A Phase 3b, Randomized, Double-Blind, Placebo-Controlled Study of Sodium Zirconium Cyclosilicate for Reducing the Incidence of Predialysis Hyperkalemia

The Future of Technology-Based Kidney Replacement Therapies: An Update on Portable, Wearable, and Implantable Artificial Kidneys

Worldwide, the number of people who need lifesaving kidney replacement therapy (KRT) steadily increases, but approximately two thirds of them lack access to KRT and therefore die. Access to KRT depends on economic, social, infrastructural, ecological, and political factors. Current KRTs include kidney transplant, peritoneal dialysis, and hemodialysis. The field of xenotransplantation has been opening promising new perspectives recently but needs improvement. Unfortunately, not all patients are suitable for transplant. Peritoneal dialysis and hemodialysis will remain important KRTs, but they are expensive and strongly dependent on infrastructure, with few fundamental changes since the 1980s. The KRT field might learn from the "African mobile phone revolution" that beat infrastructural limitations, lowered costs, and increased access. We provide a nonexhaustive overview of promising ways to increase the mobility of technology-based KRTs by dialysate regeneration, chip-based nanoporous filters, bioreactor-enabling technologies, and using the gut as a "third kidney." In 2018, the Kidney Health Initiative published a road map for innovative KRTs composed by leading innovators, but the pace of innovation is slower than was targeted. Ambitious political statements about realizing this road map can only succeed if the granted funding matches the targeted time scale. Patient-centered international "coopetition" (ie, the act of cooperation between competing entities) seems to offer the quickest pathway to success.

Sodium zirconium cyclosilicate versus sodium polystyrene sulfonate for treatment of hyperkalemia in hemodialysis patients: a randomized clinical trial

BACKGROUND

Hyperkalemia is a frequent life-threatening condition in hemodialysis (HD) patients. Data comparing the usage of various K + binders in HD patients is still scarce. This study aimed to compare the efficacy and safety of Sodium zirconium cyclosilicate (SZC) and sodium polystyrene sulfonate (SPS) for treatment of hyperkalemia in HD patients.

METHODS

This prospective, double-blinded, randomized multicenter clinical trial enrolled 120 HD patients with predialysis serum potassium > 5 mmol/L. Patients were randomized to receive SZC (5 g, 3 times/wk on non-dialysis days, 15 gm/wk) or SPS (15 g, 3 times/wk on non-dialysis days, 45 gm/wk) for 8 weeks. The change in serum potassium through the 8 weeks of the study was our primary outcome.

RESULTS

Serum potassium significantly decreased in both groups compared to baseline values from the first week till the end of the study with p value of < 0.001 and < 0.001 respectively. Serum K levels in the SZC group were significantly lower (achieved normokalemia after 2 weeks) than K levels in the SPS group (achieved normokalemia after 6 weeks) through the study period (p < 0.001). Rescue therapy for hyperkalemia was less frequent in the SZC group (3.3%) than the SPS group (6.6%) (p = 0.678). Gastrointestinal side effects were non significantly fewer with SZC (5%) compared to SPS (11.6%). However, SPS was less palatable (p < 0.001).

CONCLUSIONS

When compared to SPS treatment, SZC was associated with a more rapid and efficacious resolution of hyperkalemia with potentially a better safety profile and palatability among HD patients.

CLINICAL TRIALS REGISTRATION

ClinicalTrials.gov Identifier: NCT06029179. First registration date: 9/01/2023.

Prognostic Impact of Long-Term Sodium Zirconium Cyclosilicate-Integrated Medical Therapy in Patients with Systolic Heart Failure

Background: Sodium zirconium cyclosilicate (SZC) is a novel potassium-binding agent with strong evidence supporting its efficacy in normalizing hyperkalemia. However, the long-term prognostic impact of SZC-integrated medical therapy in patients with systolic heart failure and baseline hyperkalemia remains uncertain. Methods: This study included patients with heart failure and a left ventricular ejection fraction (LVEF) of <50% who were prescribed SZC for hyperkalemia between July 2020 and February 2025. Patients who continued SZC therapy for two years or until February 2025 were classified into the SZC continuation group and followed from the initiation of SZC. Those who discontinued SZC during the study period were assigned to the SZC discontinuation group, with follow-up commencing from the point of cessation. The two-year cumulative incidence of all-cause mortality or hospital readmission was compared between the groups. Results: A total of 61 patients (median age: 79 years; 33 men; median LVEF: 42%) were included in the analysis. Serum potassium levels significantly decreased in the SZC continuation group (p < 0.001) but remained unchanged in the SZC discontinuation group (p = 0.23). The SZC continuation group demonstrated a trend toward a lower cumulative incidence of the primary outcome compared to the SZC discontinuation group (29% vs. 47%, p = 0.079). Additionally, in the SZC continuation group, the daily doses of renin-angiotensin system inhibitors and mineralocorticoid receptor antagonists increased significantly (p < 0.05 for both). Furthermore, LVEF improved significantly with SZC-integrated medical therapy (p = 0.011), whereas no such changes were observed in the SZC discontinuation group (p > 0.05 for all). Conclusions: Long-term SZC-integrated medical therapy was associated with the sustained normalization of hyperkalemia, optimization of heart failure pharmacotherapy, and improved clinical outcomes in patients with systolic heart failure and baseline hyperkalemia. These findings underscore the need for prospective randomized controlled trials in carefully selected patient populations to validate the benefits of SZC and establish its optimal supportive role in the management of systolic heart failure.

