Epidemiology, contributors to, and clinical trials of mortality risk in chronic kidney failure

Association of Adolescent Hypertension With Future End-stage Renal Disease

IMPORTANCE

Hypertension is a leading risk factor of cardiovascular morbidity and mortality. The role of nonmalignant hypertension as the sole initiating factor of end-stage renal disease (ESRD) in non-African American populations has recently been questioned.

OBJECTIVE

To investigate the association between hypertension and future ESRD in otherwise healthy adolescents.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study examined the data of 16- to 19-year-old healthy candidates for military service in the Israel Defense Forces between January 1, 1967, and December 31, 2013. Data were obtained from the central conscription registry of the Israel Defense Forces and the ESRD registry of the Israel Ministry of Health. Participants underwent a comprehensive medical assessment prior to their military service. Individuals with evidence of renal damage or kidney-related risk factors were excluded. The data analysis was conducted from February 12, 2017, to October 16, 2018.

MAIN OUTCOMES AND MEASURES

End-stage renal disease as recorded by the Israeli ESRD registry, including hemodialysis, peritoneal dialysis, renal transplant diagnosed between January 1, 1990, and December 31, 2014.

RESULTS

The cohort included 2 658 238 adolescents (1 596 709 [60.1%] male with a mean [SD] age of 17.4 [0.5] years), of whom 7997 (0.3%) had an established hypertension diagnosis. Half of the individuals in the hypertensive group were overweight (1559 [20.1%]) or obese (2243 [28.9%]), and most (7235 [90.5%]) were male. During a median follow-up of 19.6 years (52 287 945 person-years), 2189 individuals developed ESRD, with an incidence rate of 3.9 per 100 000 person-years. Adolescent hypertension was found to be associated with future ESRD (crude hazard ratio [HR], 5.07; 95% CI, 3.73-6.88). In a multivariable model adjusted for sex, age, years of education, body mass index, and other sociodemographic variables, the HR was 1.98 (95% CI, 1.42-2.77). When excluding participants with severe hypertension, the association with ESRD remained statistically significant (HR, 1.93; 95% CI, 1.37-2.70). In the subanalysis of nonoverweight adolescents, the association between hypertension and ESRD was statistically significant as well (HR, 2.11; 95% CI, 1.05-4.24).

CONCLUSIONS AND RELEVANCE

Hypertension appears to be associated with a doubling of the risk of future ESRD in an otherwise healthy adolescent population.

Patient participation in the clinical pathway-Nurses' perceptions of adults' involvement in haemodialysis

AIM

To develop knowledge of nurses' perceptions of participation for patients treated with haemodialysis and their next of kin.

DESIGN

A qualitative study with a hermeneutic approach.

METHODS

The data were collected in 2015 through focus groups with 13 nurses in Central Norway.

RESULTS

The nurses reported that patient participation ranging from non-involvement to shared decision-making was related to whether dialysis was initiated as acute or scheduled. The restrictions required in chronic haemodialysis limited participation. The next of kin were not involved. The nurses highlighted interventions on both the individual and system levels to strengthen participation.

CONCLUSION

Dialysis units should develop strategies for participation related to individual needs and design treatment in cooperation with patients and their families, ensuring involvement early in the clinical pathway. Further research is needed on issues related to next of kin, including their desired level of involvement.

Associations between Hemodialysis Facility Practices to Manage Fluid Volume and Intradialytic Hypotension and Patient Outcomes

BACKGROUND AND OBJECTIVES

Fluid overload and intradialytic hypotension are associated with cardiovascular events and mortality in patients on hemodialysis. We investigated associations between hemodialysis facility practices related to fluid volume and intradialytic hypotension and patient outcomes.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Data were analyzed from 10,250 patients in 273 facilities across 12 countries, from phase 4 of the Dialysis Outcomes and Practice Patterns Study (DOPPS; 2009-2012). Cox regression models (shared frailty) were used to estimate associations between facility practices reported by medical directors in response to the DOPPS Medical Directors Survey and all-cause and cardiovascular mortality and hospitalization, and cardiovascular events, adjusting for country, age, sex, dialysis vintage, predialysis systolic BP, cardiovascular comorbidities, diabetes, body mass index, smoking, residual kidney function, dialysis adequacy, and vascular access type.

RESULTS

Of ten facility practices tested (chosen a priori), having a protocol that specifies how often to assess dry weight in most patients was associated with lower all-cause (hazard ratio [HR], 0.78; 99% confidence interval [99% CI], 0.64 to 0.94) and cardiovascular mortality (HR, 0.72; 99% CI, 0.55 to 0.95). Routine orthostatic BP measurement to assess dry weight was associated with lower all-cause hospitalization (HR, 0.86; 99% CI, 0.77 to 0.97) and cardiovascular events (HR, 0.85; 99% CI, 0.73 to 0.98). Routine use of lower dialysate temperature to limit or prevent intradialytic hypotension was associated with lower cardiovascular mortality (HR, 0.76; 99% CI, 0.58 to 0.98). Routine use of an online volume indicator to assess dry weight was associated with higher all-cause hospitalization (HR, 1.19; 99% CI, 1.02 to 1.38). Routine use of sodium modeling/profiling to limit or prevent intradialytic hypotension was associated with higher all-cause mortality (HR, 1.36; 99% CI, 1.14 to 1.63), cardiovascular mortality (HR, 1.34; 99% CI, 1.04 to 1.73), and cardiovascular events (HR, 1.21; 99% CI, 1.03 to 1.43).

CONCLUSIONS

Hemodialysis facility practices relating to the management of fluid volume and intradialytic hypotension are associated with patient outcomes.

Dual Roles of the Mineral Metabolism Disorders Biomarkers in Prevalent Hemodilysis Patients: In Renal Bone Disease and in Vascular Calcification

Background

Vascular calcification (VC) is highly prevalent in dialysis (HD) patients, and its mechanism is multifactorial. Most likely that systemic or local inhibitory factor is overwhelmed by promoters of VC in these patients. VC increased arterial stiffness, and left ventricular hypertrophy. Thus, the present study aimed to investigate the association of VC and myocardial remodeling and to analyze their relationship with VC promoters (fibroblast growth factor 23-FGF23, Klotho, intact parathormon-iPTH, vitamin D) in 56 prevalent HD patients (median values: age 54 yrs, HD vintage 82 months).

Methods

Besides routine laboratory analyzes, serum levels of FGF 23, soluble Klotho, iPTH, 1,25-dihydroxyvitamin D3; pulse wave velocity (PWV); left ventricular (LV) mass by ultrasound; and VCs score by Adragao method were measured.

Results

VC was found in 60% and LV concentric or eccentric hypertrophy in 50% patients. Dialysis vintage (OR 1.025, 95%CI 1.007–1.044, p=0.006) FGF23 (OR 1.006, 95% CI 0.992–1.012, p=0.029) and serum magnesium (OR 0.000, 95%CI 0.000–0.214, p=0.04) were associated with VC. Changes in myocardial geometry was associated with male sex (beta=-0.273, 95% CI -23.967 1.513, p=0.027), iPTH (beta 0.029, 95%CI -0.059–0.001, p=0.027) and vitamin D treatment (beta 25.49, 95%CI 11.325–39.667, p=0.001). Also, patients with the more widespread VC had the highest LV remodeling categories. PWV was associated patient’s age, cholesterol, diastolic blood pressure, LV mass (positively) and serum calcium (negatively), indicating potential link with atherosclerotic risk.

Conclusions

Despite to different risk factors for VC and myocardial remodeling, obtained results could indicate that risk factors intertwine in long-term treatment of HD patients and therefore careful and continuous correction of mineral metabolism disorders is undoubtedly of the utmost importance.

Associations of vitamin K status with mortality and cardiovascular events in peritoneal dialysis patients

PURPOSE

Vitamin K deficiency, expressed by a high level of desphospho-uncarboxylated matrix GLA protein (dp-ucMGP), is highly prevalent in dialysis patients. However, the predictive ability of the vitamin K status remains unclear in continuous ambulatory peritoneal dialysis (CAPD) patients.

