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

Association between Bone Mineral Density and Severity of Chronic Kidney Disease

OBJECTIVE

We sought to evaluate the association between femoral neck (FN) and lumbar spine (LS) bone mineral densities (BMDs) with severity of chronic kidney disease (CKD) and prevalence of osteopenia or osteoporosis (OP) among the CKD group.

METHODS

Cross-sectional data from 11050 participants aged ≥20 years from the National Health and Nutrition Examination Survey (NHANES) were analyzed. Specifically, Pearson correlation was applied to analyze the relationship between BMD and estimated glomerular filtration rate (eGFR). General linear models (GLMs) were adjusted for potential confounders and used to analyze mean BMD, based on CKD and CKD stages.

RESULTS

FN BMD was positively correlated with the eGFR in the total and male CKD, but not in the female CKD population. LS BMD was not significantly associated with eGFR. After controlling for partial correlations, FN T-score was positively correlated with the eGFR in the total at-risk population. According to FN BMD, OP prevalence was positively associated with CKD stage. However, according to LS BMD, there was no significant association between OP and CKD stage.

CONCLUSION

Our results may explain the higher prevalence of hip fracture, relative to that of the spine, among CKD patients and generate meaningful insights to guide care, prevention, and treatment regimens for CKD patients. However, the fact that this was a cross-sectional study may limit the possibility of drawing concrete conclusions. Nevertheless, these findings open up a new frontier for further studies to uncover the higher decrease of FN BMD compared to LS BMD among CKD cases.

Kidney function and its association to imminent, short- and long-term fracture risk-a longitudinal study in older women

Reduced kidney function is associated with an increased fracture risk, although the relationship between an age-related decline and fractures needs further investigation. We followed kidney function and fracture risk for 10 years. A mild-moderate decline in kidney function was associated with fracture, but not in advanced age.

INTRODUCTION

With age, kidney function declines. Though well known that chronic kidney disease is associated with increased fracture risk, the extent to which the typical age-related decline contributes is unclear. In the OPRA cohort, a longitudinal study of older non-selected women, we investigated the association between kidney function and fracture.

METHODS

Cystatin C-based kidney function estimates were available at age 75 (n = 981) and 80 (n = 685). Women were categorized by kidney function: normal (CKD stages 1 and 2), mild-moderate (3a), poor (3b-5), and imminent, short- and long-term fracture risk investigated. BMD measurements and kidney function for risk prediction were also evaluated; women were categorized by both reduced kidney function (stages 3-5) and osteoporosis status.

RESULTS

In the short term, 2-3 years, mild-moderate kidney dysfunction was associated with the highest risk increase: osteoporotic fractures (2 years HRadj 2.21, 95% CI 1.27-3.87) and also up to 5 years (between 75 and 80 years) (HRadj 1.51, 1.04-2.18). Hip fracture risk was similarly increased. This association was not observed from age 80 nor for women with poorest kidney function. Reduced kidney function was associated with higher risk even without osteoporosis (osteoporotic fracture; HRadj 1.66, 1.08-2.54); risk increased by having both osteoporosis and reduced function (HRadj 2.53, 1.52-4.23).

CONCLUSION

Older women with mild-moderate reduction of kidney function are at increased risk of fractures, but not those with the worst function. Our findings furthermore confirm the value of osteoporosis assessment and it is possible that in this age group, age-related decline of kidney function has limited contribution compared with BMD.

Comparison of fractional excretion of electrolytes in patients at different stages of chronic kidney disease: A cross-sectional study

Kidney handling of electrolytes varies in different stages of chronic kidney disease (CKD). Diabetes mellitus (DM) plays an important role in CKD. Fractional excretion (FE) is an important means in clinical practice. The relationship between FE of electrolytes in patients at different stages of CKD is worth further investigating.We designed a cross-sectional study in 1 teaching hospital, consecutive CKD patients were enrolled between February 2016 and January 2017. Including clinical demographic features, laboratory examination including spot urine electrolytes, blood biochemistries, and relevant medications were determined.A total of 762 CKD patients completed the study. Of these, 218 (28.6%) had DM. Participants were grouped according to estimated glomerular filtration rate into 7 categories: hyperfiltration (HF), CKD1, CKD2, CKD3a, CKD3b, CKD4, and CKD5. Groups HF, CKD1, 2, 3a, 3b, 4 and 5 contained 83, 143, 192, 94, 82, 82, and 86 patients, respectively. FE of electrolytes tended to increase along with the decline of renal function (CKD1-CKD5) (P < .001). The relationship was similar between the DM and non-DM groups. Diabetic patients demonstrated higher FE of magnesium compared with non-DM subjects at CKD2 and CKD5 (P < .05).CKD patients showed a progressive increase in the FE of electrolytes; FE of magnesium seemed to increase more among diabetic patients with CKD, and could be a potential predictor of CKD progression.

Relationship between serum phosphate levels and survival in chronic hemodialysis patients: interactions with age, malnutrition and inflammation

Background

Evidence indicates that the inverse relationships between phosphate levels and mortality maybe modified by age. Furthermore, malnutrition and inflammation could strengthen the risk associated with phosphate abnormalities. This study aimed to assess the associations between phosphate levels and mortality while accounting for the interactions with age and parameters associated with malnutrition and inflammation in hemodialysis (HD) patients.

Methods

Adult HD patients (n = 245 853) treated in Fresenius Medical Care North America clinics from January 2010 to October 2018 were enrolled. Baseline was defined as Months 4-6 on dialysis, with the subsequent 12 months as the follow-up period. Univariate and multivariate Cox proportional hazard models with spline terms were applied to study the nonlinear relationships between serum phosphate levels and mortality. The interactions of phosphate levels with albumin, creatinine, normalized protein catabolic rate (nPCR) and neutrophil-lymphocyte ratio (NLR) were assessed with smoothing spline analysis of variance Cox proportional hazard models.

Results

Older patients tended to have lower levels of serum phosphate, albumin, creatinine and nPCR. Additionally, both low (<4.0 mg/dL) and high (>5.5 mg/dL) phosphate levels were associated with higher risk of mortality across all age strata. The U-shaped relationships between phosphate levels and outcome persisted even for patients with low or high levels of serum albumin, creatinine, nPCR and NLR, respectively.

Conclusion

The consistent U-shaped relationships between serum phosphate and mortality across age strata and levels of inflammatory and nutritional status should prompt the search for underlying causes and potentially nutritional intervention in clinical practice.

Abdominal aortic calcification is superior to other arteries calcification in predicting the mortality in peritoneal dialysis patients - a 8 years cohort study

BACKGROUND

In recent years, there has been a growing concern that abdominal aortic calcification (AAC) has a predictive effect on the prognosis of patients with end-stage renal disease (ESRD). However, whether other vascular calcification (VC) can predict the occurrence of adverse events in patients, and whether it is necessary to assess the calcification of other blood vessels remains controversial. This study aimed to assess VC in different sites using X-ray films, and to investigate the predictive effects of VC at different sites on all-cause mortality and cardiovascular (CV) mortality in peritoneal dialysis (PD) patients.

