Sex and the Risk of Atheromatous and Non-Atheromatous Cardiovascular Disease in CKD: Findings From the CKD-REIN Cohort Study.

RATIONALE & OBJECTIVE: Sex differences in cardiovascular disease (CVD) are well-established, but whether chronic kidney disease (CKD) modifies these risk differences, and whether they differ between atheromatous (ACVD) and non-atheromatous (N-ACVD) CVD is unknown. Assessing this interaction was the principal goal of this study. STUDY DESIGN: Prospective cohort study. SETTING & PARTICIPANTS: Adults enrolled in the CKD-Renal Epidemiology and Information Network (CKD-REIN) cohort from from 2013 to 2020, a nationally representative sample of 40 nephrology clinics in France. EXPOSURE: Sex. OUTCOMES: Fatal and non-fatal composite ACVD events (ischaemic coronary, cerebral, and peripheral artery disease) and composite N-ACVD events (heart failure, haemorrhagic stroke, and arrhythmias). ANALYTICAL APPROACH: Multivariable cause-specific Cox proportional hazards models. RESULTS: 1,044 women and 1,976 men with moderate to severe CKD (median age, 67 vs. 69; mean estimated glomerular filtration rate [eGFR], 32±12 vs. 33±12 mL/min/1.73m2) were studied. Over a median follow-up of 5.0 (interquartile range, 4.8;5.2) years, the ACVD rate (per 100 patient-years) was significantly lower in women than men: 2.1 (95% confidence interval: 1.6-2.5) vs 3.6 (3.2-4.0) (P<0.01), while the N-ACVD rate was not: 5.7 (5.0-6.5) vs 6.4 (5.8-7.0) (P=0.55). N-ACVD had a steeper relationship with eGFR than did ACVD. There was an interaction (P<0.01) between sex and baseline eGFR and the ACVD hazard: the adjusted hazard ratio for women compared to men was 0.42 (0.25;0.71) at 45 mL/min/1.73m2 and gradually attenuated at lower levels of eGFR, reaching 1.00 (0.62;1.63) at 16 mL/min/1.73m2. In contrast, the N-ACVD hazard did not differ between the sexes across the eGFR range studied. LIMITATIONS: Cardiovascular biomarkers and sex hormones were not assessed. CONCLUSION: This study shows how the lower risk of ACVD among women compared to men attenuates fully with kidney disease progression. The equal risk of N-ACVD between sexes across CKD stages and its steeper association with eGFR suggest an important contribution of CKD to the development of this CVD type.

Haemoglobin trajectories in chronic kidney disease and risk of major adverse cardiovascular events.

BACKGROUND: The trajectories of haemoglobin in patients with chronic kidney disease (CKD) have been poorly described. In such patients, we aimed to identify typical haemoglobin trajectory profiles and estimate their risks of major adverse cardiovascular events (MACE). METHODS: We used 5-year longitudinal data from the CKD-REIN cohort patients with moderate to severe CKD enrolled from 40 nationally representative nephrology clinics in France. A joint latent class model was used to estimate, in different classes of haemoglobin trajectory, the competing risks of (i) MACE + defined as the first event among cardiovascular death, non-fatal myocardial infarction, stroke or hospitalization for acute heart failure, (ii) initiation of kidney replacement therapy (KRT) and (iii) non-cardiovascular death. RESULTS: During the follow-up, we gathered 33 874 haemoglobin measurements from 3011 subjects (median, 10 per patient). We identified five distinct haemoglobin trajectory profiles. The predominant profile (n = 1885, 62.6%) showed an overall stable trajectory and low risks of events. The four other profiles had nonlinear declining trajectories: early strong decline (n = 257, 8.5%), late strong decline (n = 75, 2.5%), early moderate decline (n = 356, 11.8%) and late moderate decline (n = 438, 14.6%). The four profiles had different risks of MACE, while the risks of KRT and non-cardiovascular death consistently increased from the haemoglobin decline. CONCLUSION: In this study, we observed that two-thirds of patients had a stable haemoglobin trajectory and low risks of adverse events. The other third had a nonlinear trajectory declining at different rates, with increased risks of events. Better attention should be paid to dynamic changes of haemoglobin in CKD.

A review of the latest real-world evidence studies in diabetic kidney disease: What have we learned about clinical practice and the clinical effectiveness of interventions?

