KDOQI US commentary on the 2009 KDIGO Clinical Practice Guideline for the Diagnosis, Evaluation, and Treatment of CKD-Mineral and Bone Disorder (CKD-MBD)

Severe vitamin D deficiency is a risk factor for renal hyperfiltration

Background

Vitamin D deficiency is associated with renal progression in chronic kidney disease. Moreover, improvement of clinical outcomes after vitamin D supplementation has been reported in the diabetic and chronic kidney disease population.

Objective

We investigated the association between renal hyperfiltration (RHF) and vitamin D status in a relatively healthy population.

Design

Data were retrieved from the Korean NHANES, a nationwide population-based cross-sectional study from 2008 to 2015. Overall, 33,210 subjects with normal renal function were included in the final analysis. Severe vitamin D deficiency was defined as serum 25-hydroxyvitamin D concentration <10 ng/mL. RHF was defined as estimated glomerular filtration rate with residual in the >95th percentile after adjustment for age, sex, height, weight, and history of hypertension or diabetes.

Results

The mean ± SD age of subjects was 48.1 ± 15.9 y, and the number of women was 18,779 (56.5%). Estimated glomerular filtration rate was negatively associated with serum 25-hydroxyvitamin D concentrations in multivariable linear regression analysis (β: -0.02; 95% CI: -0.02, -0.01; P < 0.001). Furthermore, 1637 (4.9%) subjects were categorized into the RHF group, and the prevalence of RHF was significantly higher in the severe vitamin D deficiency group than in the sufficiency group (5.8% compared with 5.0%, P < 0.001). In a multivariable logistic regression model, severe vitamin D deficiency was a significant risk factor for RHF (OR: 2.41; 95% CI, 1.72, 3.43; P < 0.001).

Conclusions

Severe vitamin D deficiency is significantly associated with increasing prevalence of RHF in a relatively healthy adult population.

Mineral and bone disorder management in hemodialysis patients: comparing PTH control practices in Japan with Europe and North America: the Dialysis Outcomes and Practice Patterns Study (DOPPS)

Background

High-circulating level of parathyroid hormone (PTH) is associated with elevated mortality in dialysis patients. The Japanese Society for Dialysis Therapy guideline suggests a lower PTH target than other international guidelines; thus, PTH control may differ in Japan compared with other regions, and be associated with mortality.

Methods

We analyzed data from hemodialysis patients with ≥3 measurements of PTH during the first 9 months after enrollment in the Dialysis Outcomes and Practice Patterns Study (DOPPS) phases 4–5 (2009–2015). PTH control was assessed by the mean, slope, and mean squared error (MSE) of all PTH measurements over the 9-month run-in period. Distribution of each PTH control was assessed by regions (Europe/Australia/New Zealand [Eur/ANZ], Japan and North America) and dialysis vintage. Mortality rates were compared across PTH control categories using Cox regression models.

Results

Mean PTH was lower in Japan than in other regions across dialysis vintage categories. In patients with dialysis vintage < 90 days, PTH level was more likely to decline > 5% per month in Japan (48% of patients) versus Eur/ANZ (35%) and North America (35%). In patients with dialysis vintage > 1 year, Japanese patients maintained steady PTH, while patients in Eur/ANZ and North America were more likely to experience a PTH increase. Mean PTH was associated with mortality in the overall samples (highest mortality rate for PTH > 600 pg/mL, hazard ratio, 1.35; 95% confidence interval, 1.20 to 1.52 vs PTH 200–399 pg/mL), and the association was obvious in the prevalent patients (hazard ratio, 1.44; 95% confidence interval, 1.26 to 1.65). PTH slope and MSE did not show significant association with mortality in the overall sample as well as in subjects stratified both by region and dialysis vintage.

Conclusion

PTH control in hemodialysis patients, as measured by keeping a stable PTH level over 9 months, was observed in Japan contrasted with other regions. High PTH mean, but not increased PTH slope and MSE, was associated with mortality especially in prevalent patients.

Overview of the 2017 KDIGO CKD-MBD Update: Practice Implications for Adult Hemodialysis Patients

Renal dietitians play a pivotal role in the ongoing management of chronic kidney disease in patients on hemodialysis. Awareness of changes to clinical practice guidelines that may impact laboratory parameters associated with chronic kidney disease-mineral and bone disorder is important for optimal patient care. In this article, the Kidney Disease: Improving Global Outcomes 2017 Clinical Practice Guideline Update recommendations related to the treatment of secondary hyperparathyroidism in adults on hemodialysis are reviewed and treatment implications for renal dietitians discussed. Specific attention is given to the integration of updated recommendations such as the use of calcimimetics as part of a combination approach to the existing treatment paradigm. Renal dietitians can directly apply the updated clinical recommendations in the evaluation of diet composition; food additives; medication adherence challenges with phosphate binder type and use and serial monitoring of phosphorus, calcium, and parathyroid hormone levels to inform clinical decisions on treatment options for patients.

The effect of a previous created distal arteriovenous-fistula on radial bone DXA measurements in prevalent renal transplant recipients

Background

Accelerated bone loss occurs rapidly following renal transplantation due to intensive immunosuppression and persistent hyperparathyroidism. In renal transplant recipients (RTRs) due to the hyperparathyroidism the non-dominant forearm is often utilized as a peripheral measurement site for dual-energy x-ray absorptiometry (DXA) measurements. The forearm is also the site of previous created distal arteriovenous fistulas (AVF). Although AVF remain patent long after successful transplantation, there are no data available concerning their impact on radial bone DXA measurements.

Methods

In this cross-sectional study we performed DXA in 40 RTRs with preexisting distal AVF (RTRs-AVF) to assess areal bone mineral density (aBMD) differences between both forearms (three areas) and compared our findings to patients with chronic kidney disease (CKD, n = 40), pre-emptive RTRs (RTRs-pre, n = 15) and healthy volunteers (n = 20). In addition, we assessed relevant demographic, biochemical and clinical aspects.

Results

We found a marked radial asymmetry between the forearms in RTRs with preexisting AVF. The radial aBMD at the distal AVF forearm was lower compared to the contralateral forearm, resulting in significant differences for all three areas analyzed: the Rad-1/3: median (interquartile range) in g/cm², Rad-1/3: 0.760 (0.641–0.804) vs. 0.742 (0.642, 0.794), p = 0.016; ultradistal radius, Rad-UD: 0.433 (0.392–0.507) vs. 0.420 (0.356, 0.475), p = 0.004; and total radius, Rad-total: 0.603 (0.518, 0.655) vs. 0.599 (0.504, 0.642), p = 0.001). No such asymmetries were observed in any other groups. Lower aBMD in AVF forearm subregions resulted in misclassification of osteoporosis.

Conclusions

In renal transplant recipients, a previously created distal fistula may exert a negative impact on the radial bone leading to significant site-to-site aBMD differences, which can result in diagnostic misclassifications.

Evidence basis for integrated management of mineral metabolism in patients with end-stage renal disease

PURPOSE OF REVIEW

Treatment of mineral metabolism is a mainstay of dialysis care including some of its most widely used and costly pharmaceuticals. Although many mineral metabolites are associated with increased risk of mortality, cardiovascular disease, and other morbidities, few clinical trials are available to guide therapy and most focus on single drug approaches. In practice, providers manage many aspects of mineral metabolism simultaneously in integrated treatment approaches that incorporate multiple agents and changes in the dialysis prescription. The present review discusses the rationale and existing evidence for evaluating integrated, as opposed to single drug, approaches in mineral metabolism.

