically searched. Studies were eligible if the association of biomarker and mortality was reported as time-to-event data [hazard Ratio (HR)] or as effect size with a fixed time of follow-up [odds Ratio (OR)]. Abstracted HRs were converted onto a standard scale of effect and combined using a random effects model.

Results

From a total of 1170 studies identified in initial searches, 21 met the inclusion criteria. In hemodialysis patients, comparing the lower third with the upper third of baseline FGF23 distribution, pooled HRs (95% confidence intervals) were 1.94 (1.47, 2.56) for all-cause mortality and 2.4 (1.64, 3.51) for cardiovascular mortality. For the same comparison of baseline OPG distribution, pooled HRs were 1.8 (0.95, 3.39) for all-cause mortality and 2.53 (1.29, 4.94) for cardiovascular mortality. Reported risk estimates of RANK ligand, OPN, Klotho protein and BMP-7 were not suitable for pooling; however, only Klotho protein was significantly related to mortality. For kidney graft recipients, four studies that investigated the relationship of FGF23 and OPG with mortality were identified, all of which reported a significant association.

Conclusions

In hemodialysis patients, FGF23 is a predictor of all-cause and cardiovascular mortality, whereas the predictive value of OPG is restricted to cardiovascular mortality. Further studies are needed in order to gain insight into the prognostic value of these biomarkers in renal transplant recipients.

Effectiveness of phosphate binders in adult patients with end stage renal disease receiving hemodialysis: a systematic review protocol

REVIEW QUESTION

The question of this review is what is the effectiveness of the use of phosphate binders on mortality and serum levels of phosphorus, calcium and intact parathyroid hormone in adult patients with end stage renal disease receiving hemodialysis?

Nursing educational intervention for the identification of Adverse Events in hemodialysis

ABSTRACT Objective: To develop an educational program aimed at the qualification of the nursing technicians that makes possible the understanding of Adverse Events (AE), aiming to adapt the data records; to elaborate tools for the records of the AE in hemodialysis patients; and to assess the knowledge before and after the educational program. Method: An educational intervention was conducted through a classroom and online course on how to recognize and record AE in hemodialysis. The effectiveness of the program was assessed through the gain of knowledge measured through online record of the AE in fictitious problem cases before and after the course. Result: Sixteen nursing technicians participated in the study. In the initial test, the mean score was 3.7 ± 0.3 points and in the final assessment was 4.2 ± 0.3 points (p=0.0002). Conclusion: It was possible to verify that the educational intervention contributed to increase the knowledge of the participants and that the training of these can be achieved with classroom and online learning courses.

Achievement of Kidney Disease: Improving Global Outcomes mineral and bone targets between 2010 and 2014 in incident dialysis patients in France: the Photo-Graphe3 study

Background

Abnormal serum phosphate, calcium and parathyroid hormone (PTH) levels in patients with chronic kidney disease (CKD) undergoing haemodialysis have been associated with poor survival. The French Phosphorus and Calcium Observatory (Photo-Graphe^® 3) aimed to estimate the percentage of CKD patients achieving the three Kidney Disease: Improving Global Outcomes (KDIGO) targets about optimal serum phosphate, calcium and PTH over a 3.5-year follow-up period.

Methods

This was a prospective, multicentre, epidemiological observational study conducted with nephrologists in France, selected using a clustering approach. Eligible patients were adults undergoing intermittent haemodialysis or haemodiafiltration therapy started within the preceding 12 months. Data about clinical events, serum biochemistry and treatment were collected once every 6 months for 2.5 years and 12 months thereafter.

Results

Overall, 9010 incident patients were included (men, 63%; median age, 71 years) of whom 7515 (83.4%) were treated by haemodialysis and 1495 (16.6%) by haemodiafiltration. None had a history of fracture or revascularization while 89 (1%) patients had a history of parathyroidectomy >6 months. Overall, 874 (10%) patients received a kidney graft, 2183 (24%) died and 1148 (13%) were lost to follow-up. The proportion achieving the three KDIGO targets increased significantly from 11% to 16% (P < 0.0001) until Year 2, but remained stable afterwards. The percentage of incident dialysis patients with normal serum phosphate (P < 0.0001) or normal serum calcium (P < 0.0001) levels increased significantly over time, while no significant change was observed for those with controlled PTH.

Conclusion

Less than 20% of patients achieved the KDIGO recommendations although their proportion increased slightly over time.

Phosphorus and mortality risk in end-stage renal disease: A meta-analysis

BACKGROUND

Studies on the association of abnormal serum phosphorus level with all-cause mortality in patients with end-stage renal disease (ESRD) have yielded inconsistent results.