Diabetic nephropathy, also known as diabetic kidney disease (DKD), remains a challenge in clinical practice as this is the major cause of kidney failure worldwide. Clinical trials do not answer all the questions raised in clinical practice and real-world evidence provides complementary insights from randomized controlled trials. Real-life longitudinal data highlight the need for improved screening and management of diabetic nephropathy in primary care. Adherence to the recommended guidelines for comprehensive care appears to be suboptimal in clinical practice in patients with DKD. Barriers to the initiation of sodium-glucose cotransporter-2 (SGLT2) inhibitors for patients with DKD persist in clinical practice, in particular for the elderly. Attainment of blood pressure targets often remains an issue. Initiation of glucagon-like peptide-1 receptor agonists (GLP-1RAs) in routine clinical practice is associated with a reduced risk of albuminuria progression and a possible beneficial effect on kidney function. Real-world evidence confirms a beneficial effect of SGLT2 inhibitors on the decline of glomerular filtration, even in the absence of albuminuria, with a lower risk of acute kidney injury events compared to GLP-1RA use. In addition, SGLT2 inhibitors confer a lower risk of hyperkalaemia after initiation compared with dipeptidyl peptidase-4 inhibitors in patients with DKD. Data from a large population indicate that diuretic treatment increases the risk of a significant decline in glomerular filtration rate in the first few weeks of treatment after SGLT2 inhibitor initiation. The perspective for a global approach targeting multifaceted criteria for diabetic individuals with DKD is emerging based on real-world evidence but there is still a long way to go to achieve this goal.

The number of nephroprotection targets attained is associated with cardiorenal outcomes and mortality in patients with diabetic kidney disease. The CKD-REIN cohort study.

AIM: The risk of cardiorenal events remains high among patients with diabetes and chronic kidney disease (CKD), despite the prescription of recommended treatments. We aimed to determine whether the attainment of a combination of nephroprotection targets at baseline (glycated haemoglobin <7.0%, urinary albumin-creatinine ratio <300 mg/g, blood pressure <130/80 mmHg, renin-angiotensin system inhibition) was associated with better cardiorenal outcomes and lower mortality. MATERIALS AND METHODS: From the prospective French CKD-REIN cohort, we studied 1260 patients with diabetes and CKD stages 3-4 (estimated glomerular filtration rate: 15-60 ml/min/1.73 m2); 69% were men, and at inclusion, mean ± SD age: 70 ± 10 years; estimated glomerular filtration rate: 33 ± 11 ml/min/1.73 m2. The median follow-up was 4.9 years. RESULTS: In adjusted Cox regression models, the attainment of two nephroprotection targets was consistently associated with a lower risk of cardiorenal events [hazard ratio 0.70 (95% confidence interval 0.57-0.85)], incident kidney failure with replacement therapy [0.58 (0.43-0.77)], four major adverse cardiovascular events (cardiovascular death, myocardial infarction, stroke, hospitalization for heart failure) [0.75 (0.57-0.99)] and all-cause mortality [0.59 (0.42-0.82)] when compared with the attainment of zero or one target. For patients with a urinary albumin-creatinine ratio ≥300 mg/g, those who attained at least two targets had lower hazard ratios for cardiorenal events [0.61 (0.39-0.96)], four major adverse cardiovascular events [0.53 (0.28-0.98)] and all-cause mortality [0.35 (0.17-0.70)] compared with those who failed to attain any targets. CONCLUSIONS: These findings suggest that the attainment of a combination of nephroprotection targets is associated with better cardiorenal outcomes and a lower mortality rate in people with diabetic kidney disease.

Dietary Intake and Nutritional Status in Diabetic and Nondiabetic Patients With Chronic Kidney Disease Stage 4-5 (NutriDiab Study).

