Treatment of Chronic Kidney Disease-Related Metabolic Acidosis With Fruits and Vegetables Compared to NaHCO3 Yields More and Better Overall Health Outcomes and at Comparable Five-Year Cost

Lack of a role of NHE4 in renal ammonia metabolism

The cation exchanger, Na+/H+ exchanger isoform 4 (NHE4), has been thought to have a central role in renal ammonia metabolism and handling by acting in a Na+ for NH4+ exchange mode at the basolateral plasma membrane in the thick ascending limb (TAL) of the loop of Henle. These studies aimed to determine the effect of NHE4 deletion on ammonia metabolism under basal conditions and in response to metabolic acidosis. Constitutive NHE4 deletion resulted in increased urine ammonia excretion associated with significantly lower urine pH; this increase did not lead to metabolic alkalosis. In response to exogenous acid-loading, NHE4 deletion did not impair the changes in ammonia excretion. Immunoblot analysis and immunohistochemistry showed mild increases in proximal tubule ammoniagenic enzyme expression with NHE4 deletion. Both immunoblot analysis and immunohistochemistry showed no detectable NHE4 protein expression in the mouse kidney. Single-nucleus RNAseq of mouse kidneys showed no NHE4 mRNA expression in renal epithelial cells. Analysis of five publicly available mouse and human cell-specific RNAseq datasets also showed a lack of NHE4 mRNA expression in the TAL. We conclude that NHE4 is unnecessary for ammonia metabolism either under basal conditions or in response to acid-loading because it is not expressed in the TAL.NEW & NOTEWORTHY NHE4 has previously been suggested to mediate a critical role in renal ammonia metabolism through its role in thick ascending limb (TAL) ammonia transport. This manuscript shows that its deletion does not alter renal ammonia handling and that neither the mouse nor human kidney expresses NHE4 in the TAL.

Effects of dietary interventions for metabolic acidosis in chronic kidney disease: a systematic review and meta-analysis

BACKGROUND

Metabolic acidosis is a common complication of kidney disease and can result in further disease progression. Alkali therapy has been used to treat metabolic acidosis for decades. However, some concerns have been raised regarding its safety and long-term tolerability. Existing data suggest that dietary interventions can be beneficial in the management of chronic kidney disease (CKD). This systematic review and meta-analysis aims to summarize findings from studies comparing dietary interventions with placebo/usual care/no treatment in the management of metabolic acidosis in outpatient adults with CKD.

METHODS

Medline, Embase, Cochrane Central, CINAHL and Web of Science Core Collection were searched from inception to June 2022. Our primary outcome measure was change in serum bicarbonate. Any dietary intervention looking to manipulate dietary acid load was considered as an intervention. Data screening and extraction were performed by two independent reviewers. Random effects meta-analysis was performed to pool data.

RESULTS

Dietary interventions resulted in clinically significant improvement in serum bicarbonate [mean difference 2.98 (95% confidence interval 0.77, 5.19); I2: 91%] and higher estimated glomerular filtration rate (eGFR) levels [mean difference 3.16 (95% confidence interval 0.24, 6.08); I2: 67%] compared with controls. Serum potassium, albumin and body mass index remained unchanged. Dietary interventions were reported to be safe. Subgroup analyses indicated a superiority of plant-based over non-plant-based interventions in the improvement of acid-base balance and eGFR; however, these findings are from low-quality and heterogenous studies.

CONCLUSION

Our findings support the beneficial effects of dietary interventions aimed at reducing acid or adding base in the management of metabolic acidosis and kidney function in adults with CKD, with no adverse effects on serum potassium and nutritional status. Well-designed clinical trials looking at the treatment of metabolic acidosis with dietary interventions with a focus on adding base through fruit and vegetables are required.

Plant-Based Diets across the Spectrum of Kidney Disease

Diet is gaining traction as a major CKD-related risk factor for death and disability. Furthermore, a "healthy" diet in patients with CKD is associated with reduced mortality. The data to be discussed support diet as the foundational, "food integrated with pharmacologic therapy," approach to management of individuals with CKD, and those at risk for it. This is the reverse of the current approach in which pharmacologic therapy is considered as foundational to CKD management. In this review, we will discuss the following: ( 1 ) overview of plant diet approaches-discuss different types of Plant-Based Diet (PBD) Approaches, ( 2 ) evidence from trials and observational studies regarding CKD incidence and progression in participants without known CKD with PBDs, and ( 3 ) efficacy of PBDs in participants with known CKD and across various stages of CKD.

