Assessment of Patiromer Monotherapy for Hyperkalemia in an Acute Care Setting

Hyperkalemia management: a multidisciplinary expert panel's perspective on the role of new potassium binders

Hyperkalemia is a potentially life-threatening condition frequently encountered in clinical practice, particularly among patients with chronic kidney disease, heart failure, diabetes, and hypertension and those undergoing treatment with renin-angiotensin-aldosterone system inhibitors (RAASi). The management of chronic and acute hyperkalemia is complex and requires timely intervention to prevent severe complications such as cardiac arrhythmias and sudden death. Traditional therapeutic approaches to chronic hyperkalemia, including dietary potassium restriction, use of diuretics, and administration of cation-exchange resins like sodium polystyrene sulfonate, often suffer from limitations like gastrointestinal side effects, variable efficacy, delayed onset of action, and RAASi treatment discontinuation. In recent years, the development of new potassium binders, specifically patiromer and sodium zirconium cyclosilicate (SZC), has revolutionized the management of hyperkalemia. Patiromer, a non-absorbed polymer, binds potassium in the gastrointestinal tract in exchange for calcium, thus facilitating its excretion. SZC operates by exchanging sodium and hydrogen ions for potassium, leading to efficient potassium removal. Both agents have demonstrated rapid and sustained reductions in serum potassium levels, coupled with favorable safety and tolerability profiles, in multiple clinical trials. This review article, authored by a multidisciplinary group of Portuguese experts in hyperkalemia management, provides an in-depth analysis of the efficacy and safety of current therapeutic strategies and highlights the clinical potential of new potassium binders. The introduction of patiromer and SZC offers significant advantages over traditional therapies, providing effective and better-tolerated options for patients. The review highlights the role of these novel agents in contemporary hyperkalemia management and calls for ongoing research to further refine treatment protocols and improve patient outcomes.

A Retrospective Study of Patiromer as Adjunct to Insulin Therapy for Acute Hyperkalemia in the Emergency Department

Objective

To investigate the clinical utility of administering patiromer as an adjunct to insulin for potassium reduction in patients presenting to the emergency department (ED) with hyperkalemia.

Methods

 This retrospective cohort study used electronic health record data to identify adults treated with at least one intravenous dose of regular insulin for hyperkalemia within the ED. Patients who were administered patiromer within one hour before or after their insulin dose were categorized as the intervention group. Matching was performed at a 1:1 ratio. The primary outcome, mean change in potassium from baseline to the latest value within the 4-12 hour interval, was compared. Secondary outcomes included net clinical benefit, defined as the mean difference in the number of potassium-lowering interventions minus the change in potassium.

Results

The final analysis included 133 patients treated with patiromer plus insulin and 133 patients treated with insulin alone. Participants had a mean age of 71 years; 43% were female, 31% self-identified as Black, and 38% self-identified as Latinx. No significant changes were observed in potassium from baseline (mean levels 6.2 mEq/L in each group) to the 4-12 hour time frame (patiromer: -0.90 mEq/L, n=78 vs insulin-only: -0.98 mEq/L, n=81; p = 0.51). The calculated net clinical benefit of potassium reduction was -0.25 in favor of the patiromer plus insulin group; however, this difference did not reach statistical significance. In the subgroup of eGFR >30 mL/min, patiromer group received numerically less potassium-lowering interventions (0.63 vs 1.12, p = 0.057).

Conclusion

In this study of patients with acute hyperkalemia in the ED setting, concurrent administration of patiromer did not result in more sustained potassium reduction compared to insulin alone in the overall cohort. The trend in favor of adjunct patiromer in the subgroup with adequate renal function warrants further investigation.

Evaluation of the introduction of novel potassium binders in routine care; the Stockholm CREAtinine measurements (SCREAM) project

BACKGROUND

The pharmacological management of hyperkalemia traditionally considered calcium or sodium polystyrene sulfonate and, since recently, the novel binders patiromer and sodium zirconium cyclosilicate. We evaluated their patterns of use, duration of treatment and relative effectiveness/safety in Swedish routine care.

METHODS

Observational study of adults initiating therapy with sodium polystyrene sulfonate or a novel binder (sodium zirconium cyclosilicate or patiromer) in Stockholm 2019-2021. We quantified treatment duration by repeated dispensations, compared mean achieved potassium concentration within 60 days, and potential adverse events between treatments.

