No additional benefit of prescribing a very low-protein diet in patients with advanced chronic kidney disease under regular nephrology care: a pragmatic, randomized, controlled trial

Effect of intensive water-salt diet nursing intervention on blood pressure and volume load in patients with chronic renal failure

BACKGROUND

This study aimed to investigate the impact of a comprehensive nursing intervention targeting high water and salt intake on blood pressure and volume burden in patients with chronic renal failure.

METHOD

From January 2020 to January 2023, 120 patients diagnosed with chronic renal failure were treated at our hospital. Participants were randomly allocated to either a control group (n = 60) receiving standard dietary education or an observation group (n = 60) receiving intensive water-salt diet nursing intervention alongside standard education. Blood pressure, volume load, and related parameters were compared after a 6-month observation period.

RESULT

Both groups exhibited reduced systolic and diastolic blood pressure post-intervention (p < 0.05). The observation group demonstrated a significantly lower extracellular water-to-total body water ratio (ECW/TBW) compared to the control group (p < 0.05). The observation group also showed higher 24-hour urine volume (p < 0.05), hemoglobin levels, creatinine clearance rates (p < 0.05), and treatment compliance (p < 0.05), alongside a lower complication rate (3.33% vs. 13.33%; χ2 = 3.927, p < 0.05). A negative correlation was observed between the Therapeutic Intervention Scoring System (TISS) scale and post-intervention blood pressure/volume load (r = -2.924, -2.184; p < 0.05).

CONCLUSION

Intensive water-salt diet nursing interventions effectively control blood pressure, reduce volume load, and mitigate complications in chronic renal failure patients. This approach should be widely implemented in clinical practice.

Fad diets for non-dialysis chronic kidney disease patients: Can "the miracle diet" be a threat?

In the pursuit of an effortless "miracle cure", there has been a significant increase in the proliferation of fad diets. These diets generally exclude a food group or macronutrients and may also restrict energy intake; they become popular quickly but often lack substantial scientific evidence to support their efficacy and safety. They only show short-term results rather than promoting a lifestyle change. Fad diets are nutritionally unbalanced and can be dangerous for some individuals. Most fad diets are generally restrictive in carbohydrates, high in protein, or unbalanced and have low energy intake, which can harm patients with early stages of chronic kidney damage (CKD) who need a low-protein diet with adequate energy intake. This narrative review discusses the risk of fad diet prescriptions for non-dialysis CKD patients.

The impact of low-protein diet on residual renal function in dialysis patients: a systematic review and metaanalysis

OBJECTIVE

A low-protein diet is essential for the nutritional management of chronic kidney diseases as it can reduce renal burden. However, the effect of low-protein diets on dialysis patients compared to pre-dialysis patients remains unclear. This study aims to compare residual renal function among dialysis patients following a low-protein diet versus a normal diet, offering valuable insights into the optimal nutritional strategy for preserving residual renal function.

METHODS

This meta-analysis has been registered on PROSPERO, an international registry of prospective systematic reviews. We conducted a comprehensive and systematic literature search using PubMed, Cochrane Library and Web of Science (WOS). Our search strategy was designed to discover all relevant studies investigating the influence of low-protein diets on residual renal function among dialysis patients. Four studies met the inclusion criteria. Heterogeneity was discussed through subgroup analysis of dialysis method, the addition of ketoacid and other relevant factors.

RESULTS

We included four prospective studies of low-protein diets among dialysis patients, each of which included at least 40 participants. Individuals receiving a 12-months low-protein diet had a higher GFR (MD = 1.37 ml/min; 95% CI:0.18 to 2.55), while daily urine volume decreasing more slowly (MD = 660 ml; 95% CI: 110 to 1210). In addition, dialysis patients undergoing a low-protein diet for 4 or 12 months had reduced serum phosphorus (MD=-0.74 g/dl; 95% CI: -1.04 to -0.45). Their serum albumin was higher than dialysis patients received a free-choice diet (MD = 4.00 g/dl; 95% CI: 2.46 to 5.54).

CONCLUSION

Dialysis patients who adhere to a long-term low-protein diet may have a positive effect on residual kidney function. In addition, dialysis patients receiving a low-protein diet increased serum albumin, reduced serum phosphorus levels, and maintained a better nutritional status and electrolyte balance.

The 60:40 conundrum: are women with CKD discriminated after referral to a nephrology clinic?

Background

Epidemiological data show that chronic kidney disease (CKD) is more prevalent among females than males but the prevalence of women in dialysis is lower, as is their representation in nephrology trials. We aimed to test whether sex distribution varies at nephrology referral, inclusion in a trial, or at the starting of dialysis.

Methods

We evaluated patients' characteristics at the time of the first consultation in the Unit for the Care of Advanced CKD (UIRAV), at the inclusion in an observational study (PRO-RE-RE-PRO) and at the beginning of dialysis. Patient and renal survival analysis was performed in the pre-dialysis phase and after dialysis start. Reasons for denying participation to the proposed study and causes of death or withdrawal from follow-up and dialysis were likewise examined.

