KDIGO 2017 Clinical Practice Guideline Update for the Diagnosis, Evaluation, Prevention, and Treatment of Chronic Kidney Disease-Mineral and Bone Disorder (CKD-MBD)

Teriparatide Treatment for Hypercalcemia Associated With Adynamic Bone Disease

Hypercalcemia most often results from primary hyperparathyroidism and malignancy. Adynamic bone disease (ABD) is a form of renal osteodystrophy characterized by reduced bone turnover, which can limit the ability of bone to release or store calcium, potentially leading to low, normal, or high serum calcium levels. We describe a 51‐year‐old dialysis‐dependent female with hypercalcemia after parathyroidectomy. A demeclocycline‐labeled bone biopsy confirmed adynamic bone disease. Teriparatide, a recombinant form of parathyroid hormone (PTH) used to treat postmenopausal osteoporosis, was prescribed for 12 months and normalized serum calcium levels. Although previous case reports and series have described favorable changes in spine bone mineral density when teriparatide was prescribed for ABD, ours is the first documented case in which teriparatide resolved hypercalcemia due to ABD. © 2019 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.

Long-term follow-up of biomarkers of vascular calcification after switch from traditional hemodialysis to online hemodiafiltration

Rapid progression of vascular calcification (VC) in hemodialysis (HD) patients is caused by several factors including inflammation and an imbalance between active inducers and inhibitors of VC. Growing evidence shows that online hemodiafiltration (ol-HDF), a combination of diffusive and convective solute transport, has positive effects on the uremic environment that affects patients on dialysis. However, we recently reported that serum 25-hydroxyvitamin D (25(OH)D) decreased after a switch from HD to ol-HDF. As a consequence of this finding, the present study was undertaken to investigate if inducers and inhibitors of VC (i.e. the inactive matrix Gla protein fractions dp-ucMGP and t-ucMGP, fetuin-A, Gla-rich protein (GRP), osteopontin (OPN), bone-specific alkaline phosphatase (BALP), and osteoprotegerin (OPG)) also are affected by ol-HDF. This non-comparative prospective study comprised 35 prevalent patients who were investigated 6, 12, and 24 months after their switch from HD to ol-HDF. Most patients had increased levels of the calcification inhibitors OPN and OPG; and of the inactive calcification inhibitor dp-ucMGP during the study period irrespective of the dialysis modality. BALP and t-ucMGP were mostly within the reference interval, but fetuin-A was mostly below the reference interval during the study period. OPN was significantly associated with BALP and parathyroid hormone, r = 0.62 and r = 0.65 (p < .001), respectively. In conclusion, in contrast to decreased 25(OH)D levels, no differences were found for any of the measured biomarkers of VC following the switch from HD to ol-HDF. Further studies are needed to elucidate how these biomarkers can contribute to calcification risk assessment.

Effectiveness of sucroferric oxyhydroxide in patients on on-line hemodiafiltration in real-world clinical practice: A retrospective study

Introduction:

Hyperphosphatemia is a serious consequence of chronic kidney disease and has been associated with an increased risk for cardiovascular disease. Controlling serum phosphorus levels in patients on dialysis is a challenge for the clinicians and implies, in most cases, the use of phosphate binders (PB). Part of the reason for this challenge is poor adherence to treatment because of the high pill burden in this patient group.

Objective:

To assess the real-world effectiveness of sucroferric oxyhydroxide (SO) in controlling serum phosphorus levels and determine the associated pill burden.

Methods:

A multicenter, quantitative, retrospective, before-after study was conducted with patients receiving online hemodiafiltration. Patients who switched to SO as a part of routine care were included in the study. PB treatment, number of pills, serum phosphorus levels, and intravenous iron medication and dosage were collected monthly during the six months of treatment with either PB or SO.

Results:

A total of 42 patients were included in the study. After switching from a PB to SO, the prescribed pills/day was reduced 67% from 6 pills/day to 2 pills/day (p < 0.001) and the frequency of pill intake was lowered from 3 times/day to 2 times/day (p < 0.001). During the treatment with SO, the proportion of patients with serum phosphorus ≤ 5.5 mg/dL increased from 33.3% at baseline to 45% after six months of treatment.

Conclusion:

During the six-month follow-up with SO, serum phosphorus levels were controlled with one third of the pills/day compared to other PB.

Electrolytes disturbances after kidney transplantation

Objectives: Water and electrolytes disturbances often occur in renal transplant recipients. The objective is to describe the pathophysiology and the treatment of the most prevalent abnormalities. Methods: We screened PubMed for the following words in various combination: kidney transplantation and (disturbances or abnormalities) of (electrolytes or sodium or potassium or phosphate or calcium or acid-base). Results: We found abnormalities in all major electrolytes, as a consequence of tubular dysfunction caused by both rejection episodes and toxic effects of calcineurin inhibitors (CNIs; cyclosporine or tacrolimus). The renal tubular acidosis found in kidney transplant recipients is characterized by a normal anion gap and normal or high serum chloride levels. The incidence of hyperkalemia is 5-40% of patients treated with CNIs. The majority of kidney transplant recipients develop hypomagnesemia within the first weeks and months. Both cyclosporine and tacrolimus do induce hypomagnesemia by several mechanisms. Severe magnesium depletion may include clinical manifestations such as confusion, muscle weakness, tremor, dysphagia, tetany and convulsions. The immediate posttransplant period (first 3 months) is often accompanied by a decline in serum phosphate. Phosphate substitution is needed when serum levels fall below 0.5 mmol/l, or in patients with clinical symptoms and serum levels between 0.5 and 1.0 mmol/l. Hypercalcemia is also a common disorder in the chronic posttransplant phase, and is most often due to persistent hyperparathyroidism. Conclusions: Patients with kidney transplants display electrolytes abnormalities more frequently than non-transplanted patients with the same levels of renal function. A good knowledge of their physiopathology and treatment is important in the care of those patients.

Chronic Kidney Disease and Dietary Measures to Improve Outcomes

Chronic kidney disease is an ongoing deterioration of renal function that often progresses to end-stage renal disease. Management goals in children include slowing disease progression, prevention and treatment of complications, and optimizing growth, development, and quality of life. Nutritional management is critically important to achieve these goals. Control of blood pressure, proteinuria, and metabolic acidosis with dietary and pharmacologic measures may slow progression of chronic kidney disease. Although significant progress in management has been made, further research is required to resolve many outstanding controversies. We review recent developments in pediatric chronic kidney disease, focusing on dietary measures to improve outcomes.

Vitamin D testing and treatment: a narrative review of current evidence

Vitamin D testing and treatment is a subject of controversial scientific discussions, and it is challenging to navigate through the expanding vitamin D literature with heterogeneous and partially opposed opinions and recommendations. In this narrative review, we aim to provide an update on vitamin D guidelines and the current evidence on the role of vitamin D for human health with its subsequent implications for patient care and public health issues. Vitamin D is critical for bone and mineral metabolism, and it is established that vitamin D deficiency can cause rickets and osteomalacia. While many guidelines recommend target serum 25-hydroxyvitamin D (25[OH]D) concentrations of ≥50 nmol/L (20 ng/mL), the minimum consensus in the scientific community is that serum 25(OH)D concentrations below 25-30 nmol/L (10-12 ng/mL) must be prevented and treated. Using this latter threshold of serum 25(OH)D concentrations, it has been documented that there is a high worldwide prevalence of vitamin D deficiency that may require public health actions such as vitamin D food fortification. On the other hand, there is also reason for concern that an exploding rate of vitamin D testing and supplementation increases costs and might potentially be harmful. In the scientific debate on vitamin D, we should consider that nutrient trials differ from drug trials and that apart from the opposed positions regarding indications for vitamin D treatment we still have to better characterize the precise role of vitamin D for human health.

Peritoneal dialysis can alleviate the clinical course of hungry bone syndrome after parathyroidectomy in dialysis patients with secondary hyperparathyroidism

PURPOSE

It is unclear whether clinical courses of hungry bone syndrome (HBS) after parathyroidectomy (PTX) in peritoneal dialysis (PD) and hemodialysis (HD) patients are different. The present study aimed to investigate the possible differences of postoperative hypocalcemia and hyperkalemia between PD and HD patients.

