Life-threatening hyperkalemia in a patient with normal renal function

National Initiatives on Salt Substitutes: Scoping Review

BACKGROUND

Salt substitutes are edible salts that contain less sodium chloride owing to its partial substitution with other minerals, which serve as an important and effective intervention and public health strategy targeting hypertension and its secondary diseases, despite a small degree of controversy.

OBJECTIVE

This study aimed to identify the current salt substitute initiatives in various nations and intergovernmental organizations (IGOs) worldwide and summarize their types and characteristics.

METHODS

A scoping review was performed based on Arksey and O'Malley's framework and the latest guidance from the Joanna Briggs Institute. Searches were conducted on Google; government websites on food, health, and other related topics; PubMed; Web of Science; and Google Scholar from January 2022 to May 2022. Initiatives related to salt substitutes that were included in the study focused on the involvement of governments or IGOs through the publication of standards, actions, collaborations, funding, and so on. Data were extracted into Microsoft Excel (version 2019; Microsoft Corp) based on predefined items and analyzed using narrative synthesis and frequency count methods.

RESULTS

A total of 35 initiatives from 11 countries (of which 9 are high-income countries) and 3 IGOs were identified. We classified all salt substitute initiatives into 5 types, namely benefit-risk assessments and cautions; plans and actions; regulations and standards; labels; and food reformulation, cooperation with the food industry, and media. More than half (18/35, 51%) of the salt substitute initiatives were launched within the past 5 years. Except for regulations and standards, salt substitute initiatives are, in general, part of the salt reduction framework. No nation or IGO has yet reported on the monitoring and implications of the use of salt substitutes.

CONCLUSIONS

Despite the limited number of salt substitute initiatives worldwide at present, a review on the different types and characteristics of such initiatives could be helpful in providing a reference for policy makers and stakeholders. Given the great potential of salt substitutes in improving hypertension and stroke, we call on more nations to pay attention to these substitutes and propose salt substitute initiatives in line with their national conditions.

Salt substitution and salt-supply restriction for lowering blood pressure in elderly care facilities: a cluster-randomized trial

There is a paucity of high-quality evidence on the effectiveness and safety of salt reduction strategies, particularly for older people, who have the most to benefit but are at higher risk of adverse effects. Here, we conducted a clinical trial in which 48 residential elderly care facilities in China (1,612 participants including 1,230 men and 382 women, 55 years or older) were cluster-randomized using a 2 × 2 factorial design to provision of salt substitute (62.5% NaCl and 25% KCl) versus usual salt and to a progressively restricted versus usual supply of salt or salt substitute for 2 years. Salt substitute compared with usual salt lowered systolic blood pressure (-7.1 mmHg, 95% confidence interval (CI) -10.5 to -3.8), meeting the primary outcome of the trial, whereas restricted supply compared with usual supply of salt or salt substitute had no effect on systolic blood pressure. Salt substitute also lowered diastolic blood pressure (-1.9 mmHg, 95% CI -3.6 to -0.2) and resulted in fewer cardiovascular events (hazard ratio (HR) 0.60, 95% CI 0.38-0.96), but had no effect on total mortality (HR 0.84, 95% CI 0.63-1.13). From a safety standpoint, salt substitute increased mean serum potassium and led to more frequent biochemical hyperkalemia, but was not associated with adverse clinical outcomes. In contrast, salt restriction had no effect on any study outcome. The results of this trial indicate that use of salt substitute, but not efforts to restrict salt supply, may achieve blood pressure lowering and deliver health benefits to residents of elderly care facilities in China. Clinicaltrials.gov registration: NCT03290716.

Potassium Derangements: A Pathophysiological Review, Diagnostic Approach, and Clinical Management

Potassium is an essential cation critical in fluid and electrolyte balance, acid–base regulation, and neuromuscular functions. The normal serum potassium is kept within a narrow range of 3.5–5.2 meq/L while the intracellular concentration is approximately 140–150 meq/L. The total body potassium is about 45–55 mmol/kg; thus, a 70 kg male has an estimated ~136 g and 60 kg female has ~117 g of potassium. In total, 98% of the total body potassium is intracellular. Skeletal muscle contains ~80% of body potassium stores. The ratio of intracellular to extracellular potassium concentration (Ki/Ke) maintained by Na+/K+ ATPase determines the resting membrane potential. Disturbances of potassium homeostasis lead to hypo- and hyperkalemia, which if severe, can be life-threatening. Prompt diagnosis and management of these problems are important.

The potential role of the eGFR in differentiating between true and pseudohyperkalaemia

BACKGROUND

Differentiating between true and pseudohyperkalaemia is essential for patient management. The common causes of pseudohyperkalaemia include haemolysis, blood cell dyscrasias and EDTA contamination. One approach to differentiate between them is by checking the renal function, as it is believed that true hyperkalaemia is rare with normal function. This is logical, but there is limited published evidence to support it. The aim of this study was to investigate the potential role of the estimated glomerular filtration rate in differentiating true from pseudohyperkalaemia.