Adequate Vegetable Intake Improves Metabolic Indices in Healthy Japanese Participants: A Randomized Crossover Study

AIM

We aimed to elucidate the effect of a healthy diet containing adequate amounts of protein and vegetables on metabolic indices.

METHODS

In this randomized crossover study, twenty-two healthy Japanese participants ingested two different test meals: fish diet (F) or fish diet with adequate vegetable content (FV). Each 5-day diet load test was separated by a washout period of at least seven days. Metabolic indices were measured in fasting blood and 24-h urine samples.

RESULTS

The delta (Δ) plasma glucose and Δserum low-density lipoprotein (LDL) cholesterol concentrations were significantly larger in the participants in group FV than in group F (p=0.042, p=0.013, respectively). The urinary pH in participants in group F on day 6 was significantly lower than on day 1 (p=0.008), and the Δurinary pH and Δnet gastrointestinal absorption of alkali of participants in group FV tended to be smaller than in group F (p=0.070, p=0.075, respectively).

CONCLUSIONS

This study showed that a healthy diet containing adequate protein and vegetables reduced the dietary acid load and improved plasma glucose and serum LDL concentrations in healthy Japanese participants.

Does the Nutritional Intake and Diet Quality of Children With Chronic Kidney Disease Differ From Healthy Controls? A Comprehensive Evaluation

OBJECTIVE

Children with chronic kidney disease (CKD) experience many obstacles to achieving optimal dietary intake. Dietary intake patterns remain unexplored or poorly described. This study compares nutritional intake and diet quality of Australian children with CKD to controls.

METHODS

A food frequency questionnaire captured intake data and was compared to controls. Nutritional intake was determined using individualized nutrient reference values, and diet quality described using the Australian Guide to Healthy Eating and the Australian Child and Adolescent Recommended Food Score.

RESULTS

Children with CKD (n = 36) and controls (n = 82) were studied. Children with CKD had lower weight and height z scores, but higher body mass index (P < .0001 for all parameters). Children with CKD had adequate energy intake, and excessive protein and sodium intake (336% and 569%). They were significantly less likely to meet requirements for vitamin A (P < .001), thiamine (P = .006), folate (P = .01), vitamin C (P = .008), calcium (P < .0001), iron (P = .01), magnesium (P = .0009), and potassium (P = .002). No child met recommended vegetable intake; however, less than half of children with CKD met fruit (44%), grains (31%), and dairy serves (31%). They were also less likely to meet recommended fruit and dairy serves (P = .04 and P = .01, respectively). Non-core foods provided 36% of energy, and although comparable to controls, was contributed more by takeaway foods (P = .01).

CONCLUSION

Children with CKD have reduced nutritional intake of key nutrients and consume more takeaways than controls. Attention to increasing core foods, limiting sodium intake, and managing restrictions while promoting nutrient density appears necessary.

The Role of Dietary Acid Load on Progression of Estimated Glomerular Filtration Rate Among Individuals Diagnosed With Chronic Kidney Disease

OBJECTIVE

Individuals with chronic kidney disease (CKD) are at an increased risk for developing metabolic acidosis. Metabolic acidosis has been shown to worsen kidney function and exacerbate systemic inflammation. Diets high in protein foods can exacerbate metabolic acidosis as protein foods tend to be more acidic, while fruits and vegetables are more alkalotic. The main objective of this systematic review was to determine if higher consumption of fruits and vegetables in adults with CKD stages 1-5 reduces the rate of decline of estimated glomerular filtration rate.

METHODS

Searches of Cumulated Index to Nursing and Allied Health Literature (CINAHL -Elton B. Stephens Company [EBSCO]), Cochrane Library (Wiley), Dissertation & Thesis Global (ProQuest), Embase (Elsevier), Medline (OVID), PubMed (National Library of Medicine), Scopus (Elsevier), and Web of Sciences (Clarivate) identified 1,451 articles published between January 2015 and June 2023.

RESULTS

After independent review, 7 total studies were included. Six of the studies found an association between dietary acid load and progression of CKD.

CONCLUSIONS

Dietary counseling focusing on decreasing dietary acid load may be beneficial for individuals with CKD.