METHODS

We performed retrospectively 29 PD patients as the PD group and 169 HD patients as the HD group undergoing successful total PTX with autotransplantation. Calcium supplement after surgery was recorded. Higher levels of serum potassium during and immediately after surgery were recorded as K⁺_d0. K⁺_d3 was recorded as peak pre-dialysis serum potassium level 3 days post-surgery.

RESULTS

There were 157 (92.90%) patients in HD group and 22 (75.86%) patients in PD group suffered from HBS after surgery, with significant difference between the groups (P = 0.004). Patients in PD group had significantly shorter intravenous calcium supplement duration (P = 0.037) and significantly smaller intravenous calcium supplement dosage (P = 0.042) and total calcium supplement dosage during hospitalization (P = 0.012) than patients in HD group. The levels of serum K⁺_d0 (P < 0.001) and K⁺_d3 (P < 0.001) were both significantly lower in PD group than those in HD group. Peritoneal dialysis was one of the independent influencing factors with negative correlation for calcium supplement, serum K⁺_d0 and serum K⁺_d3.

CONCLUSIONS

Compared with HD patients, the clinical course of HBS after PTX in PD patients was alleviated. Efforts should be devoted to individual perioperative management for PD patients undergoing PTX.

The Effect of Long-Term Cholecalciferol Supplementation on Vascular Calcification in Chronic Kidney Disease Patients With Hypovitaminosis D

OBJECTIVE

The role of vitamin D supplementation on vascular calcification (VC) in patients with chronic kidney disease (CKD) is controversial. The objective of this study was to evaluate the effects of long-term cholecalciferol supplementation on VC in nondialysis patients with CKD stages 3-4 with hypovitaminosis D.

DESIGN AND METHODS

Eighty patients aged 18-85 years with creatinine clearance between 15 and 60 mL/min/1.73 m² and serum 25(OH)D level < 30 ng/mL were enrolled in a 18-month prospective study. Individuals with vitamin D insufficiency (25-hydroxyvitamin D [25(OH)D] level between 16 and 29 ng/mL) were included in a randomized, double-blind, two-arm study to receive cholecalciferol or placebo. Patients with vitamin D deficiency [25(OH)D < 15 ng/mL] were included in an observational study and mandatorily received cholecalciferol. The coronary artery calcium score was obtained by multislice computed tomography at baseline and the 18th month.

RESULTS

During the study, VC did not change in the treated insufficient group (418 [81-611] to 364 [232-817] AU, P = 0.25) but increased in the placebo group (118 [37-421] to 199 [49-490] AU, P = 0.01). The calcium score change was inversely correlated with 25(OH)D change (r = -0.45; P = 0.037) in the treated insufficient group but not in the placebo group. Renal function did not change in the insufficient, treated, and placebo groups. In multivariate analysis, there was no difference in VC progression between the treated and placebo insufficient groups (interaction P = 0.92). In the deficient group, VC progressed (265 [84-733] to 333 [157-745] AU; P = 0.006) and renal function declined (33 [26-43] to 23 [17-49] mL/min/1.73 m²; P = 0.04). The calcium score change was inversely correlated with cholecalciferol cumulative doses (r = -0.41; P = 0.048) and kidney function change (r = -0.43; P = 0.033) but not with 25(OH)D change (r = -0.08; P = 0.69).

CONCLUSION

Vitamin D supplementation did not attenuate VC progression in CKD patients with hypovitaminosis D.

CONCLUSION

Vitamin D supplementation did not attenuate VC progression in CKD patients with hypovitaminosis D.

Variability in Cinacalcet Prescription across US Hemodialysis Facilities

BACKGROUND AND OBJECTIVES

Calcimimetic drugs used to treat secondary hyperparathyroidism are being considered for inclusion in the Medicare ESRD Prospective Payment System bundle after an evaluation period. Understanding of utilization patterns of calcimimetics across dialysis facilities may help align financial incentives with clinical objectives. Our study's purpose was to describe the distribution of cinacalcet prescription across United States hemodialysis facilities and to explore factors that may influence cinacalcet utilization.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We used monthly cross-sectional data from the Dialysis Outcomes and Practice Patterns Study in 2014 to characterize the distribution of cinacalcet prescription across 203 United States hemodialysis facilities (10,521 patients). On the basis of associations with parathyroid hormone levels from patient-level analyses, we used linear mixed-effects regressions to estimate the associations between three facility-level exposures (black race, <65 years old, and having ≥3 years on dialysis [vintage]) and the prevalence of cinacalcet prescription, adjusting for facility- and patient-level potential confounders.

RESULTS

The mean percentage of patients in each facility with cinacalcet prescription was 23% in June 2014 (median, 22%; interquartile range, 13%-30%). Adjusted for facility-level and nonexposure patient-level variables, the difference in prevalence of cinacalcet prescription between facilities with the highest and lowest quartiles of percentage of black patients was 7.8% (95% confidence interval [95% CI], 0.8% to 14.8%; P for trend =0.03). The adjusted prevalence difference was 7.3% for the percentage of patients aged <65 years (95% CI, -0.1% to 14.7%; P for trend =0.06) and 11.9% for the percentage of patients with ≥3 years of dialysis (95% CI, 2.4% to 21.4%; P for trend =0.02). These associations changed appreciably, becoming much weaker or even reversing, after further adjusting for the patient-level exposure variables.

CONCLUSIONS

Facilities treating more patients who are black, under age 65 years, and having dialysis vintage ≥3 years have higher average levels of cinacalcet prescription. However, these differences were strongly attenuated after accounting for the unbalanced distributions of these patient case-mix variables.

One-Year Historical Cohort Study of the Phosphate Binder Sucroferric Oxyhydroxide in Patients on Maintenance Hemodialysis

Objective:

The high pill burden of many phosphate binders (PBs) may contribute to increased prevalence of hyperphosphatemia and poor nutritional status observed among patients undergoing maintenance hemodialysis therapy. We examined the real-world effectiveness of sucroferric oxyhydroxide (SO), a PB with low pill burden, in managing serum phosphorus in patients with prevalent hemodialysis over a 1-year period.

Design:

Historical cohort analyses of de-identified electronic medical records.

Subjects:

In-center hemodialysis patients switched from another PB to SO therapy as part of routine care with 12 months of uninterrupted SO prescriptions recorded, and documented serum phosphorus levels were eligible for inclusion. Clinical data were extracted from a pharmacy service, FreseniusRx, database and Fresenius Kidney Care clinical data warehouse.

Main outcome measures:

Comparisons were made between the 91-day period before SO initiation (i.e., baseline) and the 4 consecutive 91-day intervals of SO treatment (Q1-Q4). Clinical measures included achievement of target phosphorus levels (#5.5 mg/dL) and mean number of PB pills/day.

Results:

Among 530 analyzed patients, the proportion achieving target serum phosphorus levels increased by >100% 1 year after switching to SO therapy, that is, from 17.7% at baseline to 24.5%, 30.5%, 36.4%, and 36.0% at Q1 through Q4, respectively (P < .0001 for all). Reductions in serum phosphorus were observed at all follow-up timepoints (P <.0001), irrespective of baseline PB. From a mean baseline PB pill burden of 8.5 pills/day, patients experienced an average 50% pill burden reduction during SO treatment (P <. 0001). Phosphorus-attuned albumin and phosphorus-attuned protein intake (normalized protein catabolic rate) improved significantly after transition to SO (P < .0001). The effectiveness of SO was evident in prespecified subgroups of interest (i.e., black/African-American patients, Hispanic/Latino patients, and women).

Conclusion:

Among patients on hemodialysis, switching to SO resulted in a 2-fold greater likelihood of achieving target phosphorus levels while halving daily PB pill burden. Increases in phosphorus-attuned albumin and protein intake suggest improved nutritional status.