METHODS

The data of Radiographs (lateral abdominal plain film, frontal pelvic radiograph and both hands radiograph) were collected to evaluate the calcification of abdominal aorta, iliac artery, femoral artery, radial artery, and finger arteries. Patients' demographic data, clinical characteristics, laboratory data were recorded. The total follow-up period was 8 years, and the time and cause of death were recorded. Survival curves were estimated using Kaplan-Meier analysis. COX regression analysis was used to examine independent predictors of all-cause mortality and CV mortality.

RESULTS

One hundred fifty PD patients were included, a total of 79 patients (52.7%) died at the end of follow-up. After adjusting variables in the multivariate COX regression analysis, AAC was an independent predictor of all-cause mortality in PD patients (HR = 2.089, 95% CI: 1.089-4.042, P = 0.029), and was also an independent predictor of CV mortality (HR = 4.660, 95% CI: 1.852-11.725, P = 0.001). We also found that femoral artery calcification had a predictive effect on all-cause and CV mortality. But the calcification in iliac artery, radial artery, and finger arteries were not independent predictors of patients' all-cause and CV mortality in PD patients.

CONCLUSION

AAC was more common in PD patients and was an independent predictor of all-cause mortality and CV mortality. The femoral artery calcification also can predict the mortality, but the calcification of iliac artery, radial artery, and finger arteries cannot predict the mortality of PD patients.

Bone Health in Glomerular Kidney Disease

PURPOSE OF REVIEW

To summarize the literature regarding alterations in bone health in patients with glomerular kidney disease and highlight areas in need of additional investigation.

RECENT FINDINGS

There is mounting evidence that children and adults with glomerular conditions, with or without compromised kidney function, comprise a distinct subgroup of patients with unique risk factors for altered bone health. Patients with glomerular kidney disease are exposed to both disease-related and treatment-related factors that affect bone structure and function. In addition to chronic kidney disease-related risk factors for impaired bone health, high rates of exposure to osteotoxic medications, varying degrees of systemic inflammation, and altered vitamin D metabolism may contribute to compromised bone health in individuals with glomerular disease. Further study is needed to better understand these risk factors and the complex interaction between the immune system and bone cells in glomerular disease.

Position Statement on the Use of Bone Turnover Markers for Osteoporosis Treatment

Current evidences continue to support the clinical application of bone turnover markers (BTMs) in the management of postmenopausal osteoporosis. The limitations of bone mineral density measured by dual energy X-ray absorptiomet especially emphasize the beneficial roles of BTMs, such as serum C-terminal telopeptide of type I collagen and serum procollagen type I N-propeptide, as monitoring tools to assess the responses to treatment. Therefore, the proper application and assessment of BTM in clinical practice is very important. However, their use in Korea is still insufficient. Therefore, the BTM committee has set up by the Korean Society for Bone and Mineral Research have been constituted and provided a position statement which will suggest on the clinical application of BTM for the management of postmenopausal osteoporosis in Korea.

The Frequency of Routine Blood Sampling and Patient Outcomes Among Maintenance Hemodialysis Recipients

RATIONALE & OBJECTIVE

Surveillance blood work is routinely performed in maintenance hemodialysis (HD) recipients. Although more frequent blood testing may confer better outcomes, there is little evidence to support any particular monitoring interval.

STUDY DESIGN

Retrospective population-based cohort study.

SETTING & PARTICIPANTS

All prevalent HD recipients in Ontario, Canada, as of April 1, 2011, and a cohort of incident patients commencing maintenance HD in Ontario, Canada, between April 1, 2011, and March 31, 2016.

EXPOSURE

Frequency of surveillance blood work, monthly versus every 6 weeks.

OUTCOMES

The primary outcome was all-cause mortality. Secondary outcomes were major adverse cardiovascular events, all-cause hospitalization, and episodes of hyperkalemia.

ANALYTICAL APPROACH

Cox proportional hazards with adjustment for demographic and clinical characteristics was used to evaluate the association between blood testing frequency and all-cause mortality. Secondary outcomes were evaluated using the Andersen-Gill extension of the Cox model to allow for potential recurrent events.

RESULTS

7,454 prevalent patients received care at 17 HD programs with monthly blood sampling protocols (n=5,335 patients) and at 8 programs with blood sampling every 6 weeks (n=2,119 patients). More frequent monitoring was not associated with a lower risk for all-cause mortality compared to blood sampling every 6 weeks (adjusted HR, 1.16; 95% CI, 0.99-1.38). Monthly monitoring was not associated with a lower risk for any of the secondary outcomes. Results were consistent among incident HD recipients.

LIMITATIONS

Unmeasured confounding; limited data for center practices unrelated to blood sampling frequency; no information on frequency of unscheduled blood work performed outside the prescribed sampling interval.

CONCLUSIONS

Monthly routine blood testing in HD recipients was not associated with a lower risk for death, cardiovascular events, or hospitalizations as compared with testing every 6 weeks. Given the health resource implications, the frequency of routine blood sampling in HD recipients deserves careful reassessment.

Mineral and bone disorder in hemodialysis patients in the Tibetan Plateau: a multicenter cross-sectional study

Background: Mineral and bone disorder (MBD) in hemodialysis patients is associated with increased morbidity and mortality. Studies on the MBD status of hemodialysis patients at high altitudes are extremely limited. Methods: A total of 146 hemodialysis patients from 5 local hospitals across all districts with hemodialysis centers in the Tibetan Plateau were enrolled in this cross-sectional study. Parameters related to MBD, including serum phosphorus (P), calcium (Ca), and intact parathyroid hormone (iPTH) levels, were measured. The achievement of MBD goals was compared with the achievement in the Dialysis Outcomes and Practice Study (DOPPS) 3, DOPPS 4 and a multicenter study of MBD in China. Factors associated with hyperphosphatemia were examined. Results: Altogether, 146 hemodialysis patients were recruited from the Tibetan Plateau. According to the K/DIGO guidelines, there were low achievement rates for serum Ca (40.4%), P (29.7%), and iPTH (47.1%). As for the (KDOQI) guidelines, the rates of achievement of defined targets were 38.4%, 33.7% and 16.4% for serum Ca, P and iPTH, respectively. The percentages of patients reaching the KDOQI targets for corrected Ca, P, and iPTH were significantly lower for Tibetan patients than the percentages found in DOPPS 3 (38.4% vs. 50.4%, 33.7% vs. 49.8%, and 16.4% vs. 31.4%, respectively, all p < .001) and DOPPS 4 (38.4% vs. 56.0%, 33.7% vs. 54.5%, and 16.4% vs. 35.3%, respectively, all p < .001). The percentage of patients reaching the KDOQI targets for iPTH was significantly lower in Tibet than in the plain areas of China (16.4% vs. 26.5%, p < .001). The proportion of patients with hypocalcemia was higher in Tibet than in the plain areas (44.5% vs. 19.4%, p < .001). The percentage of local patients with optimal P was significantly higher for patients with an activated vitamin D prescription than for patients without an activated vitamin D prescription (45.3% vs. 19.3%, p < .001). Age and the activated vitamin D prescription were independently associated with hyperphosphatemia. Conclusion: The MBD status of hemodialysis patients in Tibet is far from the ideal level. High altitude is one of the possible causes of the differences found, but not the principal one. It is necessary for medical staff in Tibet to improve the detection and treatment of MBD.