OBJECTIVES: The aim of the present study was to assess the dietary intake and nutritional status of patients with chronic kidney disease (CKD) stage 4-5 according to the presence of diabetes. METHODS: This observational and cross-sectional study included adult patients with CKD stage 4-5 referred to a nephrology unit, between October 2018 and March 2019. Daily dietary intake was evaluated by 24-hour dietary inquiry and urine excretion. Nutritional status was assessed by measuring body composition using bioimpedance analysis and muscle function using handgrip strength. Undernutrition was considered using the protein energy wasting score. RESULTS: A total of 75 CKD patients were included, 36 (48%) of whom had diabetes; median age (interquartile range) was 71 (60-80) years. The median weight-adjusted dietary energy intake (DEI) was 22.6 (19.1-28.2) kcal/kg/day and the mean weight-adjusted dietary protein intake (DPI) was 0.86 ± 0.19 g/kg/day. There was no significant difference in DEI and DPI between patients with diabetes and those without, except for weight-adjusted DPI which was significantly lower in diabetic patients (P = .022). In univariate analysis, diabetes was associated with weight-adjusted DPI (coefficient [95% confidence interval] -0.237 [-0.446; -0.004] kcal/kg/day; P = .040), but this association did not remain significant in multivariate analysis. Nutritional status did not differ significantly between diabetic and nondiabetic patients except for lean tissue mass, which was lower in diabetic patients (P = .046). The proportion of patients with protein energy wasting was not significantly different between diabetic and nondiabetic patients (13.9% vs. 10.2%, respectively). CONCLUSIONS: In the present cohort, DPI and DEI were not significantly different between diabetic and nondiabetic CKD patients. Diabetes was not found to be associated with dietary intakes in CKD stage 4-5 patients.

Sulforaphane Supplementation Did Not Modulate NRF2 and NF-kB mRNA Expressions in Hemodialysis Patients.

BACKGROUND: Patients with chronic kidney disease (CKD) have reduced expression of erythroid nuclear factor-related factor 2 (NRF2) and increased nuclear factor κB (NF-κB). "Food as medicine" has been proposed as an adjuvant therapeutic alternative in modulating these factors. No studies have investigated the effects of sulforaphane (SFN) in cruciferous vegetables on the expression of these genes in patients with CKD. OBJECTIVE: The study aimed to evaluate the effects of SFN on the expression of NRF2 and NF-κB in patients on hemodialysis (HD). DESIGN AND METHODS: A randomized, double-blind, crossover study was performed on 30 patients on regular HD. Fourteen patients were randomly allocated to the intervention group (1 sachet/day of 2.5 g containing 1% SFN extract with 0.5% myrosinase) and 16 patients to the placebo group (1 sachet/day of 2.5 g containing corn starch colored with chlorophyll) for 2 months. After a washout period of 2 months, the groups were switched. NRF2 and NF-κB mRNA expression was evaluated by real-time quantitative polymerase chain reaction, and tumor necrosis factor alpha and interleukin-6 levels were quantified by enzyme-linked immunosorbent assay. Malondialdehyde was evaluated as a marker of lipid peroxidation. RESULTS: Twenty-five patients (17 women, 55 [interquartile range = 19] years and 55 [interquartile range = 74] months on HD) completed the study. There was no significant difference concerning the expression of mRNA NRF2 (P = .915) and mRNA NF-κB (P = .806) after supplementation with SFN. There was no difference in pro-inflammatory and oxidative stress biomarkers. CONCLUSION: 150 µmol of SFN for 2 months had no antioxidant and anti-inflammatory effect in patients with CKD undergoing HD.

Kidney Function Decline and Serious Adverse Drug Reactions in Patients With CKD.

RATIONALE & OBJECTIVE: Adverse drug reactions (ADRs) are common in patients with chronic kidney disease (CKD). The impact of kidney function decline on serious ADR risk has been poorly investigated. We comprehensively describe ADRs and assess the relationship between estimated glomerular filtration rate (eGFR) and serious ADR risk. STUDY DESIGN: Prospective cohort study. SETTING & PARTICIPANTS: 3,033 participants in French Chronic Kidney Disease-Renal Epidemiology and Information Network (CKD-REIN) cohort study, a nationwide sample of nephrology outpatients with moderate to advanced CKD. PREDICTORS: Demographic and biological data (including eGFR), medication prescriptions. OUTCOME: ADRs (preventable or not) were prospectively identified from hospital discharge reports, medical records, and patient interviews. Expert pharmacologists used validated tools to adjudicate ADRs. ANALYTICAL APPROACH: Restricted cubic splines in fully adjusted cause-specific Cox proportional hazard models were used to evaluate the relationship between eGFR and the risk of serious ADRs (overall and by subtype). RESULTS: During a median follow-up period of 4.7 years, 360 patients experienced 488 serious ADRs. Kidney and urinary disorders (n=170) and hemorrhage (n=170) accounted for 70% of serious ADRs. The most common medications classes were antithrombotics and renin-angiotensin system inhibitors. The majority of those serious ADRs were associated with hospitalization (n=467), with 32 directly or indirectly associated with death and 22 associated with a life-threatening event. More than 27% of the 488 serious ADRs were preventable or potentially preventable. The eGFR is a major risk factor for serious ADRs. The risk of acute kidney injury was 2.2% higher and risk of bleeding ADRs was 8% higher for each 1mL/min/1.73m2 lower baseline eGFR. LIMITATIONS: The results cannot be extrapolated to patients who are not being treated by a nephrologist. CONCLUSIONS: ADRs constitute a major cause of hospitalization in CKD patients for whom lower eGFR level is a major risk factor. PLAIN-LANGUAGE SUMMARY: Patients with chronic kidney disease (CKD) have complex clinical presentations, take multiple medications, and often receive inappropriate prescriptions. Using data from a large, prospective CKD cohort, we found a high incidence of serious adverse drug reactions (ADRs). The 2 most common serious ADRs were drug-induced acute kidney injury and bleeding. A large proportion of serious ADRs required hospital admission, and 11% led to death or were life threatening. Lower kidney function was a major risk factor for serious ADRs. Many of these serious ADRs were determined to be partly preventable through greater adherence to prescription guidelines. This report enhances our understanding of the potential toxicity of drugs taken by patients with moderate to advanced CKD. It emphasizes the importance of monitoring kidney function when prescribing drugs, particularly for high-risk medications such as antithrombotic agents.