Parathyroidectomy in dialysis patients: Indications, methods, and consequences

Secondary hyperparathyroidism, characterized by increased PTH synthesis and secretion, is often seen in advanced stages of chronic kidney disease. Excessive proliferation of parathyroid cells leads to the development of diffuse hyperplasia that subsequently progresses to nodular histology. Refractory hyperparathyroidism occurs when parathyroid glands fail to respond to medical therapy. Parathyroidectomy (PTX), surgical resection of parathyroid glands, is usually performed in cases of persistent serum levels of PTH above 1000 pg/mL associated with hypercalcemia or when hyperparathyroidism is refractory to conservative therapy. Parathyroidectomy can be carried out using different procedures: subtotal PTX or total PTX with or without parathyroid autotransplantation. Parathyroid surgery may have undesirable consequences due to PTH oversuppression, such as the development of adynamic bone disease; hungry bone syndrome is quite common after this surgery. However, PTX improves survival and parameters of mineral metabolism. Parathyroidectomy needs to be considered in those patients with severe hyperparathyroidism with a poor response to pharmacological treatment and with distinct undesirable effects of PTH on bone and mineral metabolism parameters.

[Short-term effects with sucroferric oxyhydroxide in hemodialysis patients: Experience in NephroCare France]

INTRODUCTION

Despite a better management of hyperphosphatemia in haemodialysis patients observed during the past years, most of them remain insufficiently treated and exposed to bone and cardiovascular complications that are associated with this biological abnormality. The availability of calcium-free phosphate binders among therapeutical options is confirmed to significantly reduce serum phosphate levels without the risk of excess exposure to calcium. Currently sucroferric oxyhydroxyde (SO) is the only iron-based phosphate binder available in France.

METHODS

A cohort of patients prescribed OHS has been extracted from the EUCLID 5 database between June 2016 and December 2017. The effects on bone mineral metabolism and ferritin have been retrospectively studied.

RESULTS

Two hundred and sixty-two patients with OHS prescription have been identified. The OHS treatment duration median was 4.3 months (1.84-10.99). The average midweek phosphatemia decreased significantly after OHS prescription (from 1.99 to 1.83 mmol/L ; P<0.0001) with a significant increase of the proportion of patients (12.1 to 25.7% ; P<0.0001) reaching the phosphate target of 1.5 mmol/L, without significant change in calcemia and PTH. Ferritinemia significantly increased from 362 to 427 μg/L in 3 months (P=0.0049). OHS therapy has been stopped and replaced in 18% of the cases.

DISCUSSION

Among the NephroCare cohort, OHS therapy was efficient to decrease phosphatemia and to increase significantly the proportion of patients in target. There were no short term changes in calcemia and PTH. The slight increase in ferritin confirms the findings of the phase III study and its extension. The effects on the pills count and the OHS side-effects are analyzed from literature. The risk of iron overload and the impact on the anemia management including EPO sparing are currently under study.

CONCLUSION

OHS therapy appears to be a new efficient alternative to non-calcium phosphate binders. A better knowledge of its side effects will help the patients and the physician to optimize the phosphate balance management. The slight increase in ferritin can be considered as an epiphenomenon because of the important iron needs and frequent check of this parameter in the anemia management.

The impact of antihypertensive pharmacotherapy on interplay between protein-bound uremic toxin (indoxyl sulfate) and markers of inflammation in patients with chronic kidney disease

Purpose

Indoxyl sulfate (IS) is one of the most potent uremic toxins involved in chronic kidney disease (CKD) progression, induction of inflammation, oxidative stress, and cardiovascular diseases occurrence. It is proved that hypertension is a common CVD complication and a major death risk factor as well as contributes for decline in a renal function. The aim of our study was to investigate how implementing of antihypertensive therapy impact IS concentrations and the associations between IS and markers of renal function, inflammation and oxidative stress.

Methods

Study was conducted on 50 patients diagnosed with CKD and hypertension, divided into three groups: without hypotensive therapy (CKD-NONE), hypotensive monotherapy (CKD-MONO), and hypotensive polypharmacotherapy (CKD-POLI), and 18 healthy volunteers. The markers of inflammation [interleukin-6, tumor necrosis factor-alpha (TNF-α), high-sensitive C-reactive protein (hs-CRP), neopterin, ferritin], oxidative status [superoxide dismutase (Cu/Zn-SOD), antibodies against oxidized low-density lipoprotein (oxLDL-abs)], and selectins were determinate using immunoenzymatic methods. IS levels were assayed using high-performance liquid chromatography and other parameters were analysed using routine laboratory techniques. Then cross-sectional analysis was performed.

Results

Elevated levels of IS, indicators of kidney function, markers of inflammation and blood pressure values were observed in each CKD subgroups. There was no effect of antihypertensive therapy on IS levels between studied groups, as well as there was no clear relationship between IS and blood pressure values in each studied group. The positive associations between IS and Cu/Zn SOD, neopterin, hs-CRP, creatinine and neutrophils/lymphocytes ratio were observed in CKD-NONE and CKD-POLI subgroups. Additionally, in CKD-POLI group IS positively correlated with TNF-α, ferritin and neutrophils. In CKD-MONO group, IS was positively related to oxLDL-abs, neopterin, E-selectin and creatinine, whereas it was inversely associated with hs-CRP.

Conclusions

Our study showed for the first time that the antihypertensive therapy has no impact on IS levels in CKD patients with hypertension. However, the introduction of the antihypertensive therapy modified the dependencies between IS and the studied markers of kidney function, inflammation, oxidative stress and hematological parameters that are crucial for mortality and morbidity amongst the CKD patients with hypertension.

Electronic supplementary material

The online version of this article (10.1007/s11255-018-02064-3) contains supplementary material, which is available to authorized users.

Calcimimetics and Bundled Reimbursement

Since 2011, the Centers for Medicare & Medicaid Services has provided reimbursement for renal dialysis services furnished to Medicare beneficiaries through a bundled payment system known as the Prospective Payment System. Medications that have no injectable equivalent, known as "oral-only medications," are currently excluded from the bundle and are paid separately through Medicare Part D. Thus, before the development of etelcalcetide, the first injectable calcimimetic, calcimimetics were reimbursed outside the bundle. Etelcalcetide's introduction and approval for use in Medicare triggered a transition payment for a minimum of 2 years that will eventually result in the incorporation of calcimimetics into the dialysis bundle. Consequently, providers may face incentives to reduce calcimimetic use when the transition period has expired. The complexity of bone-mineral management in conjunction with the paucity of evidence-based recommendations in this area makes it difficult to predict the impact of this transition. Because these medications are expensive, a poor transition could have financial ramifications for dialysis organizations and potentially patient health. To ensure that patients are not adversely affected, it is critical that Medicare incorporate these medications into the bundle carefully, with close monitoring of outcomes.

Risk Assessment of Severe Congenital Anomalies of the Kidney and Urinary Tract (CAKUT): A Birth Cohort

Recent advances in the early diagnosis of fetal CAKUT with an increase in fetal surgical interventions have led to a growing number of neonatal survivors born with severe renal dysfunction. This, in turn, has required the development of multi-disciplinary treatment paradigms in the individualized management of these infants with advanced stage kidney disease from birth. Early multi-modal management includes neonatal surgical interventions directed toward establishing adequate urine flow, respiratory support with the assessment of pulmonary hypoplasia, and establishing metabolic control to avoid the need for dialysis intervention. The development of specialized imaging to assess for residual renal mass with non-invasive 3-dimensional techniques are rapidly evolving. The use of non-radioactive imaging offers improved safety and allows for early prognostic-based planning including anticipatory guidance for progression to end stage renal disease (ESRD). The trajectory of kidney function during the neonatal period as determined by peak and nadir serum creatinine (SCr) and cystatin C (CysC) during the first months of life provides a guide toward individualized prospective management. This is a single center experience based on a birth cohort of 42 subjects followed prospectively from birth for an average of 6.1 ± 2.8 years at the University of Miami/Holtz Children's Hospital during the past decade. There was an 8:1 male: female ratio. The birth cohort was divided into 3 subgroups according to CKD Stages at the current age: CKD 1-2 (Group 1) (eGFR ≥ 60 ml/min/1.73 m²) (N = 15), CKD stage 3-5 (Group 2) (eGFR ≤ 59 ml/min/1.73 m²) (N = 12), and ESRD-Dialysis and/or Transplantation (Group 3) (N = 15). A neonatal CysC >3.0 mg/L predicted progression to ESRD while a nadir SCr >0.6 mg/dL predicted progression to CKD 3-5 with the highest specificity and sensitivity by ROC-AUC analysis (P < 0.0001). Medical management was directed toward nutritional support with novel formula designs, early introduction of growth hormone and strict control of mineral bone disorder. One of the central aspects of the management was to avoid dialysis for as long as feasible with a primary goal toward pre-emptive transplantation.