Refractory secondary hyperparathyroidism in waiting list for parathyroidectomy: who we should operate first in a quaternary hospital in Brazil regarding survival

BACKGROUND

Few centers in Brazil perform parathyroidectomy (PTX) for recalcitrant secondary hyperparathyroidism (SHPT) generating a long queue. There is little data regarding prioritize criteria besides chronological order and survival.

OBJECTIVES

To determine the difference of clinical and laboratory factors between PTX patients and those who remained in the line despite the need for surgery and their survival.

METHODS

A retrospective cohort study was conducted in a quaternary hospital in Brazil, where 43 patients with PTX indication due to severe SHPT were followed from 2009 to 2016. While 31 patients underwent PTX, 12 remained in the queue. Data on clinical and laboratory factors were collected for comparison and Kaplan-Meier and Cox regression survival analysis were used.

RESULTS

PTX group was younger (40.9 vs. 49.3 years, p = .03), had higher PTH levels (2578 vs. 1937 pg/ml, p = .01) and higher CaxP product (62 vs. 47.5, p = .02). There were no percentage differences between groups of fractures, calciphylaxis and other complications due to SHPT. Patients who were not operated had a worst overall survival (5 y 62.2% vs. 96.7%, p = .04) with a HR for death of 8.08 (p = .07, PTX as a TVC). Other variables associated with decreased survival included a history of previous myocardial infarction (HR: 10.4, p = .01) and age per additional year (HR: 1.09, p = .02).

CONCLUSIONS

Patients with severe SHPT are at increased risk of death while waiting for PTX. Clinical events like fracture were not used to prioritize patients beyond consecutive order. Therefore, optimizing priority criteria for PTX may result in improved survival in this population.

Inflammation-Related Patterns in the Clinical Staging and Severity Assessment of Chronic Kidney Disease

Chronic kidney disease (CKD) is an irreversible loss of kidney function, and it represents a major global public health burden due to both its prevalence and its continuously increasing incidence. Mineral bone disorders (MBDs) constitute a hallmark of CKD, and alongside cardiovascular complications, they underlie a poor prognosis for these patients. Thus, our study focused on novel CKD biomarker patterns and their impact on the clinical staging of the disease. As a first testing approach, the relative expression levels of 105 proteins were assessed by the Proteome Profiler Cytokine Array Kit for pooled CKD stage 2–4 serum samples to establish an overall view regarding the proteins involved in CKD pathogenesis. Among the molecules that displayed significant dysregulation in the CKD stages, we further explored the involvement of Dickkopf-related protein 1 (Dkk-1), a recognised inhibitor of the Wnt signalling pathway, and its crosstalk with 1,25OH₂D₃ (calcitriol) as new players in renal bone and vascular disease. The serum levels of these two molecules were quantified by an ELISA (76 samples), and the results reveal decreasing circulating levels of Dkk-1 and calcitriol in advanced CKD stages, with their circulating expression showing a downward trend as the CKD develops. In the next step, we analysed the inflammation and MBD biomarkers' expression in CKD (by xMAP array). Our results show that the molecules involved in orchestrating the inflammatory response, interleukin-6 (IL-6) and tumour necrosis factor alpha (TNFα), as well as the mineral biomarkers osteoprotegerin (OPG), osteocalcin (OC), osteopontin (OPN), and fibroblast growth factor 23 (FGF-23), correlate with Dkk-1 and calcitriol, raising the possibility of them being potential useful CKD biomarkers. These results reveal the impact of different biomarker patterns in CKD staging and severity, thus opening up novel approaches to be explored in CKD clinical management.

Controversies in the Management of Secondary Hyperparathyroidism in Chronic Kidney Disease

Secondary hyperparathyroidism is a frequent complication of chronic kidney disease that begins early in the course of renal insufficiency as an adaptive response to maintain mineral homeostasis. This complex disorder affects the bone, leading to an increase in fracture risk and is associated with increased risks of vascular calcification and mortality. PURPOSE OF REVIEW: In this review, we examine the different strategies available to manage secondary hyperparathyroidism. Particularly, we focus on the adequate control of serum phosphorus by restricting intake and the use of phosphate binders, correction of hypocalcemia while minimizing calcium burden, and reduction in PTH levels through the use of vitamin D sterols and calcimimetics. RECENT FINDINGS: It was observed that although numerous agents directed at the correction of these abnormalities have demonstrated effectiveness on biochemical markers, there is still a relative scarcity of studies demonstrating treatment effectiveness as measured by hard clinical outcomes. In addition, most agents have side effects that may limit their use, even in patients in which the treatment has demonstrated efficacy in controlling these parameters. There is still controversy as to what therapeutic regimens to choose for a particular patient and what parameter should be used to follow their effects, including outcomes, side effects, pill burden, and costs, among others. In the present article, we analyze controversial aspects of the different therapeutic agents available. Although many tools and regimens are available, no one by itself is enough for an adequate management of the patient. But rather, combined therapy and individualization of approaches are recommended for better results. We suggest that new studies analyzing the effectiveness of therapeutic approaches to the management of secondary hyperparathyroidism should be directed not only to controlling parathyroid hormone levels but also to the evaluation of long-term outcomes, based on modification of morbidity, mortality, and end organ impact, while reducing side effects and controlling costs, among others.

Chronic Kidney Disease Diagnosis and Management: A Review

Importance

Chronic kidney disease (CKD) is the 16th leading cause of years of life lost worldwide. Appropriate screening, diagnosis, and management by primary care clinicians are necessary to prevent adverse CKD-associated outcomes, including cardiovascular disease, end-stage kidney disease, and death.

Observations

Defined as a persistent abnormality in kidney structure or function (eg, glomerular filtration rate [GFR] <60 mL/min/1.73 m2 or albuminuria ≥30 mg per 24 hours) for more than 3 months, CKD affects 8% to 16% of the population worldwide. In developed countries, CKD is most commonly attributed to diabetes and hypertension. However, less than 5% of patients with early CKD report awareness of their disease. Among individuals diagnosed as having CKD, staging and new risk assessment tools that incorporate GFR and albuminuria can help guide treatment, monitoring, and referral strategies. Optimal management of CKD includes cardiovascular risk reduction (eg, statins and blood pressure management), treatment of albuminuria (eg, angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers), avoidance of potential nephrotoxins (eg, nonsteroidal anti-inflammatory drugs), and adjustments to drug dosing (eg, many antibiotics and oral hypoglycemic agents). Patients also require monitoring for complications of CKD, such as hyperkalemia, metabolic acidosis, hyperphosphatemia, vitamin D deficiency, secondary hyperparathyroidism, and anemia. Those at high risk of CKD progression (eg, estimated GFR <30 mL/min/1.73 m2, albuminuria ≥300 mg per 24 hours, or rapid decline in estimated GFR) should be promptly referred to a nephrologist.

Conclusions and Relevance

Diagnosis, staging, and appropriate referral of CKD by primary care clinicians are important in reducing the burden of CKD worldwide.