RECENT FINDINGS

Drugs used to treat mineral metabolism have numerous, and sometimes, opposing effects on biochemical risk factors, such as fibroblast growth factor 23 (FGF23), calcium, and phosphorus. Although vitamin D sterols raise these risk markers when lowering parathyroid hormone (PTH), calcimimetics lower them. Trials demonstrate that combined approaches best 'normalize' the mineral metabolism axis in end-stage renal disease (ESRD). Observations embedded within major trials of calcimimetics reveal that adjustment of calcium-based binders and dialysate calcium is a common approach to adverse effects of these drugs with some initial, but inconclusive, evidence that these co-interventions may impact outcomes.

SUMMARY

The multiple, and often opposing, biochemical effects of many mineral metabolism drugs provides a strong rationale for studying integrated management strategies that consider combinations of drugs and co-interventions as a whole. This remains a current gap in the field with opportunities for clinical trials.

Extracellular Fluid Excess Is Significantly Associated With Coronary Artery Calcification in Patients With Chronic Kidney Disease

BACKGROUND

Extracellular fluid (ECF) excess is an independent predictor of cardiovascular morbidity in patients undergoing dialysis. This study aimed to investigate the relationship between ECF status, which is affected by renal function, and coronary artery calcification (CAC), which is a marker of cardiovascular disease, in patients with chronic kidney disease (CKD).

METHODS AND RESULTS

A total of 1741 patients at all stages of pre-dialysis CKD from the prospective observational cohort of CMERC-HI (Cardiovascular and Metabolic Disease Etiology Research Center-High Risk) were analyzed for the association between ECF status and CAC. ECF status was defined as extracellular water-to-total body water ratio (ECW/TBW) measured using bioelectrical impedance analysis. ECF excess was defined as ECW/TBW ≥0.390 or ≥0.400 depending on its severity. To define CAC, Agatston coronary artery calcium scores were measured. A total coronary artery calcium score of ≥400 was defined as CAC. The CKD stages were defined according to estimated glomerular filtration rate calculated using the CKD Epidemiology Collaboration equation. ECW/TBW and the proportion of ECF excess increased with progressing CKD stages. Multivariable logistic regression analyses showed that ECW/TBW was independently associated with CAC (per 0.01 increase of ECW/TBW, odds ratio 1.168, 95% confidence interval, 1.079-1.264, P<0.001). The adjusted R2 for predicting higher coronary artery calcium scores and CAC significantly improved after ECW/TBW was added to conventional factors. This association was further confirmed by net reclassification and integrated discriminant improvements, sensitivity analysis, and subgroup analysis.

CONCLUSIONS

ECF status is independently associated with a high risk of CAC in patients with CKD.

STUDY REGISTRATION

URL: https://www.clinicaltrials.gov/. Unique identifier: NCT02003781.

Cross-Sectional Assessment of Achievement of Therapeutic Goals in a Canadian Multidisciplinary Clinic for Patients With Advanced Chronic Kidney Disease

Background

The implementation of advanced chronic kidney disease (CKD) multidisciplinary clinics has now demonstrated their effectiveness in delaying and even avoiding dialysis for patients with CKD. However, very little has been documented on the management and achievement of targets for a number of parameters in this context.

Objective

Our goal was to assess our multidisciplinary clinic therapy performance in relation to the targets for hypertension, anemia, and calcium phosphate assessment.

Methods

Design and setting

A cross-sectional descriptive study was conducted with a cohort including all patients followed up in our multidisciplinary clinic in July 2014.

Measurements

Comorbidity, laboratory, and clinical data were collected and compared with the recommendations of scientific organizations.

Results

The cohort included 128 patients, 37.5% of whom were women. Mean follow-up time was 26.6 ± 25.1 months and mean estimated glomerular filtration rate (eGFR) was 14.0 ± 4.7 mL/min/1.73 m². A total of 24.2% of patients with diabetes achieved blood pressure targets of <130/80 mm Hg, while 56.5% of patients without diabetes achieved targets of <140/90 mm Hg. Hemoglobin of patients treated with erythropoiesis-stimulating agents was 100 to 110 g/L in 36.2% of the patients, below 100 for 39.7% of them, and above 110 for 24.1%, whereas 67.2% were within the acceptable limits of 95 to 115 g/L. In addition, 63.4% of patients had a serum phosphate of <1.5 mmol/L, and 90.9% of patients had total serum calcium <2.5 mmol/L.

Limitations

Our study is a single center study with the majority of our patients being Caucasian. This limits the generalizability of our findings.

Conclusion

The control rates of various parameters were satisfactory given the difficult clinical context, but could be optimized. We publish these data in the hope that they are helpful to others engaged in quality improvement in their own programs or more generally.

Effects of genetic variants on serum parathyroid hormone in hyperparathyroidism and end-stage renal disease patients: A systematic review and meta-analysis

BACKGROUND

Parathyroid hormone (PTH) is one of the principal regulators of calcium homeostasis, crucial for normal functioning of the kidneys, bones, heart, and nervous system. Different pathologic conditions can affect serum PTH level resulting in hyperparathyroidism or hypoparathyroidism. Our study assessed the association of previously reported polymorphisms with the level of PTH (expressed in pg/mL) among individuals with different pathologic conditions affecting PTH level.

METHODS

We searched Web of Science, MEDLINE, and Scopus to identify relevant articles published up to July 2017. The search yielded 6967 publications of which 44 fulfilled the inclusion criteria. We conducted meta-analyses for calcium-sensing receptor gene (CaSR) rs1801725 polymorphism in patients with primary hyperparathyroidism and vitamin D receptor gene (VDR) rs1544410 polymorphism in patients with end-stage renal disease (ESRD).

RESULTS

None of the polymorphisms were significantly associated with PTH levels in the overall population. In subgroup analysis by ethnicity for VDR rs1544410 gene polymorphism, we found significant differences under dominant model (SMD: -0.18 [-0.32, -0.05], P < .01) and AA versus GG comparison (SMD: -0.29 [-0.52, -0.06], P < .01) in Asian patients with ESRD, while nominally significant results (P < .05) were observed for AG versus GG and AA versus GG comparisons in European individuals with ESRD.

CONCLUSION

Scientific evidence of genetic association of serum PTH level among individuals with different pathologic conditions remains deficient and published results provide weak evidence. Further well-conducted studies on larger sample sets designed according to evidence-based principles are warranted to assure clinically applicable findings.

Safety of Low-calcium Dialysate and its Effects on Coronary Artery Calcification in Patients Undergoing Maintenance Hemodialysis

To determine the safety of low-calcium-dialysate in patients undergoing maintenance hemodialysis (MHD) and its effects on coronary artery calcification (CAC) and analyze clinical risk factors for CAC. A total of 174 MHD patients were recruited and randomly divided into two groups: high-calcium dialysate (HCD, 1.5 mmol/L Ca²⁺) and low-calcium dialysate (LCD, 1.25 mmol/L Ca²⁺). Changes in CAC score (CACS) and cardiac function were evaluated using spiral computed tomography and echocardiography, respectively. Clinical and laboratory parameters were measured. Intra-dialysis adverse reactions were recorded and compared between the two groups. CACS was significantly lower in the LCD group than in the HCD group by the end of the study. Cardiac E/A_max was significantly higher in the LCD group than in the HCD group by the end of the study. There was no significant difference in the frequency of any intra-dialysis adverse reactions between the two groups during the study. LCD is helpful in maintaining cardiac diastolic function and postponing CAC progression. LCD does not increase intra-dialysis adverse reactions. Age may be the most important factor impacting CAC in MHD patients.

Chronic kidney disease-mineral and bone disorder: Guidelines for diagnosis, treatment, and management

Chronic kidney disease affects 23 million Americans and is associated with many complications, one of the most complex of which is mineral and bone disorder. Pathophysiologic mechanisms begin to occur early in CKD but when the glomerular filtration rate declines to <50% of normal, biochemical and bone matrix abnormalities, which vary and are multifactorial, begin to be clinically apparent. Mainstays of treatment remain management of hyperphosphatemia and prevention or treatment of secondary hyperparathyroidism.