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.

EMCREG-International Multidisciplinary Consensus Panel on Management of Hyperkalemia in Chronic Kidney Disease and Heart Failure

BACKGROUND

Hyperkalemia, generally defined as serum potassium levels greater than 5.0 mEq/L, poses significant clinical risks, including cardiac toxicity and muscle weakness. Its prevalence and severity increase in patients with chronic kidney disease (CKD), diabetes mellitus, and heart failure (HF), particularly when compounded by medications like angiotensin converting inhibitors, angiotensin receptor blockers, and potassium sparing diuretics. Hyperkalemia arises from disruptions in potassium regulation involving intake, excretion, and intracellular-extracellular distribution. In CKD and acute kidney injury, these regulatory mechanisms are impaired, leading to heightened risk. The management of chronic hyperkalemia presents a challenge due to the necessity of balancing effective cardiovascular and renal therapies against the risk of elevated potassium levels.

SUMMARY

The emergency department management of acute hyperkalemia focuses on preventing cardiac complications through strategies that stabilize cellular membranes and shift potassium intracellularly. Chronic management often involves dietary interventions and pharmacological treatments. Pharmacological management of acute hyperkalemia includes diuretics, which enhance kaliuresis, and potassium binders such as patiromer and sodium zirconium cyclosilicate, which facilitate fecal excretion of potassium. While diuretics are commonly used, they carry risks of volume contraction and renal function deterioration. The newer potassium binders have shown efficacy in lowering chronically elevated potassium levels in CKD and HF patients, offering an alternative to diuretics and other older agents such as sodium polystyrene sulfonate, which has significant adverse effects and limited evidence for chronic use.

KEY MESSAGES

We convened a consensus panel to describe the optimal management across multiple clinical settings when caring for patients with hyperkalemia. This consensus emphasizes a multidisciplinary approach to managing hyperkalemia, particularly in patients with cardiovascular kidney metabolic syndrome, to avoid fragmentation of care and ensure comprehensive treatment strategies. The primary goal of this manuscript is to describe strategies to maintain cardiovascular benefits of essential medications while effectively managing potassium levels.

Effects of dialysate potassium concentration of 3.0 mmol/l with sodium zirconium cyclosilicate on dialysis-free days versus dialysate potassium concentration of 2.0 mmol/l alone on rates of cardiac arrhythmias in hemodialysis patients with hyperkalemia

The optimal approach towards managing serum potassium (sK+) and hemodialysate potassium concentrations is uncertain. To study this, adults receiving hemodialysis for three months or more with hyperkalemia (pre-dialysis sK+ 5.1-6.5 mmol/l) had cardiac monitors implanted and were randomized to either eight weeks of 2.0 mmol/l potassium/1.25 mmol/l calcium dialysate without sodium zirconium cyclosilicate (SZC) (2.0 potassium/noSZC) or 3.0 mmol/l potassium/1.25 mmol/l calcium dialysate combined with SZC (3.0 potassium/SZC) on non-dialysis days to maintain pre-dialysis sK+ 4.0-5.5 mmol/l, followed by treatment crossover for another eight weeks. The primary outcome was the rate of adjudicated atrial fibrillation (AF) episodes of at least 2 minutes duration. Secondary outcomes included clinically significant arrhythmias (bradycardia, ventricular tachycardia, and/or asystole) and the proportion of sK+ measurements within an optimal window of 4.0-5.5 mmol/l. Among 88 participants (mean age: 57.1 years; 51% male; mean pre-dialysis sK+: 5.5 mmol/l) with 25.5 person-years of follow-up, 296 AF episodes were detected in nine patients. The unadjusted AF rate was lower with 3.0 potassium/SZC versus 2.0 potassium/noSZC; 9.7 vs. 13.4/person-year (modeled rate ratio 0.52; 95% confidence interval 0.41-0.65). Clinically significant arrhythmias were reduced with 3.0 potassium/SZC vs. 2.0 potassium/noSZC (6.8 vs. 10.2/person-year modeled rate ratio 0.47; 0.38; 0.58). Fewer sK+ measurements outside the optimal window occurred with 3.0 potassium/SZC (modeled odds ratio: 0.27; 0.12-0.35). Hypokalemia was less frequent (33 vs. 58 patients) with 3.0 potassium/SZC compared with 2.0 potassium/noSZC. Thus, in patients with hyperkalemia on maintenance hemodialysis, a combination of hemodialysate potassium 3.0 mmol/l and SZC on non-hemodialysis days reduced the rates of AF, other clinically significant arrhythmias, and post-dialysis hypokalemia compared with hemodialysate potassium 2.0/noSZC.