RESULTS

A total of 1879 adults started treatment with sodium polystyrene sulfonate, and 147 with novel binders (n = 41 patiromer and n = 106 sodium zirconium cyclosilicate). Potassium at baseline for all treatments was 5.7 mmol/L. Sodium polystyrene sulfonate patients stayed on treatment a mean of 61 days (14% filled ≥3 consecutive prescriptions) compared to 109 days on treatment (49% filled ≥3 prescriptions) for novel binders. After 15 days of treatment, potassium similarly decreased to 4.6 (SD 0.6) and 4.8 (SD 0.6) mmol/L in the sodium polystyrene sulfonate and novel binder groups, respectively, and was maintained over the 60 days post-treatment. In multivariable regression, the odds ratio for novel binders (vs sodium polystyrene sulfonate) in reaching potassium ≤ 5.0 mmol/L after 15 days was 0.65 (95% CI 0.38-1.10) and after 60 days 0.89 (95% CI 0.45-1.76). Hypocalcemia, hypokalemia, and initiation of anti-diarrheal/constipation medications were the most-commonly detected adverse events. In multivariable analyses, the OR for these events did not differ between groups.

CONCLUSION

We observed similar short-term effectiveness and safety for all potassium binders. However, treatment duration was longer for novel binders than for sodium polystyrene sulfonate.

Management of hyperkalemia in children

PURPOSE OF REVIEW

Hyperkalemia is a potentially fatal electrolyte abnormality with no standardized management. The purpose of this review is to provide the knowledge needed for timely and effective management of hyperkalemia in children. It describes the utility of existing and novel therapies.

RECENT FINDINGS

Two newer oral potassium binding agents, patiromer sorbitex calcium and sodium zirconium cyclosilicate, have been FDA-approved for the management of hyperkalemia in adults. These newer agents offer hope for improved management, even though their use in pediatric patients requires further exploration.

SUMMARY

This review highlights the causes and life-threatening effects of hyperkalemia and provides a comprehensive overview of the management of hyperkalemia in both acute and chronic settings along with upcoming treatment strategies.

Practical patient care appraisals with use of new potassium binders in heart failure and chronic kidney diseases

Hyperkalaemia is a life-threatening condition leading to significant morbidity and mortality. It is common in heart failure and in chronic kidney disease (CKD) patients due to the diseases themselves, which often coexist, the high co-presence of diabetes, the fluctuations in renal function, and the use of some drugs [i.e. renin-angiotensin-aldosterone system (RAAS) inhibitors]. Hyperkalaemia limits their administration or uptitration, thus impacting on mortality. New K + binders, namely patiromer and sodium zirconium cyclosilicate (ZS-9), are an intriguing option to manage hyperkalaemia in heart failure and/or CKD patients, both to reduce its fatal effects and to let clinicians uptitrate RAAS inhibition. Even if their real impact on strong outcomes is still to be determined, we hereby provide a practical approach to favour their use in routine clinical practice in order to gain the correct confidence and provide an additive tool to heart failure and CKD patients' wellbeing. New trials are welcome to fill the gap in knowledge.

Potassium homeostasis - Physiology and pharmacology in a clinical context

Membrane voltage controls the function of excitable cells and is mainly a consequence of the ratio between the extra- and intracellular potassium concentration. Potassium homeostasis is safeguarded by balancing the extra-/intracellular distribution and systemic elimination of potassium to the dietary potassium intake. These processes adjust the plasma potassium concentration between 3.5 and 4.5 mmol/L. Several genetic and acquired diseases but also pharmacological interventions cause dyskalemias that are associated with increased morbidity and mortality. The thresholds at which serum K+ not only associates but also causes increased mortality are hotly debated. We discuss physiologic, pathophysiologic, and pharmacologic aspects of potassium regulation and provide informative case vignettes. Our aim is to help clinicians, epidemiologists, and pharmacologists to understand the complexity of the potassium homeostasis in health and disease and to initiate appropriate treatment strategies in dyskalemic patients.

Pharmacological strategies to manage hyperkalaemia: out with the old, in with the new? Not so fast…

Since the 1950s, sodium polystyrene sulphonate (SPS) has been the dominant cation exchange agent prescribed for hyperkalaemia. Clinicians have had plenty of time to learn of SPS's advantages and limitations. The demands of drug regulatory agencies regarding the incorporation of medications into the market were not so stringent then as they are today, and the efficacy and safety of SPS have been questioned. In recent years, two novel cation exchangers, patiromer and sodium zirconium cyclosilicate, have received (or are in the process of receiving) regulatory approval in multiple jurisdictions globally, after scrutiny of carefully conducted trials regarding their short-term and mid-term efficacy. In this debate, we defend the view that all three agents are likely to have similar efficacy. Harms are much better understood for SPS than for newer agents, but currently there are no data to suggest that novel agents are safer than SPS. Drug choices need to consider costs, access and numbers-needed-to-treat to prevent clinically important events; for potassium exchangers, we need trials directly examining clinically important events.