Results

During the period 2017-2023, 866 patients were referred to the UIRAV, 59% males and 41% females. Female patients were older, had lower comorbidity and were referred at the same eGFR than males. The same male/female proportion was observed in patients included in the PRO-RE-RE-PRO study and at dialysis start. Survival was significantly higher in females. Overall, distribution across sex remained stable over time.

Conclusions

Males and females are referred at similar eGFR levels, which appears to be the main reason for seeking nephrology care. Afterward, the ratio between males and females remains stable, suggesting that if a sex-selection bias exists, it should be sought before the first nephrology referral. However, further studies are needed to ensure that health equity is respected across sexes.

Prognostic nutritional index as an independent risk factor for disease progression in patients with IgA nephropathy

Background

Immunoglobulin A nephropathy (IgAN), a common primary glomerulonephritis worldwide, has been investigated, and complex factors are involved in disease progression. A group of evidence emerged that nutrition status plays a nonsubstitutable role in the management of chronic kidney disease. Meanwhile, a novel marker of nutrition and inflammation, the prognostic nutritional index (PNI), has been studied in various diseases. Whether PNI can predict the renal outcome of patients with IgAN remains unclear. Thus, we aimed to evaluate the relationships between PNI and clinicopathologic features, renal progression and renal prognosis in patients with IgAN.

Methods

A total of 1,377 patients with biopsy-proven IgAN were recruited for this retrospective study. All patients were divided into two groups based on the cutoff value of PNI: the high group (PNI ≥ 47.1, n = 886) and the low group (PNI < 47.1, n = 491). Our study endpoint was end-stage renal disease [estimated glomerular filtration rate (eGFR) < 15 mL/min/1.73 m2 or performance of renal replacement therapy]. A correlation test was conducted to explore the relationship between PNI and other important clinicopathologic parameters. The predictive value was determined by the area under the receiver operating characteristic curve (AUROC). Kaplan-Meier and Cox proportional hazards analyses were performed to assess the value of PNI in predicting renal progression and prognosis.

Results

The correlation test revealed that PNI was positively associated with eGFR (r = 0.16, p < 0.001) and negatively related to 24-h proteinuria (r = -0.387, p < 0.001). Multivariate Cox regression analysis indicated that low PNI was an independent risk factor for IgAN patients even after adjusting for important clinical and pathological parameters (HR, 0.664; 95% CI, 0.443-0.994; p = 0.047). Kaplan-Meier analysis showed that low PNI was significantly correlated with severe renal outcome in patients with IgAN (p < 0.001). Moreover, the subgroup analyses of Kaplan-Meier survival demonstrated that low PNI predicted severe renal prognosis in different types of IgAN patients when considering the level of glomerular filtration rate, 24 h proteinuria and hemoglobin.

Conclusion

PNI is associated with renal function and pathologic lesions in IgAN patients and could be a novel marker for the evaluation of renal progression and prognosis.

Plant-Dominant Low-Protein Diets: A Promising Dietary Strategy for Mitigating Disease Progression in People with Chronic Kidney Disease-A Comprehensive Review

Chronic kidney disease (CKD) is a global health crisis affecting over 10% of the population, with mortality rates increasing significantly. Current management strategies, including expensive medications and renal replacement therapies, highlight the need for cost-effective, conservative approaches. This review examines the evidence for plant-dominant low-protein diets (PLADO) in managing non-dialysis-dependent CKD. Existing guidelines for protein restriction in CKD vary considerably, with inconsistencies and a lack of personalization noted in the KDOQI and KDIGO recommendations. While traditional low-protein diet trials show limited success due to poor adherence and marginal benefits, PLADO offers a potentially more sustainable alternative. PLADO's advantages include improved nutrient density, reduced dietary acid load, anti-inflammatory effects, and beneficial modulation of the gut microbiome, potentially reducing uremic toxins and improving cardiovascular health. However, challenges remain, including adherence issues, potential nutrient deficiencies, and potassium management. Although observational studies show promise, further large-scale randomized controlled trials are necessary to validate PLADO's efficacy and establish optimal dietary composition. A personalized, multidisciplinary approach is essential for successful implementation and monitoring to maximize PLADO's benefits in improving outcomes for individuals with NDD-CKD.