Influence of pH and phosphate concentration on the phosphate binding capacity of five contemporary binders. An in vitro study

AIM

Hyperphosphataemia is associated with increased mortality and morbidity in end stage renal disease. Despite phosphate binder therapy, a large proportion of patients do not reach the treatment target. In five contemporary binders we explored the influence of pH and phosphate concentration on phosphate binding. This interaction could be of relevance in clinical practice.

METHODS

Phosphate binding was quantified in vitro in 25 mL of purified water containing phosphate concentrations of 10, 15 and 20 mM and baseline pH values of 3.0 or 6.0, with a binder over 6 h. Lanthanum carbonate, calcium acetate/magnesium carbonate, sevelamer carbonate, calcium carbonate and sucroferric oxyhydroxide, 67 mg of each, were used. The experiments were performed in duplicate. The primary outcome was the difference in the amount of bound phosphate for each binder after 6 h in solutions at two different pH values. Secondary outcomes were the influence of phosphate concentration on phosphate binding, next to binding patterns and phosphate binder saturation.

RESULTS AND CONCLUSION

In this specific in vitro setting, lanthanum carbonate, sevelamer carbonate, calcium carbonate and sucroferric oxyhydroxide bound more phosphate in the solution with baseline pH of 3.0. Differences however were small except for lanthanum carbonate. Calcium acetate/magnesium carbonate was most effective in a solution with baseline pH of 6.0. All phosphate binders bound more phosphate in solutions with higher concentrations of phosphate. Sevelamer carbonate, calcium acetate/magnesium carbonate and sucroferric oxyhydroxide bound most phosphate in the first hour and reached maximum binding capacity in less than 6 h.

Hungry bone syndrome

PURPOSE OF REVIEW

In the United States, the number of parathyroidectomies among patients with chronic dialysis has remained stable in the last decade. A fall in serum calcium concentration is common postparathyroidectomy in patients with hyperparathyroidism, which usually resolves in 2-4 days. A severe drop in serum total calcium concentration less than 2.1 mmol/L and/or prolonged hypocalcemia for more than 4 days postparathyroidectomy is called hungry bone syndrome (HBS). Concomitant hypophosphatemia, hypomagnesemia, and hyperkalemia can be seen. Hypocalcemia and hypophosphatemia can persist for months to years. In contemporary clinical practice, HBS may be more commonly seen in patients with secondary compared to primary hyperparathyroidism. Preoperative radiological changes in bone, elevated serum alkaline phosphatase and parathyroid hormone (PTH) levels, and high numbers of osteoclasts on bone biopsy may identify patients at risk. Treatment consists of high-dose oral calcium and calcitriol supplementation. A low-dose pamidronate infusion 1-2 days prior to surgery may prevent HBS.

RECENT FINDINGS

Recent in-vitro studies reported net calcium movement into bone because of a sudden fall in serum PTH level after a prolonged period of elevation. This supports a previous hypothesis that a sudden drop in serum PTH level after surgery results in the unopposed action of osteoblasts and influx of calcium into bone.

SUMMARY

Incidence of HBS and its association with morbidity and mortality remains unclear in contemporary clinical practice. It is more common to encounter HBS in chronic dialysis patients with secondary hyperparathyroidism than those with primary hyperparathyroidism that undergo parathyroidectomies. Use of bisphosphonates to prevent HBS should be explored in future studies.

Ferric citrate controls serum phosphorus in dialysis patients: retrospective data

Ferric citrate is an approved phosphate binder for use in patients with chronic kidney disease on dialysis. Clinical trials demonstrated that ferric citrate controlled serum phosphorus levels and increased iron stores. The aim of this retrospective chart review was to evaluate real-world bone mineral and anemia parameter data from patients treated with ferric citrate. 92 adult dialysis patients taking ferric citrate (average starting dose of 6 tablets/day) for at least 6 months were included. Bone mineral, anemia, and iron biomarker levels were extracted from patient medical records before and during the first 6 months of ferric citrate treatment; 21 (23%) patients were phosphate binder naïve, and 71 (77%) patients had been on other phosphate binders. Before starting ferric citrate, 22% of patients had serum phosphorus ≤ 5.5 mg/dL, increasing to 65% of patients at 6 months of treatment (month 6). Mean (standard error of the mean (SEM)) baseline serum phosphorus was 6.55 ± 0.17 mg/dL decreasing to 5.40 ± 0.17 mg/dL at month 6. Mean (SEM) baseline hemoglobin, ferritin, and transferrin saturation were 10.6 ± 0.2 g/dL, 734 ± 65 ng/mL, and 27.1 ± 1.6%, respectively, and 11.1 ± 0.2 g/dL, 947 ± 66 ng/mL, and 37 ± 1.9%, respectively, at month 6. The serum phosphorus and anemia biomarker levels observed in this retrospective chart review were similar to those seen in clinical trials.

CKD-MBD KDIGO guidelines: how difficult is reaching the 'target'?

Patients with chronic kidney disease (CKD) are affected by mineral and bone disorder (MBD), resulting in abnormalities in serum calcium (Ca), phosphorous (P) and parathyroid hormone (PTH). Changes in mineral metabolism have also been associated with higher rates of both all-cause and cardiovascular-related mortality. The majority of haemodialysis patients are also deficient in the endogenous hormone 1,25-dihydroxyvitamin D (calcitriol), often contributing to increased secondary hyperparathyroidism (SHPT) and consequently to abnormal levels of Ca, P and PTH. Thus P overload and SHPT are well-known targets of medical treatments, such as P binders, vitamin D and calcimimetics, although with still limited evidence-based advantages in terms of survival. The tough hedge that is still keeping nephrologists far from a conclusive and winning approach against CKD-MBD is reasonably related to the still partial comprehension of the molecular pathways involved in a complex, multifactorial and extreme process.

Impact of Serum Phosphorus Levels on Outcomes After Implantation of Drug-Eluting Stents in Patients on Hemodialysis

BACKGROUND

Elevated serum phosphorus level is an important risk factor for cardiovascular death in general patients on hemodialysis (HD). However, the effect of serum phosphorus levels on outcomes after drug-eluting stent (DES) implantation in HD patients is unknown.

METHODS AND RESULTS

This was a post-hoc study of the OUCH study series, a series of prospective multicenter registries of HD patients who underwent DES implantation comprising 359 patients from 31 centers in Japan. Patients were categorized into 3 groups according to their preprocedural serum phosphorus levels. The 1-year clinical outcomes of the 336 patients treated for de novo lesions were evaluated. Compared with patients with high (>5.5 mg/dL; n=65) or normal (3.5-5.5 mg/dL; n=219) serum phosphorus levels, those with low serum phosphorus levels (<3.5 mg/dL; n=52) had significantly fewer target lesion revascularization events (13.9% vs. 16.9% vs. 1.9%; P=0.0090) and major adverse cardiac and cerebrovascular events (29.2% vs. 31.1% vs. 13.5%; P=0.032). Multivariate logistic regression analysis revealed that low serum phosphorus level was an independent negative predictor for major adverse cardiac and cerebrovascular events (adjusted odds ratio, 0.31; 95% confidence interval, 0.12-0.70; P=0.0036).

CONCLUSIONS

Lowering of serum phosphorus levels beyond the current recommended range may be considered in HD patients who undergo DES implantation.

Near total parathyroidectomy for the treatment of renal hyperparathyroidism

Background

Different surgical strategies are used to treat medical refractory renal hyperparathyroidism. Our preferred choice in patients with moderate secondary hyperparathyroidism (SHPT) and in patients with low compliance with medical treatment is to leave a very small parathyroid remnant in situ: we name this operation "near total parathyroidectomy" (ntPTX). We report here our results with this technique.