Assessment of dialysis initiation by a fuzzy mathematics equation (ADIFE): a study protocol for a randomised controlled trial

INTRODUCTION

Starting dialysis early or late both result in a low quality of life and a poor prognosis in patients undergoing haemodialysis. However, there remains no consensus on the optimal timing of dialysis initiation, mainly because of a lack of suitable methods to assess variations in dialysis initiation time. We have established a novel equation named DIFE (Dialysis Initiation based on Fuzzy-mathematics Equation) through a retrospective, multicentre clinical cohort study in China to determine the most suitable timing of dialysis initiation. The predictors of the DIFE include nine biochemical markers and clinical variables that together influence dialysis initiation. To externally validate the clinical accuracy of DIFE, we designed the assessment of DIFE (ADIFE) study as a prospective, open-label, multicentre, randomised controlled trial to assess the clinical outcomes among patients who initiate dialysis in an optimal start dialysis group and a late-start dialysis group, based on DIFE.

METHODS AND ANALYSIS

A total of 388 enrolled patients with end-stage renal disease will be randomised 1:1 to the optimal start dialysis group, with a DIFE value between 30 and 35, or the late-start dialysis group, with a DIFE value less than 30, using the Randomization and Trial Supply Management system. Participants will be assessed for changes in signs and symptoms, dialysis mode and parameters, biochemical and inflammatory markers, Subjective Global Assessment, Kidney Disease Quality of Life Short Form, Cognitive Assessment, medical costs, adverse events and concomitant medication at baseline, predialysis visiting stage and postdialysis visiting stage, every 12-24 weeks. The following data will be recorded on standardised online electronic case report forms. The primary endpoint is 3-year all-cause mortality. The secondary endpoints include non-fatal cerebrocardiovascular events, annual hospitalisation rate, quality of life, medical costs and haemodialysis related complications.

ETHICS AND DISSEMINATION

Ethical approval was obtained from the Ethics Committee of the First Affiliated Hospital of Dalian Medical University China (registration no: YJ-KY-2017-119) and the ethics committees of all participating centres. The final results of the ADIFE trial will be presented to the study sponsor, clinical researchers and the patient and public involvement reference group. Findings will be disseminated through peer-reviewed journals, Clinical Practice Guidelines and at scientific meetings.

TRIAL REGISTRATION NUMBER

ClinicalTrial.gov. Registry (NCT03385902); pre-results.

Role of parathyroid hormone in anorexia on maintenance hemodialysis patients

BACKGROUND AND AIM

Anorexia, which is a common condition in patients on hemodialysis (HD), is characterized by impaired appetite, a subjective condition that hinders anorexia diagnosis. Anorexia is frequently associated with protein energy wasting and inflammation, increasing morbidity and mortality risk. The aim of the study was to evaluate the association between appetite and nutritional, inflammatory, hormonal, and dietary intake parameters in patients on maintenance HD.

METHODS

Cross-sectional study with clinical, laboratory, and anthropometric parameters, body composition, muscle function, and dietary intake assessment. To evaluate appetite, a three simple questions questionnaire previously validated was used. After appetite classification, the sample was dichotomized in "normal appetite" and "impaired appetite" and compared. Multiple logistic regression was used to identify association between variables and outcome.

RESULTS

125 patients on HD were included, aged 60.6 ± 14.12 years old, median HD vintage 35.5 months. In dichotomized sample, 78.4% patients showed "normal appetite", and 21.6% "impaired appetite". "Impaired appetite" was independently associated with increased serum PTH (OR 1.001; 95% CI 1.000-1.002; p = 0.03), low zinc intake (OR 0.860; 95% CI 0.746-0.991; p = 0.03) and lower urea serum (OR 0.982; 95% CI 0.965-0.999; p = 0.04). Both groups showed insufficient dietary intake.

CONCLUSIONS

Appetite was independently associated with increased serum of PTH, low serum concentration of urea, and low zinc intake which may infer association of appetite with mineral bone disease, protein intake and zinc deficiency.

Correlation of Fgf23 and Balp with Bone Mineral Density in Hemodialysis Patients

Background

Chronic kidney disease (CKD) is associated with numerous complications such as bone mineral disorder. The aim of our study was to analyze the correlation of bone turnover markers with Bone Mineral Density (BMD) measurements in Tunisian end stage renal diseases (ESRD) patients.

Methods

This study included 100 ESRD Tunisian patients. Their estimated glomerular filtration rate (eGFR) was < 15 mL × min^-1 × (1.73 m²)^-1, which requires hemodialysis. Bone-specific alkaline phosphatase (BALP) serum concentration was determined with a chemiluminescence immunoassay. Fibroblast Growth Factor 23 (FGF23) serum was assessed by Enzyme-Linked Immunosorbent Assay method. The serum levels of 25-Hydroxyvitamin D (25(OH)D), intact parathyroid hormone (iPTH) and Beta cross-laps (CTX) was measured by Electrochemiluminescence Technology. DEXA (dual-energy x-ray absorptiometry) technique was used to evaluate BMD.

Results

We observed a statistically significant negative correlation between BALP levels and total body BMD (r = -0.268; P = 0.015) particularly in femoral neck (FN) (r = -0.219; P = 0.037). BALP concentrations were negatively associated with total BMD especially in FN for patients with BMI < 30, FGF23 concentrations were also negatively correlated with BMD in lumbar spine site (LS) (r = -0.209; P = 0.046). For osteopenic patients we found an inverse correlation between 25(OH)D concentrations and BMD in LS position (r = -0.336; P = 0.038). In men group, we have also found a negative correlation between iPTH and total BMD (r = -0.326; P = 0.015). However we found a positive correlation between calcium expression and BMD in LS site (r = 0.270; P = 0.031).

Conclusions

FGF23 and BALP can predict bone loss in ESRD through their strong correlation with BMD in LS and FN sites respectively.

A Primer on Quality Assurance and Performance Improvement for Interprofessional Chronic Kidney Disease Care: A Path to Joint Commission Certification

Interprofessional care for chronic kidney disease facilitates the delivery of high quality, comprehensive care to a complex, at-risk population. Interprofessional care is resource intensive and requires a value proposition. Joint Commission certification is a voluntary process that improves patient outcomes, provides external validity to hospital administration and enhances visibility to patients and referring providers. This is a single-center, retrospective study describing quality assurance and performance improvement in chronic kidney disease, Joint Commission certification and quality outcomes. A total of 440 patients were included in the analysis. Thirteen quality indicators consisting of clinical and process of care indicators were developed and measured for a period of two years from 2009–2017. Significant improvements or at least persistently high performance were noted for key quality indicators such as blood pressure control (85%), estimation of cardiovascular risk (100%), measurement of hemoglobin A1c (98%), vaccination (93%), referrals for vascular access and transplantation (100%), placement of permanent dialysis access (61%), discussion of advanced directives (94%), online patient education (71%) and completion of office visit documentation (100%). High patient satisfaction scores (94–96%) are consistent with excellent quality of care provided.