A basic solution for a complex problem: does treatment of metabolic acidosis slow CKD progression?

PURPOSE OF THIS REVIEW

Metabolic acidosis is frequently encountered in patients with chronic kidney disease (CKD), with increasing prevalence as kidney function worsens. Treating electrolyte disturbances is the sine qua non of Nephrologists, and alkali therapy to normalize serum bicarbonate levels and slow progression of kidney disease has been embedded in clinical practice guidelines for decades on the basis of animal models and controversial clinical trials. This review will critically appraise the literature base for this recommendation and determine whether the available evidence supports this common practice, which is a timely endeavor considering the impending demotion of metabolic acidosis treatment from recommendation to practice point in forthcoming KDIGO guidelines.

RECENT FINDINGS

Earlier, open-label, studies supporting the utility of sodium bicarbonate therapy to slow progression of chronic kidney disease have been challenged by more recent, blinded, studies failing to show benefit on CKD progression. This was further demonstrated in the absence of concomitant sodium administration with the hydrochloric acid binder veverimer, which failed to demonstrate benefit on renal death, end stage kidney disease or 40% reduction in estimated glomerular filtration rate in a large multicenter trial.

SUMMARY

The current body of literature does not support the routine treatment of metabolic acidosis in patients with CKD and the authors agree with the forthcoming KDIGO guidelines to de-emphasize this common practice.

Dietary acid load in health and disease

Maintaining an appropriate acid-base equilibrium is crucial for human health. A primary influencer of this equilibrium is diet, as foods are metabolized into non-volatile acids or bases. Dietary acid load (DAL) is a measure of the acid load derived from diet, taking into account both the potential renal acid load (PRAL) from food components like protein, potassium, phosphorus, calcium, and magnesium, and the organic acids from foods, which are metabolized to bicarbonate and thus have an alkalinizing effect. Current Western diets are characterized by a high DAL, due to large amounts of animal protein and processed foods. A chronic low-grade metabolic acidosis can occur following a Western diet and is associated with increased morbidity and mortality. Nutritional advice focusing on DAL, rather than macronutrients, is gaining rapid attention as it provides a more holistic approach to managing health. However, current evidence for the role of DAL is mainly associative, and underlying mechanisms are poorly understood. This review focusses on the role of DAL in multiple conditions such as obesity, cardiovascular health, impaired kidney function, and cancer.

A Therapeutic Approach in the Management of Chronic Kidney Disease: Plant-Based Dietary Models and Associated Parameters

PURPOSE OF REVIEW

Chronic kidney disease is one of the leading causes of death worldwide today. Nutrition and nutrition-related factors have a very important role in both the prevention and management of the disease. Plant-based dietary practices are one of the promising approaches to chronic kidney disease. This review aims to examine the potential benefits and risks of plant-based diet models on symptoms and indices used in diet quality in chronic kidney disease.

RECENT FINDINGS

Recently, a growing body of evidence has shown that, unlike animal-based diets, diets rich in plant-based nutrients may play an active role in the incidence of chronic kidney disease in many ways and the management of common symptoms, such as metabolic acidosis, uremic toxicity, and hyperphosphatemia. Implementation of existing plant-based dietary patterns in patients with chronic kidney disease may increase the efficacy of the diet and improve patients' quality of life by expanding their food choices. While there are concerns about creatine deficiency, dietary adequacy, and accessibility regarding plant-based diets, available information is limited.

Dieta de la Milpa: A Culturally-Concordant Plant-Based Dietary Pattern for Hispanic/Latine People with Chronic Kidney Disease

Chronic kidney disease (CKD) disproportionately affects minorities in the United States, including the Hispanic/Latine population, and is a public health concern in Latin American countries. An emphasis on healthy dietary patterns, including the Mediterranean and the Dietary Approaches to Stop Hypertension (DASH) diets, has been suggested as they are associated with a lower incidence of CKD, slower CKD progression, and lower mortality in kidney failure. However, their applicability may be limited in people from Latin America. The Dieta de la Milpa (Diet of the Cornfield) was recently described as the dietary pattern of choice for people from Mesoamerica (Central Mexico and Central America). This dietary pattern highlights the intake of four plant-based staple foods from this geographical region, corn/maize, common beans, pumpkins/squashes, and chilies, complemented with seasonal and local intake of plant-based foods and a lower intake of animal-based foods, collectively classified into ten food groups. Limited preclinical and clinical studies suggest several health benefits, including cardiometabolic health, but there is currently no data concerning CKD. In this narrative review, we describe and highlight the potential benefits of the Dieta de la Milpa in CKD, including acid-base balance, protein source, potassium and phosphorus management, impact on the gut microbiota, inflammation, and cultural appropriateness. Despite these potential benefits, this dietary pattern has not been tested in people with CKD. Therefore, we suggest key research questions targeting measurement of adherence, feasibility, and effectiveness of the Dieta de la Milpa in people with CKD.