Cognitive performance is associated with glomerular filtration rate in patients with chronic kidney disease: results from the CKD-REIN cohort.

BACKGROUND: Chronic kidney disease (CKD) is associated with cognitive impairment in general population. We assessed the association between kidney and cognitive functions in patients with CKD and the influence of cardiovascular (CV) risk factors, and depression on this association. METHODS: The CKD-Renal Epidemiology and Information Network cohort included 3033 patients with CKD stages 3-4, followed for 5 years. Cognitive function was assessed with the Mini-Mental State Examination (MMSE) and estimated glomerular filtration rate (eGFR) with the CKD-Epidemiology Collaboration equation-creatinin formula. Evolution of the MMSE score over time and its association with baseline eGFR were investigated with linear mixed models. We assessed the risk of incident cognitive outcome (hospitalisation or death with relevant International Classification of Disease-10 codes), with a Cox proportional hazard model. RESULTS: The mean age was 66.8, the mean eGFR was 33 mL/min/1.73 m2 and 387 patients (13.0%) had an MMSE score below 24 at baseline. A 10 mL/min/1.73 m2 decrement of baseline eGFR was associated with a mean MMSE decrease of 0.12 (95% CI 0.04 to 0.19) after adjustment for demographic characteristics, depression, CV risk factors and disease; but baseline eGFR was not associated with MMSE temporal evolution. HR for cognitive outcome during follow-up (median 2.01 years) associated with a 10 mL/min/1.73 m2 decrement of baseline eGFR was 1.35 (1.07, 1.70) (p=0.01) after adjustment. CONCLUSIONS: In patients with CKD, lower eGFR was associated with worse cognitive performance and incident cognitive events, independently of demographics, CV risk factors and depression. TRIAL REGISTRATION NUMBER: NCT03381950.

Ageing meets kidney disease.

Chronic kidney disease (CKD) is defined as abnormalities of kidney structure or function, present for ˃3 months, with implications for health. The most used diagnostic criteria are a urinary albumin: creatinine ratio ≥30 mg/g or an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m2. Either of these diagnostic thresholds is associated with adverse health outcomes. GFR decreases with age and the prevalence of CKD is highest in older adults; moreover, the presence of CKD is associated with an increased risk of all-cause and cardiovascular death related to accelerated ageing in all age ranges, and the absolute increase in risk is highest for those aged ˃75 years. Indeed, premature death is a more common outcome than CKD progression to kidney failure requiring kidney replacement therapy. The progressive ageing of the world population contributes to the projection that CKD will become the second most common cause of death before the end of the century in countries with long life expectancy. The current collection of selected studies on kidney disease and ageing published in Age&Ageing, NDT and CKJ provides an overview of key topics, including cognitive decline, sarcopaenia, wasting and cardiovascular and non-cardiovascular morbidity and mortality, the management of kidney failure and gender differences in CKD progression.

Factors associated with kalemia in renal disease.