Integrating the new pharmacological standard of care with traditional nutritional interventions in non-dialysis CKD

Chronic kidney disease (CKD) is widely recognized as a leading and growing contributor to global morbidity and mortality worldwide. Nutritional therapy is the basic treatment for metabolic control, and may contribute to nephroprotection; however, the absence of solid evidence on slowing CKD progression together with poor adherence to dietary prescription limit de facto its efficacy and prevent its more widespread use. Sodium-glucose transport protein 2 inhibitors (SGLT2is) are now considered the new standard of care in CKD; in addition, novel potassium binders, glucagon-like peptide-1 receptor antagonists (GLP1-RAs) and nonsteroidal mineralocorticoid receptor antagonists (nsMRAs) show either direct (SGLT2i, GLP1-RA, nsMRA) or indirect (potassium binders that enable the optimal use of renin-angiotensin-aldosterone system inhibitors) nephroprotective effects. These drugs could potentially lead to a more permissive diet, thereby allowing the patient to reap the benefits of this approach. In particular, SGLT2is, and to a lesser extent also GLP1-RAs and nsMRAs in patients with diabetic kidney disease, can counterbalance hyperfiltration as well as the higher protein intake often recorded in obese patients; on the other hand, potassium binders can facilitate following plant-based diets, which are considered healthy because of the high content of essential micronutrients such as antioxidant vitamins, minerals, alkalies, and fibers. In this review paper, we discuss the current pharmacological paradigm shift that places a new, broader standard of care in light of its interaction with nutritional therapy in order to optimize the global approach to patients with CKD not on dialysis.

Efficacy and safety of ketoanalogue supplementation combined with protein-restricted diets in advanced chronic kidney disease: a systematic review and meta-analysis

BACKGROUND

The benefits and harms of protein-restricted diets supplemented with ketoanalogues in patients with chronic kidney disease (CKD) remain uncertain. We aimed to evaluate the effects of ketoanalogues supplemented to protein-restricted diets in patients with advanced CKD.

METHODS

We conducted systematic literature searches of PubMed, Embase, Scopus, and Cochrane Library up to June 3, 2024. Randomized controlled trials comparing ketoanalogue supplementation with a low- or very low-protein diet versus a low-protein diet alone in stages 3-5 CKD patients were selected. Outcomes included glomerular filtration rate (GFR), end-stage kidney disease (ESKD), all-cause mortality, and blood levels of urea nitrogen, calcium, phosphorus, and albumin. Triceps skin fold, mid-arm muscle circumference, lean body mass, and subjective global assessment were also evaluated. The protocol for this systematic review was registered in the International Prospective Register of Systematic Reviews (PROSPERO; registration number CRD42023465754).

RESULTS

A total of 16 trials comprising 1344 participants were identified, with a median follow-up of 13 months. Compared to a low-protein diet alone, ketoanalogues supplemented to a protein-restricted diet resulted in a significantly higher GFR, decreased levels of urea nitrogen and phosphorus, and increased levels of calcium. Furthermore, ketoanalogues combined with a protein-restricted diet showed a marginally lower risk of ESKD in participants without diabetes. No significant differences were observed in all-cause mortality, albumin, mid-arm muscle circumference, lean body mass, and subjective global assessment.

CONCLUSIONS

For stages 3-5 CKD patients, ketoanalogues combined with a protein-restricted diet may help postpone initiation of dialysis, improve calcium-phosphate homeostasis, and slow GFR decline, while maintaining a similar nutritional status and survival. Larger, long-term studies are needed to confirm these potential benefits, especially in CKD patients with diabetes.

The Key Role of Nutritional Intervention in Delaying Disease Progression and the Therapeutic Management of Diabetic Kidney Disease-A Challenge for Physicians and Patients

Chronic kidney disease (CKD) represents an increasingly common pathology that affects patients' quality of life, and it is frequently associated with a high mortality rate, especially in the final stages of the disease. At the same time, diabetes mellitus is a chronic disease that contributes to the increased number of patients with CKD through diabetic kidney disease (DKD). The alternation of hypoglycemia with hyperglycemia is a condition in the occurrence of microvascular complications of diabetes, including DKD, which involves structural and functional changes in the kidneys. The therapeutic management of diabetic nephropathy is a much-discussed topic, both from nutritional medical recommendations and a pharmacotherapy perspective. The diet starting point for patients with DKD is represented by a personalized and correct adjustment of macro- and micronutrients. The importance of nutritional status in DKD patients is given by the fact that it represents a modifiable factor, which contributes to the evolution and prognosis of the disease. Since, in most cases, it is necessary to restrict many types of food, malnutrition must be considered and avoided as much as possible.

Low-Protein Diets Could Be Effective and Safe in Elderly Patients with Advanced Diabetic Kidney Disease

Low-protein diets (LPDs) seem to improve metabolic complications of advanced CKD, thus postponing kidney replacement therapy (KRT) initiation. However, the nutritional safety of LPDs remains debatable in patients with diabetic kidney disease (DKD), especially in the elderly. This is a sub-analysis of a prospective unicentric interventional study which assessed the effects of LPD in patients with advanced DKD, focusing on the feasibility and safety of LPD in elderly patients. Ninety-two patients with DKD and stable CKD stage 4+, proteinuria >3 g/g creatininuria, good nutritional status, with confirmed compliance to protein restriction, were enrolled and received LPD (0.6 g mixed proteins/kg-day) supplemented with ketoanalogues of essential amino acids for 12 months. Of the total group, 42% were elderly with a median eGFR 12.6 mL/min and a median proteinuria 5.14 g/g creatininuria. In elderly patients, proteinuria decreased by 70% compared to baseline. The rate of kidney function decline was 0.1 versus 0.5 mL/min-month before enrolment. Vascular events occurred in 15% of cases, not related to nutritional intervention, but to the severity of CKD and higher MAP. LPDs seem to be safe and effective in postponing KRT in elderly patients with advanced DKD while preserving the nutritional status.