Methods

Retrospective study [2001-2015] of all patients submitted to ntPTX in a single centre.

Results

Forty-seven patients were submitted to ntPTX (32 males) aged 47.3 years. Follow-up time is 8.5 years. Thirty-five patients (74%) are alive, 12 are dead. One patient in this series had a functioning renal transplant at time of ntPTX (tertiary hyperparathyroidism), and other 27 subsequently received a renal transplantation (RTx) after ntPTX (still functioning at last follow-up or at death in 19). Amongst the 35 current survivors, the renal graft is functioning in 16 (45.7%). Parathyroid hormone (PTH) at follow-up was 116.1±135.5 pg/mL and calcium 8.6±0.9 mg/dL. Among patients with a functioning RTx PTH was 83 pg/mL and calcium 8.7 mg/dL. There was no persistent disease, and 3 patients (6.4%) had a relapse of hyperparathyroidism at follow-up.

Conclusions

ntPTX is associated to very satisfying rates of normal parathyroid function and of relapse of hyperparathyroidism (6.4%) at long term, either in case of RTx or of maintenance hemodialysis: the concept of "small amount" remnant represents a valuable choice for patients undergoing PTX with a realistic chance of receiving a RTx.

Total Parathyroidectomy with Subcutaneous Parathyroid Forearm Autotransplantation in the Treatment of Secondary Hyperparathyroidism: A Single-Center Experience

INTRODUCTION

Secondary hyperparathyroidism is common in chronic kidney disease. Parathyroidectomy is indicated in refractory hyperparathyroidism when medical treatments and so the parathyroid hormone levels cannot be lowered to acceptable values without causing significant hyperphosphatemia or hypercalcemia. The aim of this study is to compare the efficacy and safety of total parathyroidectomy with subcutaneous forearm autotransplantation with total parathyroidectomy with intramuscular forearm autotransplantation.

MATERIALS AND METHODS

A single-center retrospective cohort study of total parathyroidectomy with forearm autotransplantation from January 2002 to February 2013 was performed. According to the surgical technique, patients were divided into an intramuscular group (Group 1) and a subcutaneous group (Group 2). 38 patients with secondary hyperparathyroidism were enrolled; 23 patients were subjected to total parathyroidectomy with parathyroid tissue replanting in the subcutaneous forearm of the upper nondominant limb, while 15 patients were subjected to replanting in the intramuscular seat.

RESULTS

A total of 38 patients (56 ± 13 years) were enrolled. In both groups, the preoperative iPTH value was markedly high, 1750 ± 619 pg/ml in the intramuscular autotransplantation group and 1527 ± 451 pg/ml in the subcutaneous autotransplantation group (p = 0.079). Transient hypoparathyroidism was shown in 7 patients, and 1 patient showed persistent hypoparathyroidism (p = 0.387). 2 patients showed persistent hyperparathyroidism (p = 0.816), and in 2 others was found recurrent hyperparathyroidism (p = 0.816); 3 of them underwent autograftectomy. The anterior compartment of the forearm nondominant limb was sacrificed in 1 case of intramuscular autotransplantation with functional arm deficit.

CONCLUSIONS

The efficacy and safety of parathyroid tissue autotransplantation in the subcutaneous forearm of the upper nondominant limb is confirmed with a good rate of tissue engraftment and with a comparable number of postsurgical transient and persistent hypoparathyroidism and hyperparathyroidism incidence in both techniques. Furthermore, this technique preserves arm functionality in the case of autograftectomy. Consequently, it is our opinion that total parathyroidectomy with subcutaneous forearm autotransplantation is currently the best choice.

Comparison of a Handheld Indirect Calorimetry Device and Predictive Energy Equations Among Individuals on Maintenance Hemodialysis

OBJECTIVES

Practical methods for determining resting energy expenditure (REE) among individuals on maintenance hemodialysis (MHD) are needed because of the limitations of indirect calorimetry. Two disease-specific predictive energy equations (PEEs) have been developed for this metabolically complex population. The aim of this study was to compare estimated REE (eREE) by PEEs to measured REE (mREE) with a handheld indirect calorimetry device (HICD).

METHODS

A prospective pilot study of adults on MHD (N = 40) was conducted at 2 dialysis clinics in Houston and Texas City, Texas. mREE by an HICD was compared with eREE determined by 6 PEEs using Bland-Altman analysis with a band of acceptable agreement of ±10% of the group mean mREE. Paired t-test and the intraclass correlation coefficient were also used to compare the alternate methods of measuring REE. A priori alpha was set at P < .05.

RESULTS

The mean (±standard deviation) age was 56.7 ± 12.9 years, 52.5% (n = 21) were female, and 85% (n = 34) were African American. Body mass index (BMI) ranged from 18.1 to 47.1 kg/m², 67.5% were overweight (BMI ≥25 kg/m²) and 50% were obese (BMI ≥30 kg/m²). The Maintenance Hemodialysis Equation-Creatinine version (MHCD-CR) was the most accurate PEE with 52.5% of values within the band of acceptable agreement, followed by the Mifflin-St. Jeor Equation and the Vilar et al. Equation at 45.0% and 42.5%, respectively.

CONCLUSION

When compared with mREE by the HICD, the MHDE-CR was more accurate and precise than other PEEs evaluated; however, this must be interpreted with caution as mREE was consistently lower than eREE from all PEEs. Further research is needed to validate the MHDE-CR and other practical methods for determining REE among individuals on MHD.

Dental restorative treatment expenditure and resource utilization in patients with chronic kidney disease: A nationwide population-based study

Background/purpose

There is a variety of pathological alterations occurring in the oral cavity are strongly associated with chronic kidney disease (CKD) or CKD therapy. The aim of this study is to conduct a retrospective analysis to examine the possible correlation between the dental restorative treatment modalities and the progression of kidney disease in CKD population.

Materials and methods

A total of 10,457 individuals were divided into three groups: (HC) group (n = 1438), high risk (HR) group (n = 3392), and CKD group (n = 5627). HR group were defined for those with an eGFR ≥60 (mL/min/1.73 m²) in addition to fulfilling one of the following requirements: (1) being diagnosed diabetes mellitus (DM), hypertension, or cardiovascular disease; (2) having a family member diagnosed with CKD or receiving dialysis treatment. Demographic characteristics, dental restorative treatment utilization and expenditures, including amalgam filling, composite resin filling on anterior teeth or posterior teeth, were analyzed retrospectively (2000–2008) among these groups using a nationwide database.

Results

The utilization and expenditures for various restorative treatments were significantly different among investigated groups, and the health insurance usage exhibited an inverse relationship with CKD stages, especially at CKD stages 4 and 5. A sustained decline in utilization and expenditures for restorative treatment was associated with the deterioration of kidney function. The lowest usage of these restorative modalities was noted in the CKD group and a marked difference was noted among investigated groups.

Conclusion

The findings do, however, provide indirect evidence that if patients with progressive renal failure and receive less dental care.

Hypoparathyroidism

Hypoparathyroidism is a disease characterized by inadequately low circulating concentrations of parathyroid hormone (PTH) resulting in low calcium levels and increased phosphate levels in the blood. Symptoms of the disease result from increased neuromuscular irritability caused by hypocalcaemia and include tingling, muscle cramps and seizures. The most common cause of the disease is inadvertent removal of, or injury to, the parathyroid glands during neck surgery, followed by genetic, idiopathic and autoimmune aetiologies. Conventional treatment includes activated vitamin D and/or calcium supplements, but this treatment does not fully replace the functions of PTH and can lead to short-term problems (such as hypocalcaemia, hypercalcaemia and increased urinary calcium excretion) and long-term complications (which include nephrocalcinosis, kidney stones and brain calcifications). PTH replacement has emerged as a new treatment option. Clinical trials using human PTH(1-34) and PTH(1-84) showed that this treatment was safe and effective in studies lasting up to 6 years. Recombinant human PTH(1-84) has been approved in the United States and Europe for the management of hypoparathyroidism; however, its effect on long-term complications is still being evaluated. Clinical practice guidelines, which describe the consensus of experts in the field, have been published and recognize the need for more research to optimize care. In this Primer, we summarize current knowledge of the prevalence, pathophysiology, clinical presentation and management of hypoparathyroidism.