Retrospective Analysis of Bone Metabolism in Patients on Waiting List for Simultaneous Pancreas-Kidney Transplantation

Posttransplant osteoporosis, which evolves from preexisting bone pathologies, represents a serious complication with deteriorating consequences. The aim of our study was to evaluate epidemiological data on bone mineral density (BMD) in subjects with type 1 diabetes (T1DM) in advanced stages of diabetic nephropathy indicated for simultaneous pancreas-kidney transplantation (SPK). We retrospectively compiled biochemical and densitometrical data from 177 patients with T1DM at CKD (chronic kidney disease) stages G4-G5 (115 men, 62 women, median age 40 yr, diabetes duration 23 yr) enrolled on waiting list for SPK for the first time between the years 2011 and 2016. Median Z-scores were as follows: lumbar spine (LS): -0.8 [interquartile range -1.75 to 0.1]; total hip (TH): -1.2 [-1.75 to -0.6]; femoral neck (FN): -1.2 [-1.9 to -0.7]; and distal radius (DR): -0.8 [-1.4 to -0.1]. We noted a gender difference in LS, with worse results for men (-1.1 vs. -0.3) even after adjusting for BMI (body mass index) and glomerular filtration (p < 0.001). Osteoporotic and osteopenic ranges (based on T-scores) for all major sites were 27.7% and 56.5%, respectively, with similar results across both genders. Women had a significantly higher proportion of normal BMD in LS than men (67.7 vs. 49.4%, p < 0.05). Patients with T1DM at CKD stages G4-G5 exhibited serious BMD impairment despite their young age. Men surprisingly displayed lower Z-scores and higher percentages of pathological BMD values in LS than women did. The introduction of adequate preventive measures during the advanced stages of diabetic nephropathy to prevent bone loss is recommended.

Cinacalcet as rescue therapy for refractory hyperparathyroidism in young children with advanced chronic kidney disease

BACKGROUND

Studies in the use of the calcimimetic, cinacalcet, in pediatric chronic kidney disease (CKD) are few and limited to older children with secondary hyperparathyroidism (sHPT), a major morbid complication contributing to poor growth, bone deformities, and cardiovascular disease. Our objectives were to determine a safe and effective dosing regimen of cinacalcet in the treatment of infants and young children with sHPT that was refractory to standard care and to examine their growth during treatment.

METHODS

Ten young pediatric patients with advanced CKD were studied retrospectively during 11 courses of treatment with cinacalcet. All had severe sHPT with intact parathyroid hormone (iPTH) levels ≥ 500 pg/ml and were refractory to standard therapy with phosphate binders and active vitamin D analogs at high doses for > 30 days. The cinacalcet dose was advanced by 50% every 2-4 weeks to achieve a decline in the iPTH to a goal of 150-300 pg/ml. Linear growth was assessed at 6-month intervals by change in z-scores (△SDS) for length before and during cinacalcet therapy.

RESULTS

Median age at initiation of cinacalcet was 18 months (IQR 6, 36) with an average starting dose of 0.7 ± 0.2 mg/kg/day. Median effective dose required to reach iPTH goal of 150-300 pg/ml was 2.8 mg/kg/day (IQR 2.0, 3.1), and time to goal was 112 days (IQR 56, 259) with a median overall decline in iPTH of 82% from baseline by 6 months (p < 0.0001). No subject experienced a clinical adverse event, although 4 had biochemical asymptomatic hypocalcemia. Linear growth improved significantly during cinacalcet therapy (△SDS - 0.62 ± 1.2 versus + 0.91 ± 1.4; p < 0.005). By multiple regression analysis, the primary determinants of growth were concurrent treatment with growth hormone and age < 2 years (R² = 89.6%; p < 0.001). A shorter treatment time required to achieve iPTH goals also was associated with improved growth (r = - 0.75; p < 0.01).

CONCLUSIONS

Cinacalcet may be used effectively and safely in infants and small children with refractory sHPT in advanced CKD using a cautious dosing regimen. Cinacalcet successfully brings iPTH to target level and supports growth when other treatments have been ineffective.

Comparison of clinical, biochemical and histomorphometric analysis of bone biopsies in dialysis patients with and without fractures

Chronic kidney disease-mineral bone disorders (CKD-MBD) are associated with increased risk of fracture. Studies report about 3% of fractures in CKD patients, and these occur earlier than in the general population, namely 16 and 13 years earlier for men and women, respectively. Better understanding of the pathophysiology of fractures would probably contribute to new therapeutic approaches. This study aimed to evaluate report of long bone fractures from a bone biopsies bank from patients on hemodialysis and compare clinical and biochemical characteristics, as well as the results of the histomorphometric analysis of trabecular and cortical bone of these patients with a control group (without fractures), paired for age, gender, and time on hemodialysis. Bone proteins (SOST, DMP1 and MEPE) were evaluated by immunohistochemistry. Seventeen patients with fracture and controls were studied. Fracture prevalence was 0.82/1000 patients/year. Serum phosphorus levels were significantly lower in the fracture group. Histomorphometric analysis revealed that all the patients had high turnover disease, and the fracture group had smaller volume and trabecular thickness, greater osteoid surface, smaller eroded surface, smaller mineralizing surface, formation rate and longer mineralization lag time when compared to controls; the DMP1 expression in the cortical bone was smaller and the SOST in the trabecular bone was higher in fractured patients. As conclusion, we found low prevalence of fractures. Both groups had high turnover disease, but the fractured ones presented more impaired bone microarchitecture, as well as lower formation and greater mineralization defect. Bone proteins expression correlated with parameters involved in bone remodeling.

Nutritional Management for Chronic Kidney Disease Patients who Undergo Bariatric Surgery: A Narrative Review

Bariatric surgery (BS) may be effective for chronic kidney disease (CKD) patients by reducing microalbuminuria and proteinuria, and by facilitating their meeting inclusion criteria for kidney transplantation. However, nutritional management for this population is complex and specific guidelines are scarce. A literature search was performed to create dietetic practice for these patients based on the most recent evidence. For the purposes of nutritional recommendations, we divided the patients into 2 subgroups: 1) patients with CKD and dialysis, and 2) patients after kidney transplantation. Before surgery, nutritional care includes nutritional status evaluation and adjusting doses of supplements to treat deficiencies and daily nutrient intake according to the dietary restrictions derived from kidney disease, including quantities of fluids, protein, phosphorus, potassium, and vitamins. After BS, these patients are at major risk for lean body mass loss, malnutrition and dehydration because of fluid restriction and diuretics. Postoperative nutritional recommendations should be carefully tailored according to CKD nutritional limitations and include specific considerations regarding protein, fluids, and supplementation, in particular calcium, vitamin A, and vitamin D. Nutritional management of CKD and kidney transplant patients undergoing BS is challenging and future studies are required to establish uniform high-level evidence-based guidelines.

Routine Laboratory Testing Every 4 Versus Every 6 Weeks for Patients on Maintenance Hemodialysis: A Quality Improvement Project

RATIONALE & OBJECTIVE

Few data exist revealing how the frequency of routine blood work for patients on maintenance hemodialysis therapy affects patient outcomes and the costs of care. Our objective was to determine the effect of changing the frequency of blood work from 4- to 6-week intervals on the achievement of anemia and chronic kidney disease-mineral and bone disorder (CKD-MBD) targets.

STUDY DESIGN

Retrospective interrupted time series from June 1, 2012, to December 31, 2015.