METHODS

158 prevalent CAPD patients with a median level of dp-ucMGP of 1093 (752, 1485) pmol/L were enrolled. Patient outcomes including all-cause mortality and cardiovascular events (CVEs) were recorded during follow-up. Survival curves were performed using Kaplan-Meier method, and the influences of dp-ucMGP on outcomes were analyzed by Cox regression models.

RESULTS

A total of 59 deaths and 82 new episodes of CVEs occurred during median follow-up of 31.4 ± 13.1 months (range: 3.8-48.0 months). Kaplan-Meier analysis revealed patients with higher dp-ucMGP levels (≥ 1093 pmol/L) had an increased risk for both mortality (P = 0.005) and CVEs (P < 0.001). Multivariable Cox regression confirmed that higher dp-ucMGP levels increase the mortality risk [hazard ratio (HR), 1.763; 95% CI 1.045-3.291] and CVEs (HR, 1.846; 95% CI 1.074-3.172). For every 100 pmol/L increase in serum dp-ucMGP, the adjusted HRs for mortality and CVEs were 1.054 (95% CI 1.008-1.106) and 1.034 (95% CI 1.012-1.089), respectively.

CONCLUSIONS

Vitamin K deficiency, as expressed by high dp-ucMGP levels, showed independently associations with mortality and CVEs in CAPD patients.

Proteomics for Clinical Assessment of Kidney Disease

Kidney disease is one of the fastest growing causes of death worldwide, disclosing an unmet clinical need for early diagnosis and optimized risk stratification that allows high risk patient selection for clinical trials and for more intensive nephroprotective interventions in the clinic. The current issue of PROTEOMICS-Clinical Applications contains four manuscripts that explore different aspects of clinical proteomics implementation in the context of acute kidney injury, chronic kidney disease and, more specifically, diabetic kidney disease, and kidney transplantation from a diagnostic and risk stratification point of view. Overall, the evidence discussed suggests that chronic kidney disease is an example where clinical proteomics has become a valuable tool ready for clinical implementation, expected to have a major impact in patient management.

Cardiovascular Disease Outcomes Related to Early Stage Renal Impairment After Liver Transplantation

BACKGROUND

In the general population, even mild renal disease is associated with increased cardiovascular (CV) complications. Whether this is true in liver transplant recipients (LTR) is unknown.

METHODS

This was a retrospective cohort study of 671 LTR (2002-2012) from a large urban tertiary care center and 37 322 LTR using Vizient hospitalization data linked to the United Network for Organ Sharing. The 4-variable Modification of Diet in Renal Disease equation estimated glomerular filtration rate (eGFR). Outcomes were 1-year CV complications (death/hospitalization from myocardial infarction, heart failure, atrial fibrillation, cardiac arrest, pulmonary embolism, or stroke) and mortality. Latent mixture modeling identified trajectories in eGFR in the first liver transplantation (LT) year in the 671 patients.

RESULTS

Mean (SD) eGFR was 72.1 (45.7) mL/min per 1.73 m. Six distinct eGFR trajectories were identified in the local cohort (n = 671): qualitatively normal-slow decrease (4% of cohort), normal-rapid decrease (4%), mild-stable (18%), mild-slow decrease (35%), moderate-stable (30%), and severe-stable (9%). In multivariable analyses adjusted for confounders and baseline eGFR, the greatest odds of 1-year CV complications were in the normal-rapid decrease group (odds ratio, 10.6; 95% confidence interval, 3.0-36.9). Among the national cohort, each 5-unit lower eGFR at LT was associated with a 2% and 5% higher hazard of all-cause and CV-mortality, respectively (P < 0.0001), independent of multiple confounders.

CONCLUSIONS

Even mild renal disease at the time of LT is a risk factor for posttransplant all-cause and CV mortality. More rapid declines in eGFR soon after LT correlate with risk of adverse CV outcomes, highlighting the need to study whether early renal preservation interventions also reduce CV complications.

Clarifying the concept of chronic kidney disease for non-nephrologists

Chronic kidney disease (CKD) expands the prior concept of chronic renal insufficiency by including patients with relatively preserved renal function, as assessed by the estimated glomerular filtration rate (eGFR), as even these early CKD stages are associated with an increased risk for all-cause death and cardiovascular death, CKD progression and acute kidney injury. A decreased eGFR (<60 mL/min/1.73 m²) is by itself diagnostic of CKD when persisting for >3 months. However, when eGFR is ≥60 mL/min/1.73 m², an additional criterion is required to diagnose CKD. In a recent clinical trial published in The New England Journal of Medicine, all 6190 participants were reported to have CKD: 47% had Stages 1 and 2 CKD and 53% had Stage 3 CKD. This illustrates a widespread misunderstanding of the concept of CKD. Moreover, CKD categories in this study were assigned based on the estimated creatinine clearance. Since both estimated creatinine clearance and creatinine clearance overestimate eGFR, this illustrates another frequent misunderstanding: equating GFR with creatinine clearance. In this commentary, we clarify the concept of CKD and of CKD categories for non-nephrologists. Assigning a diagnosis of CKD to a patient with normal renal function and absence of other evidence of CKD may have negative consequences for the individual (e.g. insurance and others) as well as for the medical community at large by creating confusion about the concept.

Development and preliminary results on the feasibility of a renal diet specific question prompt sheet for use in nephrology clinics

Background

Adherence to the diet prescription for chronic kidney disease is suboptimal. Interventions to improve dietary adherence suggest that improving communication between the patient and the health professional is fundamental to improving outcomes. Providing patients with a question prompt sheet prior to the consultation has been demonstrated to be an effective method for improving communication between patient and health professional. In the absence of a renal diet specific version, the aims of this study were to develop and test the feasibility of a renal diet specific question prompt sheet for use in nephrology clinics.

Methods

Phase one utilized social listening methodology, online content analysis and clinic observations to obtain an extensive list of frequently asked questions about the renal diet. Following refinement with health professionals, the draft question prompt sheet was then sent in Phase two to patients one week prior to their scheduled consultation with the renal dietitian. Feedback was obtained from patients, carers and dietitians using semi structured interviews post clinic consultation. Quantitative data was analyzed using counts and proportions, while free text responses were analyzed thematically.

Results

A total of 769 unique renal diet related questions were reduced to an 18-item question prompt sheet. Feedback from thirteen patients (six males), six carers and six dietitians involved in the preliminary feasibility study was overwhelmingly positive. The majority of patients found the question prompt sheet to be easy to understand and agreed it facilitated communication with the dietitian. All participants agreed that they would recommend use of question prompt sheet to other patients. Suggestions for future use included health professional training in use of the sheet, particularly about how to help patients prioritize their most important questions.

Conclusions

The 18-item renal diet question prompt sheet developed in this preliminary study appears to be a feasible tool for use in nephrology consultations especially by dietitians. Further research quantifying the impact on question asking and patient centeredness should be undertaken. In addition, user testing with patients from culturally diverse and low literacy backgrounds would be useful.

Electronic supplementary material

The online version of this article (10.1186/s12882-019-1231-3) contains supplementary material, which is available to authorized users.

Higher Intra-Dialysis Serum Phosphorus Reduction Ratio as a Predictor of Mortality in Patients on Long-Term Hemodialysis

Background

Rapid shifting between extracellular and intracellular phosphorus can occur during dialysis sessions, which can cause aberrant intracellular signaling in long-term hemodialysis (LTHD) patients. However, the effect of these intra-dialysis fluctuations of phosphorus on clinical outcomes has not been examined. Therefore, we investigated the relationship between intradialysis serum phosphorus reduction ratio (IDSPRR) and mortality in LTHD patients.

Material/Methods

This was a retrospective, observational cohort study to assess the predictive power of IDSPRR (>0.63 vs. ≤0.63) on mortality in a total of 805 LTHD patients. All these fatal events were analyzed using the Cox proportional hazards regression model.

Results

After multivariable analysis, baseline IDSPRR higher than 0.63 was significantly predictive of all-cause mortality (hazard ratio [HR]: 1.58; 95% confidence interval [CI]: 1.10–2.26), but not for cardiovascular (CV) mortality (HR: 1.41; 95% CI: 0.91–2.18). However, when time-varied IDSPRRs were applied, a value greater than 0.63 was not only significantly predictive of all-cause mortality (HR: 1.74, 95% CI: 1.16–2.63), but also CV mortality (HR: 2.04, 95% CI: 1.23–3.40).