BACKGROUND: International recommendations promote a strict potassium diet in order to avoid hyperkalemia in chronic kidney disease (CKD) patients. However, the efficiency of such a dietary recommendation has never been demonstrated. The objectives of this study were to define the relationship between kalemia, dietary potassium intake estimated by kaliuresis and renal function, and to define the factors associated with kalemia in patients using artificial intelligence. METHODS: To this extent, data from patients followed in a nephrology unit, included in the UniverSel study and whose kalemia (measured on the day of urine collection; n = 367) were analyzed. RESULTS: The patients included had a wide range of estimated glomerular filtration rate (eGFR), but few had stage 5 CKD. Kalemia was negatively and linearly correlated to eGFR (P < .001) but was not correlated to kaliuresis (P = .55). Kaliuresis was not correlated to eGFR (P = .08). Factors associated with kalemia were analyzed using a Bayesian network. The five variables most associated with kalemia were, in descending order, eGFR, original nephropathy, age, diabetes and plasma bicarbonate level. CONCLUSION: The results of this study do not support a strict dietary potassium control to regulate kalemia in stage 1-4 CKD patients.

Prediction of all-cause mortality for chronic kidney disease patients using four models of machine learning.

BACKGROUND: The prediction tools developed from general population data to predict all-cause mortality are not adapted to chronic kidney disease (CKD) patients, because this population displays a higher mortality risk. This study aimed to create a clinical prediction tool with good predictive performance to predict the 2-year all-cause mortality of stage 4 or stage 5 CKD patients. METHODS: The performance of four different models (deep learning, random forest, Bayesian network, logistic regression) to create four prediction tools was compared using a 10-fold cross validation. The model that offered the best performance for predicting mortality in the Photo-Graphe 3 cohort was selected and then optimized using synthetic data and a selected number of explanatory variables. The performance of the optimized prediction tool to correctly predict the 2-year mortality of the patients included in the Photo-Graphe 3 database were then assessed. RESULTS: Prediction tools developed using the Bayesian network and logistic regression tended to have the best performances. Although not significantly different from logistic regression, the prediction tool developed using the Bayesian network was chosen because of its advantages and then optimized. The optimized prediction tool that was developed using synthetic data and the seven variables with the best predictive value (age, erythropoietin-stimulating agent, cardiovascular history, smoking status, 25-hydroxy vitamin D, parathyroid hormone and ferritin levels) had satisfactory internal performance. CONCLUSIONS: A Bayesian network was used to create a seven-variable prediction tool to predict the 2-year all-cause mortality in patients with stage 4-5 CKD. Prior to external validation, the proposed prediction tool can be used at: https://dev.hed.cc/?a=jpfauvel&n=2022-05%20Modele%20Bayesien%2020000%20Mortalite%207%20variables%20Naif%20Zou%20online(1).neta for research purposes.

A New Approach for Cognitive Impairment Pattern in Chronic Kidney Disease.

BACKGROUND AND HYPOTHESIS: Chronic kidney disease (CKD) is associated with an elevated risk of neurocognitive disorders (NCDs). It remains unclear whether CKD-related NCDs have specific cognitive pattern or are earlier-onset phenotypes of the main NCDs (vascular NCDs and Alzheimer's disease). METHODS: We used the Mini Mental State Examination score (MMSE) to assess cognitive pattern in 3003 CKD patients (stage 3 to 4) followed up over 5 years in the Chronic Kidney Disease-Renal Epidemiology and Information Network (CKD-REIN) cohort. After normalizing MMSE scores to a 0-to-100 scale, the associations between the baseline estimated glomerular filtration rate (eGFR, using the CKD-EPI-creatinine formula) and changes in each MMSE domain score were assessed in linear mixed models. RESULTS: Patients (age: 67±13 years old; males: 65%, mean eGFR: 33±12 ml/min/1.73 m²) had a good baseline cognitive functions: the mean MMSE score was 26.9/30 ±2.9. After adjustment for age, sex, educational level, depression (past or present), cardiovascular risk factors, cerebrovascular disease, a lower baseline eGFR (per 10 ml/min/1.73 m²) was associated with a 0.53-point decrement (p<0.001; 95%CI [-0.98,-0.08]) for orientation, a 1.04-point decrement (p=0.03; 95%CI [-1.96,-0.13]) for attention and calculation, a 0.78-point decrement (p=0.003; 95%CI [-1.30,-0.27]) for language, and a 0.94-point decrement (p=0.02; 95%CI [-1.75,-0.13]) for praxis. Baseline eGFR was not, however, associated with significant changes over time in MMSE domain scores. CONCLUSION: A lower eGFR in CKD patients was associated with early impairments in certain cognitive domains: praxis, language and attention domains before an obvious cognitive decline. Early detection of NCD in CKD patients must be perform before clinically cognitive decline using preferably tests assessing executive, attentional functions and language than memory test. This could lead to a better management of cognitive impairment and their consequences on CKD management.