Association between serum calcium levels and prognosis, hematoma volume, and onset of cerebral hemorrhage in patients undergoing hemodialysis

BACKGROUND

High serum calcium levels should be avoided in patients on hemodialysis (HD) because they can induce cardiovascular diseases and worsen the patient's prognosis. In contrast, low serum calcium levels worsen the prognosis of patients with cerebral hemorrhage in the general population. So far, whether serum calcium levels in patients on HD are associated with cerebral hemorrhage remains unknown. This study aimed to reveal the association between serum calcium and cerebral hemorrhage in patients on HD, including in-hospital death, volume of hematoma, and onset of cerebral hemorrhage.

METHODS

This cross-sectional case-control study included 99 patients on HD with cerebral hemorrhage at a single center between July 1, 2007 and December 31, 2017. Controls included 339 patients on HD at a single HD center between July 1, 2011 and June 30, 2012. Data on serum calcium level, patient demographics, and comorbid conditions were collected, and associations between cerebral hemorrhage and subsequent death were evaluated by multivariate logistic regression analysis. Further, the association of these backgrounds and hematoma volume was evaluated by multiple regression analysis.

RESULTS

Of the 99 patients, 32 (32%) died from cerebral hemorrhage. The corrected serum calcium level (odds ratio [OR], 2.49; 95% confidence interval [CI], 1.43-4.35; P < 0.001) and antiplatelet drug use (OR, 3.95; 95% CI, 1.50-10.4; P = 0.005) had significant effects on the prognosis. Moreover, the corrected serum calcium (P = 0.003) and antiplatelet drug use (P = 0.01) were significantly correlated with hematoma volume. In the patients, the corrected serum calcium level (OR, 1.54; 95% CI, 1.07-2.22; P = 0.02) was associated with the onset of cerebral hemorrhage, as was pre-hemodialysis systolic blood pressure (per 10 mmHg) (OR, 1.40; 95% CI, 1.23-1.59; P < 0.001).

CONCLUSIONS

Although the precise mechanisms remain unknown, a high serum calcium level is associated with cerebral hemorrhage in patients on HD. Thus, we should pay attentions to a patient's calcium level.

Chronic kidney disease is associated with low BMD at the hip but not at the spine

Although chronic kidney disease is associated with other bone disorders, osteoporosis can be found in this context, and it is defined based on bone mineral density (BMD), measured by dual-energy X-ray absorptiometry. As CKD progresses, the percentage of normal BMD decreases, whereas that of osteopenia/osteoporosis increases, mostly due to hip involvement, particularly in patients with reduced renal function.

INTRODUCTION

Osteoporosis is a highly prevalent disease in patients with chronic kidney disease (CKD). We investigated the features of bone mineral density (BMD) in patients with assorted kidney diseases and hypothesized that low BMD, as measured by dual-energy X-ray absorptiometry (DXA), would be more prevalent as kidney function decreased and would correlate with biomarkers of mineral and bone disease.

METHODS

DXA obtained from January 1, 2008, to December 31, 2017, clinical, demographic, and biochemical data at the time of image acquisition were recorded. Data from 1172 patients were included in this study (81.3% women, 79.9% white, and 8.1% diabetic).

RESULTS

Osteopenia and osteoporosis in at least one site (total hip or spine) were found in 32.7% and 20.0% of patients, respectively. As CKD progressed, the percentage of patients with normal BMD decreased, whereas the percentage of osteopenia and osteoporosis increased, which was mostly due to the total hip involvement, particularly in patients with estimated glomerular filtration rate (eGFR) < 60 ml/min/1.73 m². Older age and hyperparathyroidism were independent risk factors for osteopenia/osteoporosis at the total hip; female gender, older age, and higher iCa were independently associated with the risk of osteopenia/osteoporosis at the spine. With eGFR > 90 ml/min as reference, the odds ratios for osteoporosis/osteopenia at the hip were 1.51 (95% CI 1.01-2.24) and 1.91 (95% CI 1.13-3.20) for patients with eGFR 30-60 and 15-30 ml/min/1.73 m², respectively. No CKD stage was significantly associated with the risk of osteoporosis/osteopenia at the spine.

CONCLUSION

Our results highlighted that low BMD in patients with CKD is associated with age and hyperparathyroidism, and affects predominantly the hip.

Vitamin D and Atherosclerotic Cardiovascular Disease

CONTEXT

A large body of experimental and observational data has implicated vitamin D deficiency in the development of cardiovascular disease. However, evidence to support routine vitamin D supplementation to prevent or treat cardiovascular disease is lacking.

EVIDENCE ACQUISITION

A comprehensive literature review was performed using Pubmed and other literature search engines.

EVIDENCE SYNTHESIS

Mounting epidemiological evidence and data from Mendelian randomization studies support a link between vitamin D deficiency and adverse cardiovascular health outcomes, but randomized trial evidence to support vitamin D supplementation is sparse. Current public health guidelines restrict vitamin D intake recommendations to the maintenance of bone health and prevention of fractures. Two recently published large trials (VITAL and ViDA) that assessed the role of moderate-to-high dose vitamin D supplementation as primary prevention for cardiovascular outcomes in the general population had null results, and previous randomized trials have also been generally negative. These findings from general population cohorts that are largely replete in vitamin D may not be applicable to chronic kidney disease (CKD) populations, in which the use of active (1α-hydroxylated) vitamin D compounds is prevalent, or to other high-risk populations. Additionally, recent trials in the CKD population, and trials using vitamin D analogues have been limited.

CONCLUSIONS

Current randomized trials of vitamin D supplementation do not support benefits for cardiovascular health, but the evidence remains inconclusive. Additional randomized trials assessing larger numbers of participants with low baseline vitamin D levels, having longer follow-up periods, and testing higher vitamin D dosages, are needed to guide clinical practice.

The role of phosphate-containing medications and low dietary phosphorus-protein ratio in reducing intestinal phosphorus load in patients with chronic kidney disease

Chronic kidney disease-mineral and bone disorder (CKD-MBD) is a common complication in patients experiencing end-stage renal disease (ESRD). It includes abnormalities in bone and mineral metabolism and vascular calcification. Hyperphosphatemia is a major risk factor leading to morbidity and mortality in patients with chronic kidney disease. Increased mortality has been observed in patients with ESRD, with serum phosphorus levels of >5.5 mg/dL. Therefore, control of hyperphosphatemia is a major therapeutic goal in the prevention and treatment of CKD-MBD. The treatment of hyperphosphatemia includes decreasing intestinal phosphorus load and increasing renal phosphorus removal. Decreasing the intestinal load of phosphorus plays a major role in the prevention and treatment of CKD-MBD. Among the dietary sources of phosphorus, some of the commonly prescribed medications have also been reported to contain phosphorus. However, drugs are often ignored even though they act as a potential source of phosphorus. Similarly, although proteins are the major source of dietary phosphorus, reducing protein intake can increase mortality in patients with CKD. Recently, the importance of phosphorus/protein ratio in food have been reported to be a sensitive marker for controlling dietary intake of phosphorus. This review summarizes the progress in the research on phosphate content in drugs as an excipient and the various aspects of dietary management of hyperphosphatemia in patients with CKD, with special emphasis on dietary restriction of phosphorus with low dietary phosphate/protein ratio.