Conclusions

High IDSPRR (>0.63) is independently associated with increased all-cause and CV mortality, which shows the negative effect of rapid intracellular phosphorus-shifting on LTHD patients.

Are cell-based therapies for kidney disease safe? A systematic review of preclinical evidence

The number of individuals affected by acute kidney injury (AKI) and chronic kidney disease (CKD) is constantly rising. In light of the limited availability of treatment options and their relative inefficacy, cell based therapeutic modalities have been studied. However, not many efforts are put into safety evaluation of such applications. The aim of this study was to review the existing published literature on adverse events reported in studies with genetically modified cells for treatment of kidney disease. A systematic review was conducted by searching PubMed and EMBASE for relevant articles published until June 2018. The search results were screened and relevant articles selected using pre-defined criteria, by two researchers independently. After initial screening of 6894 abstracts, a total number of 97 preclinical studies was finally included for full assessment. Of these, 61 (63%) presented an inappropriate study design for the evaluation of safety parameters. Only 4 studies (4%) had the optimal study design, while 32 (33%) showed sub-optimal study design with either direct or indirect evidence of adverse events. The high heterogeneity of studies included regarding cell type and number, genetic modification, administration route, and kidney disease model applied, combined with the consistent lack of appropriate control groups, makes a reliable safety evaluation of kidney cell-based therapies impossible. Only a limited number of relevant studies included looked into essential safety-related outcomes, such as inflammatory (48%), tumorigenic and teratogenic potential (12%), cell biodistribution (82%), microbiological safety with respect to microorganism contamination and latent viruses' reactivation (1%), as well as overall well-being and animal survival (19%). In conclusion, for benign cell-based therapies, well-designed pre-clinical studies, including all control groups required and good manufacturing processes securing safety, need to be done early in development. Preferably, this should be performed side by side with efficacy evaluation and according to the official guidelines of leading health organizations.

Efficacy and safety of intradialytic exercise in haemodialysis patients: a systematic review and meta-analysis

OBJECTIVE

To assess the efficacy and safety of intradialytic exercise for haemodialysis patients.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Databases, including PubMed, Embase, the Cochrane Library, China Biology Medicine and China National Knowledge Infrastructure, were screened from inception to March 2017.

ELIGIBILITY CRITERIA

Randomised controlled trials (RCTs) aimed at comparing the efficacy and safety of intradialytic exercise versus no exercise in adult patients on haemodialysis for at least 3 months. A minimum exercise programme period of 8 weeks.

DATA EXTRACTION

Study characteristics and study quality domains were reviewed. Studies were selected, and data extracted by two reviewers.

DATA ANALYSIS

The pooled risk ratios and mean differences (MDs) with 95% CIs for dichotomous data and continuous data were calculated, respectively.

RESULTS

A total of 27 RCTs involving 1215 subjects were analysed. Compared with no exercise, intradialytic exercise increased dialysis adequacy (Kt/V) (MD 0.07, 95% CI 0.01 to 0.12, p=0.02) and maximum volume of oxygen that the body can use during physical exertion peak oxygen consumption (MD 4.11, 95% CI 2.94 to 5.27, p<0.0001), alleviated depression standardised mean difference (-1.16, 95% CI -1.86 to -0.45, p=0.001) and improved physical component summary-short form-36 (SF-36) level (MD 7.72, 95% CI 1.93 to 13.51, p=0.009). Also, intradialytic exercise could significantly reduce systolic blood pressure (MD -4.87, 95% CI -9.20 to -0.55, p=0.03) as well as diastolic blood pressure (MD -4.11, 95% CI -6.50 to -1.72, p=0.0007). However, intradialytic exercise could not improve mental component summary-SF-36 level (MD 3.05, 95% CI -1.47 to 7.57, p=0.19). There was no difference in the incidence of adverse events between the intradialytic exercise and control groups.

CONCLUSIONS

Intradialytic exercise resulted in benefits in terms of improving haemodialysis adequacy, exercise capacity, depression and quality of life for haemodialysis.

Frequency and Predictors of Renal Transplantation Among Patients Rendered Surgically Anephric for Sporadic Renal Cancer

OBJECTIVE

To assess the frequency of renal transplantation in patients rendered surgically anephric during treatment of renal cancers as well as the clinicopathologic factors associated with receipt of transplantation.

METHODS

A retrospective review was conducted to identify patients rendered surgically anephric between 2001 and 2016 due to cancer in both renal units or cancer in an anatomically or functionally solitary kidney. Patient demographics, comorbidities, and cancer features were compared between patients who subsequently received a renal transplantation and those who did not. Time-to-event analysis was used to compare time to transplantation across varied identified parameters.

RESULTS

Among 27 patients rendered anephric, 4 (15%) received a renal transplantation over a median follow-up of 21.6 months (interquartile range 7.2, 53.3). All transplanted patients were less than 70 years of age and had cT1a renal parenchymal mass at the time of nephrectomy. No patient undergoing completion nephrectomy for upper tract urothelial carcinoma received transplantation. Patients who were evaluated by the transplant service prior to nephrectomy were more likely to eventually undergo transplantation (60% vs 5%; P < .01). On time-to-event analyses, a cT1a renal parenchymal mass (P < .01) and a pre-nephrectomy transplant evaluation (P < .01) were associated with receipt of a transplant.

CONCLUSION

Patients rendered anephric via nephrectomy for cancer are more likely to receive renal transplantation if they are less than 70 years old, have a cT1a renal parenchymal mass, and receive transplant consultation before nephrectomy. These data may inform future patient counseling.

Apolipoproteins A and B and PCSK9: Nontraditional Cardiovascular Risk Factors in Chronic Kidney Disease and in End-Stage Renal Disease

PURPOSE

Nontraditional cardiovascular risk factors as apolipoprotein A (ApoA), apolipoprotein B (ApoB), and the proprotein convertase subtilisin/kexin type 9 (PCSK9) increase the prevalence of cardiovascular mortality in chronic kidney disease (CKD) or in end-stage renal disease (ESRD) through quantitative alterations. This review is aimed at establishing the biomarker (ApoA, ApoB, and PCSK9) level variations in uremic patients, to identify the studies showing the association between these biomarkers and the development of cardiovascular events and to depict the therapeutic options to reduce cardiovascular risk in CKD and ESRD patients.

METHODS

We searched the electronic database of PubMed, Scopus, EBSCO, and Cochrane CENTRAL for studies evaluating apolipoproteins and PCSK9 in CKD and ESRD. Randomized controlled trials, observational studies (including case-control, prospective or retrospective cohort), and reviews/meta-analysis were included if reference was made to those keys and cardiovascular outcomes in CKD/ESRD.

RESULTS

18 studies met inclusion criteria. Serum ApoA-I has been significantly associated with the development of new cardiovascular event and with cardiovascular mortality in ESRD patients. ApoA-IV level was independently associated with maximum carotid intima-media thickness (cIMT) and was a predictor for sudden cardiac death. The ApoB/ApoA-I ratio represents a strong predictor for coronary artery calcifications, cardiovascular mortality, and myocardial infarction in CKD/ESRD. Plasma levels of PCSK9 were not associated with cardiovascular events in CKD patients.

CONCLUSIONS

Although the "dyslipidemic status" in CKD/ESRD is not clearly depicted, due to different research findings, ApoA-I, ApoA-IV, and ApoB/ApoA-I ratio could be predictors of cardiovascular risk. Serum PCSK9 levels were not associated with the cardiovascular events in patients with CKD/ESRD. Probably in the future, the treatment of dyslipidemia in CKD/ESRD will be aimed at discovering new effective therapies on the action of these biomarkers.