Long-term effects of etelcalcetide as intravenous calcimimetic therapy in hemodialysis patients with secondary hyperparathyroidism

BACKGROUND

Secondary hyperparathyroidism (SHPT) is a serious major complication in hemodialysis patients with chronic kidney disease. Long-term maintenance of serum phosphate, calcium, and parathyroid hormone (PTH) levels in appropriate ranges in these patients is a major challenge. We investigated the efficacy and safety of long-term treatment with etelcalcetide, a novel intravenous calcimimetic, in Japanese SHPT patients on long-term hemodialysis.

METHODS

This study was a multicenter open-label study. A total of 191 hemodialysis patients with serum intact PTH (iPTH) > 240 pg/mL were enrolled. Etelcalcetide was administered thrice weekly for 52 weeks, with an initial dose of 5 mg and flexibility to adjust the dose between 2.5 and 15 mg and to adjust the dosing of concomitant medications for SHPT. The efficacy endpoint was the proportion of patients with serum iPTH decreased to the target range (60-240 pg/mL).

RESULTS

Serum iPTH levels decreased immediately after etelcalcetide was started. At the end of the study, 87.5% (95% confidence interval 81.4-92.2; 140/160 patients) of patients achieved target serum iPTH levels, with control of serum calcium and phosphate levels. Adverse events, mostly mild to moderate, were reported by 96.8% of patients and led to study discontinuation in 7.4% of patients. Nausea, vomiting, and symptomatic hypocalcemia were found in 4.7, 9.5, and 1.1%, with 0.5, 1.1, and 1.1% considered treatment-related.

CONCLUSIONS

Etelcalcetide effectively maintained serum iPTH, calcium, and phosphate levels in appropriate ranges with concomitant medications for SHPT for 52 weeks in Japanese hemodialysis patients, and was safe and well tolerated.

REGISTRATION NUMBER

JapicCTI-142665.

Deoxycholic Acid, a Metabolite of Circulating Bile Acids, and Coronary Artery Vascular Calcification in CKD

BACKGROUND

Vascular calcification is common among patients with chronic kidney disease (CKD), and it is associated with all-cause and cardiovascular disease mortality. Deoxycholic acid, a metabolite of circulating bile acids, is elevated in CKD and induces vascular mineralization and osteogenic differentiation in animal models.

STUDY DESIGN

Cohort analysis of clinical trial participants.

SETTING & PARTICIPANTS

112 patients with moderate to severe CKD (estimated glomerular filtration rate, 20-45mL/min/1.73m²) who participated in a randomized controlled study to examine the effects of phosphate binders on vascular calcification.

PREDICTOR

Serum deoxycholic acid concentration.

OUTCOMES

Baseline coronary artery calcification (CAC) volume score and bone mineral density (BMD) and change in CAC volume score and BMD after 9 months.

MEASUREMENTS

Deoxycholic acid was assayed in stored baseline serum samples using liquid chromatography-tandem mass spectrometry, CAC was measured using a GE-Imitron C150 scanner, and BMD was determined using computed tomographic scans of the abdomen with calibrated phantom of known density.

RESULTS

Higher serum deoxycholic acid concentrations were significantly correlated with greater baseline CAC volume and lower baseline BMD. After adjusting for demographics, coexisting illness, body mass index, estimated glomerular filtration rate, and concentrations of circulating markers of mineral metabolism, including serum calcium, phosphorus, vitamin D, parathyroid hormone, and fibroblast growth factor 23, a serum deoxycholic acid concentration > 58ng/mL (the median) was positively associated with baseline CAC volume (β=0.71; 95% CI, 0.26-1.16; P=0.003) and negatively associated with baseline BMD (β = -20.3; 95% CI, -1.5 to -39.1; P=0.04). Serum deoxycholic acid concentration > 58ng/mL was not significantly associated with change in CAC volume score after 9 months (β=0.06; 95% CI, -0.09 to 0.21; P=0.4). The analysis for the relationship between baseline deoxycholic acid concentrations and change in BMD after 9 months was not statistically significant, but was underpowered.

LIMITATIONS

The use of nonfasting serum samples is a limitation because deoxycholic acid concentrations may vary based on time of day and dietary intake. Few trial participants with complete data to evaluate the change in CAC volume score (n=75) and BMD (n=59). No data for changes in deoxycholic acid concentrations over time.

CONCLUSIONS

Among patients with moderate to severe CKD, higher serum deoxycholic acid concentrations were independently associated with greater baseline CAC volume score and lower baseline BMD.

Prospective cohort study: Cinacalcet-mediated lowering of PTH level and cardiovascular disease mortality in younger Korean patients with stage 5 CKD at a Korean secondary hospital

WHAT IS KNOWN AND OBJECTIVES

Cinacalcet may reduce cardiovascular disease (CVD) mortality in elderly patients with chronic kidney disease (CKD). However, previous studies of the clinical responses to cinacalcet have exhibited discrepancies due to highly variable baseline levels of parathyroid hormone (PTH), kidney function and age. Little is known about the true effect of cinacalcet on stage 5 CKD. The objective of the current observational study was to evaluate whether cinacalcet-mediated lowering of PTH levels improves all-cause mortality and cardiovascular disease mortality in younger stage 5 CKD patients (mean age <55 years).

METHODS

This prospective, cohort study reviewed the electronic medical records (EMRs) of CKD patients (n=540) with secondary hyperparathyroidism (SHPT) for a period of 36 months. Of 540 patients, 104 subjects met the inclusion criteria and were included in the final evaluation (mean serum iPTH 688.7 pg/mL). Patients were divided into a cinacalcet group (n=43) and a non-cinacalcet group (n=61).

RESULTS AND DISCUSSION

Comparing the cinacalcet group to the non-cinacalcet group, Cox proportional hazard modelling found that all-cause mortality was five (31.3%) in the cinacalcet group and three (15.8%) in the non-cinacalcet group for patients with serum levels of PTH>600 pg/mL [P=.277, hazard ratio 2.213, 95% confidence interval (CI): 0.529-9.262]. Cardiovascular disease mortality (CVD: heart disease) occurred in two (5.3%) in the cinacalcet group and one (2.1%) in the non-cinacalcet group [P=.425, HR 2.611, 95% CI: 0.228-9.939]. Overall, there were no significant differences in CVD mortality between the two groups.

WHAT IS NEW AND CONCLUSION

Cinacalcet was not associated with decreases in all-cause mortality or CVD mortality in younger stage 5 CKD patients with high PTH levels (>600 pg/mL). This could be explained by the diversity of the population in terms of the patient's age, health insurance policies, target serum level of biochemical and PTH, and glomerular filtration rate (GFR) at admission. These data, although based on an observational study, indicate that adding cinacalcet to the current standard care for younger stage 5 CKD patients should be re-evaluated.

Imaging in Chronic Kidney Disease-Metabolic Bone Disease

Musculoskeletal manifestations in chronic kidney disease (CKD) are the result of a series of complex alterations in mineral metabolism, which has been defined as chronic kidney disease - mineral and bone-related disorder (CKD-MBD). Biochemical assessment and, at times, bone biopsy remains the mainstay of disease assessment, however, radiological imaging is an important adjunct in evaluating disease severity. This review aims to illustrate the radiological features of CKD-MBD, such as secondary hyperparathyroidism, osteomalacia, adynamic bone disease, osteopenia, and extra-skeletal calcifications.