Low Protein Diet Reduces Proteinuria and Decline in Glomerular Filtration Rate in Advanced, Heavy Proteinuric Diabetic Kidney Disease

Low protein diet (LPD) seems beneficial in ameliorating the complications of chronic kidney disease (CKD), in reducing proteinuria and the decline in kidney function, thus postponing the need for kidney replacement therapy (KRT). However, this type of intervention was less investigated in diabetic kidney disease (DKD). This is a single-center, prospective, interventional study that aims to assess the efficacy of reducing proteinuria and the rate of decline in the estimated glomerular filtration rate (eGFR). Patients with advanced DKD (stable proteinuria > 3 g/g and eGFR < 30 mL/min) with a good nutritional status and accepting a LPD were evaluated for inclusion. Ninety-two of the 452 screened patients (66% males, median age 61 years, proteinuria 4.8 g/g creatininuria, eGFR 11.7 mL/min/1.73 m2) completed the study. Intervention consisted of LPD supplemented with ketoanalogues of essential amino acids (KA) along with conventional nephroprotective therapy. Efficacy parameters were the variation in proteinuria and in eGFR from baseline to the end of the study. Proteinuria decreased 3-fold, and the rate of decline in eGFR decreased 5-fold in the intervention phase. No patient initiated KRT or died. LPD supplemented with KA seems effective in safely postponing KRT by reducing proteinuria and the decline in kidney function in advanced DKD.

Estimated glomerular filtration rate in observational and interventional studies in chronic kidney disease

Estimated glomerular filtration rate is considered the principal measure of kidney function and, together with albuminuria, is a relevant prognostic factor for the development of end-stage kidney disease. Due to the strong association between estimated glomerular filtration rate and clinical events, such as commencement of dialysis, cardiovascular outcomes and all-cause death, estimated glomerular filtration rate is crucial for clinical decision-making in terms of scheduling follow-up and pharmacological interventions, and planning renal replacement therapies in advanced chronic kidney disease. In this review we discuss the available methods for measuring glomerular filtration rate and for estimating it through mathematical equations developed over the last few decades. We summarize the prognostic association of different percentages of estimated glomerular filtration rate decline and the main clinical outcomes, and how treatments modify estimated glomerular filtration rate decline and the risk of future endpoints. We also examine the role of pre-clinical trial slope and that of estimated glomerular filtration rate as a useful biomarker when evaluating patients for inclusion into both observational and interventional studies.

Secular Trend in GFR Decline in Non-Dialysis CKD Based on Observational Data From Standard of Care Arms of Trials

RATIONALE & OBJECTIVE

The standard of care (SoC) group of randomized controlled trials (RCTs) is a useful setting to explore the secular trends in kidney disease progression because implementation of best clinical practices is pursued for all patients enrolled in trials. This meta-analysis evaluated the secular trend in the change of glomerular filtration rate (GFR) decline in the SoC arm of RCTs in chronic kidney disease (CKD) published in the last 30 years.

STUDY DESIGN

Systematic review and meta-analysis of the SoC arms of RCTs analyzed as an observational study.

SETTING & STUDY POPULATIONS

Adult patients with CKD enrolled in the SoC arm of RCTs.

SELECTION CRITERIA FOR STUDIES

Phase 3 RCTs evaluating GFR decline as an outcome in SoC arms.

DATA EXTRACTION

Two independent reviewers evaluated RCTs for eligibility and extracted relevant data.

ANALYTICAL APPROACH

The mean of GFR declines extracted in the SoC arm of selected RCTs were pooled by using a random effects model. Meta-regression analyses were performed to identify factors that may explain heterogeneity.

RESULTS

The SoC arms from 92 RCTs were included in the meta-analysis with a total of 32,202 patients. The overall mean GFR decline was-4.00 (95% CI, -4.55 to-3.44) mL/min/1.73m2 per year in the SoC arms with a high level of heterogeneity (I2, 98.4% [95% CI, 98.2-98.5], P<0.001). Meta-regression analysis showed an association between publication year (β estimate, 0.09 [95% CI, 0.032-0.148], P=0.003) and reduction in GFR over time. When evaluating publication decade categorically, GFR decline was-5.44 (95% CI, -7.15 to-3.73), -3.92 (95% CI, -4.82 to-3.02), and -3.20 (95% CI, -3.75 to -2.64) mL/min/1.73m2 per year during 1991-2000, 2001-2010, and 2011-2023, respectively. Using meta-regression, the heterogeneity of GFR decline was mainly explained by age and proteinuria.