Hyperkalemia burden and treatment patterns in Chinese patients on hemodialysis: final analysis of a prospective multicenter cohort study (PRECEDE-K)

OBJECTIVES

Patients with end-stage renal disease (ESRD) on hemodialysis (HD) are at risk for hyperkalemia (HK), associated with cardiac arrhythmia and sudden death. Data on the burden of HK and management techniques among HD patients in China are still scarce. This study assessed the treatment modalities, recurrence, and prevalence of HK in Chinese HD patients.

METHODS

In this prospective cohort study conducted from May 2021 to July 2022, patients aged ≥18 years who had ESRD and were on HD were enrolled from 15 centers in China (up to 6 months).

RESULTS

Overall, 600 patients were enrolled. At the baseline visit, mean (± standard deviation) urea reduction ratio was 68.0% ± 9.70 and Kt/V was 1.45 ± 0.496. Over 6 months, 453 (75.5%) patients experienced HK, of whom 356 (78.6%) recurred. Within 1, 2, 3, 4, 5, and 6 months, 203 (44.8%), 262 (57.8%), 300 (66.2%), 326 (72.0%), 347 (76.6%), and 356 (78.6%) patients had at least one HK recurrence event, respectively. The proportions of patients with ≥1, 2, 3, 4, 5, or 6 HK recurrence events were 356 (78.6%), 306 (67.5%), 250 (55.2%), 208 (45.9%), 161 (35.5%), and 110 (24.3%), respectively. Among the 453 patients who experienced HK, only 24 (5.3%) were treated with potassium binders: seven (1.5%) with sodium polystyrene sulfonate, 13 (2.9%) with calcium polystyrene sulfonate, and six (1.3%) with sodium zirconium cyclosilicate.

CONCLUSION

Since HK is a chronic illness, long-term care is necessary. Patients on HD should have effective potassium management on non-dialysis days, yet our real-world population rarely used potassium binders.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier NCT04799067.

Utilization of Potassium Binders for the Management of Hyperkalemia in Chronic Kidney Disease: A Position Statement by US Nephrologists

Two potassium (K+) binders-patiromer sorbitex calcium and sodium zirconium cyclosilicate-are recommended by international guidelines for the management of hyperkalemia. There is, however, no universally accepted best practice for how to appropriately utilize K+ binders in the long-term clinical management of CKD. A panel of eight US-based nephrologists convened in October 2022 to develop a consensus statement regarding utilizing K+ binders in clinical practice to help manage patients with nonemergent, persistent/recurrent hyperkalemia in CKD. Consensus was reached on the following topics: (1) identifying risk factors for hyperkalemia; (2) serum K+ monitoring before and during K+ binder use; (3) utilizing K+ binders in patients receiving renin-angiotensin-aldosterone system inhibitors and dialysis; and (4) when to initiate K+ binders and their duration of use. These consensus statements for the use of K+ binders may assist the nephrology community in optimizing management of hyperkalemia in patients across the spectrum of CKD.

Randomized Trial of Patiromer on Efficacy to Reduce Episodic Hyperkalemia in Patients with ESKD Treated With Hemodialysis

Introduction

Individuals with end-stage kidney disease (ESKD) maintained on hemodialysis (HD) carry a high risk of cardiac arrhythmias. This risk is heightened by episodic hyperkalemia. The purpose of the study was to investigate whether patiromer administered daily reduced episodes of hyperkalemia in those with ESKD who receive HD, and to explore whether prescription of patiromer reduced the number of significant arrhythmia events.

Methods

This was a prospective, randomized, open-label trial. Eligible patients with ESKD on HD were identified. Participants were randomized 1:1 to patiromer versus usual care. Those randomized to patiromer were administered the medication daily, and the dose was titrated based on serum potassium concentrations at the start of weeks 1, 2, and 3. All participants received 7-day continuous cardiac monitors at baseline and at week 4.