The Role of the Endocrine System in the Regulation of Acid-Base Balance by the Kidney and the Progression of Chronic Kidney Disease

Systemic acid-base status is primarily determined by the interplay of net acid production (NEAP) arising from metabolism of ingested food stuffs, buffering of NEAP in tissues, generation of bicarbonate by the kidney, and capture of any bicarbonate filtered by the kidney. In chronic kidney disease (CKD), acid retention may occur when dietary acid production is not balanced by bicarbonate generation by the diseased kidney. Hormones including aldosterone, angiotensin II, endothelin, PTH, glucocorticoids, insulin, thyroid hormone, and growth hormone can affect acid-base balance in different ways. The levels of some hormones such as aldosterone, angiotensin II and endothelin are increased with acid accumulation and contribute to an adaptive increase in renal acid excretion and bicarbonate generation. However, the persistent elevated levels of these hormones can damage the kidney and accelerate progression of CKD. Measures to slow the progression of CKD have included administration of medications which inhibit the production or action of deleterious hormones. However, since metabolic acidosis accompanying CKD stimulates the secretion of several of these hormones, treatment of CKD should also include administration of base to correct the metabolic acidosis.

Alkaline Water: Help or Hype for Uric Acid and Cystine Urolithiasis?

PURPOSE

The consumption of alkaline water, water with an average pH of 8 to 10, has been steadily increasing globally as proponents claim it to be a healthier alternative to regular water. Urinary alkalinization therapy is frequently prescribed in patients with uric acid and cystine urolithiasis, and as such we analyzed commercially available alkaline waters to assess their potential to increase urinary pH.

MATERIALS AND METHODS

Five commercially available alkaline water brands (Essentia, Smart Water Alkaline, Great Value Hydrate Alkaline Water, Body Armor SportWater, and Perfect Hydration) underwent anion chromatography and direct chemical measurements to determine the mineral contents of each product. The alkaline content of each bottle of water was then compared to that of potassium citrate (the gold standard for urinary alkalinization) as well as to other beverages and supplements used to augment urinary citrate and/or the urine pH.

RESULTS

The pH levels of the bottled alkaline water ranged from 9.69 to 10.15. Electrolyte content was minimal, and the physiologic alkali content was below 1 mEq/L for all brands of alkaline water. The alkali content of alkaline water is minimal when compared to common stone treatment alternatives such as potassium citrate. In addition, several organic beverages, synthetic beverages, and other supplements contain more alkali content than alkaline water, and can achieve the AUA and European Association of Urology alkali recommendation of 30 to 60 mEq per day with ≤ 3 servings/d.

CONCLUSIONS

Commercially available alkaline water has negligible alkali content and thus provides no added benefit over tap water for patients with uric acid and cystine urolithiasis.

In the "Plant-Based" Era, Patients With Chronic Kidney Disease Should Focus on Eating Healthy

In the era of plant-based diets, it is important for Nephrology providers to know the evidence regarding their healthfulness in patients with chronic kidney disease (CKD). A whole food, plant-based diet, which emphasizes fresh, minimally processed or refined plant-based foods and limits animal products, has shown benefits for patients with CKD. These include reduced dietary acid load, lower bioavailability of potassium and phosphorus, increased dietary fiber intake, nutritional adequacy, and cardiovascular and mortality benefits. Potential drawbacks include the need for specific knowledge, skills, and cost involved in preparing varied, healthy, and appetizing plant-based meals, leading to lower acceptability and accessibility to certain populations. Liberalization of the standard CKD diet to include healthy, minimally processed foods such as fruits, vegetables, nuts, legumes, and whole grains is likely beneficial, though more research is needed to determine whether a plant-based-only diet is the optimal way to achieve healthier eating in patients with CKD.