Moderate Protein Restriction in Advanced CKD: A Feasible Option in An Elderly, High-Comorbidity Population. A Stepwise Multiple-Choice System Approach

Background: Protein restriction may retard the need for renal replacement therapy; compliance is considered a barrier, especially in elderly patients. Methods: A feasibility study was conducted in a newly organized unit for advanced kidney disease; three diet options were offered: normalization of protein intake (0.8 g/kg/day of protein); moderate protein restriction (0.6 g/kg/day of protein) with a “traditional” mixed protein diet or with a “plant-based” diet supplemented with ketoacids. Patients with protein energy wasting (PEW), short life expectancy or who refused were excluded. Compliance was estimated by Maroni-Mitch formula and food diary. Results: In November 2017–July 2018, 131 patients started the program: median age 74 years (min–max 24-101), Charlson Index (CCI): 8 (min-max: 2–14); eGFR 24 mL/min (4–68); 50.4% were diabetic, BMI was ≥ 30 kg/m² in 40.4%. Normalization was the first step in 75 patients (57%, age 78 (24–101), CCI 8 (2–12), eGFR 24 mL/min (8–68)); moderately protein-restricted traditional diets were chosen by 24 (18%, age 74 (44–91), CCI 8 (4–14), eGFR 22 mL/min (5–40)), plant-based diets by 22 (17%, age 70 (34–89), CCI 6.5 (2–12), eGFR 15 mL/min (5–46)) (p < 0.001). Protein restriction was not undertaken in 10 patients with short life expectancy. In patients with ≥ 3 months of follow-up, median reduction of protein intake was from 1.2 to 0.8 g/kg/day (p < 0.001); nutritional parameters remained stable; albumin increased from 3.5 to 3.6 g/dL (p = 0.037); good compliance was found in 74%, regardless of diets. Over 1067 patient-months of follow-up, 9 patients died (CCI 10 (6–12)), 7 started dialysis (5 incremental). Conclusion: Protein restriction is feasible by an individualized, stepwise approach in an overall elderly, high-comorbidity population with a baseline high-protein diet and is compatible with stable nutritional status.

Serum heat shock protein 27 levels predict cardiac mortality in hemodialysis patients

Background

Decreased heat shock protein 27 (HSP27) participates in many processes that are involved in cardiovascular (CV) disease. The objective of the study was to evaluate if HSP27 level was predictive of mortality as well as to evaluate factors associated with HSP27 level in a group of patients treated with HD.

Methods

Enrolled to the study were 202 HD patients. Clinical data, biochemical, echocardiographic, and carotid atherosclerosis parameters were evaluated. Patients were splited into groups on the basis of the cut-off lower and higher 50th percentile of serum HSP27 levels, and were followed-up for 28.68 ± 6.12 months.

Results

No significant difference was observed between serum HSP27 levels in patients and controls. Low HSP27 patients were older, had higher left ventricular mass index, lower ejection fraction, higher prevalence of diabetes, myocardial infarction and carotid atherosclerosis, higher C-reactive protein level, and worse oxidant/antioxidant status. The multiple regression analysis identified that HSP27 levels were independently, negatively associated with serum oxidized LDL and the number of carotid plaques. Using the Kaplan–Meier analysis it was shown that the cumulative incidences of both CV and sudden cardiac death (SCD) mortality were higher in low HSP27 group in comparison with high serum HSP27 group. A multivariate Cox analysis showed that HSP27 level is an independent and strong predictor of CV as well as SCD mortality.

Conclusions

Low serum HSP27 level is independently associated with both CV and SCD mortality but not with all-cause mortality. Low serum HSP27 level is associated with carotid atherosclerosis and oxidative stress.

Predictors of atherosclerotic events in patients on haemodialysis: post hoc analyses from the AURORA study

Background

Patients on haemodialysis (HD) are at high risk for cardiovascular events, but heart failure and sudden death are more common than atherosclerotic events. The A Study to Evaluate the Use of Rosuvastatinin in Subjects on Regular Hemodialysis: An Assessment of Survival and Cardiovascular Events (AURORA) trial was designed to assess the effect of rosuvastatin on myocardial infarction and death from any cardiac cause in 2773 HD patients. We studied predictors of the atherosclerotic cardiovascular events in AURORA.

Methods

We readjudicated all deaths and presumed myocardial infarctions according to the criteria used in the Study of Heart and Renal Protection (SHARP); these were specifically developed to separate atherosclerotic from non-atherosclerotic cardiovascular events. The readjudicated atherosclerotic end point included the first event of the following: non-fatal myocardial infarction, fatal coronary heart disease, non-fatal and fatal non-haemorrhagic stroke, coronary revascularization procedures and death from ischaemic limb disease. Stepwise Cox regression analysis was used to identify the predictors of such events.

Results

During a mean follow-up of 3.2 years, 506 patients experienced the new composite atherosclerotic outcome. Age, male sex, prevalent diabetes, prior cardiovascular disease, weekly dialysis duration, baseline albumin [hazard ratio (HR) 0.96; 95% confidence interval (CI) 0.94-0.99 per g/L increase], high-sensitivity C-reactive protein (HR 1.13; 95% CI 1.04-1.22 per mg/L increase) and oxidized low-density lipoprotein (LDL) cholesterol (HR 1.09; 95% CI 1.03-1.17 per 10 U/L increase) were selected as significant predictors in the model. Neither LDL cholesterol nor allocation to placebo/rosuvastatin therapy predicted the outcome.

Conclusions

Even with the use of strict criteria for end point definition, non-traditional risk factors, but not lipid disturbances, predicted atherosclerotic events in HD patients.

Mechanisms and Modulation of Oxidative/Nitrative Stress in Type 4 Cardio-Renal Syndrome and Renal Sarcopenia

Chronic kidney disease (CKD) is a public health problem and a recognized risk factor for cardiovascular diseases (CVD). CKD could amplify the progression of chronic heart failure leading to the development of type 4 cardio-renal syndrome (T4CRS). The severity and persistence of heart failure are strongly associated with mortality risk in T4CRS. CKD is also a catabolic state leading to renal sarcopenia which is characterized by the loss of skeletal muscle strength and physical function. Renal sarcopenia also promotes the development of CVD and increases the mortality in CKD patients. In turn, heart failure developed in T4CRS could result in chronic muscle hypoperfusion and metabolic disturbances leading to or aggravating the renal sarcopenia. The interplay of multiple factors (e.g., comorbidities, over-activated renin-angiotensin-aldosterone system [RAAS], sympathetic nervous system [SNS], oxidative/nitrative stress, inflammation, etc.) may result in the progression of T4CRS and renal sarcopenia. Among these factors, oxidative/nitrative stress plays a crucial role in the complex pathomechanism and interrelationship between T4CRS and renal sarcopenia. In the heart and skeletal muscle, mitochondria, nicotinamide adenine dinucleotide phosphate (NADPH) oxidases, uncoupled nitric oxide synthase (NOS) and xanthine oxidase are major ROS sources producing superoxide anion (O2^·−) and/or hydrogen peroxide (H₂O₂). O2^·− reacts with nitric oxide (NO) forming peroxynitrite (ONOO⁻) which is a highly reactive nitrogen species (RNS). High levels of ROS/RNS cause lipid peroxidation, DNA damage, interacts with both DNA repair enzymes and transcription factors, leads to the oxidation/nitration of key proteins involved in contractility, calcium handling, metabolism, antioxidant defense mechanisms, etc. It also activates the inflammatory response, stress signals inducing cardiac hypertrophy, fibrosis, or cell death via different mechanisms (e.g., apoptosis, necrosis) and dysregulates autophagy. Therefore, the thorough understanding of the mechanisms which lead to perturbations in oxidative/nitrative metabolism and its relationship with pro-inflammatory, hypertrophic, fibrotic, cell death and other pathways would help to develop strategies to counteract systemic and tissue oxidative/nitrative stress in T4CRS and renal sarcopenia. In this review, we also focus on the effects of some well-known and novel pharmaceuticals, nutraceuticals, and physical exercise on cardiac and skeletal muscle oxidative/nitrative stress in T4CRS and renal sarcopenia.

Early Effects of Renal Replacement Therapy on Cardiovascular Comorbidity in Children With End-Stage Kidney Disease: Findings From the 4C-T Study

BACKGROUND

The early impact of renal transplantation on subclinical cardiovascular measures in pediatric patients has not been widely investigated. This analysis is performed for pediatric patients participating in the prospective cardiovascular comorbidity in children with chronic kidney disease study and focuses on the early effects of renal replacement therapy (RRT) modality on cardiovascular comorbidity in patients receiving a preemptive transplant or started on dialysis.