METHODS

GP serum potassium results >6.0 mmol/L from 1 January 2017 to 31 December 2017, with a repeat within seven days, were included. Entries were retrospectively classified as true or pseudohyperkalaemia based on the potassium reference change value and reference interval. If the initial sample had a full blood count, it was classified as normal/abnormal to remove blood cell dyscrasias. Different estimated glomerular filtration rate cut-points were used to determine the potential in differentiating true from pseudohyperkalaemia.

RESULTS

A total of 272 patients were included with potassium results >6.0 mmol/L, with 145 classified as pseudohyperkalaemia. At an estimated glomerular filtration rate of 90 ml/min/1.73 m², the negative predictive value was 81% (95% CI: 67-90%); this increased to 86% (95% CI: 66-95%) by removing patients with abnormal full blood counts. When only patients with an initial potassium ≥6.5 mmol/L were included (regardless of full blood count), at an estimated glomerular filtration rate of 90 ml/min/1.73 m², the negative predictive value was 100%. Lower negative predictive values were seen with decreasing estimated glomerular filtration rate cut-points.

CONCLUSION

Normal renal function was not associated with true hyperkalaemia, making the estimated glomerular filtration rate a useful tool in predicting true from pseudohyperkalaemia, especially for potassium results ≥6.5 mmol/L.

Hyperkalemia: A persisting risk. A case report and update on current management

We report a case of hemodynamic instability due to bradycardia on the basis of severe hyperkalemia. Diabetic ketoacidosis and acute kidney injury together with polypharmacy triggered the acute onset. Potentially life-threatening hyperkalemia is often induced by drug interactions. ECG features may be crucial for diagnosis, and treatment depends on setting and resources.

Potassium-Enriched Salt Substitutes as a Means to Lower Blood Pressure: Benefits and Risks

Use of salt substitutes containing potassium chloride is a potential strategy to reduce sodium intake, increase potassium intake, and thereby lower blood pressure and prevent the adverse consequences of high blood pressure. In this review, we describe the rationale for using potassium-enriched salt substitutes, summarize current evidence on the benefits and risks of potassium-enriched salt substitutes and discuss the implications of using potassium-enriched salt substitutes as a strategy to lower blood pressure. A benefit of salt substitutes that contain potassium chloride is the expected reduction in dietary sodium intake at the population level because of reformulation of manufactured foods or replacement of sodium chloride added to food during home cooking or at the dining table. There is empirical evidence that replacement of sodium chloride with potassium-enriched salt substitutes lowers systolic and diastolic blood pressure (average net Δ [95% CI] in mm Hg: -5.58 [-7.08 to -4.09] and -2.88 [-3.93 to -1.83], respectively). The risks of potassium-enriched salt substitutes include a possible increased risk of hyperkalemia and its principal adverse consequences: arrhythmias and sudden cardiac death, especially in people with conditions that impair potassium excretion such as chronic kidney disease. There is insufficient evidence regarding the effects of potassium-enriched salt substitutes on the occurrence of hyperkalemia. There is a need for additional empirical research on the effect of increasing dietary potassium and potassium-enriched salt substitutes on serum potassium levels and the risk of hyperkalemia, as well as for robust estimation of the population-wide impact of replacing sodium chloride with potassium-enriched salt substitutes.

Potassium Chloride-Based Salt Substitutes: A Critical Review with a Focus on the Patent Literature

High dietary sodium intake (DSI) represents a major health-related public issue in most countries all over the world. Such a diet can lead to increased risk of hypertension and related cardiovascular diseases. This situation has resulted in important public policies for various salt reduction strategies. One of these is based on the use of salt substitutes or salts with reduced sodium content. Among several options, potassium chloride (KCl) has proved to be a key nutritional ingredient for this purpose. It provides similar properties like common salt (NaCl), but with several unwanted side effects, of which the most important have relatively offensive side tastes: bitter, acrid, and metallic. To successfully formulate KCl-based salt substitutes, numerous taste-improving agents and formulation concepts have been used. The field of salt substitutes is mainly described in the patent literature. Since patents are both scientific and legal documents, careful and critical consideration is required when using them as a source of scientific information. This review brings a deep insight into the area of KCl-based salt substitutes with a focus on the patent literature through the eyes of food science and technology. The most important classes of taste-improving agents that have been employed in numerous formulation concepts of KCl-based salt substitutes are nutritionally acceptable mineral salts; food acids, amino acids, and their nutritionally acceptable salts; simple carbohydrates and sugar substitutes; food polymers; umami ingredients; spices, vegetables, and flavors; miscellaneous taste improvers; as well as a plethora of their specific combinations. A critical review of the respective patent literature is given.

Hyperkalemia from Dietary Supplements

Hyperkalemia is a common electrolyte problem in patients with chronic kidney disease. It is typically caused by medications in patients with poor kidney function. Patients with comorbodities such as heart failure and diabetes are predisposed to electrolyte problems. Salt substitutes and dietary supplements are uncommon causes of hyperkalemia, but we propose that they are under-recognized and underdiagnosed causes in patients with chronic kidney disease. Our case report and literature review illustrates that a careful dietary history is essential in patients presenting with electrolyte disorders, especially hyperkalemia.