The Fruit and Veggies for Kidney Health Study: A Prospective Randomized Trial

Rationale & Objective

Providing fruits and vegetables (F&Vs) to health care system patients with elevated urine albumin-creatinine ratio (ACR) reduced ACR, slowed chronic kidney disease (CKD) progression and reduced cardiovascular disease (CVD) risk factors in previous studies. This study evaluated a community-based strategy in lower-income populations to identify African Americans with elevated ACR before health care system involvement and sustain them in a 6-month F&V protocol with (F&V + Cook) and without (F&V Only) cooking instructions, with the hypothesis that adjuvant cooking instructions with F&Vs would further reduce ACR.

Study Design

Prospective, randomized, parallel 2-arm design.

Setting & Participants

African American adults with ACR >10 mg/g creatinine randomized to 1 of 2 study arms.

Interventions

Two cups/day of F&Vs with or without cooking instructions in participants followed 6 months.

Outcomes

Participants sustaining the F&V protocol and between-group indicators of CVD risk, kidney injury, and dietary intake at 6 weeks and 6 months.

Results

A total of 142 African American adults (mean age, 57.0 years; ACR, 27.4 mg/g; body mass index, 34.4; 24.9% CKD 1; 24.8% CKD 2; 50.4% CKD 3; 55% female) randomized to F&V Only (n=72) or F&V + Cook (n=70), and 71% were retained at 6 months. Participants received 90% of available F&V pick-ups over 6 weeks and 69% over 6 months. In the adjusted model, 6-month ACR was 31% lower for F&V + Cook than F&V Only (P = 0.02). Net 6-week F&V intake significantly increased and biometric variables improved for participants combined into a single group.

Limitations

Small sample size, low-baseline ACR, and potential nonresponse bias for 24-hour dietary recall measure.

Conclusions

These data support the feasibility of identifying community-dwelling African Americans with ACR indicating elevated CVD and CKD risk and sustaining a F&V protocol shown to improve kidney outcomes and CVD risk factors and provides preliminary evidence that cooking instructions adjuvant to F&Vs are needed to lower ACR.

Funding

National Institute on Diabetes, Digestive, and Kidney Diseases grant "Reducing chronic kidney disease burden in an underserved population" (R21DK113440).

Trial Registration

NCT03832166.

Plain-Language Summary

African Americans, particularly those in low-income communities, have increased rates of chronic kidney disease (CKD) with worsening outcomes over time. Giving fruits and vegetables to individuals with CKD identified in health care systems was previously shown to reduce kidney damage, measured by urine protein albumin, and slow kidney function decline. We recruited African Americans in low-income communities with increased urine albumin levels. They received fruits and vegetables for 6 months, and we tested whether added cooking instructions further reduced urine albumin levels. Most participants continued to receive fruits and vegetables throughout the 6 months. Those given cooking instructions had lower urine albumin levels after 6 months, indicating decreased kidney damage. Providing cooking instructions with fruits and vegetables appears to lessen kidney damage more than just fruits and vegetables alone.

Effects of correcting metabolic acidosis on muscle mass and functionality in chronic kidney disease: a systematic review and meta-analysis

Metabolic acidosis unfavourably influences the nutritional status of patients with non-dialysis dependent chronic kidney disease (CKD) including the loss of muscle mass and functionality, but the benefits of correction are uncertain. We investigated the effects of correcting metabolic acidosis on nutritional status in patients with CKD in a systematic review and meta-analysis. A search was conducted in MEDLINE and the Cochrane Library from inception to June 2023. Study selection, bias assessment, and data extraction were independently performed by two reviewers. The Cochrane risk of bias tool was used to assess the quality of individual studies. We applied random effects meta-analysis to obtain pooled standardized mean difference (SMD) and 95% confidence intervals (CIs). We retrieved data from 12 intervention studies including 1995 patients, with a mean age of 63.7 ± 11.7 years, a mean estimated glomerular filtration rate of 29.8 ± 8.8 mL/min per 1.73 m2 , and 58% were male. Eleven studies performed an intervention with oral sodium bicarbonate compared with either placebo or with standard care and one study compared veverimer, an oral HCl-binding polymer, with placebo. The mean change in serum bicarbonate was +3.6 mEq/L in the intervention group and +0.4 mEq/L in the control group. Correcting metabolic acidosis significantly improved muscle mass assessed by mid-arm muscle circumference (SMD 0.35 [95% CI 0.16 to 0.54], P < 0.001) and functionality assessed with the sit-to-stand test (SMD -0.31 [95% CI -0.52 to 0.11], P = 0.003). We found no statistically significant effects on dietary protein intake, handgrip strength, serum albumin and prealbumin concentrations, and blood urea nitrogen. Correcting metabolic acidosis in patients with CKD improves muscle mass and physical function. Correction of metabolic acidosis should be considered as part of the nutritional care for patients with CKD.