Patiromer utility as an adjunct treatment in patients needing urgent hyperkalaemia management (PLATINUM): design of a multicentre, randomised, double-blind, placebo-controlled, parallel-group study

INTRODUCTION

Hyperkalaemia is common, life-threatening and often requires emergency department (ED) management; however, no standardised ED treatment protocol exists. Common treatments transiently reducing serum potassium (K+) (including albuterol, glucose and insulin) may cause hypoglycaemia. We outline the design and rationale of the Patiromer Utility as an Adjunct Treatment in Patients Needing Urgent Hyperkalaemia Management (PLATINUM) study, which will be the largest ED randomised controlled hyperkalaemia trial ever performed, enabling assessment of a standardised approach to hyperkalaemia management, as well as establishing a new evaluation parameter (net clinical benefit) for acute hyperkalaemia treatment investigations.

METHODS AND ANALYSIS

PLATINUM is a Phase 4, multicentre, randomised, double-blind, placebo-controlled study in participants who present to the ED at approximately 30 US sites. Approximately 300 adult participants with hyperkalaemia (K+ ≥5.8 mEq/L) will be enrolled. Participants will be randomised 1:1 to receive glucose (25 g intravenously <15 min before insulin), insulin (5 units intravenous bolus) and aerosolised albuterol (10 mg over 30 min), followed by a single oral dose of either 25.2 g patiromer or placebo, with a second dose of patiromer (8.4 g) or placebo after 24 hours. The primary endpoint is net clinical benefit, defined as the mean change in the number of additional interventions less the mean change in serum K+, at hour 6. Secondary endpoints are net clinical benefit at hour 4, proportion of participants without additional K+-related medical interventions, number of additional K+-related interventions and proportion of participants with sustained K+ reduction (K+ ≤5.5 mEq/L). Safety endpoints are the incidence of adverse events, and severity of changes in serum K+ and magnesium.

ETHICS AND DISSEMINATION

A central Institutional Review Board (IRB) and Ethics Committee provided protocol approval (#20201569), with subsequent approval by local IRBs at each site, and participants will provide written consent. Primary results will be published in peer-reviewed manuscripts promptly following study completion.

TRIAL REGISTRATION NUMBER

NCT04443608.

In pursuit of balance: renin-angiotensin-aldosterone system inhibitors and hyperkalaemia treatment

Hyperkalaemia is a life-threatening condition leading to significant morbidity and mortality. It is common in heart failure (HF) patients due to the disease itself, which often co-exists with chronic kidney disease and diabetes mellitus, the fluctuations in renal function, and the use of some drugs [i.e. renin-angiotensin-aldosterone system (RAAS) inhibitors]. In particular, hyperkalaemia opposes to their administration or up-titration, thus impacting on mortality. New K+ binders, namely, patiromer and sodium zirconium cyclosilicate, are an intriguing option to manage hyperkalaemia in HF patients, both to reduce its fatal effects and to let clinicians up-titrate RAAS inhibitors. Even if their real impact on strong outcomes is still to be determined, we hereby provide an overview of hyperkalaemia in HF and its current management. New trials are welcome to fill the gap in knowledge.

A New Understanding of Potassium's Influence Upon Human Health and Renal Physiology

Potassium channels are expressed in virtually all cell types, and their activity is the dominant determinant of cellular membrane potential. As such, potassium flux is a key regulator of many cellular processes including the regulation of action potentials in excitable cells. Subtle changes in extracellular potassium can initiate signaling processes vital for survival (insulin signaling) while more extreme and chronic changes may lead to pathological states (acid-base disturbances and cardiac arrhythmia). While many factors acutely influence extracellular potassium levels, it is principally the role of the kidneys to maintain potassium balance by matching urinary excretion with dietary intake. When this balance is disrupted, human health is negatively impacted. In this review, we discuss evolving views of dietary potassium intake as means of preventing and mitigating diseases. We also provide an update on a molecular pathway called the potassium switch, a mechanism by which extracellular potassium regulates distal nephron sodium reabsorption. Finally, we review recent literature describing how several popular therapeutics influence potassium homeostasis.

The Role of Dietary Potassium in the Cardiovascular Protective Effects of Plant-Based Diets

Dietary intervention is an essential factor in managing a multitude of chronic health conditions such as cardiovascular and chronic kidney disease. In recent decades, there has been a host of research suggesting the potential benefit of plant-based diets in mitigating the health outcomes of these conditions. Plant-based diets are rich in vegetables and fruits, while limiting processed food and animal protein sources. The underlying physiological mechanism involves the interaction of several macronutrients and micronutrients such as plant protein, carbohydrates, and dietary potassium. Specifically, plant-based foods rich in potassium provide cardiorenal protective effects to include urinary alkalization and increased sodium excretion. These diets induce adaptive physiologic responses that improve kidney and cardiovascular hemodynamics and improve overall metabolic health. A shift toward consuming plant-based diets even in subjects with cardiorenal decrements may reduce their morbidity and mortality. Nonetheless, randomized controlled trials are needed to confirm the clinical benefits of plant-based diets.