SETTING & PARTICIPANTS

Tertiary hospital in Ontario, Canada, that provides maintenance hemodialysis therapy to 350 to 400 adult patients.

QUALITY IMPROVEMENT ACTIVITIES

Institution-wide switch of the interval for routine blood work from 4 to 6 weeks on March 24, 2014.

OUTCOMES

Achievement of recommended hemoglobin and phosphate level targets. Cost savings attributable to a change in frequency of blood work for hemoglobin, ferritin, iron saturation, calcium, and phosphate comparing 252-day periods under each testing frequency condition.

ANALYTICAL APPROACH

Statistical process control to analyze variation in the clinical outcomes.

RESULTS

The proportion of patients who achieved hemoglobin (10-12g/dL) and phosphate (2.5-4.6mg/dL) targets remained stable (average of 60% and 46%, respectively), with no measurements beyond 3 standard deviations from the mean. The hemodialysis unit mortality rate also remained stable (average of 2% per month). Reducing blood work frequency to every 6 weeks was associated with a saving of $85 per patient-year, corresponding to a program-wide savings of $35,000.

LIMITATIONS

No case-mix adjustment due to use of aggregate hemodialysis unit data, and absence of data for hospitalizations and transfusions limiting assessment of the full cost of patient care.

CONCLUSIONS

After switching the frequency of routine blood work from 4- to 6-week intervals, performance on anemia and CKD-MBD targets did not change and the reduction in blood work was associated with laboratory cost savings. Reducing the frequency of blood work may represent an opportunity for hemodialysis providers to devote greater efforts toward other care elements that better improve patient outcomes.

Moving from the second to the third generation Roche PTH assays: what are the consequences for clinical practice?

Background The determination of parathyroid hormone (PTH) is essential for exploring phosphocalcic disorders especially in patients with renal failure. At present, second or third generation PTH assays are available on the market from Roche Diagnostics as well as from others companies but the lack of standardization has complicated the interpretation. Methods We wanted to assess the clinical impact by measuring the PTH levels with the two generations concomitantly on different groups of populations including 46 healthy, 103 pre-dialyzed and 73 hemodialyzed (HD) patients. Results In healthy subjects, the PTH concentrations were not different whatever the generation used, whereas beyond 200 pg/mL, we reported an overestimation of the second generation PTH. In patients with chronic kidney disease (CKD) stage 3-5 the observed differences between the two generations increase with increasing PTH levels and decreasing glomerular filtration rate (GFR). Classification according to the kidney disease: improving global outcomes (KDIGO) revealed a high percentage of discordant results between the two generations (κ coefficient <0.20). These discrepancies are clinically relevant as PTH levels remain the cornerstone for diagnosis and treatment of the CKD-mineral and bone disorder (CKD-MBD). Conclusions The introduction of a new PTH assay generation in clinical practice should be carried out with caution.

Active Vitamin D in Chronic Kidney Disease: Getting Right Back Where We Started from?

Background

The vitamin D system is essential for optimal health in humans. Circulating calcitriol, a key metabolite in maintaining calcium and phosphorus homeostasis, is produced in the kidney. In kidney failure, calcitriol levels progressively decrease, contributing to the development of renal secondary hyperparathyroidism (SHPT).

Summary

For years, SHPT had a central role in the disturbed mineral metabolism of renal patients. As calcitriol deficiency contributes to SHPT development, treatment with calcitriol or other compounds able to activate the vitamin D receptor (VDR) was one of the mainstays of therapy for renal patients in the last 40 years. In this review, we discuss how the treatment with VDR activators (VDRA) evolved during this time in the United States, as well as the main factors responsible for these changes.

Key Messages

Management of SHPT with VDRA in renal patients has undergone a few paradigm shifts over the last 40 years. When treating SHPT, the newly developed therapies as well as VDRA need to be carefully considered and used appropriately. Nephrologists need to use an integrated approach that avoids excessive use of VDRA, ensures replenishment of vitamin D stores, and avoids hypercalcemia and hyperphosphatemia.

PTH, FGF23, and Intensive Blood Pressure Lowering in Chronic Kidney Disease Participants in SPRINT

BACKGROUND AND OBJECTIVES

The Systolic Blood Pressure Intervention Trial (SPRINT) demonstrated that intensive BP lowering reduced the risk of cardiovascular disease, but increased eGFR decline. Serum parathyroid hormone (PTH) and fibroblast growth factor-23 (FGF23) concentrations are elevated in CKD and are associated with cardiovascular disease. We evaluated whether intact PTH or intact FGF23 concentrations modify the effects of intensive BP control on cardiovascular events, heart failure, and all-cause mortality in SPRINT participants with CKD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We measured PTH and FGF23 in 2486 SPRINT participants with eGFR<60 ml/min per 1.73 m2 at baseline. Cox models were used to evaluate whether serum PTH and FGF23 concentrations were associated with cardiovascular events, heart failure, and all-cause mortality, and whether PTH and FGF23 modified the effects of intensive BP control.

RESULTS

The mean age of this subcohort was 73 years, 60% were men, and mean eGFR was 46±11 ml/min per 1.73 m2. Median PTH was 48 (interquartile range [IQR], 35-67) pg/ml and FGF23 was 66 (IQR, 52-88) pg/ml. There were 261 composite cardiovascular events, 102 heart failure events, and 179 deaths within the subcohort. The adjusted hazard ratio (HR) per doubling of PTH concentration for cardiovascular events, heart failure, and all-cause mortality were 1.29 (95% confidence interval [95% CI], 1.06 to 1.57), 1.32 (95% CI, 0.96 to 1.83), and 1.04 (95% CI, 0.82 to 1.31), respectively. There were significant interactions between PTH and BP arm for both the cardiovascular (P-interaction=0.01) and heart failure (P-interaction=0.004) end points. Participants with a PTH above the median experienced attenuated benefits of intensive BP control on cardiovascular events (adjusted HR, 1.02; 95% CI, 0.72 to 1.42) compared with participants with a PTH below the median (adjusted HR, 0.67; 95% CI, 0.45 to 1.00). FGF23 was not independently associated with any outcome and did not modify the effects of the intervention.

CONCLUSIONS

SPRINT participants with CKD and a high serum PTH received less cardiovascular protection from intensive BP therapy than participants with a lower serum PTH.

Mineral and Bone Disease in Kidney Transplant Recipients

PURPOSE OF REVIEW

Despite metabolic improvements following kidney transplantation, transplant recipients still often suffer from complex mineral and bone disease after transplantation.

RECENT FINDINGS

The pathophysiology of post-transplant disease is unique, secondary to underlying pre-transplant mineral and bone disease, immunosuppression, and changing kidney function. Changes in modern immunosuppression regimens continue to alter the clinical picture. Modern management includes reducing cumulative steroid exposure and correcting the biochemical abnormalities in mineral metabolism. While bone mineral density screening appears to help predict fracture risk and anti-osteoporotic therapy appears to have a positive effect on bone mineral density, more data regarding specific treatment is necessary. Patients with mineral and bone disease after kidney transplantation require special care in order to properly manage and mitigate their mineral and bone disease. Recent changes in clinical management of transplant patients may also be changing the implications on patients' mineral and bone disease.

The Role of Vitamin D and Oxidative Stress in Chronic Kidney Disease

Chronic kidney disease (CKD) is a major non-communicable disease associated with high rates of premature morbidity and mortality. The prevalence of hypovitaminosis D (deficiency of 25(OH)D or 25D) is greater in racial/ethnic minorities and in patients with CKD than the general population. Low 25D is associated with bone and mineral disorders as well as immune, cardiometabolic and cardiovascular (CV) diseases. Thus, it has been suggested that low 25D contributes to the poor outcomes in patients with CKD. The prevalence of hypovitaminosis D rises progressively with advancing severity of kidney disease with over 30% of patients with CKD stage 3 and 70% patients with CKD stage 5 estimated to have low levels of 25D. This report describes several of the abnormal physiologic and counter-regulatory actions related to low 25D in CKD such as those in oxidative stress and inflammatory systems, and some of the preclinical and clinical evidence, or lack thereof, of normalizing serum 25D levels to improve outcomes in patients with CKD, and especially for the high risk subset of racial/ethnic minorities who suffer from higher rates of advanced CKD and hypovitaminosis D.