Imaging for Vascular Calcification

Chronic decline in renal function is accompanied by deterioration of bone structure and function and progressive calcification of the vascular system. Both disease states have been linked with increased morbidity and mortality in chronic kidney disease. The severe alterations of mineral metabolism inherent with loss of renal function have an impact on vascular calcification development and progression, and several investigators have focused on ways to reduce their impact on vascular health. Imaging has contributed an important role in the assessment of vascular calcification, and the impact of various interventions aimed at curbing their progression.

Secondary Hyperparthyroidism: Pathogenesis, Diagnosis, Preventive and Therapeutic Strategies

Uremic secondary hyperparathyroidism is a multifactorial and complex disease often present in advanced stages of chronic kidney disease. The accumulation of phosphate, the increased FGF23 levels, the reduction in active vitamin D production, and the tendency to hypocalcemia are persistent stimuli for the development and progression of parathyroid hyperplasia with increased secretion of PTH. Parathyroid proliferation may become nodular mainly in cases of advanced hyperparathyroidism. The alterations in the regulation of mineral metabolism, the development of bone disease and extraosseous calcifications are essential components of chronic kidney disease-mineral and bone disorder and have been associated with negative outcomes. The management of hyperparathyroidism includes the correction of vitamin D deficiency and control of serum phosphorus and PTH without inducing hypercalcemia. An update of the leading therapeutic tools available for the prevention and clinical management of secondary hyperparathyroidism, its diagnosis, and the main mechanisms and factors involved in the pathogenesis of the disease will be described in this review.

Roles of Serum Calcium, Phosphorus, PTH and ALP on Mortality in Peritoneal Dialysis Patients: A Nationwide, Population-based Longitudinal Study Using TWRDS 2005-2012

Biomarkers of chronic kidney disease-mineral and bone disorder (CKD-MBD) correlate with morbidity and mortality in dialysis patients. However, the comparative roles of each CKD-MBD biomarker remained undetermined on long-term peritoneal dialysis (PD) patients. This retrospective study, employing a population-based database, aimed to evaluate the performance and provide the best evidence of each biomarker of CKD-MBD as predictor of all-cause mortality. Throughout the 8-year study period, total 12,116 PD patients were included in this study. Cox proportional regression and Kaplan-Meier method were used for survival analysis. For Cox regression model, baseline measurements and time-varying covariates were used for analysis. In Cox regression model using time-dependent covariates, serum calcium level of ≧9.5 mg/dL was associated with increased mortality. For phosphorus, serum levels of either ≧6.5 mg/dL or <3.5 mg/dL were associated with increased mortality. For parathyroid hormone (PTH), higher serum levels were not associated increased mortality. For alkaline phosphatase (ALP), mortality increased at levels ≧100 IU/L. Our findings suggested that the detrimental effect of ALP on survival was more consistent, while serum calcium, phosphorus and PTH may have a less prominent effect on mortality. This study provided additional information for manipulating CKD-MBD biomarkers in PD patients.

Calcium and Bone Metabolism Indices

Calcium and inorganic phosphate are of critical importance for many body functions, thus the regulations of their plasma concentrations are tightly controlled by the concerted actions of reabsorption/excretion in the kidney, absorption in the intestines, and exchange from bone, the major reservoir for calcium and phosphate in the body. Parathyroid hormone (PTH) and 1,25-dihydroxyvitamin D (1,25(OH)₂D) control calcium homeostasis, whereas PTH, 1,25(OH)₂D, and bone-derived fibroblast growth factor 23 (FGF 23) control phosphate homeostasis. Hypoparathyroidism can cause hypocalcemia and hyperphosphatemia, whereas deficient vitamin D actions can cause osteomalacia in adults and rickets in children. Hyperparathyroidism, alternatively, can cause hypercalcemia and hypophosphatemia. Laboratory tests of calcium, phosphate, PTH, and 25-hydroxyvitamin D are very useful in the diagnosis of abnormalities associated with calcium and/or phosphate metabolisms. Bone is constantly remodeled throughout life in response to mechanical stress and a need for calcium in extracellular fluids. Metabolic bone diseases such as osteoporosis, osteomalacia in adults or rickets in children, and renal osteodystrophy develop when bone resorption exceeds bone formation. Bone turnover markers (BTM) such as serum N-terminal propeptide of type I procollagen (P1NP) and C-terminal collagen cross-link (CTX) may be useful in predicting future fracture risk or monitoring the response to anti-resorptive therapy. There is a need to standardize sample collection protocols because certain BTMs exhibit large circadian variations and tend to be influenced by food intakes. In the United States, a project to standardize BTM sample collection protocols and to establish the reference intervals for serum P1NP and serum CTX is ongoing. We anticipate the outcome of this project to shine lights on the standardization of BTM assays, sample collection protocols, reference intervals in relation to age, sex, and ethnic origins, and clinical utilities of BTMs. This review will briefly discuss the regulations of calcium and phosphate homeostasis, laboratory's role in the diagnosis, and monitoring of bone and calcium metabolism, as well as the usefulness and controversies of the utilities of BTMs in the diagnosis and monitoring of metabolic bone diseases.

Perspective and priorities for improvement of parathyroid hormone (PTH) measurement - A view from the IFCC Working Group for PTH

Parathyroid hormone (PTH) measurement in serum or plasma is a necessary tool for the exploration of calcium/phosphate disorders, and is widely used as a surrogate marker to assess skeletal and mineral disorders associated with chronic kidney disease (CKD), referred to as CKD-bone mineral disorders (CKD-MBD). CKD currently affects >10% of the adult population in the United States and represents a major health issue worldwide. Disturbances in mineral metabolism and fractures in CKD patients are associated with increased morbidity and mortality. Appropriate identification and management of CKD-MBD is therefore critical to improving clinical outcome. Recent increases in understanding of the complex pathophysiology of CKD, which involves calcium, phosphate and magnesium balance, and is also influenced by vitamin D status and fibroblast growth factor (FGF)-23 production, should facilitate such improvement. Development of evidence-based recommendations about how best to use PTH is limited by considerable method-related variation in results, of up to 5-fold, as well as by lack of clarity about which PTH metabolites these methods recognise. This makes it difficult to compare PTH results from different studies and to develop common reference intervals and/or decision levels for treatment. The implications of these method-related differences for current clinical practice are reviewed here. Work being undertaken by the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) to improve the comparability of PTH measurements worldwide is also described.

Iron deficiency or anemia of inflammation? : Differential diagnosis and mechanisms of anemia of inflammation

Iron deficiency and immune activation are the two most frequent causes of anemia, both of which are based on disturbances of iron homeostasis. Iron deficiency anemia results from a reduction of the body's iron content due to blood loss, inadequate dietary iron intake, its malabsorption, or increased iron demand. Immune activation drives a diversion of iron fluxes from the erythropoietic bone marrow, where hemoglobinization takes place, to storage sites, particularly the mononuclear phagocytes system in liver and spleen. This results in iron-limited erythropoiesis and anemia. This review summarizes current diagnostic and pathophysiological concepts of iron deficiency anemia and anemia of inflammation, as well as combined conditions, and provides a brief outlook on novel therapeutic options.

Adherence rates to ferric citrate as compared to active control in patients with end stage kidney disease on dialysis

INTRODUCTION

Oral phosphate binders are the main stay of treatment of hyperphosphatemia. Adherence rates to ferric citrate, a recently approved phosphate binder, are unknown.

METHODS

We conducted a post-hoc analysis to evaluate whether adherence rates were different for ferric citrate vs. active control in 412 subjects with end stage kidney disease (ESKD) who were randomized to ferric citrate vs. active control (sevelamer carbonate and/or calcium acetate). Adherence was defined as percent of actual number of pills taken to total number of pills prescribed.