Diet and Metabolism in CKD-Related Metabolic Acidosis

Metabolic acidosis is a common complication in patients with chronic kidney disease that occurs when the daily nonvolatile acid load produced in metabolism cannot be excreted fully by the kidney. A reduction in urine net acid excretion coupled with a high nonvolatile acid load may play a role in its pathogenesis. Diet is important in generation of the nonvolatile acid load. Acids are produced from metabolism of dietary protein and from the endogenous production of organic anions from neutral precursors. Acids can be balanced by alkali precursors ingested in the diet in the form of combustible organic anions. These typically are reflected indirectly by the excess of mineral cations to mineral anions in a food or diet. These principles underscore widely used methods to estimate the nonvolatile acid load from dietary intake using formulas such as the net endogenous acid production equation and the potential renal acid load equation. Empiric data largely validate these paradigms with high net endogenous acid production and potential renal acid load contributed by foods such as protein, grains, and dairy, and low net endogenous acid production and potential renal acid load contributed by fruits and vegetables along with corresponding dietary patterns. Although further studies are needed to understand the health benefits of altering nonvolatile acid load via diet, this review provides a detailed assessment on our current understanding of the role of diet in chronic kidney disease-related acidosis, providing an updated resource for researchers and clinicians.

Demographic and clinical profile of black patients with chronic kidney disease attending a tertiary hospital in Johannesburg, South Africa

Background

The prevalence of chronic kidney disease (CKD) is increasing worldwide; black patients have an increased risk of developing CKD and end stage kidney disease (ESKD) at significantly higher rates than other races.

Methods

A cross sectional study was carried out on black patients with CKD attending the kidney outpatient clinic at Charlotte Maxeke Johannesburg Academic Hospital (CMJAH) in South Africa, between September 2019 to March 2020. Demographic and clinical data were extracted from the ongoing kidney outpatient clinic records and interviews, and were filled in a questionnaire. Patients provided blood and urine for laboratory investigations as standard of care, and data were descriptively and inferentially entered into REDcap and analysed using STATA version 17. Multivariable logistic regression analysis was used to identify demographic and clinical variables associated with advanced CKD.

Results

A total of 312 black patients with CKD were enrolled in the study with a median age of 58 (IQR 46–67) years; 58% patients had advanced CKD, 31.5% of whom had grossly increased proteinuria, 96.7% had hypertension, 38.7% had diabetes mellitus and 38.1% had both hypertension and diabetes mellitus. In patients with advanced CKD, the median age was 61 (IQR 51–69) years, eGFR 33 (30–39) mL/min/1.73 m2, serum bicarbonate 22 (IQR 20–24), haemoglobin 12.9 (IQR 11.5–14.0) g/dl and serum uric acid 0.43 (IQR 0.37–0.53). The prevalence of metabolic acidosis was 62.4%, anemia 46.4% and gout 30.9% among those with advanced CKD, while the prevalence of metabolic acidosis and anaemia was 46.6% and 25.9% respectively in those with early CKD. Variables with higher odds for advanced CKD after multivariable logistic regression analysis were hypertension (OR 3.3, 95% CI 1.2–9.2, P = 0.020), diabetes mellitus (OR 1.8, 95% CI 1.1–3.3, P = 0.024), severe proteinuria (OR 3.5, 95% CI 1.9–6.5, P = 0.001), angina (OR 2.5, 95% CI 1.2–5.1, P = 0.008), anaemia (OR 2.9, 95% CI 1.7–4.9, P = 0.001), hyperuricemia (OR 2.4, 95% CI 1.4–4.1, P = 0.001), and metabolic acidosis (OR 2.0, 95% CI 1.2–3.1, P = 0.005). Other associations with advanced CKD were loss of spouse (widow/widower) (OR 3.2, 95% CI 1.4–7.4, P = 0.006), low transferrin (OR 2.4, 95% CI 1.1–5.1, P = 0.028), hyperkalemia (OR 5.4, 95% CI 1.2–24.1, P = 0.029), use of allopurinol (OR 2.4, 95% CI 1.4–4.3, P = 0.005) and doxazosin (OR 1.9, 95% CI 1.2–3.1, P = 0.006).