Parathyroid Hormone Fragments: New Targets for the Diagnosis and Treatment of Chronic Kidney Disease-Mineral and Bone Disorder

As a common disorder, chronic kidney disease (CKD) poses a great threat to human health. Chronic kidney disease-mineral and bone disorder (CKD-MBD) is a complication of CKD characterized by disturbances in the levels of calcium, phosphorus, parathyroid hormone (PTH), and vitamin D; abnormal bone formation affecting the mineralization and linear growth of bone; and vascular and soft tissue calcification. PTH reflects the function of the parathyroid gland and also takes part in the metabolism of minerals. The accurate measurement of PTH plays a vital role in the clinical diagnosis, treatment, and prognosis of patients with secondary hyperparathyroidism (SHPT). Previous studies have shown that there are different fragments of PTH in the body's circulation, causing antagonistic effects on bone and the kidney. Here we review the metabolism of PTH fragments; the progress being made in PTH measurement assays; the effects of PTH fragments on bone, kidney, and the cardiovascular system in CKD; and the predictive value of PTH measurement in assessing the effectiveness of parathyroidectomy (PTX). We hope that this review will help to clarify the value of accurate PTH measurements in CKD-MBD and promote the further development of multidisciplinary diagnosis and treatment.

New insights from the application of the FAbry STabilization indEX in a large population of Fabry cases

Background

The FAbry STabilization indEX (FASTEX) is an innovative index allowing the assessment of clinical stability over time in Fabry disease patients. This index was developed in a population of 28 male patients with the classical form of Fabry disease.

Objectives

The aim of the study was to test the accuracy of the FASTEX in evaluating Fabry disease stability in 132 male and female patients with classical and non-classical Fabry disease from nine Italian centres and it also aimed to define the sensitivity and specificity of this new tool. In particular, we aimed to investigate the correlation between the FASTEX and clinical judgement in a large-scale cohort of the study population.

Methods

Statistical methods applied to this investigation included the calculation of accuracy, specificity and sensitivity, receiver operating characteristic (ROC) curves and Cohen's κ index related to the FASTEX and clinical judgement.

Results

The patient population included 58 males (43.9%). The mean age of the overall population was 46.3 ± 15. 1 years (range 31.2-61.4). The median interval between the two multidisciplinary evaluations used for FASTEX calculation was 398 days. Since no gold standard method is available to define the overall clinical condition of Fabry patients over time, the results of the FASTEX were compared with clinical judgements given by the physicians involved in this study. In this way, the FASTEX classified 121 of 132 (92%) patients correctly. In particular, the FASTEX correctly identified 93% (41/44) of clinically 'unstable' and 91% (80/88) of clinically 'stable' patients. The area under the curve of the ROC related to the FASTEX index cut-off (20) was equal to 0.967, very close to its theoretical maximum (1), which means that it is an excellent test for classifying patients as 'stable' or 'unstable' compared with clinical judgement. In addition, the FASTEX cut-off >20 provides the most acceptable balance between sensitivity and specificity. The Cohen's κ index value obtained in our study was 0.82, showing a highly statistically significant P-value < 0.01 related to the agreement between the FASTEX and clinical judgement.

Conclusions

The FASTEX is demonstrated here to be a specific and sensitive tool. When applied to a large cohort of Fabry patients, it was shown to be a valid instrument in helping physicians to discriminate objectively the clinical stability of individual Fabry patients.

Fractional excretion of phosphorus and vascular calcification in stage 3 chronic kidney disease

The role of renal excretion of Pi in relation to vascular calcification (VC) in patients in the early stages of chronic kidney disease (CKD) is controversial. Thus, we determine the relation between fractional excretion of phosphorus (FEP) and VC, measured using two methods in a cross-sectional study of patients with stage 3 CKD. We recorded demographic data, anthropometry, comorbidities and active treatment. We measured 24-hour urine FEP and, in serum, measured fibroblast growth factor 23 (FGF23), α-Klotho, intact parathyroid hormone (iPTH), calcium and phosphorus. VC was measured by lateral abdominal radiography (Kauppila index (KI)) and CT of the abdominal aorta (measured in Agatston units). In 57% of subjects, abnormal VC was present when measured using CT, and in only 17% using lateral abdominal radiography. Factors associated with VC using CT were age, cardiovascular risk factors, vascular comorbidity, microalbuminuria and levels of FGF23, phosphorus and calcium x phosphorus product (CaxP); although only age (OR 1.25, 95% CI 1.11 to 1.41), smoking (OR 21.2, CI 4.4 to 100) and CaxP (OR 1.21, CI 1.06 to 1.37) maintained the association in a multivariate analysis. By contrast, only age (OR 1.35, 95% CI 1.07 to 1.74), CaxP (OR 1.14, CI 1.13 to 1.92) and FEP (OR 1.07,95% CI 1004 to 1.14) were associated with abnormal VC in the lateral abdominal radiography. In conclusion, in patients with stage 3 CKD, the detection of VC by abdominal CT is more sensitive than conventional X-rays. Moreover, CaxP is associated with cardiovascular risk factors and vascular comorbidity; quantification of FEPi in these patients provides additional clinical information in advanced VC detected by KI.

Safety and efficacy of subtotal or total parathyroidectomy for patients with secondary or tertiary hyperparathyroidism in four academic centers in the Netherlands

Purpose

Hyperparathyroidism (HPT) is a common abnormality in patients with end-stage renal disease (ESRD). Since the introduction of cinacalcet in 2004, a shift from surgery toward predominantly medical treatment has occurred. Surgery is thought to be associated with more complications than oral medication. The aim of this retrospective study was to evaluate 30-day outcomes and effectiveness of parathyroidectomy (PTx) in ESRD patients in the Netherlands.

Methods

A national database containing data from four academic medical centers in the Netherlands of patients with ESRD-related HPT, who had undergone PTx and kidney transplantation between 1994 and 2015, was established. Primary endpoints were 30-day mortality and complication rate. Secondary endpoints were biochemical measurements.

Results

We identified 187 HPT patients undergoing PTx, with a median age of 46 years. Median preoperative PTH level was 866 pg/mL (interquartile range [IQR] 407–1547 pg/mL). At 3 months, the median PTH drop from baseline was 93% (IQR, 71–98%) to a median of 61 pg/mL (IQR, 23–148 pg/mL, p < 0.001). Over the 25-year inclusion period, 13 patients (7.0%) required re-exploration for persistent or recurrent disease. Thirty-day mortality and complication rate were 0.0% and 7.9% respectively. Median serum calcium levels improved significantly postoperatively from 2.6 (2.4–2.8) mmol/L to 2.3 (2.1–2.5) mmol/L (p < 0.001).

Conclusions

PTx is a safe and effective procedure in the frail ESRD population. These data show that there should be no reluctance for surgical intervention and when indicated, nephrologists can safely refer these patients for PTx.

Medication Safety Principles and Practice in CKD

Ensuring patient safety is a priority of medical care because iatrogenic injury has been a primary concern. Medications are an important source of medical errors, and kidney disease is a thoroughfare of factors threatening safe administration of medicines. Principal among these is reduced kidney function because almost half of all medications used are eliminated via the kidney. Additionally, kidney patients often suffer from multimorbidity, including diabetes, hypertension, and heart failure, with a range of prescribers who often do not coordinate treatments. Patients with kidney disease are also susceptible to further kidney injury and metabolic derangements from medications, which can worsen the disease. In this review, we will present the key issues and threats to safe medication use in kidney disease, with a focus on predialysis CKD, as the scope of medication safety in ESKD and transplantation are unique and deserve their own consideration. We discuss drugs that need to be avoided or dose modified, and review the complications of a range of medications routinely administered in CKD, as these also call for cautious use.

Treatment strategy of end stage renal disease-related hyperparathyroidism before, during, and after the era of calcimimetics

BACKGROUND

Since 2004, end-stage renal disease related hyperparathyroidism patients are treated mainly with cinacalcet, which ceased to be subsidized through the Australian Pharmaceutical Benefits Scheme in 2015. We aimed to investigate the impact of these changes on the treatment strategy in the Australian end-stage renal disease population.