METHODS

We compared measures indicating subclinical cardiovascular organ damage (aortal pulse wave velocity, carotid intima media thickness, left ventricular mass index) and evaluated cardiovascular risk factors in 166 pediatric patients before and 6 to 18 months after start of RRT (n = 76 transplantation, n = 90 dialysis).

RESULTS

RRT modality had a significant impact on the change in arterial structure and function: compared to dialysis treatment, transplantation was independently associated with decreases in pulse wave velocity (ß = -0.67; P < 0.001) and intima media thickness (ß = -0.40; P = 0.008). Independent of RRT modality, an increase in pulse wave velocity was associated with an increase in diastolic blood pressure (ß = 0.31; P < 0.001). Increasing intima media thickness was associated with a larger increase in body mass index (ß = 0.26; P = 0.003) and the use of antihypertensive agents after RRT (ß = 0.41; P = 0.007). Changes in left ventricular mass index were associated with changes in systolic blood pressure (ß = 1.47; P = 0.01).

CONCLUSIONS

In comparison with initiating dialysis, preemptive transplantation prevented further deterioration of the subclinical vascular organ damage early after transplantation. Classic cardiovascular risk factors, such as hypertension and obesity are of major importance for the development of cardiovascular organ damage after renal transplantation.

Association of Serum Aluminum Levels with Mortality in Patients on Chronic Hemodialysis

Despite reported evidence on the relationship between higher serum aluminum levels and poor outcomes in patients on chronic hemodialysis (CHD), the acceptable cutoff value of serum aluminum for mortality remains unclear. A retrospective observational cohort study with 636 Taiwanese patients on CHD was conducted to investigate the impact of serum aluminum levels on mortality. The predictors were bivariate serum aluminum level (<6 and ≥6 ng/mL) and the Outcomes were all-cause and cardiovascular (CV) mortality. During the mean follow-up of 5.3 ± 2.9 years, 253 all-cause and 173 CV deaths occurred. Crude analysis showed that a serum aluminum level of ≥6 ng/mL was a significant predictor of all-cause [hazard ratio (HR), 1.80; 95% confidence interval (CI), 1.40–2.23] and CV (HR, 1.84; 95% CI, 1.36–2.50) mortality. After multivariable adjustment, the serum aluminum level of ≥6 ng/mL remained a significant predictor of all-cause mortality (HR, 1.37, 95% CI, 1.05–1.81) but became insignificant for CV mortality (HR, 1.29; 95% CI, 0.92–1.81). Therefore, our study revealed that a serum aluminum level of ≥6 ng/mL was independently associated with all-cause death in patients on CHD, suggesting that early intervention for aluminum level in patients on CHD might be beneficial even in the absence of overt aluminum toxicity.

Missed Hemodialysis Treatments: International Variation, Predictors, and Outcomes in the Dialysis Outcomes and Practice Patterns Study (DOPPS)

RATIONALE & OBJECTIVE

Missed hemodialysis (HD) treatments not due to hospitalization have been associated with poor clinical outcomes and related in part to treatment nonadherence. Using data from the Dialysis Outcomes and Practice Patterns Study (DOPPS) phase 5 (2012-2015), we report findings from an international investigation of missed treatments among patients prescribed thrice-weekly HD.

STUDY DESIGN

Prospective observational study.

SETTING & PARTICIPANTS

8,501 patients participating in DOPPS, on HD therapy for more than 120 days, from 20 countries. Longitudinal and cross-sectional analyses were performed based on the 4,493 patients from countries in which 4-month missed treatment risk was > 5%.

PREDICTORS

The main predictor of patient outcomes was 1 or more missed treatments in the 4 months before DOPPS phase 5 enrollment; predictors of missed treatments included country, patient characteristics, and clinical factors.

OUTCOMES

Mortality, hospitalization, laboratory measures, patient-reported outcomes, and 4-month missed treatment risk.

ANALYTICAL APPROACH

Outcomes were assessed using Cox proportional hazards, logistic, and linear regression, adjusting for case-mix and country.

RESULTS

The 4-month missed treatment risk varied more than 50-fold across all 20 DOPPS countries, ranging from < 1% in Italy and Japan to 24% in the United States. Missed treatments were more likely with younger age, less time on dialysis therapy, shorter HD treatment time, lower Kt/V, longer travel time to HD centers, and more symptoms of depression. Missed treatments were positively associated with all-cause mortality (HR, 1.68; 95% CI, 1.37-2.05), cardiovascular mortality, sudden death/cardiac arrest, hospitalization, serum phosphorus level > 5.5mg/dL, parathyroid hormone level > 300pg/mL, hemoglobin level < 10g/dL, higher kidney disease burden, and worse general and mental health.

LIMITATIONS

Possible residual confounding; temporal ambiguity in the cross-sectional analyses.

CONCLUSIONS

In the countries with a 4-month missed treatment risk > 5%, HD patients were more likely to die, be hospitalized, and have poorer patient-reported outcomes and laboratory measures when 1 or more missed treatments occurred in a 4-month period. The large variation in missed treatments across 20 nations suggests that their occurrence is potentially modifiable, especially in the United States and other countries in which missed treatment risk is high.

Novel Urinary Biomarkers For Improved Prediction Of Progressive Egfr Loss In Early Chronic Kidney Disease Stages And In High Risk Individuals Without Chronic Kidney Disease

Chronic kidney disease is associated with increased risk of CKD progression and death. Therapeutic approaches to limit progression are limited. Developing tools for the early identification of those individuals most likely to progress will allow enriching clinical trials in high risk early CKD patients. The CKD273 classifier is a panel of 273 urinary peptides that enables early detection of CKD and prognosis of progression. We have generated urine capillary electrophoresis-mass spectrometry-based peptidomics CKD273 subclassifiers specific for CKD stages to allow the early identification of patients at high risk of CKD progression. In the validation cohort, the CKD273 subclassifiers outperformed albuminuria and CKD273 classifier for predicting rapid loss of eGFR in individuals with baseline eGFR > 60 ml/min/1.73 m². In individuals with eGFR > 60 ml/min/1.73 m² and albuminuria <30 mg/day, the CKD273 subclassifiers predicted rapid eGFR loss with AUC ranging from 0.797 (0.743-0.844) to 0.736 (0.689-0.780). The association between CKD273 subclassifiers and rapid progression remained significant after adjustment for age, sex, albuminuria, DM, baseline eGFR, and systolic blood pressure. Urinary peptidomics CKD273 subclassifiers outperformed albuminuria and CKD273 classifier for predicting the risk of rapid CKD progression in individuals with eGFR > 60 ml/min/1.73 m². These CKD273 subclassifiers represented the earliest evidence of rapidly progressive CKD in non-albuminuric individuals with preserved renal function.

Neutrophil Elastase Inhibitors and Chronic Kidney Disease

End-stage renal disease (ESRD), the last stage of chronic kidney disease (CKD), is characterized by chronic inflammation and oxidative stress. Neutrophils are the front line cells that mediate an inflammatory response against microorganisms as they can migrate, produce reactive oxygen species (ROS), secrete neutrophil serine proteases (NSPs), and release neutrophil extracellular traps (NETs). Serine proteases inhibitors regulate the activity of serine proteases and reduce neutrophil accumulation at inflammatory sites. This review intends to relate the role of neutrophil elastase in CKD and the effects of neutrophil elastase inhibitors in predicting or preventing inflammation.

Impact of Altered Intestinal Microbiota on Chronic Kidney Disease Progression

In chronic kidney disease (CKD), accumulation of uremic toxins is associated with an increased risk of CKD progression. Some uremic toxins result from nutrient processing by gut microbiota, yielding precursors of uremic toxins or uremic toxins themselves, such as trimethylamine N-Oxide (TMAO), p-cresyl sulphate, indoxyl sulphate and indole-3 acetic acid. Increased intake of some nutrients may modify the gut microbiota, increasing the number of bacteria that process them to yield uremic toxins. Circulating levels of nutrient-derived uremic toxins are associated to increased risk of CKD progression. This offers the opportunity for therapeutic intervention by either modifying the diet, modifying the microbiota, decreasing uremic toxin production by microbiota, increasing toxin excretion or targeting specific uremic toxins. We now review the link between nutrients, microbiota and uremic toxin with CKD progression. Specific focus will be placed on the generation specific uremic toxins with nephrotoxic potential, the decreased availability of bacteria-derived metabolites with nephroprotective potential, such as vitamin K and butyrate and the cellular and molecular mechanisms linking these toxins and protective factors to kidney diseases. This information provides a conceptual framework that allows the development of novel therapeutic approaches.