OBJECTIVE

To evaluate the association of abnormal serum phosphorus level with all-cause mortality in patients with ESRD requiring dialysis by conducting a meta-analysis.

METHODS

Pubmed and Embase databases were searched through March 2017 to identify all observational studies that assessed the association between abnormal serum phosphorus level and all-cause mortality risk in patients with ESRD requiring dialysis. Pooled hazard risk (HR) with 95% confidence interval (CI) was calculated for the highest versus referent phosphorus category and lower versus referent phosphorus category, separately.

RESULTS

Nine cohort studies were eligible for analysis. During 12 to 97.6months follow-up duration, 24,463 death events occurred among 1,992,869 ESRD patients. Meta-analysis showed that the pooled HR of all-cause mortality was 1.16 (95% CI 1.06-1.28) for the lower versus referent serum phosphorus category. Similarly, patients with highest serum phosphorus levels were associated with an increased risk of all-cause mortality (HR 1.39; 95% CI 1.31-1.47) compared with those in the referent phosphorus category. Subgroup analyses revealed that the effect of phosphorus on the all-cause mortality risk appeared to be stronger within 2years follow-up.

CONCLUSIONS

Both very high and very low values of phosphorus are independently associated with an increased risk for all-cause mortality in ESRD patients requiring dialysis. This meta-analysis highlighted a non-linear association of serum phosphorus with all-cause mortality among dialysis-dependent ESRD patients.

High Serum Phosphorus Level Is Associated with Left Ventricular Diastolic Dysfunction in Peritoneal Dialysis Patients

Objectives

We initiated this study to explore the relationships of serum phosphorus level with left ventricular ultrasound features and diastolic function in peritoneal dialysis (PD) patients.

Methods

174 patients with end-stage renal disease (ESRD) receiving PD were enrolled in this retrospective observational study. Conventional echocardiography examination and tissue Doppler imaging (TDI) were performed in each patient. Clinical information and laboratory data were also collected. Analyses of echocardiographic features were performed according to phosphorus quartiles groups. And multivariate regression models were used to determine the association between serum phosphorus and Left ventricular diastolic dysfunction (LVDD).

Results

With the increase of serum phosphorus levels, patients on PD showed an increased tissue Doppler-derived E/e’ ratio of lateral wall (P < 0.001), indicating a deterioration of left ventricular diastolic function. Steady growths of left atrium and left ventricular diameters as well as increase of left ventricular muscle mass were also observed across the increasing quartiles of phosphorus, while left ventricular ejection fraction remained normal. In a multivariate analysis, the regression coefficient for E/e’ ratio in the highest phosphorus quartile was almost threefold higher relative to those in the lowest quartile group. And compared with patients in the lowest phosphorus quartile (<1.34 mmol/L) those in the highest phosphorus quartile (>1.95 mmol/L) had a more than fivefold increased odds of E/e’ ratio >15.

Conclusions

Our study showed an early impairment of left ventricular diastolic function in peritoneal dialysis patients. High serum phosphorus level was independently associated with greater risk of LVDD in these patients. Whether serum phosphorus will be a useful target for prevention or improvement of LVDD remains to be proved by further studies.

To assess vascular calcification in the patients of hypoparathyroidism using multidetector computed tomography scan

BACKGROUND

Our pilot data showed an increased intima media thickness in the patients with sporadic idiopathic hypoparathyroidism (SIH). Alteration in homeostasis of calcium, phosphate, and parathyroid hormone (PTH) may predispose to increase the risk of cardiovascular morbidity and mortality. The data on objective assessment of this increased risk is however lacking.

OBJECTIVE

To assess the effect of altered calcium, phosphate, and PTH homeostasis in the patients with SIH on coronary calcium score (a marker of increase vascular risk) by multidetector computed tomography scan (MDCT).

METHODS

In this case-control study, we measured coronary CT calcium score in 30 patients of SIH and compared with 40 age and sex matched healthy subjects. Correlation of coronary calcium score with biochemical parameters was evaluated.

RESULTS

Three of the 30 cases (10%) with SIH were found to have coronary artery calcification (CAC) of varying degree, whereas none of the control showed CAC (P = 0.07). The patients with CAC had significantly lower serum calcium levels (albumin corrected), as compared to the patients without CAC. Inverse correlation of CAC was found with serum calcium levels. No correlation was found with other biochemical parameters.

CONCLUSION

The vascular risk is increased in the patients with SIH as assessed by coronary calcium score measured by MDCT. Low serum calcium levels might be a predisposing factor for this increased risk.