Management of Post-transplant Hyperparathyroidism and Bone Disease

Significant advances in immunosuppressive therapies have been made in renal transplantation, leading to increased allograft and patient survival. Despite improvement in overall patient survival, patients continue to require management of persistent post-transplant hyperparathyroidism. Medications that treat persistent hyperparathyroidism include vitamin D, vitamin D analogues, and calcimimetics. Medication side effects such as hypocalcemia or hypercalcemia, and adynamic bone disease, may lead to a decrease in the drugs. When medical management fails to control persistent post-transplant hyperparathyroidism, treatment is a parathyroidectomy. Surgical techniques are not uniform between centers and surgeons. Undergoing the surgery may include a subtotal technique or a technique including total parathyroid gland resection with partial heterotopic gland reimplantation. In addition, there are possible post-surgical complications. The ideal treatment for persistent post-transplant hyperparathyroidism is the treatment and prevention of the condition while patients are being managed for their late-stage chronic kidney disease and end-stage renal disease.

The use of anticoagulants in chronic kidney disease: Common point of view of cardiologists and nephrologists

In patients diagnosed with chronic kidney disease (CKD), atrial fibrillation (AF) is associated with an increased risk of thromboembolism and stroke. Moreover, patients with CKD - especially those in end-stage renal disease - also present an increased risk of bleeding. Oral anticoagulation is the most effective form of thromboprophylaxis in patients with AF and an increased risk of stroke. However, the underuse of these drugs was observed, mainly due to safety reasons and restricted evidence on efficacy. Much evidence suggests that non-vitamin K-dependent oral anticoagulant agents significantly reduce the risk of stroke, intracranial hemorrhage, and mortality, with lower to similar major bleeding rates compared with vitamin K antagonists, such as warfarin, in normal renal function subjects. Thus, they are currently recommended for that group of patients. However, their metabolism is largely dependent on the kidneys for elimination, and current knowledge in this area is limited due to patients with a decreased glomerular filtration rate are usually excluded from clinical trials. The present review article focuses on currently available data on oral anticoagulants in patients with moderate to advanced chronic kidney disease and those with end stage renal disease.

Sofosbuvir-based regimen is safe and effective for hepatitis C infected patients with stage 4-5 chronic kidney disease: a systematic review and meta-analysis

BACKGROUND

Whether sofosbuvir is suitable for hepatitis C virus (HCV) infected patients with severe renal impairment is inconclusive. This systematic review aims to evaluate the safety and effectiveness of SOF-based regimen in the setting of stage 4 and 5 chronic kidney disease (CKD).

METHODS

We conducted a systematic literature search in PubMed, Web of Science, EMBASE and Google Scholar with searching strategy: (sofosbuvir OR Sovaldi OR Harvoni OR Epclusa OR Vosevi) AND (severe kidney impairment OR severe renal impairment OR end-stage renal disease OR dialysis OR renal failure OR ESRD OR renal insufficiency OR hepatorenal syndrome OR HRS). Sustained virological response (SVR12/24) rate and serious adverse event (SAE) rate with 95% confidence intervals were aggregated. Subgroup analysis was implemented to evaluate the impact of treatment strategy and patient characteristics.

RESULTS

Twenty-one studies met inclusion criteria, totaling 717 HCV infected patients with CKD stage 4 or 5 (58.4% on dialysis). Pooled SVR12/24 was 97.1% (95% CI 93.9-99.3%), and SAE rate was 4.8% (95% CI 2.1-10.3%). There was no significant difference at SVR12/24 (97.1% vs 96.2%, p = 0.72) or SAE rate (8.8% vs 2.9%, p = 0.13) between subgroups applying full or decreased dose of sofosbuvir. Cirrhotic and non-cirrhotic patients achieved comparable sustained virological response (RR 0.93, 95% CI 0.85-1.02). Four studies reported eGFR/serum creatinine pre- and post- treatment, with no significant modification.

CONCLUSIONS

Our study suggests SOF-based regimen might be used safely and effectively in patients living with HCV infection/stage 4-5 CKD, with normal and reduced dose of sofosbuvir. Prospective and well-controlled trials are needed to confirm these findings.

TRIAL REGISTRATION

PROSPERO CRD42018107440 .

Impact of Recent Clinical Trials on Nephrology Practice: Are We in a Stagnant Era?

BACKGROUND

Although renal replacement therapy prevents death from uremia, survival among patients with acute and chronic kidney diseases (CKD) remains an imperative concern. The expected life span of US dialysis patients 60-64 years of age is approximately 4.5 years; this is similar to that of patients with lung cancer. Despite substantial progress in many medical specialties over the past decades (e.g., notable reductions in myocardial infarction, stroke, and mortality rates in the general population), survival among dialysis patients has not improved significantly over the same period. A few decades ago, HIV infection and AIDS were pretty much a death sentence. Because of progress in HIV treatment, now it can be controlled with a daily pill, and ongoing research is pushing treatment even further and controls the virus with longer-acting treatment. A cure is no longer impossible for HIV and other viral infections such as hepatitis B and C and many malignancies, but so far there is no cure for CKD.

SUMMARY

Billions of dollars have been spent on kidney disease research in the past decades, with no tangible progress in clinical practice. The challenges of improving the quantity and quality of trials in nephrology are enormous. The number of randomized controlled trials (RCTs) published in nephrology is lower than that in other medical subspecialties, and most of the big RCTs in nephrology yield negative results. Nephrology studies evaluating hard clinical endpoints or surrogate endpoints are scarce.

KEY MESSAGE

Herein we discuss the slow progress in nephrology research that has impacted clinical practice over the last couple of decades and highlight the major obstacles, challenges, and potential solutions.

Clinical Application of Bone Turnover Markers in Osteoporosis in Korea

Bone turnover markers (BTMs) have important role in the management of osteoporosis. Recently the clinical application of BTMs has achieved significant progress and measurement of BTMs give us better understanding of pathogenesis of osteoporosis. However, the use of BTMs is still insufficient in Korea. We summarized the available methods and standard interval of the BTMs in Korea. Also we reviewed published literatures on pre-analytical variability in the measurement of BTMs and provided recommendations for standardized sample handling and patient preparation for reducing those pre-analytical variabilities. The clinical application of BTMs in patients with chronic kidney disease who have a higher fracture risk than the general population is summarized.

Microwave ablation vs. parathyroidectomy for secondary hyperparathyroidism in maintenance hemodialysis patients

INTRODUCTION

Secondary hyperparathyroidism (SHPT) is a serious and common problem in patients undergoing maintenance hemodialysis. Minimally invasive microwave ablation (MWA) has been used to treat SHPT and shows some advantages. However, its efficacy is still undefined. The primary purpose of this study was to determine the efficacy and safety of MWA compared to total parathyroidectomy plus forearm autotransplantation.

METHODS

The SHPT patients who were undergoing maintenance hemodialysis (follow-up for 6 to 24 months after treatments) were divided into a MWA group (n = 33) and a parathyroidectomy group (n = 48). The efficacy (serum intact parathyroid hormone [iPTH], calcium, and phosphorus levels) and safety (hoarseness, hypocalcaemia, and persistently low iPTH) were compared between the two groups. Additionally, the study explored potential predictors of response to MWA by a logistic regression analysis.