Qualitative exploration of the experiences of renal dietitians and how they help patients with end stage kidney disease to understand the renal diet

AIM

Dietary modification is integral to the management of end stage kidney disease. However, adherence to the renal diet is poor. Few studies have explored the perspectives of renal dietitians and how they work with patients to facilitate dietary change. The objectives of this study were to explore the experiences of renal dietitians about educating patients with end stage kidney disease; and to describe the strategies perceived to help patients understand the renal diet.

METHODS

Semi-structured interviews based on Sensemaking theory were conducted with renal dietitians (n = 27) working in Australia and New Zealand from a range of metropolitan, regional and remote areas.

RESULTS

Five major themes across two categories were derived from the data. The renal dietitians in this study experienced feelings of frustration, frequently worked in practice environments with limited or inadequate resources and perceived that establishing trust and demonstrating empathy were important to sense making. Renal dietitians helped patients make sense of and understand the diet by clarifying ambiguities and conflicting information; and simplifying complexity by using simple explanations, individualised advice and practical support. These strategies were considered critical to the renal diet sense making process.

CONCLUSIONS

The experience of providing renal diet advice to adults with end stage kidney disease was emotionally and professionally challenging. Alternative approaches to patient education may help dietitians to empower patients to better understand the renal diet. Further research exploring the experiences of learning about the renal diet from the patient and carer perspective would also help to inform future alternative approaches.

Hyperkalaemia prevalence, recurrence and management in chronic haemodialysis: a prospective multicentre French regional registry 2-year survey

Background

Observational studies have reported increased mortality rates in hyperkalaemic or hypokalaemic chronic haemodialysis patients. This study assessed the prevalence and recurrence of hyperkalaemia (HK) along with the concomitant prescription of low-potassium (K) dialysis baths and of K-binding agents in a registry within a French regional disease management programme.

Methods

This was a prospective multicentre (14 chronic haemodialysis centres, Lorraine Region) study encompassing 527 chronic haemodialysis patients followed from 2 January 2014 to 31 December 2015. Predialysis serum K (14 734) measurements, dialysis bath K concentrations and concomitant K binder prescriptions were collected with an electronic health record system.

Results

At baseline, 26.4%, 13.8% and 4.9% of patients were hyperkalaemic (i.e. K >5.1, 5.5 or 6 mmol/L, respectively) and 12.5%, 1.9% and 0.4% were hypokalaemic (i.e. K<4, 3.5 or 3 mmol/L, respectively). A total of 61% of patients were prescribed a K-binding resin [essentially sodium polystyrene sulfonate (SPS)], while 2 mmol/L and 3 mmol/L K concentration baths were used relatively equally. Over time, the proportion of patients being prescribed any K-binding agent increased up to 78%. The percentage of patients experiencing HK at any time was 73.8% (HK >5.1 mmol/L), 57.9% (HK >5.5 mmol/L) and 34.5% (HK >6 mmol/L). Only 6.3% of patients became normokalaemic within 3 months after an HK >5.5 mmol/L despite dynamic management of K baths and K binders (i.e. increased prescription of 2 mmol/L K baths and increased SPS doses).

Conclusions

HK was found to be highly prevalent and recurrent in this regional registry despite the widespread and dynamic prescription of low-K dialysis baths and K binders. More effective potassium mitigating strategies are eagerly warranted.

The quest for equilibrium: exploring the thin red line between bleeding and ischaemic risks in the management of acute coronary syndromes in chronic kidney disease patients

Coronary artery disease and acute coronary syndrome (ACS) are both common in patients with chronic kidney disease (CKD). CKD patients have higher risks of bleeding and thrombosis. However, they remain under-represented in major randomized clinical trials (RCTs), and there is no medical evidence-based foundation on which to issue specific recommendations about the management of ACS in CKD. CKD patients with ACS frequently are diagnosed later, receive fewer acute interventions and are at increased risk of over-dosage of medications and under-prescription/under-performance of interventional treatments than CKD patients without ACS. The lack of RCTs should not discourage reliance on clinical common sense, while clearer decisional algorithms with better outcomes are a priority for urgent development. Future guidelines should further refine the assessment of CKD with ACS while placing much greater emphasis on the correct dosing of medications based on contemporaneous renal function. Until a strategy is designed with specific measures translated into the actual decrease of bleeding risk, providers will be forced to balance the equilibrium on a thin red line that is not clearly established.

Deleting Death and Dialysis: Conservative Care of Cardio-Vascular Risk and Kidney Function Loss in Chronic Kidney Disease (CKD)

The uremic syndrome, which is the clinical expression of chronic kidney disease (CKD), is a complex amalgam of accelerated aging and organ dysfunctions, whereby cardio-vascular disease plays a capital role. In this narrative review, we offer a summary of the current conservative (medical) treatment options for cardio-vascular and overall morbidity and mortality risk in CKD. Since the progression of CKD is also associated with a higher cardio-vascular risk, we summarize the interventions that may prevent the progression of CKD as well. We pay attention to established therapies, as well as to novel promising options. Approaches that have been considered are not limited to pharmacological approaches but take into account lifestyle measures and diet as well. We took as many randomized controlled hard endpoint outcome trials as possible into account, although observational studies and post hoc analyses were included where appropriate. We also considered health economic aspects. Based on this information, we constructed comprehensive tables summarizing the available therapeutic options and the number and kind of studies (controlled or not, contradictory outcomes or not) with regard to each approach. Our review underscores the scarcity of well-designed large controlled trials in CKD. Nevertheless, based on the controlled and observational data, a therapeutic algorithm can be developed for this complex and multifactorial condition. It is likely that interventions should be aimed at targeting several modifiable factors simultaneously.

Is relative overhydration measurement by bioimpedance spectroscopy useful in reducing morbidity and mortality in chronic kidney disease?

It is well known that one of the main determinants of mortality and morbidity in chronic kidney disease (CKD) and end-stage renal disease (ESRD) patients is fluid overload acting on the cardiovascular system causing hypertension, increased arterial stiffness, left ventricular hypertrophy and eventually heart failure. Therefore, assessment and management of volume status is crucial. Bioimpedance spectroscopy is one of the most popular and practical methods for volume evaluation. Volume evaluation should be a routine part of following CKD and ESRD patients, in order to decrease associated mortality and morbidity.

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

Background

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

Methods

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

Results

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

Conclusions

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

Soluble Urokinase Plasminogen Activator Receptor (suPAR) and All-Cause and Cardiovascular Mortality in Diverse Hemodialysis Patients

Introduction

The soluble receptor of urokinase plasminogen activator (suPAR) is an innate immunity/inflammation biomarker predicting cardiovascular (CV) and non-CV events in various conditions, including type 2 diabetic patients on dialysis. However, the relationship between suPAR and clinical outcomes in the hemodialysis population at large has not been tested.

Methods

We measured plasma suPAR levels (R&D enzyme-linked immunosorbent assay [ELISA]) in 1038 hemodialysis patients with a follow-up of 2.9 years (interquartile range = 1.7−4.2) who were enrolled in the PROGREDIRE study, a cohort study involving 35 dialysis units in 2 regions in Southern Italy.

Results

suPAR was strongly (P < 0.001) and independently related to female gender (β = −0.160), age (β = 0.216), dialysis vintage (β = 0.264), CV comorbidities (β = 0.105), alkaline phosphatase (β = 0.136), albumin (β = −0.147), and body mass index (BMI; β = 0.174) (all P < 0.006). In fully adjusted analyses, suPAR tertiles predicted the risk of all-cause mortality (third tertile vs. first tertile hazard ratio (HR) = 1.91, 95% confidence interval (CI) = 1.47 – 2.48, P < 0.001), CV mortality (HR = 1.47, 95% CI = 1.03–2.09, P = 0.03), and non-CV mortality (HR = 1.94, 95% CI = 1.28–2.93, P = 0.002); these relationships were not modified by diabetes or other risk factors. suPAR added only modest prognostic risk discrimination and reclassification power for these outcomes to parsimonious models based on simple clinical variables.