FINDINGS

There were no significant differences in baseline characteristics including gender, race/ethnicity, and age between the ferric citrate and active control groups. Baseline phosphorus, calcium, and parathyroid hormone levels were similar. Mean (SD) adherence was 81.4% (17.4) and 81.7% (15.9) in the ferric citrate and active control groups, respectively (P = 0.88). Adherence remained similar between both groups after adjusting for gender, race/ethnicity, age, cardiovascular disease (CVD), and diabetic nephropathy (mean [95% CI]: 81.4% [78.2, 84.6] and 81.5% [77.7, 85.2] for ferric citrate and active control, respectively). Gender, race/ethnicity, age, and diagnosis of diabetic nephropathy did not influence adherence to the prescribed phosphate binder. Subjects with CVD had lower adherence rates to phosphate binder; this was significant only in the active control group.

DISCUSSION

Adherence rates to the phosphate binder, ferric citrate, were similar to adherence rates to active control. Similar adherence rates to ferric citrate are notable since tolerance to active control was an entry criteria and the study was open label. Gender, race/ethnicity, nor age influenced adherence.

Vascular calcification: When should we interfere in chronic kidney disease patients and how?

Chronic kidney disease (CKD) patients are endangered with the highest mortality rate compared to other chronic diseases. Cardiovascular events account for up to 60% of the fatalities. Cardiovascular calcifications affect most of the CKD patients. Most of this calcification is related to disturbed renal phosphate handling. Fibroblast growth factor 23 and klotho deficiency were incriminated in the pathogenesis of vascular calcification through different mechanisms including their effects on endothelium and arterial wall smooth muscle cells. In addition, deficient klotho gene expression, a constant feature of CKD, promotes vascular pathology and shares in progression of the CKD. The role of gut in the etio-pathogenesis of systemic inflammation and vascular calcification is a newly discovered mechanism. This review will cover the medical history, prevalence, pathogenesis, clinical relevance, different tools used to diagnose, the ideal timing to prevent or to withhold the progression of vascular calcification and the different medications and medical procedures that can help to prolong the survival of CKD patients.

Dialysate content and risk of sudden cardiac death

PURPOSE OF REVIEW

Although the overall mortality rate of patients with end-stage renal disease in the United States continues to decline, cardiac complications remain a leading cause of death in this population. The purpose of this review is to identify principles that can be used to optimize the dialysate concentration of electrolytes in order to reduce the incidence of sudden cardiac deaths (SCDs).

RECENT FINDINGS

The ratio of observed to expected SCD is 1.71 in the 12 h following the onset of a hemodialysis session. A dialysate potassium concentration of less than 2 mEq/l has been associated with an increased risk of SCD as has a dialysate calcium less than 2.5 mEq/l and an elevated serum to dialysate calcium gradient. Midweek predialysis serum bicarbonate concentrations that are less than 22 or more than 27 mEq/l have been associated with increased mortality. An elevated predialysis serum bicarbonate may be a sign of the malnutrition inflammation complex syndrome. Magnesium has not been well studied in hemodialysis patients.

SUMMARY

Dialysate content plays an important role in the risk of SCD in hemodialysis patients on hemodialysis. There is a need for further studies designed to identify patients at risk and to determine what strategies can be used to lower this risk.

The Related Risk Factors Analysis of Snake-Bite Induced Acute Kidney Injury

BACKGROUND The pathogenic mechanism of snake-bite induced acute kidney injury (AKI) remains unclear. Analyzing the risk factors for snake-bite induced AKI may provide the guidance needed for AKI prevention and early treatment. MATERIAL AND METHODS This retrospective study included 119 snake-bite patients who were hospitalized at the emergency department of Sichuan Provincial People's Hospital from January 2011 to September 2013. The patients were divided into AKI and non-AKI groups according to the 2012 Kidney Disease: Improving Global Outcomes (KDIGO) guideline. Gender, age, and clinical examination data of the patients were recorded. The Mann-Whitney U test and Fisher exact test were performed to analyze the collected data; preliminary analysis of independent risk factors was performed with multivariate logistic regression. RESULTS Among the snake-bite patients, 98.3% were farmers. The mean age of patients was 46±12 years. Of the 119 patients (13.4%), 16 suffered from AKI. There were statistically significant differences between the AKI and non-AKI groups with respect to age, time interval from snake bite to antivenin therapy, creatine kinase, blood myoglobin, advanced age, regional lymphadenopathy, incision drainage, and hemoglobin. Preliminary analysis with multivariate logistic regression showed that advanced age and increased time interval from snake bite to antivenin therapy might be independent risk factors for snake-bite induced AKI. CONCLUSIONS Age, time interval from snake bite to antivenin therapy, creatine kinase, blood myoglobin, advanced age, regional lymphadenopathy, incision drainage, and hemoglobin were risk factors for snake-bite induced AKI. Advanced age and delayed antivenin therapy might be independent risk factors for snake-bite induced AKI.

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

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

Development and Evaluation of the Psychometric Properties of the CKD-MBD Knowledge and Behavior (CKD-MBD-KB) Questionnaire for Patients With Chronic Kidney Disease

CONTEXT

Chronic kidney disease-mineral and bone disorder (CKD-MBD) is one of the most complicated morbidities among patients with end-stage renal disease. At present, a specific questionnaire assessing relevant knowledge and behavior for patients with CKD-MBD is still unavailable.

OBJECTIVES

To develop and evaluate a valid and reliable questionnaire specific to patients with CKD-MBD.

METHODS

Both quantitative and qualitative analyses were combined to develop and estimate the CKD-MBD knowledge and behavior (CKD-MBD-KB) questionnaire. Three hundred thirteen and 295 patients, respectively, participated in the investigation during the period from November 2013∼October 2014. Reliability and validity testing were conducted to analyze the psychometric properties of questionnaire.

RESULTS

The final version of the CKD-MBD-KB questionnaire encompasses two domains, five facets, and 50 items. Reliability analysis showed that the Cronbach alpha of the five facets ranged from 0.578 to 0.854. Retest correlation coefficients of the five facets ranged from 0.825 to 0.944. Nine common factors were extracted from exploratory factor analysis that interpreted the cumulative variation of 64.1%, and factor loadings of all items were greater than 0.4. The results of confirmatory factor analysis indicated that the model had a satisfactory goodness of fit; the root mean square error of approximation = 0.070. Meanwhile, a significant correlation was found between each item and its facet.

CONCLUSION

This CKD-MBD-KB questionnaire has been confirmed to have adequate psychometric properties (good reliability and validity) and may be useful in the assessment of patient-related knowledge, intervention programs, and treatment protocols.

Practical Approach to Detection and Management of Chronic Kidney Disease for the Primary Care Clinician

A panel of internists and nephrologists developed this practical approach for the Kidney Disease Outcomes Quality Initiative to guide assessment and care of chronic kidney disease (CKD) by primary care clinicians. Chronic kidney disease is defined as a glomerular filtration rate (GFR) <60 mL/min/1.73 m(2) and/or markers of kidney damage for at least 3 months. In clinical practice the most common tests for CKD include GFR estimated from the serum creatinine concentration (eGFR) and albuminuria from the urinary albumin-to-creatinine ratio. Assessment of eGFR and albuminuria should be performed for persons with diabetes and/or hypertension but is not recommended for the general population. Management of CKD includes reducing the patient's risk of CKD progression and risk of associated complications, such as acute kidney injury and cardiovascular disease, anemia, and metabolic acidosis, as well as mineral and bone disorder. Prevention of CKD progression requires blood pressure <140/90 mm Hg, use of angiotensin-converting enzyme inhibitors or angiotensin receptor blockers for patients with albuminuria and hypertension, hemoglobin A1c ≤7% for patients with diabetes, and correction of CKD-associated metabolic acidosis. To reduce patient safety hazards from medications, the level of eGFR should be considered when prescribing, and nephrotoxins should be avoided, such as nonsteroidal anti-inflammatory drugs. The main reasons to refer to nephrology specialists are eGFR <30 mL/min/1.73 m(2), severe albuminuria, and acute kidney injury. The ultimate goal of CKD management is to prevent disease progression, minimize complications, and promote quality of life.