METHODS

The following groups were formed according to the date of parathyroidectomy: A, before calcimimetics; B, during the era of calcimimetics; and C, after cinacalcet removal by the Australian Pharmaceutical Benefits Scheme. The primary outcome was time from start of dialysis to parathyroidectomy. Regression analysis was used to examine trends in parathyroidectomy rates.

RESULTS

Between 1998 and 2016, 195 parathyroidectomies were performed. Median time to referral was 69 (33-123), 67 (31-110) and 44 (23-102) months for groups A, B, and C, respectively (P = .55). Parathyroidectomy rates increased throughout the years (CI 0.09-1.13, R²=0.27, P = .02). A trend toward a dip in parathyroidectomy rates was seen during the era of cinacalcet (P = .08). Median preoperative parathyroid hormone levels increased significantly (842 [418-1,553] versus 1,040 [564-1,810] versus 1,350 [1,037-1,923] pg/mL, for groups A, B, and C, respectively [P < .01]).

CONCLUSION

Parathyroidectomy rates seem to vary according to the availability of cinacalcet. This change in treatment strategy is accompanied with increased preoperative parathyroid hormone levels, reflecting delayed surgery and increased disease severity.

Complications of Kidney Disease

Understanding the physiology of the kidney and the pathophysiology of common complications of chronic kidney disease (CKD) is essential. The rise of CKD across the United States demands that nurses be prepared to care for these patients. Cardiovascular complications, anemia, and bone formation issues are the most common complications. Approximately 30 million people (15% of adults) are reported to have CKD. By 2020 there will be a 14.4% increase in the prevalence of CKD, and by 2030, the increase will be up by 16.7%. Nurses are integral to providing care that can slow or halt the progression of CKD.

Phosphorus in food: limitations of food composition data

Limiting the amount of phosphorus in the diet is the first line for management of hyperphosphatemia in chronic kidney disease, and it is therefore important that dietitians have access to accurate data on the phosphorus content of foods. However, food composition datasets have several limitations for use. In this article, Julie Hannah and colleagues describe the limitations of food composition data, and call for further research into this area

Status of vitamin D and parameters of calcium homeostasis in renal transplant recipients in Nepal: a cross sectional study

BACKGROUND

Vitamin D, apart from being an important part of the "calcium-vitamin D-parathyroid hormone" endocrine axis, has diverse range of "non-calcemic" biological actions. A high prevalence of vitamin D deficiency has been observed in renal transplant recipients (RTRs) worldwide. This study aimed to determine the prevalence of hypovitaminosis D in Nepalese RTRs and interrelations between serum 25-hydroxyvitamin D [25(OH) D] and other biochemical parameters.

METHODS

A total of 80 adult RTRs visiting a university hospital were enrolled in this cross sectional study. Serum 25(OH) D and intact parathyroid hormone (iPTH) were measured using Enhanced Chemiluminiscent Immunoassay. The RTR population was categorized into recent transplant recipients (≤1 year) and long term recipients (> 1 year). The vitamin D status was defined as per NKF/KDOQI guidelines. SPSS version 20.0 was used to analyze the data. Appropriate statistical tests were applied to compare variables between groups and establish correlation. P < 0.05 was considered to be statistically significant.

RESULTS

The mean age of the recipients was 38.11 ± 11.47 years (68 males, 85.0%). Chronic glomerulonephritis was the leading cause of CKD. The two RTR groups (recent and long term) didn't differ in demographic and biochemical characteristics. 83.75% of the recipients had PTH levels above the upper limit of the recommended range for their stage of CKD. 57.5% had hypocalcemia and none of the recipients had hypercalcemia. The median serum 25(OH) D was 24.15 ng/ml (8.00-51.50 ng/ml). Only 27.5% had sufficient vitamin D status whereas 53.8% were vitamin D insufficient and 18.8% were vitamin D deficient, the distribution almost comparable in the 2 transplant group. The serum 25(OH) D was not significantly affected by the time post-transplant, gender and sunlight avoidance. There was a significant negative correlation between serum 25(OH) D and iPTH (Pearson's r = - 0.35, P = 0.001), but not so with the graft function.

CONCLUSION

There is a high prevalence of vitamin D insufficiency in RTRs. The deficiency status is not corrected despite of nutritional improvement and normalization of GFR post-transplantation and likely exacerbates secondary hyperparathyroidism. Vitamin D supplementation coupled with sensible sun exposure could be important strategies in optimization of the vitamin D status in this population.

[Evaluation of nephrocerebral risk with the use of cystatin C in patients with chronic kidney disease]

AIM

To study a role of cystatin C in the nephrocerebral risk in chronic kidney disease at the initial stage of the disease.

MATERIAL AND METHODS

One hundred and twenty-eight patients (63 men and 65 women) with chronic kidney disease (CKD) were examined at the pre-dialysis stage of the disease. All patients underwent a complex clinical and laboratory examination with determination of the lipid spectrum, uric acid, fibrinogen, calcium and cystatin C, and subsequent calculation of the glomerular filtration rate (GFR). To assess structural changes in carotid arteries, ultrasound dopplerography was performed. Depending on the thickness of the intima-media (TIM), the entire sample is divided into CKD groups with no signs of carotid atherosclerosis (SC), n=70 and on CKD with SC, n=58.

RESULTS

Patients of the second group (CKD with SC), had higher body mass index (p<0.05), systolic (p<0.05) and central (p<0.05) arterial pressure (BP) and blood cystatin C (p<0.05). In the same group, there was a significant decrease in the concentration of high-density lipoprotein cholesterol (p<0.05) compared with those of the first group (CKD). The age of patients and the content of cystatin C (p<0.05) influenced the increase in TIM. Significant positive correlations between cystatin C content and TIM, systolic and diastolic blood pressure (p<0.05), and a negative correlation cystatin C content and GFR were noted in patients of the second group.

CONCLUSION

The increase in the level of cystatin C in blood plasma in CKD indicates the development of structural changes in the carotid arteries, the increase in the levels of systolic and central arterial pressure, the decrease in the concentration of HDL cholesterol, which is associated with significant inhibition of GFR.

Conservative three-quarter versus subtotal seven-eighths parathyroidectomy in secondary hyperparathyroidism

OBJECTIVE

There is at present no consensus concerning surgical techniques for secondary hyperparathyroidism (SHPT) in end-stage renal disease (ESRD). Although both subtotal and total parathyroidectomy provide low rates of recurrence, they may induce hypoparathyroidism, damaging the bone and cardiovascular systems. The aim of our study was to compare 3/4 and 7/8 parathyroidectomy in this population and to discuss the potential benefit of more conservative treatment.

STUDY DESIGN

Prospective observational study in a university teaching hospital between 2010 and 2014.

METHODS

The study included 34 consecutive ESRD patients with SHPT: 19 underwent 3/4 parathyroidectomy (group A*3/4) and 15 underwent 7/8 parathyroidectomy (group B*7/8). Serum intact 1-84 PTH levels (before and 6 months after surgery) and hospital stay were compared between the two groups.

RESULTS

Before surgery, PTH levels were similar between the two groups. At month 6 following surgery, median PTH levels were significantly higher in group A*3/4 than in group B*7/8 (109 versus 24pg/mL, respectively; P<0.0006). Hospital stay was shorter in group A*3/4 (4.79 versus 6.80 days, respectively; P=0.008). Postoperative hypoparathyroidism requiring long-term calcium and 1alpha(OH) D3 treatment was reported in 5% of patients in group A*3/4 and 26% of patients in group B*7/8 (P=0.04).

CONCLUSIONS

In this preliminary study, 3/4 conservative parathyroidectomy seemed effective and safe, with less reported morbidity than 7/8 parathyroidectomy, as assessed by lower rates of irreversible hypoparathyroidism and shorter hospital stay.

LEVEL OF EVIDENCE

3b, individual case-control study.