Results

Of the 33 participants who were randomized, 1 withdrew due to adverse symptoms, and 1 withdrew due to pregnancy, leaving 31 in our analytic cohort. The mean age of randomized participants was 56 years, 55% were male, 81% were Black, and 10% were Hispanic/Latino. In week 4, the number of episodes of serum potassium ≥ 5.5 mEq/l was 13 in the patiromer group and 41 in the control group; with median number of episodes of hyperkalemia in the patiromer group significantly lower than that of control group (0 vs. 3, P = 0.024). In week 4 continuous cardiac monitors, 6 participants had > 1000/24 h premature ventricular contractions, 5 had no sustained ventricular tachycardia (VT), 3 had atrial fibrillation, and 1 had bradycardia, with no significant differences between the groups.

Conclusion

Patiromer administered daily reduced the frequency of hyperkalemia in study participants with ESKD who receive thrice-weekly HD. Larger studies are needed to determine whether patiromer reduces significant cardiac events.

Management of hyperkalemia: Expert consensus from Kuwait - a Modified Delphi Approach

Introduction

Hyperkalemia is common in heart failure (HF) patients on renin angiotensin aldosterone inhibitors (RAASi), in chronic kidney disease (CKD), and in hemodialysis, and it negatively impacts their management. New potassium binders, such as sodium zirconium cyclosilicate (SZC), are effective in management of acute and chronic hyperkalemia. However, guidelines inconsistencies and lack of standardized treatment protocols are hindering proper and wider use of such agents. Therefore, an expert panel from Kuwait developed a consensus statement to address hyperkalemia management in acute settings, in HF, in CKD, and in hemodialysis.

Methods

A three-step modified Delphi method was adopted to develop the present consensus, which consisted of two rounds of voting and in-between a virtual meeting. Twelve experts from Kuwait participated in this consensus. Statements were developed and shared with experts for voting. A meeting was held to discuss statements that did not reach consensus at the first round and then the remaining statements were shared for final voting.

Results

The consensus consists of 44 statements involving an introduction to and the management of hyperkalemia in acute settings, HF, CKD, and hemodialysis. Thirty-six statements approved unanimously in the first vote. In the second vote, four statements were removed and four were approved after editing.

Conclusion

Hyperkalemia management lacks standardized definitions, treatment thresholds and consistent guidelines and laboratory practices. This consensus is in response to lack of standardized treatment in the Arabian Gulf, and it aims to establish guidance on hyperkalemia management for healthcare practitioners in Kuwait and highlight future needs.

Plant-based diet in hyperkalemic chronic kidney disease patients receiving sodium zirconium cyclosilicate: a feasibility clinical trial

BACKGROUND

Plant-based diets (PBD) may induce hyperkalemia in chronic kidney disease (CKD) patients.

OBJECTIVES

We explored the safety and feasibility of PBD in hyperkalemic CKD patients receiving the potassium binder sodium zirconium cyclosilicate (SZC).

METHODS

In the current 6-wk trial, 26 hyperkalemic patients with CKD stage 4-5 not on dialysis received a low-protein low-potassium diet plus SZC for 3 wk and then a PBD with high potassium content delivered as a weekly food basket while continuing SZC for subsequent 3 wk. Plasma potassium was monitored weekly and SZC was titrated to achieve normokalemia. The 24-h urine excretion of potassium and sodium, 24-h food records, dietary quality, nutritional status, Bristol stool scale, Quality of life (QoL), and renal treatment satisfaction were assessed at baseline (week 0), week 3, and week 6.

RESULTS

Mean plasma potassium decreased from 5.5 to 4.4 mEq/L within 48-72 h after baseline, then rose to 4.7-5.0 mEq/L throughout the remaining study period following dose adjustments of SZC that matched the increased potassium intake of PBD from week 3 to week 6. Over the study period, 24-h urinary potassium excretion decreased from week 0 to week 3 and increased from week 3 to week 6. During the study, 58% of patients had fasting plasma potassium between 3.5 and 5.0 mEq/L and there was no episode of plasma potassium >6.5 mEq/L or <3.0 mEq/L during the study. P-carbon dioxide increased from baseline until week 6 (21 ± 2 to 23 ± 2 mEq/L; P = 0.002; mean ± SD), whereas remaining laboratory values remained unchanged. Fiber intake, dietary quality, the domain physical functioning from QoL, and 1 question of renal treatment satisfaction improved, whereas stool type and frequency did not change after starting PBD.