Caring for Patients With Advanced Chronic Kidney Disease: Dietary Options and Conservative Care Instead of Maintenance Dialysis.

An expert advisory board discussed the prevention and treatment of chronic kidney disease (CKD), with a focus on dietary options. This is timely, given the uptake of value based models for kidney care in the United States. Timing of dialysis start is influenced by patients' clinical status and complex patient-clinician interactions. Patients value personal freedom and quality of life and may want to delay dialysis, whilst physicians are sometimes more concerned with clinical outcomes. Kidney-preserving therapy can prolong the dialysis-free period and preserve residual kidney function, thus patients are asked to adjust their lifestyle and diet, to follow a low- or very low-protein diet, with or without ketoacid analogues. Multi-modal approaches include pharmacotherapies, management of symptoms, and a gradual, individualized dialysis transition. Patient empowerment is vital, including CKD education and involvement in decision making. These ideas may help patients, their families, and clinical teams to improve the management of CKD.

A prospective observational study for justification, safety, and efficacy of a third dose of mRNA vaccine in patients receiving maintenance hemodialysis.

The level of protection achieved by the standard two doses of COVID-19 mRNA vaccines in patients receiving maintenance hemodialysis (MHD) remains unclear. To study this we used the French Renal Epidemiology and Information Network (REIN) Registry to compare the incidence and severity of 1474 cases of COVID-19 diagnosed in patients receiving MHD after none, one or two doses of vaccine. Vaccination significantly reduce COVID-19 incidence and severity, but 11% of patients infected after two doses still died. Lack of vaccinal protection in patients naïve for SARS-CoV-2 could be due to defective Tfh response [38% of patients with negative spike-specific CD4+ T-cell interferon gamma release assay] and failure to generate viral neutralizing titers of anti-spike receptor binding domain (RBD) IgGs (63% of patients with titer at or under 997 BAU/ml, defining low/no responders) after two doses of vaccine. To improve protection, a third dose of vaccine was administered to 75 patients [57 low/no responders, 18 high responders after two doses] from the ROMANOV cohort that prospectively enrolled patients receiving MHD vaccinated with BNT162b2 (Pfizer). Tolerance to the third dose was excellent. High responders to two doses did not generate more anti-RBD IgGs after three doses but had more side effects. Importantly, 31 (54%) of low/no responders to two doses reached neutralizing titers of anti-RBD IgGs after three doses. A positive interferon gamma release assay and/or suboptimal titer of anti-RBD IgGs after two doses were the only predictive variables for response to three doses in multivariate analysis. Thus, the standard scheme of vaccination insufficiently protects patients receiving MHD. Anti-RBD IgG and specific CD4+ T-cell response after two doses can guide personalized administration of the third dose, which improves the humoral response of SARS-CoV-2-naïve patients receiving MHD.

A Novel Approach for Managing Protein-Energy Wasting in People With Kidney Failure Undergoing Maintenance Hemodialysis: Rationale and Call for Trials.

Protein-energy wasting (PEW) is a unique presentation of protein-energy malnutrition in people with kidney disease that is characterized by body protein catabolism exceeding anabolism. PEW is especially common in patients undergoing maintenance hemodialysis (HD) treatment. Dietary guidelines for managing PEW in HD patients primarily focus on protein adequacy and typically promote the intake of animal-based protein foods. Although intake of protein and essential amino acids is important for protein synthesis, the emphasis on protein adequacy largely fails to address-and may actually exacerbate-many of the root causes of PEW. This perspective examines the dietary determinants of PEW in people undergoing HD treatment, with an emphasis on upstream disease-related factors that reduce dietary protein utilization and impair dietary intakes. From this, we present a theoretical diet model for managing PEW that includes etiology-based dietary strategies to address barriers to intake and treat disease-related factors, as well as supportive dietary strategies to promote adequate energy and protein intakes. Given the complexity of diet-disease interactions in the pathogenesis of PEW, and its ongoing burden in HD patients, interventional trials are urgently needed to evaluate alternative diet therapy approaches for PEW in this population.