Conclusion

Hypertension and diabetes mellitus were strongly associated with advanced CKD, suggesting a need for primary and secondary population-based prevention measures. Metabolic acidosis, anemia with low transferrin levels, hyperuricemia and hyperkalemia were highly prevalent in our patients, including those with early CKD, and they were strongly associated with advanced CKD, requiring clinicians and dietitians to be proactive in supporting the needs of CKD patients in meeting their daily dietary requirements towards preventing and slowing the progression of CKD.

Metabolic acidosis post kidney transplantation

Metabolic acidosis, a common complication in patients with chronic kidney disease (CKD), results in a multitude of deleterious effects. Though the restoration of kidney function following transplantation is generally accompanied by a correction of metabolic acidosis, a subset of transplant recipients remains afflicted by this ailment and its subsequent morbidities. The vulnerability of kidney allografts to metabolic acidosis can be attributed to reasons similar to pathogenesis of acidosis in non-transplant CKD, and to transplant specific causes, including donor related, recipient related, immune mediated factors, and immunosuppressive medications. Correction of metabolic acidosis in kidney transplantation either with alkali therapy or through dietary manipulations may have potential benefits and the results of such clinical trials are eagerly awaited. This review summarizes the published evidence on the pathogenesis and clinical consequences of chronic metabolic acidosis in kidney transplant recipients.

Effects of Dietary App-Supported Tele-Counseling on Sodium Intake, Diet Quality, and Blood Pressure in Patients With Diabetes and Kidney Disease

OBJECTIVES

The aim of this study is to examine the effect of a telehealth intervention that used a dietary app, educational website, and weekly dietitian tele-counseling on sodium intake, diet quality, blood pressure, and albuminuria among individuals with diabetes and early-stage chronic kidney disease.

DESIGN AND METHODS

We examined the effects of a dietary app-supported tele-counseling intervention in a single center, single arm study of 44 participants with type 2 diabetes and stage 1-3a chronic kidney disease. Participants recorded and shared dietary data via MyFitnessPal with registered dietitians, who used motivational interviewing to provide telephone counseling weekly for 8 weeks. After the 8-week intensive intervention, participants were followed at 6 and 12 months. Outcomes included 24-hour urine sodium (2 collections per timepoint), Healthy Eating Index 2015 score (three 24-hour dietary recalls per timepoint), 24-hour systolic blood pressure (SBP) and diastolic blood pressure (DBP), and 24-hour urine albumin excretion.

RESULTS

Out of 44 consented participants (mean age 60.3 ± 11.9 years, 43% female, 89% white, median estimated glomerular filtration rate was 78.5 mL/min/1.73 m², median urine albumin excretion 52.9 mg/day, 84% hypertension), 32 (73%) completed 8-week follow-up, 27 (61%) completed 6-month follow-up, and 25 (57%) completed 12-month follow-up. Among participants who completed 12-month follow-up, reported sodium intake decreased by 638 mg/day from baseline of 2,919 mg/day (P < .001). The 24-hour mean urine sodium and albumin excretion did not decline over the study period. Healthy Eating Index 2015 score improved by 7.76 points at 12 months from a mean baseline of 54.6 (P < .001). Both 24-hour SBP and DBP declined at 12 months from baseline (SBP -5.7 mm Hg, 95% confidence interval -10.5 to -1.0, P = .02; DBP -4.1 mm Hg, 95% confidence interval -7.2 to -1.1, P = .01).

CONCLUSIONS

Overall, this study demonstrates that a short, intensive, remotely delivered dietary intervention for adults with type 2 diabetes and early chronic kidney disease at high risk for disease progression and cardiovascular complications led to improvement in blood pressure and self-reported sodium intake and diet quality, but no improvement in albuminuria. Future research studies are needed to examine whether remotely delivered dietary interventions can ultimately improve kidney health over time.