C-reactive Protein: Repeated Measurements will Improve Dialysis Patient Care

Systemic inflammation is a common feature in the uremic phenotype and associates with poor outcomes. The awareness regarding the importance of inflammation assessment in chronic kidney disease (CKD) patients has risen in recent years, and despite the development of novel biomarkers, C-reactive protein (CRP) is still the most measured inflammatory parameter. Notwithstanding, the possible weak points of CRP determination, this biomarker has demonstrated being useful both for guidance in clinical practice and for risk estimation. In addition, regular determination of CRP among dialysis patients has been associated with better outcomes in different dialysis facilities. Because persistent inflammation may be a silent reflection of various pathophysiologic alterations in CKD, it is crucial that inflammatory markers are regularly monitored and therapeutic attempts be made to target this inflammation.

[Surgical treatment of secondary hyperparathyroidism: a systematic review of the literature]

Secondary hyperparathyroidism (HPT) has a high prevalence in renal patients. Secondary HPT results from disturbances in mineral homeostasis, particularly calcium, which stimulates the parathyroid glands, increasing the secretion of parathyroid hormone (PTH). Prolonged stimulation can lead to autonomy in parathyroid function. Initial treatment is clinical, but parathyroidectomy (PTx) may be required. PTx can be subtotal or total followed or not followed by parathyroid tissue autograft. We compared the indications and results of these strategies as shown in the literature through a systematic literature review on surgical treatment of secondary HPT presented in MedLine and LILACS from January 2008 to March 2014. The search terms were: hyperparathyroidism; secondary hyperparathyroidism; parathyroidectomy and parathyroid glands, restricted to research only in humans, articles available in electronic media, published in Portuguese, Spanish, English or French. We selected 49 articles. Subtotal and total PTx followed by parathyroid tissue autograft were the most used techniques, without consensus on the most effective surgical procedure, although there was a preference for the latter. The choice depends on surgeon's experience. There was consensus on the need to identify all parathyroid glands and cryopreservation of parathyroid tissue whenever possible to graft if hypoparathyroidism arise. Imaging studies may be useful, especially in recurrences. Alternative treatments of secondary HPT, both interventional and conservative, require further study.

Oral zinc supplementation reduces the erythropoietin responsiveness index in patients on hemodialysis

Background: In hemodialysis (HD) patients, zinc depletion caused by inadequate intake, malabsorption, and removal by HD treatment leads to erythropoiesis-stimulating agent (ESA) hyporesponsiveness. This study investigated the effects of zinc supplementation in HD patients with zinc deficiency on changes in the erythropoietin responsiveness index (ERI). Methods: Patients on HD with low serum zinc levels (<65 μg/dL) were randomly assigned to two groups: The polaprezinc group (who received daily polaprezinc, containing 34 mg/day of zinc) (n = 35) and the control group (no supplementation) (n = 35) for 12 months. All the 70 patients had been taking epoetin alpha as treatment for renal anemia. ERI was measured with the following equation: Weekly ESA dose (units)/dry weight (kg)/hemoglobin (g/dL). Results: There were no significant changes in hemoglobin levels within groups or between the control and polaprezinc groups during the study period. Although reticulocyte counts were increased immediately after zinc supplementation, this change was transient. Serum zinc levels were significantly increased and serum copper levels were significantly decreased in the polaprezinc group after three months; this persisted throughout the study period. Although there was no significant change in the serum iron or transferrin saturation levels in the polaprezinc group during the study period, serum ferritin levels significantly decreased following polaprezinc treatment. Further, in the polaprezinc group, ESA dosage and ERI were significantly decreased at 10 months and nine months, respectively, as compared with the baseline value. Multiple stepwise regression analysis revealed that the change in the serum zinc level was an independent predictor of lowered ERI. Conclusions: Zinc supplementation reduces ERI in patients undergoing HD and may be a novel therapeutic strategy for patients with renal anemia and low serum zinc levels.

Effects of Uremic Toxins from the Gut Microbiota on Bone: A Brief Look at Chronic Kidney Disease

Patients with chronic kidney disease (CKD) frequently have mineral and bone disorders (CKD-MBD) that are caused by several mechanisms. Recent research has suggested that uremic toxins from the gut such as p-cresyl sulfate (PCS) and indoxyl sulfate (IS) could also be involved in the development of bone disease in patients with CKD. IS and PCS are produced by microbiota in the gut, carried into the plasma bound to serum albumin, and are normally excreted into the urine. However, in patients with CKD, there is an accumulation of high levels of these uremic toxins. The exact mechanisms of action of uremic toxins in bone disease remain unclear. The purpose of this brief review is to discuss the link between uremic toxins (IS and PCS) and bone mineral disease in chronic kidney disease.