3-methylhistidine and clinical outcomes in maintenance haemodialysis patients.

BACKGROUND: Chronic kidney disease is an important contributor to morbidity and mortality. 3-methylhistidine (3-MH) is the by-product of actin and myosin degradation reflecting skeletal muscle turnover. Markedly elevated 3-MH levels have been documented in uraemic patients, but the interpretation of high 3-MH concentration in maintenance haemodialysis (MHD) patients remains unclear. Indeed, it is not known whether elevated serum 3-MH levels are a marker of excessive muscle catabolism or a better lean tissue mass. Here, we evaluated the association between serum 3-MH levels and clinical outcomes in these patients. METHODS: Serum 3-MH concentration was measured by reverse-phase liquid chromatography/tandem mass spectrometry in a cohort of MHD patients. We analysed the relationships between various clinical/laboratory indices, lean tissue mass measured by bioimpedance spectroscopy, mortality and cardiovascular (CV) events. RESULTS: Serum 3-MH concentration was positively correlated with serum albumin, normalized protein catabolic rate (nPCR), simplified creatinine index (SCI) and lean tissue mass. Of 291 MHD patients, during a mean follow-up of 847 days, 91 patients died and 101 patients experienced a CV event. Survival was significantly better in patients with high 3-MH concentrations (P = .002). A higher level of 3-MH was also associated with a lower CV mortality and lower incidence of CV events (P = .015 and P < .001, respectively). Low serum 3-MH levels remained significantly associated with CV events but not with mortality after adjustment for demographic, metabolic and CV risk factors. CONCLUSION: Elevated serum 3-MH concentration appears to be a marker of better lean tissue mass and nutritional status. Low serum 3-MH is a robust and independent predictor of CV events in the MHD population.

Water intake and progression of chronic kidney disease: the CKD-REIN cohort study.

BACKGROUND: Optimal daily water intake to prevent chronic kidney disease (CKD) progression is unknown. Taking the kidney's urine-concentrating ability into account, we studied the relation of kidney outcomes in patients with CKD to total and plain water intake and urine volume. METHODS: Including 1265 CKD patients [median age 69 years; mean estimated glomerular filtration rate (eGFR) 32 mL/min/1.73 m2] from the Chronic Kidney Disease-Renal Epidemiology and Information Network cohort (2013-19), we assessed fluid intake at baseline interviews, collected 24-h urine volumes and estimated urine osmolarity (eUosm). Using Cox and then linear mixed models, we estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for kidney failure and eGFR decline associated with hydration markers, adjusting for CKD progression risk factors and eUosm. RESULTS: Patients' median daily intake was 2.0 L [interquartile range (IQR) 1.6-2.6] for total water and 1.5 L (1-1.7) for plain water, median urine volume was 1.9 L/24 h (IQR 1.6-2.4) and mean eUosm was 374 ± 104 mosm/L. Neither total water intake nor urine volume was associated with either kidney outcome. Kidney failure risk increased significantly with decreasing eUosm ˂292 mosm/L. Adjusted HRs (95% CIs) for kidney failure associated with plain water intake were 1.88 (1.02-3.47), 1.59 (1.06-2.38), 1.76 (0.95-3.24) and 1.55 (1.03-2.32) in patients drinking <0.5, 0.5-1.0, 1.5-2.0 and >2.0 L/day compared with those drinking 1.0-1.5 L/day. High plain water intake was also significantly associated with faster eGFR decline. CONCLUSIONS: In patients with CKD, the relation between plain water intake and progression to kidney failure appears to be U-shaped. Both low and high intake may not be beneficial in CKD.

Urea levels and cardiovascular disease in patients with chronic kidney disease.