FINDINGS

There were no significant differences in baseline characteristics between the two groups. The rates of achieving the recommended goal for iPTH were significantly higher in the MWA group than that in the parathyroidectomy group at all follow-up times: 57.58% vs. 12.50% at one-day (P < 0.001), 45.45% vs. 16.67% at 1-week (P = 0.005), 57.58% vs. 16.67% at 2-week (P < 0.001), 57.58% vs. 22.92% at 1-month (P = 0.002), and 69.70% vs. 35.42% at 3-month (P = 0.002), 76.47% vs. 28.57% at 6-month (P = 0.005), 87.50% vs. 47.37% at 12-month (P = 0.008), and 81.82% vs. 52.63% at 24-month (P = 0.015), respectively. However, there were no significant differences for phosphorus or calcium at any of the follow-up times (P > 0.05). The persistently low iPTH was more in the parathyroidectomy group (64.6%) than that in the MWA group (0%) (P < 0.001), but there was no significant difference in hoarseness or hypocalcaemia (P > 0.05). Baseline levels of iPTH (P = 0.021) and patient age (P = 0.011) were determined as predictors by univariate logistic regression analysis.

CONCLUSION

The MWA could be an alternative to parathyroidectomy for SHPT but its eventual superiority has to be demonstrated by a proper study.

Kidney Stones and Risk of Osteoporotic Fracture in Chronic Kidney Disease

Osteoporotic fracture associated with calcium dysregulation is more common in patients with kidney stones. However, little is known about the association of kidney stones and bone health status in patients with chronic kidney disease (CKD). This retrospective medical record-based study included 2282 patients with stable stage 3–4 CKD between 2007 and 2017. Of these, 113 patients were diagnosed with kidney stones. Propensity score matching for 226 patients with and without kidney stones showed that osteoporotic fracture occurred more often in patients with kidney stones (33, 29.2%) than in patients without kidney stones (16, 14.2%), resulting in rates of 5.56 and 2.63/100 patient-years, respectively (p < 0.01). In particular, Cox proportional hazard analysis revealed that kidney stones were significantly associated with osteoporotic fracture, even after adjusting for age, sex, body mass index, kidney stones, estimated glomerular filtration rate, excessive alcohol consumption, current smoking, and steroid use in patients with CKD stage 3–4 (hazard ratio, 2.32, 95% CI 1.24–4.34, p = 0.01). This study showed that the presence of kidney stones was a significant predictor for osteoporotic fracture in patients with CKD, suggesting that it should be considered as a clinical risk factor for osteoporotic fracture in them.

Factors associated with glomerular filtration rate variation in primary hyperparathyroidism after parathyroidectomy

Background/aim

Prolonged hypercalcemia impairs renal function, and a reduced glomerular filtration rate (GFR) is typical in advanced primary hyperparathyroidism (PHPT). There are scarce data related to predictors of renal impairment in patients with PHPT. Hence, we aimed to evaluate changes in kidney function in PHPT patients after parathyroidectomy (PTX) and identify factors associated with GFR variation in these patients.

Materials and methods

One hundred and twenty-five patients with PHPT who underwent surgery between 2012 and 2014 were enrolled in the study. Patients were divided into two groups according to GFR values: patients whose GFR was lower than 60 mL/min/1.73 m2 and higher than 60 mL/min/1.73 m2. Demographic and laboratory parameters were compared before and 6 months after parathyroidectomy.

Results

Prevalence of antihypertensive drug users and patients with renal cysts and parathormone (PTH) and alkaline phosphatase levels were higher in patients with GFR of ≥60 than in GFR of <60 mL/min/1.73 m2 (P < 0.05). Systolic BP, uric acid, and magnesium were decreased in patients with GFR of ≥60, but GFR did not change in the two groups after parathyroidectomy. After parathyroidectomy, calcium and PTH decreased but 25(OH)D3 and phosphorus increased in the two groups. In multiple regression analysis, age, calcium, and baseline GFR were independent predictors of GFR variation. Parathyroid adenoma volume and urinary calcium were not independent predictors of GFR change.

Conclusion

Older age, higher preoperative calcium, and GFR were factors associated with GFR increase in PHPT patients after parathyroidectomy. Further renal impairment was prevented by parathyroidectomy in PHPT patients.

Fracture risk and treatment in chronic kidney disease

PURPOSE OF REVIEW

Chronic kidney disease (CKD) is associated with the development of mineral bone disorder (MBD), osteoporosis, and fragility fractures. The purpose of this review is to provide an update on recent findings in the diagnosis and treatment of osteoporosis in patients with CKD.

RECENT FINDINGS

Multiple observational studies have shown that bone mineral density measurement using DEXA is equally predictive in CKD stages 1-3, as in the general population. Post hoc analyses from randomized trials of bisphosphonates, SERM, RANKL inhibitors and PTH agonists all suggest equal efficacy in mild-moderate CKD. A recent systematic review also found evidence for efficacy of bisphosphonates in patients with a kidney transplant.

SUMMARY

Bone mineral density measurement using DEXA is accurate in patients with CKD stages 1-3 and should be considered to guide treatment of osteoporosis. Current treatments are unaffected by mild-to-moderate decline in kidney function, and physicians should use bisphosphonates and other osteoporosis treatments in this population, whenever indicated. Studies evaluating the optimal diagnostic and management strategy in patients with CKD stages (G4-5D) are needed.

Technical aspects and 30-day outcomes of the prospective early feasibility study of the GORE EXCLUDER Thoracoabdominal Branched Endoprosthesis (TAMBE) to treat pararenal and extent IV thoracoabdominal aortic aneurysms

OBJECTIVE

This study reports the technical aspects and 30-day outcomes of the prospective, multicenter early feasibility study designed to evaluate the GORE EXCLUDER Thoracoabdominal Branch Endoprosthesis (TAMBE; W. L. Gore & Associates, Flagstaff, Ariz).

METHODS

Thirteen patients with pararenal or extent IV thoracoabdominal aortic aneurysms were prospectively enrolled at five U.S sites and one non-U.S. site from 2014 to 2016. The TAMBE included four portals with either retrograde or antegrade renal portal configuration and used GORE VIABAHN Balloon-Expandable Endoprosthesis (W. L. Gore & Associates) for stenting of the renal and mesenteric arteries. The primary end point was procedural safety at 30 days, defined by absence of major adverse events, including any-cause mortality, myocardial infarction, stroke, paraplegia, bowel ischemia, respiratory failure, severe acute kidney injury (>50% decline in estimated glomerular filtration rate), dialysis, and procedural blood loss >1000 mL.

RESULTS

There were 11 male and two female patients with a mean age of 69 ± 8 years. Mean aneurysm diameter was 61 ± 13 mm. A total of 52 renal and mesenteric arteries were incorporated (4 vessels/patient). Technical success was achieved in 12 patients (92%). One patient had inadvertent occlusion of a right renal artery due to dissection. There was no mortality, aneurysm rupture, conversion to open repair, dialysis, or spinal cord injury. Mean length of hospital stay was 5 ± 3 days. At 30 days, four patients (31%) had major adverse events, all due to procedural blood loss >1000 mL. One patient had a type I endoleak at the distal renal branch, which was successfully treated by placement of an additional renal stent before dismissal. Computed tomography angiography at 30 days showed patent target vessels and no type I or type III endoleak.