LIMITATIONS

Different methods assessing GFR in selected trials and observational design of the study.

CONCLUSIONS

In the last 3 decades, GFR decline has decreased over time in patients enrolled in RCTs who received the standard of care.

TRIAL REGISTRATION

Registered at PROSPERO with record number CRD42022357704.

PLAIN-LANGUAGE SUMMARY

This study evaluated the secular trend in the change in glomerular filtration rate (GFR) decline in the placebo arms of randomized controlled trials (RCTs) that were studying approaches to protect the kidneys in the setting of chronic kidney disease. The placebo groups of RCTs are useful for examining whether the rate of progression of kidney disease has changed over time. We found an improvement in the slope of change in GFR over time. These findings suggest that adherence to standards of kidney care as implemented in clinical trials may be associated with improved clinical outcomes, and these data may inform the design of future RCTs in nephrology.

Association between adequate dietary protein and all-cause and cardiovascular mortality in patients with selective glomerular hypofiltration syndrome

Aims: To determine the impact of dietary protein intake and protein sources on all-cause and cardiovascular mortality of selective glomerular hypofiltration syndrome (SGHS) patients. Methods: This study recruited participants from the National Health and Nutrition Examination Survey (NHANES) conducted between 1999 and 2004. Cox proportional hazard models and competing risk models were employed to investigate the effects of dietary protein intake and protein sources on all-cause and cardiovascular mortality in SGHS patients. Additionally, Cox regression models utilizing restricted cubic splines (RCS) were used to explore potential non-linear associations. Results: Over a median follow-up period of 204 months, 20.71% (449/2168) participants died, with 5.40% (117/2168) experiencing cardiovascular mortality. In the fully adjusted model, participants with the highest dietary protein intake (Q4, ≥107.13 g d-1) exhibited a 40% reduced risk of all-cause mortality (HR: 0.60, 95% CI: 0.39 to 0.94) and an 88% reduced risk of cardiovascular mortality (HR: 0.12, 95% CI: 0.04 to 0.35) compared to those with the lowest dietary protein intake (Q1, < 57.93 g d-1). Notably, non-red meat protein sources were found to reduce the risk of all-cause and cardiovascular mortality, whereas no significant association was observed with red meat consumption. Conclusion: Adequate dietary protein intake has been linked to a decreased risk of all-cause and cardiovascular mortality in individuals with selective glomerular hypofiltration syndromes. This protective effect seems to be primarily associated with protein obtained from non-red meat sources.

What is central to renal nutrition: protein or sodium intake?

Historically, nutrition intervention has been primarily focused on limiting kidney injury, reducing generation of uraemic metabolites, as well as maintaining nutrition status and preventing protein-energy wasting in patients with chronic kidney disease (CKD). This forms an important rationale for prescribing restricted protein diet and restricted salt diet in patients with CKD. However, evidence supporting a specific protein intake threshold or salt intake threshold remains far from compelling. Some international or national guidelines organizations have provided strong or 'level 1' recommendations for restricted protein diet and restricted salt diet in CKD. However, it is uncertain whether salt or protein restriction plays a more central role in renal nutrition management. A key challenge in successful implementation or wide acceptance of a restricted protein diet and a restricted salt diet is patients' long-term dietary adherence. These challenges also explain the practical difficulties in conducting randomized trials that evaluate the impact of dietary therapy on patients' outcomes. It is increasingly recognized that successful implementation of a restricted dietary prescription or nutrition intervention requires a highly personalized, holistic care approach with support and input from a dedicated multidisciplinary team that provides regular support, counselling and close monitoring of patients. With the advent of novel drug therapies for CKD management such as sodium-glucose cotransporter-2 inhibitors or non-steroidal mineralocorticoid receptor antagonist, it is uncertain whether restricted protein diet and restricted salt diet may still be necessary and have incremental benefits. Powered randomized controlled trials with novel design are clearly indicated to inform clinical practice on recommended dietary protein and salt intake threshold for CKD in this new era.

The Role of Plant-Based Diets in Preventing and Mitigating Chronic Kidney Disease: More Light than Shadows