Conclusion

In conclusion, suPAR robustly predicted all-cause and both CV and non-CV mortality in a large unselected hemodialysis population. Intervention studies are needed to definitively test the hypothesis that suPAR is causally implicated in clinical outcomes in this population.

Inactive Matrix Gla Protein, Arterial Stiffness, and Endothelial Function in African American Hemodialysis Patients

BACKGROUND

Matrix Gla protein (MGP) is a vascular calcification inhibitor dependent upon vitamin K for activation. Evidence suggests that elevated plasma inactive MGP levels (desphospho-uncarboxylated MGP, dp-ucMGP; indicating poorer vascular vitamin K status) are associated with greater cardiovascular disease (CVD) risk. Despite African Americans experiencing highest rates of kidney failure and CVD events, relationships between dp-ucMGP and CVD risk markers have not been examined in this population. We investigated vascular vitamin K status (via plasma dp-ucMGP) between African American hemodialysis (HD) patients and healthy controls, and the associations of dp-ucMGP with arterial stiffness and endothelial function in HD patients only.

METHODS

In 37 African American HD patients and 37 age- and race-matched controls, plasma dp-ucMGP was measured by enzyme immunoassay as a marker of vascular vitamin K status. Carotid-femoral pulse wave velocity (PWV; arterial stiffness measurement) and brachial artery flow-mediated dilation (FMD; endothelial function measurement) were assessed by applanation tonometry and ultrasound, respectively, in HD patients only.

RESULTS

Mean dp-ucMGP levels were 5.6 times higher in HD patients vs. controls (2,139 ± 1,102 vs. 382 ± 181 pmol/l, P < 0.01). Multiple linear regression, adjusting for age, sex, dialysis vintage, diabetes mellitus, CVD history, body mass index, and blood pressure, revealed that dp-ucMGP was independently related to PWV (standardized β = 0.49) and FMD (standardized β = -0.53) (both P < 0.01).

CONCLUSIONS

Our data suggest that the higher plasma dp-ucMGP concentrations found in African American HD patients may be associated with greater arterial stiffness and endothelial dysfunction.

Mechanisms of cardiovascular complications in chronic kidney disease: research focus of the Transregional Research Consortium SFB TRR219 of the University Hospital Aachen (RWTH) and the Saarland University

Patients with chronic kidney disease (CKD) exhibit a massively increased risk for cardiovascular (CV) events, and traditional strategies to improve CV outcome have largely failed in the context of CKD. This review article summarizes the current understanding of the pathophysiology of CVD in patients with CKD, defines the gaps in knowledge and describes the structure of the German Transregional Research Consortium SFB TRR219 which addresses "Mechanisms of Cardiovascular Complications in Chronic Kidney Disease".

Human umbilical cord mesenchymal stem cells facilitate the up-regulation of miR-153-3p, whereby attenuating MGO-induced peritoneal fibrosis in rats

MiRNAs contribute greatly to epithelial to mesenchymal transition (EMT) of peritoneal mesothelial cells (PMCs), which is a crucial step in peritoneal fibrosis (PF). In this study, we tried to profile whether miRNA expression differences exist after human umbilical cord mesenchymal stem cells (hUCMSCs) treatment in PF rats and investigate the possible role of miR‐153‐3p involved in anti‐EMT process. We randomly assigned 34 rats into three groups: control group (Group Control), MGO‐induced PF rats (Group MGO) and hUCMSCs‐treated rats (Group MGO + hUCMSCs). MiRNA microarrays and real‐time PCR analyses were conducted in three groups. α‐SMA, Snail1 and E‐cadherin expression were detected by Western blot. Luciferase reporter assays were used to detect the effects of miR‐153‐3p overexpression on Snai1 in rat peritoneal mesothelial cells (RPMCs). We identified differentially expressed miRNAs related to EMT, in which miR‐153‐3p demonstrated the greatest increase in Group MGO + hUCMSCs. Transient cotransfection of miR‐153‐3p mimics with luciferase expression plasmids resulted in a significant repression of Snai1 3′‐untranslated region luciferase activity in RPMCs. These studies suggest that miR‐153‐3p is a critical molecule in anti‐EMT effects of hUCMSCs in MGO‐induced PF rats. MiR‐153‐3p might exert its beneficial effect through directly targeting Snai1.

Phenotypic characteristics of the p.Asn215Ser (p.N215S) GLA mutation in male and female patients with Fabry disease: A multicenter Fabry Registry study

BACKGROUND

The p.Asn215Ser or p.N215S GLA variant has been associated with late-onset cardiac variant of Fabry disease.

METHODS

To expand on the scarce phenotype data, we analyzed natural history data from 125 p.N215S patients (66 females, 59 males) enrolled in the Fabry Registry (NCT00196742) and compared it with data from 401 patients (237 females, 164 males) harboring mutations associated with classic Fabry disease. We evaluated interventricular septum thickness (IVST), left ventricular posterior wall thickness (LVPWT), estimated glomerular filtration rate and severe clinical events.

RESULTS

In p.N215S males, mildly abnormal mean IVST and LVPWT values were observed in patients aged 25-34 years, and values gradually increased with advancing age. Mean values were similar to those of classic males. In p.N215S females, these abnormalities occurred primarily in patients aged 55-64 years. Severe clinical events in p.N215S patients were mainly cardiac (males 31%, females 8%) while renal and cerebrovascular events were rare. Renal impairment occurred in 17% of p.N215S males (mostly in patients aged 65-74 years), and rarely in females (3%).

CONCLUSION

p.N215S is a disease-causing mutation with severe clinical manifestations found primarily in the heart. Cardiac involvement may become as severe as in classic Fabry patients, especially in males.

Symmetric dimethylarginine, high-density lipoproteins and cardiovascular disease

Aims

The vascular effects of high-density lipoproteins (HDL) differ under certain clinical conditions. The composition of HDL is modified in patients with chronic kidney disease (CKD). As a consequence, uremic HDL induces endothelial dysfunction. We have previously shown that accumulation of symmetric dimethylarginine (SDMA) in HDL causes these adverse effects of HDL in CKD. The aim of the study is to determine the impact of the accumulation of SDMA on the association between HDL and mortality.

Methods and results

Mortality, renal function, serum SDMA and HDL-cholesterol (HDL-C) were assessed in the LURIC study including 3310 subjects undergoing coronary angiography. All-cause mortality was 30.0% during median follow-up of 9.9 years. Serum SDMA levels significantly predicted all-cause and cardiovascular mortality, and were significantly correlated with SDMA accumulation in HDL. Notably, higher serum SDMA was independently associated with lower cholesterol efflux (P = 0.004) as a measure of HDL functionality. In subjects with low SDMA levels, higher HDL-C was associated with significantly lower mortality. In contrast, in subjects with high SDMA, HDL-C was associated with higher mortality. These findings were confirmed in 1424 participants of the MONICA/KORA S3 cohort. Of note, we derived an algorithm allowing for calculation of biologically effective HDL-C' based on measured HDL-C and SDMA. We corroborated these clinical findings with invitro evidence showing that SDMA accumulation abolishes the anti-inflammatory and regenerative properties of HDL.

Conclusion

The data identify SDMA as a marker of HDL dysfunction. These findings highlight on the pivotal role of SDMA accumulation in HDL as a mediator of pre-mature cardiovascular disease in patients with CKD.

Why creating standardized core outcome sets for chronic kidney disease will improve clinical practice

Chronic kidney disease (CKD) is common and is associated with increased mortality, morbidity and cost. However, insufficient high-quality trial data are available to answer many relevant clinical questions in this field. In addition, a wide range of variable outcomes are used in studies, and often they are incompletely reported. Furthermore, there is a lack of patient-relevant outcomes, such as mortality, morbidity, quality of life, pain, need for dialysis or costs. Common problems with outcome reporting are as follows: choosing the wrong domains to measure; within domains, choosing the wrong measures (invalid surrogates, composite, non-patient relevant); within measures, choosing the wrong/variable metrics; and within metrics, choosing variable presentation methods. With this article, we aim to underline why standardized outcome reporting is key to achieving evidence-based guidance and improving clinical care for patients; highlight the frameworks available for achieving core outcome sets; and starting from these frameworks, we propose steps needed to develop a core outcome set in the field of CKD. We hope that standardized core outcome sets for nephrology will lead to the most important outcome of guideline production, improving outcomes for our patients.