Recent Progresses in Non-Dialysis Chronic Kidney Disease Patients with Hyperkalemia: Outcomes and Therapeutic Strategies

Chronic kidney disease (CKD) affects about 10% of the world's population. Hyperkalemia is a life-threatening complication in patients with CKD, as it is associated with adverse cardiovascular and kidney outcomes. There are still many challenges and questions to address to improve the currently available therapeutic strategies to treat hyperkalemia, such as how to approach the emergency management of hyperkalemia. In recent years, in addition to novel oral potassium binders, great progress has been made in the application of novel kidney protective strategies, such as mineralocorticoid receptor antagonists and sodium-glucose cotransporter 2 inhibitors (SGLT2i) in hyperkalemia therapy. This review will discuss the recent advances from clinical trials in the effective management of hyperkalemia in non-dialysis CKD patients, enhancing the knowledge of physicians and internists concerning these newer agents and providing a helpful reference for clinical practice.

A New Perspective to Longstanding Challenges with Outpatient Hyperkalemia: A Narrative Review

Purpose of Review

Outpatient hyperkalemia is a common problem with potentially deadly consequences. Potassium level thresholds to treat outpatient hyperkalemia are unstandardized and variable, leaving health care providers to rely on their own clinical judgment. This narrative review highlights the challenges of outpatient hyperkalemia management and includes recommendations for future studies that may standardize treatment, improve patient outcomes, and optimize health care utilization.

Sources of Information

PubMed, Google Scholar, and the reference lists of identified articles were used to include English, peer-reviewed studies and guidelines for this review.

Methods

This narrative review examines outpatient hyperkalemia from both a laboratory and clinical perspective. In addition to peer-reviewed literature, guidelines and expert consensus statements were included to highlight the inconsistencies and paucity of evidence that health care providers rely on to make clinical decisions.

Key Findings

There are multiple reasons why outpatient hyperkalemia management is both challenging and sub-optimal. Clinicians must discern if the potassium level result is accurate and, if so, does the result warrant referral to the emergency department. Factitious hyperkalemia, or falsely elevated potassium level results due to analytical errors, occurs frequently, but there are no ways to identify it other than for hemolyzed samples. Additionally, guidelines and expert panels are inconsistent on the thresholds for treatment and the management of hyperkalemia. Finally, there are inconsistencies between laboratories as to when and how providers are notified of results, and the suggested thresholds for urgent management. A study that integrates the expertise of clinical biochemists and clinicians is needed to inform evidence-based guidelines for the management of outpatient hyperkalemia.

Limitations

This was a comprehensive review of what is known and what still needs to be understood for the management of outpatient hyperkalemia. A formal tool to assess the quality of the included studies was not used and selection bias may have occurred.

Optimizing Therapies in Heart Failure: The Role of Potassium Binders

Heart failure (HF) is a worrisome cardiac pandemic with a negative prognostic impact on the overall survival of individuals. International guidelines recommend up-titration of standardized therapies in order to reduce symptoms, hospitalization rates, and cardiac death. Hyperkalemia (HK) has been identified in 3-18% of HF patients from randomized controlled trials and over 25% of HF patients in the "real world" setting. Pharmacological treatments and/or cardio-renal syndrome, as well as chronic kidney disease may be responsible for HK in HF patients. These conditions can prevent the upgrade of pharmacological treatments, thus, negatively impacting on the overall prognosis of patients. Potassium binders may be the best option in patients with HK in order to reduce serum concentrations of K+ and to promote correct upgrades of therapies. In addition to the well-established use of sodium polystyrene sulfonate (SPS), two novel drugs have been recently introduced: sodium zirconium cyclosilicate (SZC) and patiromer. SZC and patiromer are gaining a central role for the treatment of chronic HK. SZC has been shown to reduce K+ levels within 48 h, with guaranteed maintenance of normokalemia for up to12 months. Patiromer has resulted in a statistically significant decrease in serum potassium for up to 52 weeks. Therefore, long-term results seemed to positively promote the implementation of these compounds in clinical practice due to their low rate side effects. The aim of this narrative review is to delineate the impact of new potassium binders in the treatment of patients with HF by providing a critical reappraisal for daily application of novel therapies for hyperkalemia in the HF setting.