Chronic kidney disease (CKD) is a non-communicable disease that affects >10% of the general population worldwide; the number of patients affected by CKD is increasing due in part to the rise in risk factors such as obesity, hypertension, and diabetes mellitus. As many studies show, diet can be an important tool for preventing and mitigating the onset of non-communicable diseases. Plant-based diets (PBDs) are those that emphasize the consumption of plant foods and may or may not include small or moderate amounts of animal foods. Recently, these diets have received increasing interest because they have been associated with favourable effects on health and also appear to protect against the development and progression of CKD. PBDs, which are associated with protein restrictions, seem to offer adjunctive advantages in patients with chronic kidney disease, as compared to conventional low-protein diets that include animal proteins. The principal aims of this review are to provide a comprehensive overview of the existing literature regarding the role of plant-based diets and low-protein, plant-based diets in the context of chronic kidney disease. Moreover, we try to clarify the definition of plant-based diets, and then we analyse possible concerns about the use of PBDs in patients with chronic kidney disease (nutritional deficiency and hyperkalaemia risk). Finally, we offer some strategies to increase the nutritional value of plant-based low-protein diets. In the Materials and Methods section, many studies about plant-based diets and low-protein plant-based diets (e.g., the very-low-protein diet and vegan low-protein diet, LPD) in chronic kidney disease were considered. In the Results and Conclusion section, current data, most from observational studies, agree upon the protective effect of plant-based diets on kidney function. Moreover, in patients with advanced CKD, low-protein plant-based options, especially a very-low-protein diet supplemented with heteroanalogues (VLPDs), compared to a conventional LPD appear to offer adjunctive advances in terms of delaying dialysis and mitigating metabolic disturbances. However, further studies are necessary to better investigate the possible metabolic and cardiovascular advantages of plant-based LPDs versus conventional LPDs.

Supplemented Very Low Protein Diet (sVLPD) in Patients with Advanced Chronic Renal Failure: Clinical and Economic Benefits

The supplemented very low-protein diet (sVLPD) has proven effective in slowing the progression of stage 5 chronic renal failure and postponing the start of the dialysis treatment. However, sVLPD could expose the patient to the risk of malnutrition. This diet is also difficult to implement due to the required intake of large number of keto-analogue/amino acid tablets. In our Center, the Department of Nephrology and Dialysis of Azienda Sanitaria Territoriale n 1, Pesaro-Urbino, of Italy, respecting the guidelines of normal clinical practice, we prescribed sVLPD (0.3 g/prot/day) supplemented with only essential amino acids without the use of ketoanalogues in stage 5 patients and verified its efficacy, safety and clinical and economic effects. Over the 24 months period of observation the progression of chronic kidney disease (CKD) slowed down (mean eGFR 11.6 ± 3.3 vs. 9.3 ± 2.7 mL/min/1.73 m2, p < 0.001) and the start of the dialysis treatment (adjusted HR = 0.361, CI 0.200-0.650, p = 0.001) was delayed without evidence of malnutrition, in compliant vs. non-compliant patients. This led to a substantial cost reduction for the National Health System. This non-interventional longitudinal observational study is part of standard clinical practice and suggests that VLPD supplemented with essential amino acids could be extensively used to reduce the incidence of dialysis treatments, with a favorable economic impact on the NHS.

The Microbiome and Protein Carbamylation: Potential Targets for Protein-Restricted Diets Supplemented with Ketoanalogues in Predialysis Chronic Kidney Disease

In chronic kidney disease (CKD), metabolic derangements resulting from the interplay between decreasing renal excretory capacity and impaired gut function contribute to accelerating disease progression and enhancing the risk of complications. To protect residual kidney function and improve quality of life in conservatively managed predialysis CKD patients, current guidelines recommend protein-restricted diets supplemented with essential amino acids (EAAs) and their ketoanalogues (KAs). In clinical studies, such an approach improved nitrogen balance and other secondary metabolic disturbances, translating to clinical benefits, mainly the delayed initiation of dialysis. There is also increasing evidence that a protein-restricted diet supplemented with KAs slows down disease progression. In the present review article, recent insights into the role of KA/EAA-supplemented protein-restricted diets in delaying CKD progression are summarized, and possible mechanistic underpinnings, such as protein carbamylation and gut dysbiosis, are elucidated. Emerging evidence suggests that lowering urea levels may reduce protein carbamylation, which might contribute to decreased morbidity and mortality. Protein restriction, alone or in combination with KA/EAA supplementation, modulates gut dysbiosis and decreases the generation of gut-derived uremic toxins associated, e.g., with cardiovascular disease, inflammation, protein energy wasting, and disease progression. Future studies are warranted to assess the effects on the gut microbiome, the generation of uremic toxins, as well as markers of carbamylation.

The impact of a vegetarian diet on chronic kidney disease (CKD) progression - a systematic review

BACKGROUND

A vegetarian diet is a popular alternative to the casual diet - it is considered healthy, and was proven to positively affect cardiovascular health. The Chronic Kidney Disease (CKD) progression is a major issue in the healthcare system, and constitutes a leading cause of death for 1.5% of the global population. The objective of this systematic review was to investigate the potential impact of a vegetarian diet on kidney function in CKD patients.

METHOD

Our systematic review focused on randomized controlled trials (RCTs) which compared the effects of a vegetarian diet (experimental) and a standard omnivore diet (comparator) in terms of the estimated glomerular filtration rate (eGFR) in CKD patients. Inclusion criteria were based on PICO elements, with two researchers involved in browsing the Cochrane and Pubmed search engines. The investigation was performed using the PRISMA 2020 Checklist and PRISMA 2020 flow diagram. The search terms included: 'vegetarian diet' AND 'nephropathy', 'eGFR', 'albuminuria', 'chronic kidney disease'. Bias assessment was performed using RoB 2 tool to determine the validity of the data collected from studies.