Proton Pump Inhibitors, Histamine-2 Receptor Antagonists, and Hip Fracture Risk among Patients on Hemodialysis

BACKGROUND AND OBJECTIVES

An association between proton pump inhibitor (PPI) use and hip fracture risk has been described in the general population, where the primary causative hypothesis focuses on impaired gastrointestinal calcium absorption. The impact of acid suppressor use on hip fracture risk in a high-risk subset, patients with ESKD requiring hemodialysis, is unknown and could help further distinguish the reason for higher susceptibility among PPI users.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Using the US Renal Data System, we identified all hip fracture events recorded between 2009 and 2014 among patients dependent on hemodialysis. Eligible cases were matched on index date with ten controls. We identified PPI and histamine-2 receptor antagonist use from Medicare Part D claims covering 3 years before the index date and stratified according to proportion of days covered by filled prescriptions. Using logistic regression with multiple imputation for missing data, we estimated unadjusted and multivariable-adjusted odds ratios (ORs) and 95% confidence intervals (95% CIs).

RESULTS

We studied 4551 cases and 45,510 controls. Patients were older, more likely to be female and white, and had shorter dialysis vintage; fewer were obese. A larger proportion of patients had any prior PPI (70% versus 63%) or histamine-2 receptor antagonist (25% versus 23%) use. Use of PPI was associated with higher risk of hip fracture (adjusted OR, 1.19; 95% CI, 1.11 to 1.28). This association remained within subgroups of low, moderate, and high PPI use, yielding adjusted ORs of 1.16 (95% CI, 1.06 to 1.27), 1.21 (95% CI, 1.11 to 1.31), and 1.19 (95% CI, 1.08 to 1.31), respectively.

CONCLUSIONS

Among patients with ESKD on hemodialysis, PPIs and not histamine-2 receptor antagonists were associated with hip fracture events.

The Role of Vitamin D in CKD Stages 3 to 4: Report of a Scientific Workshop Sponsored by the National Kidney Foundation

Deficiency of 25-hydroxyvitamin D (25[OH]D) is common in patients with chronic kidney disease stages 3 and 4 and is associated with poor outcomes. However, the evaluation and management of vitamin D deficiency in nephrology remains controversial. This article reports on the proceedings from a "controversies conference" on vitamin D in chronic kidney disease that was sponsored by the National Kidney Foundation. The report outlines the deliberations of the 3 work groups that participated in the conference. Until newer measurement methods are widely used, the panel agreed that clinicians should classify 25(OH)D "adequacy" as concentrations > 20ng/mL without evidence of counter-regulatory hormone activity (ie, elevated parathyroid hormone). The panel also agreed that 25(OH)D concentrations < 15ng/mL should be treated irrespective of parathyroid hormone level. Patients with 25(OH)D concentrations between 15 and 20ng/mL may not require treatment if there is no evidence of counter-regulatory hormone activity. The panel agreed that nutritional vitamin D (cholecalciferol, ergocalciferol, or calcifediol) should be supplemented before giving activated vitamin D compounds. The compounds need further study evaluating important outcomes that observational studies have linked to low 25(OH)D levels, such as progression to end-stage kidney disease, infections, fracture rates, hospitalizations, and all-cause mortality. We urge further research funding in this field.

Factors affecting TST level in patients undergoing dialysis: a multicenter study

INTRODUCTION

The risk of TB is increased in patients with chronic kidney disease (CKD) when compared with individuals with normal renal function. We aimed to determine tuberculin skin test (TST) response and the factors which might affect the response in patients with CKD undergoing dialysis in this study.

METHODS

The purified protein derivative solution was administered to the patients and the diameter of induration was measured. Additionally, the age, gender and smoking status of the patients were interrogated. Comorbidities were recorded both by patients' self-reports and data from the hospital files. The number of Bacille Calmette-Guerin (BCG) scars was recorded by checking both shoulders.

FINDINGS

The study was conducted with a total of 371 patients (194 men and 177 women). The mean age was 60.09 ± 15.88, TST was 6.99 ± 6.9, duration of dialysis was 4.44 ± 4.5 (3.8-0.1,24). A total of 229 patients have comorbodities (61.7%, the most frequent was hypertension). Logistic regression model was performed. Gender, vitamin D treatment and high parathormone (PTH) levels remained in the final stage of the analysis and vitamin D intake and PTH levels were detected to be statistically significant (P = 0.002, 0.007, respectively).

DISCUSSION

This study is the first study which showed a correlation between TST negativity and increased PTH levels and receiving vitamin D treatment. Starting from this point, it was concluded that PTH may suppress the immune system and especially cellular immunity.

Achievement of 2009 and 2017 Kidney Disease: Improving Global Outcomes mineral and bone targets and survival in a French cohort of chronic kidney disease Stages 4 and 5 non-dialysis patients

BACKGROUND

The aim of the third French Phosphorus and Calcium Observatory (Photo-Graphe® 3) was to assess the achievement of international Kidney Disease: Improving Global Outcomes (KDIGO) recommendations on optimal serum phosphate, calcium and parathyroid hormone (PTH) levels and possible associations with mortality in patients with chronic kidney disease (CKD).

METHODS

This was a prospective, observational study conducted with nephrologists in France who were selected using a clustering approach. Adult patients with non-dialysis Stage 4 or 5 CKD and no kidney graft history were eligible. Data about clinical events, serum biochemistry and treatment were collected every 6 months for 2.5 years and 12 months thereafter. The Kaplan-Meier method was used for survival analysis and Cox proportional hazards model for identification of factors associated with survival.

RESULTS

Overall, 566 CKD Stage 4 patients (men, 56%) and 153 CKD Stage 5 patients (men, 62%) were included. In Stage 4, only 14-15% patients achieved the three main 2009 KDIGO targets during the first 2 years and 22% at 2.5 years. In Stage 5 patients, the proportion remained <6% throughout. The percentages of patients achieving the three main 2017 KDIGO targets were slightly higher at each time point. Overall, 14% of Stage 4 and 10% of Stage 5 patients died in the observation period. Only age and haemoglobin level were significantly associated with risk of all-cause mortality.

CONCLUSIONS

Few CKD patients achieved KDIGO mineral targets. Increased mortality risk was linked to older age and lower haemoglobin level, but not to serum calcium, phosphate or PTH targets.

Native vitamin D in pre-dialysis chronic kidney disease

Chronic kidney disease patients have a high prevalence of vitamin D insufficiency/deficiency. Vitamin D deficiency has been associated with a variety of bone, metabolic and cardiovascular disorders. However, the role of native vitamin D supplementation (ergocalciferol, cholecalciferol or calcifediol) remains unclear in chronic kidney disease (CKD), particularly in the pre-dialytic phase. Several international guidelines have been developed on CKD-Mineral and Bone Disorder, but the optimal strategy for native vitamin D supplementation and its clinical benefit remains a subject of debate in the scientific community. This paper aims to review the available literature, including randomized clinical trials that evaluated the effects of native vitamin D supplementation on pre-dialysis CKD on biochemical and clinically relevant outcomes.

Dietary Phosphorus to Protein Ratio for the Mexican Population with Chronic Kidney Disease

OBJECTIVE

Hyperphosphatemia is a major contributor to poor outcomes among cases of chronic kidney disease. Considering that foods with high protein content are major sources of phosphorus, a more suitable dietary phosphorus measure is the phosphorus to protein ratio. However, Mexican phosphorus to protein ratio tables do not exist. This article aims to estimate the phosphorus to protein ratio in foods commonly used by the Mexican population and to establish its usefulness in the selection of foods for patients with chronic kidney disease.

METHODS

Six tables with the phosphorus to protein ratio were developed from different data sources concerning Mexican animal food composition.

RESULTS

Egg whites have the best phosphorus to protein ratio. Partially skimmed milk has the lowest ratio among dairy products. Dairy products have high phosphorus to protein ratio variability. Red meat products have a ratio with an average of 9 mg/g. The phosphorus to protein ratio varies considerably for seafood (1.2-38.3 mg/g).

CONCLUSIONS

The phosphorus to protein ratio could be a good strategy to choose each food during chronic kidney disease dietary treatment for the Mexican population.