CONCLUSIONS

PBD in hyperkalemia-prone CKD patients receiving SZC improved dietary quality and increased the intake of healthy foods, whereas plasma potassium concentration remained stable within normal values for most patients.

TRIAL REGISTRATION NUMBER

This trial was registered at the https://clinicaltrials.gov/study/NCT04207203 as NCT04207203.

HARMONIZE Asia: A Phase III Randomized Study to Investigate the Efficacy and Safety of Sodium Zirconium Cyclosilicate in Patients with Hyperkalemia in China

PURPOSE

Sodium zirconium cyclosilicate (SZC) is an oral potassium (K+)-lowering therapy for adults with hyperkalemia. HARMONIZE Asia (ClinicalTrials.gov identifier: NCT03528681) evaluated the efficacy and safety of SZC in Chinese patients with hyperkalemia.

METHODS

This Phase III, randomized, double-blind, placebo-controlled study recruited patients with serum K+ (sK+) ≥5.1 mmol/L at 35 sites in China. Patients received SZC 10 g three times daily (TID) for 24 or 48 hours during an open-label initial phase (OLP). Those patients achieving normokalemia (sK+ 3.5-5.0 mmol/L inclusive) entered a 28-day randomized (2:2:1) treatment phase (RTP) and received SZC 5 g, SZC 10 g, or placebo once daily. The primary endpoint was mean sK+ during RTP Days 8 to 29. Secondary endpoints included mean change in sK+ during the OLP, the proportion of patients who achieved normokalemia at the end of the OLP, the proportion that maintained normokalemia during the RTP, and time to recurrence of hyperkalemia.

FINDINGS

In total, 270 patients received SZC 10 g TID during the OLP; 256 (94.8%) completed the OLP. During the OLP, mean sK+ decreased by 1.1 mmol/L from baseline (5.9 mmol/L; P < 0.001) and 87.4% of patients achieved normokalemia. During the RTP, SZC 5 g and 10 g reduced mean sK+ versus placebo in a dose-dependent manner (each P < 0.001); least-squares means (95% confidence interval [CI]) sK+ were 4.9 mmol/L (4.7, 5.0), 4.4 mmol/L (4.3, 4.6), and 5.2 mmol/L (5.1, 5.4) for SZC 5 g, 10 g, and placebo, respectively. At RTP end, the proportions of patients who maintained normokalemia were 58.8% (SZC 5 g; odds ratio vs placebo, 2.5 [95% CI: 1.1, 6.1; P = 0.035]), 76.5% (SZC 10 g; odds ratio vs placebo, 6.3 [95% CI: 2.6, 15.3; P < 0.001]), and 36.8% for placebo. Risk of recurrent hyperkalemia was reduced by 61.0% and 84.0% with SZC 5 g and SZC 10 g, respectively, versus placebo (each P < 0.001). During the RTP, the incidence of adverse events was numerically higher with SZC 5 g (50.0% of patients) and 10 g (44.0%) versus placebo (36.0%); driven primarily by peripheral edema and constipation.

IMPLICATIONS

Both SZC doses demonstrated clinically relevant and statistically significant, dose-dependent efficacy in managing sK+ levels in Chinese patients with hyperkalemia, compared with placebo. SZC tolerability was broadly aligned with the known safety profile of SZC.

Thermal Vapor Deposition of a Hydrophobic and Gas-Permeable Membrane on Zirconium Phosphate Cation Exchanger: An Oral Sorbent for the Urea Removal of Kidney Failure

An oral sorbent with high capacity for NH4+ is desirable in lowering the blood urea level and mitigating the dialysis burden for end-stage kidney disease (ESKD) patients. Zirconium phosphate (ZrP) is an amorphous cation ion exchanger with high NH4+ binding capacity as a sorbent material, but its selectivity to remove NH4+ is limited in the presence of other competing ions in water solution. We previously have developed a gas-permeable and hydrophobic perfluorocarbon coating on ZrP, which improves ZrP's NH4+ selectivity. However, the coating preparation procedure, a wet chemistry approach, is complicated and time-consuming, and more importantly, the large amount of usage of acetone poses a concern for the application of ZrP as an oral sorbent. In this study, we developed a solventless coating protocol that effectively coats ZrP with tetraethyl orthosilicate (TEOS) and 1H,1H,2H,2H-perfluorooctyltriethoxysilane (FOTS) via thermal vapor deposition (TVD) in a simplified manner. X-ray photoelectron spectroscopy (XPS) and contact angle measurements verify the two coatings are successfully deposited on the ZrP surface, and the coating condition was optimized based on an in vitro static binding study. The dynamic binding study of competing ions on Na-loaded ZrP with TVD coatings yields a maximum NH4+ removal (∼3.2 mequiv/g), which can be improved to ∼4.7 mequiv/g if H-loaded ZrP under the same coating condition is used in basic stock solutions. More importantly, both materials barely remove Ca2+ and show excellent acid resistance. The significant improvement in the NH4+ binding capacity and selectivity reported here establishes a highly promising surface modification approach to optimize oral sorbents for ESKD patients.