2021 Dietary Guidance to Improve Cardiovascular Health: A Scientific Statement From the American Heart Association

Poor diet quality is strongly associated with elevated risk of cardiovascular disease morbidity and mortality. This scientific statement emphasizes the importance of dietary patterns beyond individual foods or nutrients, underscores the critical role of nutrition early in life, presents elements of heart-healthy dietary patterns, and highlights structural challenges that impede adherence to heart-healthy dietary patterns. Evidence-based dietary pattern guidance to promote cardiometabolic health includes the following: (1) adjust energy intake and expenditure to achieve and maintain a healthy body weight; (2) eat plenty and a variety of fruits and vegetables; (3) choose whole grain foods and products; (4) choose healthy sources of protein (mostly plants; regular intake of fish and seafood; low-fat or fat-free dairy products; and if meat or poultry is desired, choose lean cuts and unprocessed forms); (5) use liquid plant oils rather than tropical oils and partially hydrogenated fats; (6) choose minimally processed foods instead of ultra-processed foods; (7) minimize the intake of beverages and foods with added sugars; (8) choose and prepare foods with little or no salt; (9) if you do not drink alcohol, do not start; if you choose to drink alcohol, limit intake; and (10) adhere to this guidance regardless of where food is prepared or consumed. Challenges that impede adherence to heart-healthy dietary patterns include targeted marketing of unhealthy foods, neighborhood segregation, food and nutrition insecurity, and structural racism. Creating an environment that facilitates, rather than impedes, adherence to heart-healthy dietary patterns among all individuals is a public health imperative.

Recent evidence on the effect of treatment of metabolic acid on the progression of kidney disease

PURPOSE OF REVIEW

Preclinical and epidemiological studies have shown an association between acidosis and progression of chronic kidney disease (CKD) and kidney fibrosis. This review discusses the recent trials evaluating the effect of treatment of metabolic acidosis on kidney outcomes.

RECENT FINDINGS

The emerging evidence suggests that bicarbonate treatment may slow the progression of CKD and reduce the risk of kidney failure. However, high-certainty evidence on the efficacy and safety of alkali therapy is still lacking. Ongoing studies are evaluating the effect of veverimer, a novel nonabsorbable polymer, on clinical kidney outcomes.

SUMMARY

Recent studies indicate a potential benefit from reduction in acid load in patients with CKD. Whilst it is reasonable that clinicians institute acid-lowering interventions in CKD patients with acidosis, adequately powered trials are required to evaluate the benefit of correction of metabolic acidosis to delay kidney disease progression.

A Systematic Review and Meta-Analysis on Effects of Bicarbonate Therapy on Kidney Outcomes

Aim

Preclinical studies suggest treatment of metabolic acidosis may slow chronic kidney disease (CKD) progression. This systematic review aimed to summarize evidence from randomized controlled trials (RCTs) concerning the benefits and risks of bicarbonate therapy on kidney outcomes.

Methods

Medline, EMBASE, and Cochrane databases were searched for RCTs with ≥3 months’ follow-up in patients with CKD (estimated glomerular filtration rate [eGFR] ≤60 ml/min per 1.73 m² and/or proteinuria) comparing the effects of sodium bicarbonate with placebo/no study medication on kidney outcomes. The primary outcome was change from baseline to last measurement in kidney function measured as either eGFR or creatinine clearance. Treatment effects were summarized using random-effects meta-analysis.

Results

Fifteen trials (2445 participants, median follow-up 12 months) were eligible for inclusion. Compared with placebo or no study medication, sodium bicarbonate retarded the decline in kidney function (standardized mean difference [SMD]: 0.26; 95% confidence interval [CI]: 0.13–0.40; I² = 50%, low certainty evidence), and reduced the risk of end-stage kidney failure (risk ratio [RR]: 0.53; 95% CI 0.32–0.89; I² = 69%, low certainty evidence). The effect of sodium bicarbonate on proteinuria (SMD: −0.09; 95% CI −0.27 to 0.09; I² = 28%, very low certainty evidence), systolic blood pressure (weighted mean difference [WMD]: −0.57 mm Hg; 95% CI −2.32 to 1.18; I² = 0%, low certainty evidence), all-cause death (RR: 0.81; 95% CI: 0.39–1.68; I² = 30%; very low certainty evidence) and edema (RR: 1.16; 95% CI: 0.90–1.50; I² = 28%; low certainty evidence) were uncertain.

Conclusion

Sodium bicarbonate may slow CKD progression. Adequately powered randomized trials are required to evaluate the benefits and risks of sodium bicarbonate in CKD.