Clinical and Practical Use of Calcimimetics in Dialysis Patients With Secondary Hyperparathyroidism

CKD and CKD-related mineral and bone disorders (CKD-MBDs) are associated with high cardiovascular and mortality risks. In randomized clinical trials (RCTs), no single drug intervention has been shown to reduce the high mortality risk in dialysis patients, but several robust secondary analyses point toward important potential beneficial effects of controlling CKD-MBD-related factors and secondary hyperparathyroidism. The advent of cinacalcet, which has a unique mode of action at the calcium-sensing receptor, represented an important step forward in controlling CKD-MBD. In addition, new RCTs have conclusively shown that cinacalcet improves achievement of target levels for all of the metabolic abnormalities associated with CKD-MBD and may also attenuate the progression of vascular and valvular calcifications in dialysis patients. However, a final conclusion on the effect of cinacalcet on hard outcomes remains elusive. Tolerance of cinacalcet is limited by frequent secondary side effects such as nausea, vomiting, hypocalcemia and oversuppression of parathyroid hormone, which may cause some management difficulties, especially for those lacking experience with the drug. Against this background, this review aims to summarize the results of studies on cinacalcet, up to and including the publication of the recent ADVANCE and EVOLVE RCTs, as well as recent post hoc analyses, and to offer practical guidance on how to improve the clinical management of the most frequent adverse events associated with cinacalcet, based on both currently available information and personal experience. In addition, attention is drawn to less common secondary effects of cinacalcet treatment and advisable precautions.

Cinacalcet versus standard treatment for chronic kidney disease: a protocol for a systematic review and meta-analysis

BACKGROUND

Chronic kidney disease-mineral and bone disorders (CKD-MBD) have been associated with poor health outcomes, including diminished quality and length of life. Standard management for CKD-MBD includes phosphate-restricted diet, active vitamin D, vitamin D analogs, and phosphate binders. Persistently elevated parathyroid hormone (PTH) levels may require the addition of Cinacalcet hydrochloride (cinacalcet) which sensitizes calcium receptors on the parathyroid glands. The objective of this systematic review is to compare the effect of cinacalcet versus standard treatment in patients with CKD-MBD.

METHODS/DESIGN

Data sources will include MEDLINE, EMBASE, the Cochrane Register of Controlled Trials, and Web of Science from 1996 to June 2015. Teams of two reviewers will, independently and in duplicate, screen titles and abstracts and potentially eligible full text reports to determine eligibility, and subsequently abstract data and assess risk of bias in eligible trials. We will calculate the effect estimates (risk ratios or mean differences) and 95 % confidence intervals, as well as statistical measures of variability in results across studies using random effect models for patient-important and intermediate outcomes. We will use the GRADE (Grading of Recommendations, Assessment, Development and Evaluation) approach to rate the quality of evidence about estimates of effect on an outcome-by-outcome basis. We will present our results with a GRADE summary table.

DISCUSSION

Our review will explore the effect of cinacalcet versus standard treatment in patients with CKD-MBD. The results of this systematic review will help guide management of this patient population, and identify targets for future research.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42015020318 http://www.crd.york.ac.uk/PROSPERO/display_record.asp?ID=CRD42015020318.

Cinacalcet, dialysate calcium concentration, and cardiovascular events in the EVOLVE trial

Among patients receiving hemodialysis, abnormalities in calcium regulation have been linked to an increased risk of cardiovascular events. Cinacalcet lowers serum calcium concentrations through its effect on parathyroid hormone secretion and has been hypothesized to reduce the risk of cardiovascular events. In observational cohort studies, prescriptions of low dialysate calcium concentration and larger observed serum-dialysate calcium gradients have been associated with higher risks of in-dialysis facility or peri-dialytic sudden cardiac arrest. We performed this study to examine the risks associated with dialysate calcium and serum-dialysate gradients among participants in the Evaluation of Cinacalcet Hydrochloride Therapy to Lower Cardiovascular Events (EVOLVE) trial. In EVOLVE, 3883 hemodialysis patients were randomized 1:1 to cinacalcet or placebo. Dialysate calcium was administered at the discretion of treating physicians. We examined whether baseline dialysate calcium concentration or the serum-dialysate calcium gradient modified the effect of cinacalcet on the following adjudicated endpoints: (1) primary composite endpoint (death or first non-fatal myocardial infarction, hospitalization for unstable angina, heart failure, or peripheral vascular event); (2) cardiovascular death; and (3) sudden death. In EVOLVE, use of higher dialysate calcium concentrations was more prevalent in Europe and Latin America compared with North America. There was a significant fall in serum calcium concentration in the cinacalcet group; dialysate calcium concentrations were changed infrequently in both groups. There was no association between baseline dialysate calcium concentration or serum-dialysate calcium gradient and the endpoints examined. Neither the baseline dialysate calcium nor the serum-dialysate calcium gradient significantly modified the effects of cinacalcet on the outcomes examined. The effects of cinacalcet on cardiovascular death and major cardiovascular events are not altered by the dialysate calcium prescription and serum-dialysate calcium gradient.

Nephrology co-management versus primary care solo management for early chronic kidney disease: a retrospective cross-sectional analysis

Background

Primary care physicians (PCPs) typically manage early chronic kidney disease (CKD), but recent guidelines recommend nephrology co-management for some patients with stage 3 CKD and all patients with stage 4 CKD. We sought to compare quality of care for co-managed patients to solo managed patients.

Methods

We conducted a retrospective cross-sectional analysis. Patients included in the study were adults who visited a PCP during 2009 with laboratory evidence of CKD in the preceding two years, defined as two estimated glomerular filtration rates (eGFR) between 15–59 mL/min/1.73 m² separated by 90 days. We assessed process measures (serum eGFR test, urine protein/albumin test, angiotensin converting enzyme inhibitor or angiotensin receptor blocker [ACE/ARB] prescription, and several tests monitoring for complications) and intermediate clinical outcomes (mean blood pressure and blood pressure control) and performed subgroup analyses by CKD stage.

Results

Of 3118 patients, 11 % were co-managed by a nephrologist. Co-management was associated with younger age (69 vs. 74 years), male gender (46 % vs. 34 %), minority race/ethnicity (black 32 % vs. 22 %; Hispanic 13 % vs. 8 %), hypertension (75 % vs. 66 %), diabetes (42 % vs. 26 %), and more PCP visits (5.0 vs. 3.9; p < 0.001 for all comparisons). After adjustment, co-management was associated with serum eGFR test (98 % vs. 94 %, p = <0.0001), urine protein/albumin test (82 % vs 36 %, p < 0.0001), and ACE/ARB prescription (77 % vs. 69 %, p = 0.03). Co-management was associated with monitoring for anemia and metabolic bone disease, but was not associated with lipid monitoring, differences in mean blood pressure (133/69 mmHg vs. 131/70 mmHg, p > 0.50) or blood pressure control. A subgroup analysis of Stage 4 CKD patients did not show a significant association between co-management and ACE/ARB prescription (80 % vs. 73 %, p = 0.26).

Conclusion

For stage 3 and 4 CKD patients, nephrology co-management was associated with increased stage-appropriate monitoring and ACE/ARB prescribing, but not improved blood pressure control.