Heart Failure and Edema Costs in Patiromer and Sodium Zirconium Cyclosilicate Users

Key Points

Prior research suggests differences in rates of heart failure hospitalization or serious emergency department visits between patients on patiromer versus sodium zirconium cyclosilicate. Total costs of heart failure–related hospitalizations and emergency department visits may be lower in patients on patiromer compared with sodium zirconium cyclosilicate.

Background

Previous work suggested differences between patients taking patiromer or sodium zirconium cyclosilicate (SZC) in real-world risk of heart failure (HF) hospitalizations and edema hospitalizations or emergency department (ED) visits (edema events). We further investigated these differences to assess economic importance. Retrospective study using published event rates and mean costs derived from Optum's deidentified Clinformatics Data Mart Database.

Methods

We designed a model to estimate adjusted economic offsets that combined respective patiromer and SZC HF hospitalization (25.1 and 35.8; difference 10.7 [95% confidence interval (CI)2, 2.6 to 18.8]) and edema event (3.4 and 7.1; difference 3.6 [95% CI, 1.7 to 7.1]) rates/100 person-years from the original published work with costs from our parallel data extract spanning 2019–2021, adjusted to 2021 US dollars.

Results

In a base case of mean HF hospitalization, edema event, and 30-count potassium-binder prescription costs from our data extract, the estimated mean savings with patiromer was $1428 per person per year (95% CI, −$1508 to $4652). Respective costs per person per year for patiromer versus SZC were $8526 versus $12,622 (difference $4096 [95% CI, $116 to $7320]) for HF hospitalization and edema events, and $10,649 versus $7981 (difference −$2668) for potassium binders, totaling $19,175 for patiromer versus $20,603 for SZC.

Conclusions

With differing drug costs, hospitalization and ED costs offset this difference when event rates were numerically small. Model outcomes were driven by HF hospitalization cost and least influenced by edema ED visit cost. A limitation was that the Clinformatics Data Mart data extract may differ from the original work.

Effectiveness, safety, and treatment pattern of sodium zirconium cyclosilicate in Chinese patients with hyperkalemia: interim analysis from a multicenter, prospective, real-world study (Actualize Study)

Introduction: Sodium zirconium cyclosilicate (SZC) is a nonabsorbed cation-exchanger approved in China for the treatment of hyperkalemia [HK; serum potassium (sK+) levels >5.0 mmol/L]. This is the first real-world study aimed to assess the effectiveness, safety, and treatment patterns of SZC in Chinese patients with HK. Here we present the results of the first interim analysis. Methods: This multicenter, prospective, cohort study included patients aged ≥18 years with documented HK within 1-year before study enrollment day. These patients were followed up for 6 months from the enrollment day after initiating SZC treatment. The treatment was categorized into correction phase (FAS-P1) and maintenance phase (FAS-P2 new and ongoing users). Subgroup analysis was performed in patients on hemodialysis (FAS-H). The primary objective was evaluation of safety profile of SZC; secondary objectives included assessment of treatment patterns of SZC and its effectiveness. Results: Of 421 screened patients, 193, 354, and 162 patients were enrolled in the FAS-P1, FAS-P2, and FAS-H groups, respectively. sK+ levels were reduced significantly from 5.9 mmol/L to 5.0 mmol/L after the correction phase. For the maintenance phase, the mean sK+ levels were maintained at 5.2 mmol/L and 5.0 mmol/L in the FAS-P2 new and ongoing user, respectively, and 5.3 mmol/L in the FAS-H subgroup. A considerable proportion of patients showed normokalemia after 48 h of SZC treatment (FAS-P1:51.3%) which was maintained up to 6 months in the maintenance phase (FAS-P2:44%). SZC was well-tolerated. Conclusion: SZC was effective and safe for the treatment of HK in real-world clinical practice in China.

Incidence of hyperkalemia in anuric hemodialysis patients treated with sacubitril/valsartan

INTRODUCTION

Sacubitril/valsartan is increasingly used in hemodialysis patients due to its cardioprotective benefits. However, its impact on serum potassium levels in anuric patients undergoing hemodialysis remains controversial.