RESULTS

Four RCTs with a total of 346 participants were included in the presented systematic review. Two largest RCTs reported an increase in eGFR following a change to a vegetarian diet (p = 0.01 and p = 0.001). Another two found no significant differences between the experimental and control groups, also these trials were associated with a high risk of bias in terms of missing data outcome and the randomization process.

CONCLUSIONS

The findings collected in this systematic review suggest that a vegetarian diet improves renal filtration function in CKD patients. Therefore, it seems essential to conduct further research involving the impact of the diet on the progression of CKD.

Nutritional status and the risk of malnutrition in older adults with chronic kidney disease - implications for low protein intake and nutritional care: A critical review endorsed by ERN-ERA and ESPEN

Increased life expectancy is posing unprecedented challenges to healthcare systems worldwide. These include a sharp increase in the prevalence of chronic kidney disease (CKD) and of impaired nutritional status with malnutrition-protein-energy wasting (PEW) that portends worse clinical outcomes, including reduced survival. In older adults with CKD, a nutritional dilemma occurs when indications from geriatric nutritional guidelines to maintain the protein intake above 1.0 g/kg/day to prevent malnutrition need to be adapted to the indications from nephrology guidelines, to reduce protein intake in order to prevent or slow CKD progression and improve metabolic abnormalities. To address these issues, the European Society for Clinical Nutrition and Metabolism (ESPEN) and the European Renal Nutrition group of the European Renal Association (ERN-ERA) have prepared this conjoint critical review paper, whose objective is to summarize key concepts related to prevention and treatment of both CKD progression and impaired nutritional status using dietary approaches, and to provide guidance on how to define optimal protein and energy intake in older adults with differing severity of CKD. Overall, the authors support careful assessment to identify the most urgent clinical challenge and the consequent treatment priority. The presence of malnutrition-protein-energy wasting (PEW) suggests the need to avoid or postpone protein restriction, particularly in the presence of stable kidney function and considering the patient's preferences and quality of life. CKD progression and advanced CKD stage support prioritization of protein restriction in the presence of a good nutritional status. Individual risk-benefit assessment and appropriate nutritional monitoring should guide the decision-making process. Higher awareness of the challenges of nutritional care in older adult patients with CKD is needed to improve care and outcomes. Research is advocated to support evidence-based recommendations, which we still lack for this increasingly large patient subgroup.

Personalized Low-Protein Diet Prescription in CKD Population: Merging Evidence From Randomized Trials With Observational Data

Nutritional therapy is a cornerstone of the clinical management of chronic kidney disease (CKD). Nevertheless, randomized controlled trials often have failed to show a relevant benefit of low-protein diets in nonselected CKD populations in terms of slowing the progression of kidney disease and need for dialysis. The more the target population is selected, the less the results can be generalizable to implement in clinical practice. On the contrary, observational studies, especially if performed with patient-centered, flexible approaches, point toward an extensive implementation of dietary protein restriction in different and unselected CKD populations. The observational evidence cannot be disregarded anymore. The most recent guidelines advise implementing low-protein diets or even very-low-protein diets in all CKD patients as early as stage 3. However, the lack of data from large randomized controlled trials on unselected CKD populations as well as on specific subpopulations, such as diabetic or obese patients, which nowadays comprise the majority of CKD subjects, reduces the generalizability of the recommendations. For some patient populations, such as those encompassing very old, nephrotic, or pregnant patients, the literature is even more limited because of the lower prevalence of these conditions and diffused prejudices against reducing protein intake. This pragmatic review discusses the need for integrating information derived from randomized trials with evidence derived from observational studies to guide feasible strategies for more successful implementation of low-protein diets in the treatment of all segments of the CKD population.

Plant-Dominant Low Protein Diet: A Potential Alternative Dietary Practice for Patients with Chronic Kidney Disease

Dietary protein restriction has long been a cornerstone of nutritional therapy for patients with chronic kidney diseases (CKD). However, the recommended amount of dietary protein intake is different across guidelines. This is partly because previous randomized controlled trials have reported conflicting results regarding the efficacy of protein restriction in terms of kidney outcomes. Interestingly, a vegetarian, very low protein diet has been shown to reduce the risk of kidney failure among patients with advanced CKD, without increasing the incidence of hyperkalemia. This finding suggests that the source of protein may also influence the kidney outcomes. Furthermore, a plant-dominant low-protein diet (PLADO) has recently been proposed as an alternative dietary therapy for patients with CKD. There are several potential mechanisms by which plant-based diets would benefit patients with CKD. For example, plant-based diets may reduce the production of gut-derived uremic toxins by increasing the intake of fiber, and are useful for correcting metabolic acidosis and hyperphosphatemia. Plant proteins are less likely to induce glomerular hyperfiltration than animal proteins. Furthermore, plant-based diets increase magnesium intake, which may prevent vascular calcification. More evidence is needed to establish the efficacy, safety, and feasibility of PLADO as a new adjunct therapy in real-world patients with CKD.