BACKGROUND: Elevated serum urea levels are common in moderate-to-advanced CKD. Several studies have shown that urea is a direct and indirect uremic toxin, especially with regard to cardiovascular disease. We sought to determine whether serum urea levels are associated with adverse cardiovascular events and death before renal replacement therapy (RRT) in patients with CKD. METHODS: CKD-REIN is a prospective cohort of CKD nephrology outpatients not receiving maintenance dialysis. The 2507 patients included in the analysis were divided into three groups according to the baseline serum urea level (T1 < 10.5, T2:10.5 to 15.1, and T3 ≥ 15.1 mmol/L). Cox proportional hazard models were used to estimate hazard ratios (HRs) for first atheromatous or nonatheromatous cardiovascular (CV) events, and all-cause mortality before RRT. The models were adjusted for baseline comorbidities, laboratory data, and medications. FINDINGS: Of the 2507 included patients (median [interquartile range (IQR)] age: 69[61-77]; mean (standard deviation) eGFR 33.5(11.6) mL/min/1.73 m²), 54% had a history of cardiovascular disease. After multiple adjustments for cardiovascular risk factors (including eGFR), patients in T3 had a higher risk of atheromatous and nonatheromatous cardiovascular events than patient in T1 (n events = 451, HR[95%CI]: 1.93[1.39-2.69]). The adjusted HRs for death before RRT (n events = 407) were 1.31[0.97; 1.76] and 1.73[1.22; 2.45] for patients T2 and those in T3, respectively. INTERPRETATION: Our data suggested that urea is a predictor of cardiovascular outcomes beyond CV risk factors including eGFR.

Barriers to conservative care from patients' and nephrologists' perspectives: the CKD-REIN study.

BACKGROUND: Conservative care is increasingly considered an alternative to kidney replacement therapy for kidney failure management, mostly among the elderly. We investigated its status and the barriers to its implementation from patients' and providers' perspectives. METHODS: We analysed data from 1204 patients with advanced chronic kidney disease (CKD) [estimated glomerular filtration rate (eGFR) <30 mL/min/1.73 m2] enrolled at 40 nationally representative nephrology clinics (2013-16) who completed a self-administered questionnaire about the information they received and their preferred treatment option, including conservative care, if their kidneys failed. Nephrologists (n = 137) also reported data about their clinics' resources and practices regarding conservative care. RESULTS: All participating facilities reported they were routinely able to offer conservative care, but only 37% had written protocols and only 5% had a person or team primarily responsible for it. Overall, 6% of patients were estimated to use conservative care. Among nephrologists, 82% reported they were fairly or extremely comfortable discussing conservative care, but only 28% usually or always offered this option for older (>75 years) patients approaching kidney failure. They used various terminology for this care, with conservative management and non-dialysis care mentioned most often. Among patients, 5% of those >75 years reported receiving information about this option and 2% preferring it. CONCLUSIONS: Although reported by nephrologists to be widely available and easily discussed, conservative care is only occasionally offered to older patients, most of whom report they were not informed of this option. The lack of a person or team responsible for conservative care and unclear information appear to be key barriers to its implementation.

New insights into acute-on-chronic kidney disease in nephrology patients: the CKD-REIN study.

BACKGROUND: Acute-on-chronic kidney disease (ACKD) is poorly understood and often overlooked. We studied its incidence, circumstances, determinants and outcomes in patients with CKD. METHODS: We used the Kidney Disease: Improving Global Outcomes criteria to identify all-stage acute kidney injury (AKI) events in 3033 nephrology outpatients with CKD Stages 3-5 participating in the CKD-Renal Epidemiology and Information Network cohort study (2013-20), and cause-specific Cox models to estimate hazard ratios [HRs; 95% confidence intervals (CIs)] of AKI-associated risk factors. RESULTS: At baseline, 22% of the patients [mean age 67 years, 65% men, mean estimated glomerular filtration rate (eGFR) 32 mL/min/1.73 m2] had a history of AKI. Over a 3-year follow-up, 443 had at least one AKI event: 27% were Stage 2 or 3 and 11% required dialysis; 74% involved hospitalization including 47% acquired as hospital inpatients; and a third were not reported in hospital discharge reports. Incidence rates were 10.1 and 4.8/100 person-years in patients with and without an AKI history, respectively. In 2375 patients without this history, male sex, diabetes, cardiovascular disease, cirrhosis, several drugs, low eGFR and serum albumin levels were significantly associated with a higher risk of AKI, as were low birth weight (<2500 g) (adjusted HR 1.98; 95% CI 1.35-2.91) and haemoglobin level (HR 1.21; 1.12-1.32 per 1 g/dL decrease). Within 1 year, only 63% of the patients had recovered their previous kidney function, 13.7% had started kidney replacement therapy and 12.7% had died. CONCLUSIONS: The study highlights the high rate of hospital-acquired AKI events in patients with CKD, and their underreporting at hospital discharge. It also reveals low birth weight and anaemia as possible new risk factors in CKD patients.