METHODS

We conducted a retrospective data from patients undergoing hemodialysis at two dialysis centers. A total of 71 out of 332 patients receiving hemodialysis treatment were enrolled. Mean serum potassium (mean value of 6-8 determinations), peak serum potassium (maximum K value observed during follow-up observations), and other biochemical parameters were recorded at baseline and during the follow-up period.

FINDINGS

After 6 months of follow-up, mean serum potassium increased from 4.84 ± 0.45 mmol/L at baseline to 5.07 ± 0.46 mmol/L at 3 months and 5.04 ± 0.46 mmol/L at 6 months (p < 0.001). Notably, no significant group differences were found in peak serum potassium concentrations between baseline and 6 months after sacubitril/valsartan therapy (5.69 ± 0.56 vs. 5.75 ± 0.41, p = 0.419). Prior to starting sacubitril/valsartan treatment, none of the patients had severe hyperkalemia; however, after 3 and 6 months of sacubitril/valsartan therapy, two (2.80%) and three (4.20%) patients experienced severe hyperkalemia, respectively; however, this difference was not statistically significant. Additionally, there was a significant reduction in blood pressure; however, serum sodium, bicarbonate, and Kt/V values did not change significantly during either period.

DISCUSSION

Sacubitril/valsartan therapy is associated with an increase in serum potassium levels in anuric hemodialysis patients. Nevertheless, the proportion of patients with severe hyperkalemia did not increase significantly. This suggests that the use of sacubitril/valsartan in anuric patients on hemodialysis is relatively safe.

[What's new in hyperkalemia management?]

Hyperkalemia is common in everyday clinical practice, and is a major risk factor for mortality. It mainly affects patients with chronic renal failure (CKD), diabetes or receiving treatment with inhibitors of the renin-angiotensin-aldosterone system (iRAAS). Therapeutic management aims not only to avoid the complications of hyperkalemia, but also to avoid discontinuation of cardio- and nephroprotective treatments such as iRAAS. The use of polystyrene sulfonate, widely prescribed, is often limited by patient acceptability. Recent data have cast doubt on its safety, particularly in terms of digestive tolerance. Two new potassium exchange molecules have appeared on the market: patiromer and zirconium sulfonate. Their value in clinical practice, and their acceptability in the event of prolonged prescription, remain to be demonstrated. The combination of a thiazide diuretic or an inhibitor of the sodium-glucose cotransporter type 2 (iSGLT2) with iRAAS therapy in CKD, may also improve control of kalemia. At present, there are no recommendations for the positioning of the various hypokalemic treatments. The choice of these treatments must be adapted to the patient's pathologies and consider the other expected effects of these molecules.

Advancing crush syndrome management: the potent role of Sodium zirconium cyclosilicate in early hyperkalemia intervention and survival enhancement in a rat model

Background: Crush Syndrome (CS), a severe trauma resulting from prolonged muscle compression, is commonly seen in large-scale disasters such as earthquakes. It not only causes localized tissue damage but also triggers electrolyte imbalances, particularly hyperkalemia, increasing the risk of early mortality. This study aims to assess the early intervention effects of Sodium Zirconium Cyclosilicate (SZC) on hyperkalemia in rat CS model. Methods: A rat CS model was established using a self-developed multi-channel intelligent small-animal crush injury platform. Rats in the experimental groups were treated with varying doses of SZC before compression and immediately post-decompression. The efficacy of SZC was evaluated by continuous monitoring of blood potassium levels and survival rates. Serum creatinine (Cre) and blood urea nitrogen (BUN) levels were analyzed, and renal damage was assessed through histopathological examination. Results: SZC treatment significantly reduced blood potassium levels and improved survival rates in rats. Compared to the placebo group, the SZC-treated rats showed a significant decrease in blood potassium levels at 6 and 12 h post-decompression, maintaining lower levels at 24 h. Biochemical analysis indicated no significant impact of SZC on renal function, with no notable differences in Cre and BUN levels between groups. Histopathological findings revealed similar levels of renal damage in both groups. Conclusion: SZC demonstrates significant early intervention effects on hyperkalemia in a rat model of crush injury, effectively improving survival rates without adverse effects on renal function. These results provide a new strategic direction for the clinical treatment of Crush Syndrome and lay the foundation for future clinical applications.

Cost-effectiveness of sodium zirconium cyclosilicate for advanced chronic kidney patients in Singapore

INTRODUCTION

Hyperkalaemia (HK) is prevalent among patients with chronic kidney disease (CKD) and chronic heart failure, especially if they are treated with renin-angiotensin-aldosterone system inhibitors (RAASi). This study evaluated the cost-effectiveness of a newly developed anti-HK therapy, sodium zirconium cyclosilicate (SZC), to the current standard of care for treating HK in advanced CKD patients from the Singapore health system perspective.