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.

Dietary protein and muscle wasting in chronic kidney disease: new insights

PURPOSE OF REVIEW

Muscle wasting is an important health problem in chronic kidney disease (CKD) patients. Protein restriction in the diet can be one of the main causes of muscle wasting in this population. In this review, we aimed to investigate the relationship between dietary protein intake and muscle wasting in CKD patients according to recent literature.

RECENT FINDINGS

The one of the main mechanisms responsible for the muscle wasting is the disturbances in skeletal muscle protein turnover. Muscle wasting primarily occurs when the rates of muscle protein breakdown exceed the muscle protein synthesis. Dietary protein intake represents an important role by causing a potent anabolic stimulus resulting a positive muscle protein balance. Compared to studies made in healthy populations, there are very limited studies in the literature about the relationship between dietary protein intake and muscle wasting in the CKD population. Majority of the studies showed that a more liberal protein intake is beneficial for muscle wasting in especially advanced CKD and hemodialysis population.

SUMMARY

Although evaluating muscle wasting in CKD patients, the amount of protein in the diet of patients should also be reviewed. Although excessive protein intake has some negative consequences on this patient group, a more liberated dietary protein intake should be taken into account in this patient group with muscle wasting and especially in dialysis patients.

[Diabetic kidney disease (update 2023) : Position paper of the Austrian Diabetes Association and the Austrian Society for Nephrology]

Epidemiological investigations have shown that approximately 2-3% of all Austrians have diabetes mellitus with renal involvement, leaving 250,000 people in Austria affected. The risk of occurrence and progression of this disease can be attenuated by lifestyle interventions as well as optimization of blood pressure, blood glucose control and special drug classes. The present article represents the joint recommendations of the Austrian Diabetes Association and the Austrian Society of Nephrology for the diagnostic and treatment strategies of diabetic kidney disease.

Ketoanalogues Supplemental Low Protein Diet Safely Decreases Short-Term Risk of Dialysis among CKD Stage 4 Patients

Background: Rigid dietary controls and pill burden make a very-low protein (0.3−0.4 g/kg body weight per day), vegetarian diet supplemented with ketoanalogues of amino acids (sVLPD) hard to follow in the long-term. This study aimed to evaluate whether a ketoanalogue supplemental low-protein diet (sLPD) (0.6 g/kg body weight per day) could also reduce the risks of dialysis among CKD stage 4 patients. Methods: Patients aged >20 years with a diagnosis of stage 4 CKD who subsequently received ketosteril treatment, which is the most commonly used ketoanalogue of essential amino acids, between 2003 and 2018 were identified from the Chang Gung Research Database (CGRD). Then, these individuals were divided into two groups according to the continuation of ketosteril for more than three months or not. The primary outcome was ESKD requiring maintenance dialysis. Results: With one-year follow-up, the continuation group (n = 303) exhibited a significantly lower incidence of new-onset end-stage kidney disease (ESKD) requiring maintenance dialysis (6.8% vs. 10.4%, hazard ratio [HR]: 0.62, 95% confidence interval [CI]: 0.41−0.94) in comparison to the discontinuation group (n = 238). Conclusions: This study demonstrated that initiating sLPDs since CKD stage 4 may additionally reduce the short-term risks of commencing dialysis without increasing CV events, infections, or mortality.

Ketoanalogue Supplementation in Patients with Non-Dialysis Diabetic Kidney Disease: A Systematic Review and Meta-Analyses

The effects of supplemental ketoanalogues (KA) in patients with diabetic kidney disease (DKD) are not well characterized. Several databases for peer-reviewed articles were systematically searched to identify studies reporting outcomes associated with the effects of a low-protein diet (LPD) or very-low protein diet (VLPD) in combination with supplemental KA in adults with DKD. Meta-analyses were conducted when feasible. Of 213 identified articles, 11 could be included in the systematic review. Meta-analyses for renal outcomes (4 studies examining glomerular filtration rate; 5 studies examining 24-h urinary protein excretion), metabolic outcomes (5 studies examining serum urea; 7 studies examining blood glucose), clinical outcomes (6 studies examining blood pressure; 4 studies examining hemoglobin), and nutritional outcomes (3 studies examining serum albumin; 4 studies examining body weight) were all in favor of KA use in DKD patients. Data from individual studies that examined other related parameters also tended to show favorable effects from KA-supplemented LPD/VLPD. The regimens were safe and well tolerated, with no evidence of adverse effects on nutritional status. In conclusion, LPD/VLPD supplemented with KA could be considered effective and safe for patients with non-dialysis dependent DKD. Larger studies are warranted to confirm these observations.