Carotid, aorta and renal arteries intima-media thickness in patients with sporadic idiopathic hypoparathyroidism

BACKGROUND

Alteration in homeostasis of calcium, phosphate and parathyroid hormone (PTH) predispose to vascular calcification that increases the risk of cardiovascular morbidity and mortality. The data on this aspect are scarce in patients with sporadic idiopathic hypoparathyroidism (SIH).

OBJECTIVE

The aim was to assess the effect of altered calcium, phosphate and PTH homeostasis in patients with SIH on intima media thickness (IMT), a surrogate marker of increased vascular risk.

METHODS

In this case-control study, we measured carotid IMT (CIMT), aortic IMT (AIMT) and renal arteries IMT (RIMT) in 30 consecutive patients with SIH, and compared with healthy subjects. IMT was measured by ultrasound by a single operator blinded to subject's details.

RESULTS

CIMT, AIMT, RIMT values in patients with SIH were significantly more than healthy subjects (0.60 ± 0.08 mm vs. 0.52 ± 0.09 mm, P = 0.001; 0.73 ± 0.09 mm vs. 0.65 ± 0.10, P = 0.004; and 0.34 ± 0.04 mm vs. 0.30 ± 0.05, P = 0.003, respectively). Clinical or biochemical parameters did not correlate with CIMT, AIMT and RIMT in patients with SIH.

CONCLUSION

The vascular risk is increased in patients with SIH as assessed by CIMT, AIMT, and RIMT.

Gaps between Global Guidelines and Local Practices in CKD-MBD

The term 'chronic kidney disease-mineral bone disorder' (CKD-MBD) is a new term that, in contrast to the old term 'renal osteodystrophy', implies a systemic syndrome associated with cardiovascular morbidity and mortality. This new terminology is in line with previous studies that show elevated serum calcium, phosphorus, and parathyroid hormone (PTH) levels associated with increased cardiovascular and all-cause mortality. In order to improve outcomes in patients with CKD-MBD, many countries have developed clinical practice guidelines. Globally, the Kidney Disease Outcome Quality Initiative (KDOQI) and Kidney Disease: Improving Global Outcomes (KDIGO) guidelines are the most commonly used. However, whether these global guidelines can be successfully implemented on a local level needs to be studied. Differences in medical care and social factors between countries may limit the generalizability of global guidelines. Reports from the Korean registry and the Dialysis Outcomes and Practice Patterns Study (DOPPS) suggest that many dialysis patients are not within the target ranges recommended by the KDOQI and KDIGO guidelines for serum calcium, phosphorus, and PTH, suggesting gaps between global guidelines and local practices. Clinical studies with Korean CKD-MBD patients are necessary to compare Korean practices and outcomes to those suggested by global guidelines and to determine the target serum mineral levels associated with the best local outcomes.

Bone mineral metabolism and subsequent hospitalization with poor quality of life in dialysis patients

Background:

Significant impairment in health-related quality of life (HRQOL) among dialysis patients could be partly explained by some co-morbid disorders, such as chronic kidney disease-mineral and bone disorder (CKD-MBD). Also disturbance in calcium and phosphorus metabolism would increase mortality and morbidity. Therefore, further efforts to treat these abnormalities may improve the survival.

Objectives:

We designed a large multicenter population-based study in Iran to describe and assess the relation between HRQOL, hospitalization, and bone metabolism markers.

Patients and Methods:

We enrolled a total of 5820 dialysis patients from 132 dialysis centers in different parts of the country whom were volunteers to cooperate between October 2010 and August 2011. The Iranian adapted version of the Kidney disease quality of life-short form (KDQOL-SF^TM) version 1.3 questionnaire was used to assess the health related quality of life. The clinical and demographic characteristics were gathered from patients’ data files.

Results:

The mean (SD) age of patients was 54.88 (16.36) years, and the range was 2 to 99 years. Of all patients, 43.1% were female. The scores of kidney disease component summary (KDCS), physical component summary, mental component summary, and total quality of life were significantly higher in the lower quartile of corrected serum calcium and higher quartile of serum parathyroid hormone (PTH) levels (P < 0.05). In a regression analysis of multilevel data, while corrected serum calcium level was associated with total KDCS and short form health survey (SF-36) scores after adjusting for other variables, hospitalization was directly correlated with serum phosphorus level and had reverse correlation with dialysis duration and quality of life.

Conclusions:

In the current study, quality of life was correlated with serum calcium level, calcium-phosphate product, and serum PTH level, while hospitalization was correlated only with serum phosphorus level. However, quality of life was inversely correlated with hospitalization.