Adhesion GPCRs in Kidney Development and Disease

Chronic kidney disease (CKD) represents the fastest growing pathology worldwide with a prevalence of >10% in many countries. In addition, kidney cancer represents 5% of all new diagnosed cancers. As currently no effective therapies exist to restore kidney function after CKD- as well as cancer-induced renal damage, it is important to elucidate new regulators of kidney development and disease as new therapeutic targets. G protein-coupled receptors (GPCRs) represent the most successful class of pharmaceutical targets. In recent years adhesion GPCRs (aGPCRs), the second largest GPCR family, gained significant attention as they are present on almost all mammalian cells, are associated to a plethora of diseases and regulate important cellular processes. aGPCRs regulate for example cell polarity, mitotic spindle orientation, cell migration, and cell aggregation; all processes that play important roles in kidney development and/or disease. Moreover, polycystin-1, a major regulator of kidney development and disease, contains a GAIN domain, which is otherwise only found in aGPCRs. In this review, we assess the potential of aGPCRs as therapeutic targets for kidney disease. For this purpose we have summarized the available literature and analyzed data from the databases The Human Protein Atlas, EURExpress, Nephroseq, FireBrowse, cBioPortal for Cancer Genomics and the National Cancer Institute Genomic Data Commons data portal (NCIGDC). Our data indicate that most aGPCRs are expressed in different spatio-temporal patterns during kidney development and that altered aGPCR expression is associated with a variety of kidney diseases including CKD, diabetic nephropathy, lupus nephritis as well as renal cell carcinoma. We conclude that aGPCRs present a promising new class of therapeutic targets and/or might be useful as diagnostic markers in kidney disease.

Women and renal replacement therapy in Europe: lower incidence, equal access to transplantation, longer survival than men

In 2018, World Kidney Day (WKD) and International Women's Day coincide. The WKD editorial focuses on women's kidney health. The European Renal Association-European Dialysis and Transplant Association (ERA-EDTA) Registry Annual Report 2015 summary provides an excellent snapshot of renal replacement therapy (RRT) epidemiology and women in Europe. The WKD editorial reports a lower incidence of RRT in women in major registries and potential limitations to women's access to transplantation. What is the situation in Europe? In Europe, the incidence of RRT is also lower in women: 38% of incident RRT patients are women. Does it represent milder chronic kidney disease (CKD) in women or barriers to RRT access? The question arises from the higher prevalence of CKD Stages G3-G5 in women than in men. However, in some European countries, such as Spain, non-dialysis CKD Stages G4-G5 is less frequent in women than in men, recapitulating the difference in RRT incidence. In the ERA-EDTA Registry, the incidence of transplantation as a first modality on Day 1 was slightly higher for women and survival on RRT was similar for women and men in the first 3 months, but an intergender gap favouring women increased as RRT vintage increased. However, women on RRT are worse off regarding survival when compared with women in the general population than men on RRT compared with men in the general population. In conclusion, the ERA-EDTA Registry Annual Report 2015 and European epidemiology data suggest a lower incidence of end-stage kidney disease in women, no gender differences in access to transplantation and better RRT survival in women.

The effects of short sleep duration on proteinuria and chronic kidney disease: a systematic review and meta-analysis

Background

The risks of proteinuria and chronic kidney disease (CKD) in adults who regularly have short sleep duration (short sleepers) are controversial. The aim of this meta-analysis was to assess the effects of short sleep duration on proteinuria and CKD.

Methods

A literature search was conducted using MEDLINE, EMBASE and the Cochrane Database of Systematic Reviews from the inception of the databases through November 2015. Studies that reported relative risks, odd ratios or hazard ratios comparing the risks of proteinuria and CKD in short sleepers were included. Pooled risk ratios (RR) and 95% confidence intervals (CI) were computed utilizing a random-effect, generic inverse variance method.

Results

Six observational studies with 252 075 individuals and three observational studies with 37 197 individuals were included in the analyses to assess the risks of CKD and proteinuria in short sleepers, respectively. The pooled RR of CKD in short sleepers was 1.51 (95% CI, 0.99-2.55). When meta-analysis was restricted only to studies with adjusted analysis for confounders assessing the risk of CKD in short sleepers, the pooled RR of CKD was 1.54 (95% CI, 0.80-2.95). The pooled RR of proteinuria in short sleepers was 1.47 (95% CI, 1.26-1.72).

Conclusions

Despite the lack of significant association between short sleep duration and CKD, our meta-analysis suggests a potential association between short sleep duration and proteinuria, a surrogate marker for kidney disease progression. Future study is required to investigate if reversal of short sleep helps reduce proteinuria.

Uremic Advanced Glycation End Products and Protein-Bound Solutes Induce Endothelial Dysfunction Through Suppression of Krüppel-Like Factor 2

BACKGROUND

Cardiovascular disease is the leading cause of morbidity and mortality in patients with end-stage renal disease. The accumulation of uremic solutes in this patient population is associated with endothelial dysfunction and accelerated cardiovascular disease. In this study, we examined the impact of the uremic milieu on the endothelial transcription factor, Krüppel-like factor 2 (KLF2), a key regulator of endothelial function and activation.

METHODS AND RESULTS

Using serum from uremic pigs with chronic renal insufficiency, our results show that KLF2 expression is suppressed by the uremic milieu and individual uremic solutes in vitro. Specifically, KLF2 expression is significantly decreased in human umbilical vein endothelial cells after treatment with uremic porcine serum or carboxymethyllysine-modified albumin, an advanced glycation end product (AGE) known to induce endothelial dysfunction. AGE-mediated suppression of KLF2 is dependent on activation of the receptor for AGE, as measured by small interfering RNA knockdown of the receptor for AGE. Furthermore, KLF2 suppression promotes endothelial dysfunction, because adenoviral overexpression of KLF2 inhibits reactive oxygen species production and leukocyte adhesion in human umbilical vein endothelial cells. In addition, the application of hemodynamic shear stress, prolonged serum dialysis, or treatment with the receptor for AGE antagonist azeliragon (TTP488) is sufficient to prevent KLF2 suppression in vitro. To decipher the mechanism by which uremic AGEs suppress KLF2 expression, we assessed the role of the receptor for AGE in activation of nuclear factor-κB signaling, a hallmark of endothelial cell activation. Using a constitutively active form of IκBα, we show that translocation of p65 to the nucleus is necessary for KLF2 suppression after treatment with uremic AGEs.

CONCLUSIONS

These data identify KLF2 suppression as a consequence of the uremic milieu, which may exacerbate endothelial dysfunction and resultant cardiovascular disease.

Role of Vitamin D in Maintaining Renal Epithelial Barrier Function in Uremic Conditions

As current kidney replacement therapies are not efficient enough for end-stage renal disease (ESRD) treatment, a bioartificial kidney (BAK) device, based on conditionally immortalized human proximal tubule epithelial cells (ciPTEC), could represent an attractive solution. The active transport activity of such a system was recently demonstrated. In addition, endocrine functions of the cells, such as vitamin D activation, are relevant. The organic anion transporter 1 (OAT-1) overexpressing ciPTEC line presented 1α-hydroxylase (CYP27B1), 24-hydroxylase (CYP24A1) and vitamin D receptor (VDR), responsible for vitamin D activation, degradation and function, respectively. The ability to produce and secrete 1α,25-dihydroxy-vitamin D₃, was shown after incubation with the precursor, 25-hydroxy-vitamin D₃. The beneficial effect of vitamin D on cell function and behavior in uremic conditions was studied in the presence of an anionic uremic toxins mixture. Vitamin D could restore cell viability, and inflammatory and oxidative status, as shown by cell metabolic activity, interleukin-6 (IL-6) levels and reactive oxygen species (ROS) production, respectively. Finally, vitamin D restored transepithelial barrier function, as evidenced by decreased inulin-FITC leakage in biofunctionalized hollow fiber membranes (HFM) carrying ciPTEC-OAT1. In conclusion, the protective effects of vitamin D in uremic conditions and proven ciPTEC-OAT1 endocrine function encourage the use of these cells for BAK application.