CONCLUSIONS

This study confirms the early feasibility of the TAMBE for treatment of pararenal and extent IV thoracoabdominal aortic aneurysms. The high technical success, no mortality, and low morbidity rate support continuation of clinical investigation in a larger population of patients.

Risedronate Attenuates Podocyte Injury in Phosphate Transporter-Overexpressing Rats

Osteoporosis patients with chronic kidney disease (CKD) are becoming common in our superaging society. Renal dysfunction causes phosphorus accumulation in the circulating plasma and leads to the development of CKD-mineral bone disorder (MBD). We have previously reported that type III Pi transporter-overexpressing transgenic (Pit-1 TG) rats manifest phosphate (Pi)-dependent podocyte injury. In the present study, we explored the effect of risedronate on Pi-induced podocyte injury in vivo. Pit-1 TG rats and wild-type rats at 5 weeks old were divided into a risedronate-treated group and an untreated group. We subcutaneously administered 5 μg/kg body weight of risedronate or saline twice a week during the experimental period. Risedronate did not alter serum creatinine levels at 5, 8, and 12 weeks of age. However, electron microscopy images showed that thickening of the glomerular basement membrane was improved in the risedronate treatment group. Furthermore, immunostaining for podocyte injury markers revealed that both desmin- and connexin43-positive areas were smaller in the risedronate-treated group than in the untreated group, suggesting that bisphosphonates could rescue Pi-induced podocyte injury. In conclusion, our findings suggest that risedronate could maintain glomerular barrier function by rescuing Pi-induced podocyte injury.

Fecal microbiota analysis of polycystic kidney disease patients according to renal function: A pilot study

IMPACT STATEMENT

The heterogeneity of the renal disease, therapeutic interventions, and the original cause of the renal failure, all directly affect the microbiota. We delineate in this report the direct effect of decreased renal function on the bacterial composition following stringent criteria to eliminate the possibilities of other confounding factors and dissect the direct effects of the uremic milieu. We analyzed the microbiome following three different approaches to further evaluate the effects of mild, moderate and advanced renal insufficiency on the microbiome. We also present here a detailed functional analysis of the projected altered pathways secondary to changes in the microbiome composition.

Measuring serum total and free indoxyl sulfate and p-cresyl sulfate in chronic kidney disease using UPLC-MS/MS

Chronic kidney disease (CKD) is a complex disorder that affects multiple organs and increases the risk of cardiovascular complications. CKD affects approximately 12% of the population in Taiwan. Loss of kidney function leads to accumulation of potentially toxic compounds such as indoxyl sulfate (IS) and p-cresyl sulfate (pCS), two protein-bound uremic solutes that can stimulate the progression of CKD. The aim of this study was to assess whether IS and pCS levels were correlated with CKD stage. We developed and validated a method for quantitating total and free IS and pCS in serum by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Serum samples were pretreated using protein precipitation with acetonitrile containing stable isotope-labeled IS and pCS as internal standards. After centrifugation, the supernatant was diluted and injected into a UPLC-MS/MS system. Analyte concentrations were calculated from the calibration curve and ion ratios between the analyte and the internal standard. The calibration curves were linear with a correlation coefficient of >0.999; the analytical measurement range was 0.05–5 mg/L. The limit of quantitation of this assay was 0.05 mg/L for both analytes. The reference interval was ≤0.05–1.15 mg/L for total-form IS, ≤0.05 −5.33 mg/L for total-form pCS, ≤0.05 mg/L for free-form IS, and ≤0.12 mg/L for free-form pCS. A positive correlation was observed between analyte concentration and CKD stage. Our sensitive UPLC-MS/MS method for quantifying total and free-form IS and pCS in serum can be used to monitor the progression of CKD in clinical settings, identify patients at risk, and facilitate development of further therapies for this devastating disease.

The Emerging Role of Nutritional Vitamin D in Secondary Hyperparathyroidism in CKD

In chronic kidney disease (CKD), hyperphosphatemia induces fibroblast growth factor-23 (FGF-23) expression that disturbs renal 1,25-dihydroxy vitamin D (1,25D) synthesis; thereby increasing parathyroid hormone (PTH) production. FGF-23 acts on the parathyroid gland (PTG) to increase 1α-hydroxylase activity and results in increase intra-gland 1,25D production that attenuates PTH secretion efficiently if sufficient 25D are available. Interesting, calcimimetics can further increase PTG 1α-hydroxylase activity that emphasizes the demand for nutritional vitamin D (NVD) under high PTH status. In addition, the changes in hydroxylase enzyme activity highlight the greater parathyroid 25-hydroxyvitmain D (25D) requirement in secondary hyperparathyroidism (SHPT); the higher proportion of oxyphil cells as hyperplastic parathyroid progression; lower cytosolic vitamin D binding protein (DBP) content in the oxyphil cell; and calcitriol promote vitamin D degradation are all possible reasons supports nutritional vitamin D (NVD; e.g., Cholecalciferol) supplement is crucial in SHPT. Clinically, NVD can effectively restore serum 25D concentration and prevent the further increase in PTH level. Therefore, NVD might have the benefit of alleviating the development of SHPT in early CKD and further lowering PTH in moderate to severe SHPT in dialysis patients.

Misclassification of Calcium Status Based on Albumin-Adjusted Calcium: Studies in a Tertiary Hospital Setting

BACKGROUND

Clinical laboratories measure total calcium and adjust for albumin concentrations to predict calcium status. We compared total and adjusted calcium (Adj-Ca) with ionized calcium (Ca2+) for correct assignment of calcium status. The effect of restriction of Adj-Ca reporting in patients with hypoalbuminemia was determined on the basis of frequency of misclassifications.

METHODS

Extraction of laboratory results was performed for 24 months. Adj-Ca was calculated from a modified Payne formula. A further prospective data set for 6 months was collected after stopping reporting of Adj-Ca for patients with an albumin &lt;3.0 g/dL. The agreement between Ca2+ and Adj-Ca or total Ca was assessed with Cohen's kappa statistic.

RESULTS

In 5553 hospitalized patients, 13604 paired Ca2+ results were analyzed retrospectively. Prospective collection in 1113 paired samples was from 450 patients. Adj-Ca was a poor predictor of calcium status compared to the Ca2+ reference standard in both data sets (agreement 56.9% in the first, 65.6% in the second data set). Renal failure and low albumin concentrations were associated with worse agreement between Adj-Ca and Ca2+. Restriction of reporting of Adj-Ca to albumin concentrations &gt;3.0g/dL improved correct classification of calcium status from 65.6% to 77.6% (P &lt; 0.0001). Total Ca performed better than Adj-Ca for low albumin (&lt;3.0g/dL) and performed similarly in samples with albumin &gt;3.0g/dL.

CONCLUSIONS

Adj-Ca is unreliable for the classification of calcium status in hospital patients when compared to Ca2+. Adj-Ca overestimates calcium for patients with renal impairment and albumin concentrations &lt;3.0g/dL. Restriction of reporting Adj-Ca for albumin below 3.0 g/dL reduces the number of misclassified patients.

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.