METHODS

We adapted a global microsimulation model to simulate individual patients' potassium level trajectories with baseline potassium ≥5.5 mmol/L, CKD progression, changes in treatment, and other fatal and non-fatal events. Effectiveness data was derived from ZS-004 and ZS-005 trials. Model parameters were localised using CKD patients' administrative and medical records at the Singapore General Hospital Department of Renal Medicine. We estimated the lifetime cost and quality-adjusted life years (QALYs) of each HK treatment, and the incremental cost-effectiveness ratio of SZC.

RESULTS

SZC demonstrated cost-effectiveness with an incremental cost-effectiveness ratsio of SGD 45 068 per QALY over a lifetime horizon, below the willingness-to-pay threshold of SGD 90 000 per QALY. Notably, SZC proved most cost-effective for patients with less severe CKD who were concurrently using RAASi. Sensitivity analyses confirmed the robustness of the findings, accounting for alternative parameter values and statistical uncertainty.

CONCLUSION

This study establishes the cost-effectiveness of SZC as a treatment for HK, highlighting its potential to mitigate the risk of hyperkalaemia and optimise RAASi therapy. These findings emphasise the value of integrating SZC into the Singapore health system for improved patient outcomes and resource allocation.

What to do with foundation therapies for heart failure for patients with end-stage kidney disease on haemodialysis

There is a significant burden of cardiovascular disease morbidity and mortality in the end-stage kidney disease population, driven by traditional and non-traditional risk factors. Despite its prevalence, heart failure is difficult to diagnose in the dialysis population due to overlapping clinical presentations, limitations of investigations, and the impact on the cardiorenal axis. 'Foundation therapies' are the key medications which improve patient outcomes in heart failure with reduced ejection fraction and include beta-blockers, renin-angiotensin-aldosterone system inhibitors and sodium-glucose cotransporter-2 inhibitors. They are underutilised in the dialysis population due to the exclusion of chronic kidney disease patients from major trials and legitimate clinical concerns e.g. hyperkalaemia, intradialytic hypotension and residual kidney function preservation. A coordinated cardiorenal multidisciplinary approach can guide appropriate diagnostic considerations (biomarkers interpretation, imaging, addressing unique complications of kidney disease), optimise dialysis management (prescription length, frequency and ultrafiltration targets) and when at euvolaemia facilitate the stepwise introduction of appropriate foundation therapies.

Pathophysiological Link and Treatment Implication of Heart Failure and Preserved Ejection Fraction in Patients with Chronic Kidney Disease

Heart failure with preserved ejection fraction (HFpEF) results from a complex interplay of age, genetic, cardiac remodeling, and concomitant comorbidities including hypertension, obesity, diabetes, and chronic kidney disease (CKD). Renal failure is an important comorbidity of HFpEF, as well as a major pathophysiological mechanism for those patients at risk of developing HFpEF. Heart failure (HF) and CKD are intertwined conditions sharing common disease pathways; the so-called "kidney tamponade", explained by an increase in intracapsular pressure caused by fluid retention, is only the latest model to explain renal injury in HF. Recognizing the different phenotypes of HFpEF remains a real challenge; the pathophysiological mechanisms of renal dysfunction may differ across the HF spectrum, as well as the prognostic role. A better understanding of the role of cardiorenal interactions in patients with HF in terms of symptom status, disease progression, and prognosis remains essential in HF management. Historically, patients with HF and CKD have been scarcely represented in clinical trial populations. Current concerns affect the practical approach to HF treatment, and, in this context, physicians are frequently hesitant to prescribe and titrate both new and old treatments. Therefore, the extensive application of HF drugs in diverse HF subtypes with numerous comorbidities and different renal dysfunction etiologies remains a controversial matter of discussion. Numerous recently introduced drugs, such as sodium-glucose-linked transporter 2 inhibitors (SGLT2i), constitute a new therapeutic option for patients with HF and CKD. Because of their protective vascular and hormonal actions, the use of these agents may be safely extended to patients with renal dysfunction in the long term. The present review delves into the phenotype of patients with HFpEF and CKD from a pathophysiological perspective, proposing a treatment approach that suggests a practical stepwise algorithm for the proper application of life-saving therapies in clinical practice.

Safety and efficacy of sodium zirconium cyclosilicate for the management of acute and chronic hyperkalemia in children with chronic kidney disease 4-5 and on dialysis

BACKGROUND

Sodium zirconium cyclosilicate (SZC), an ion-exchange resin, is effective in the control of hyperkalemia in adults with chronic kidney disease (CKD); reports of use in children are limited. Prolonged therapy with SZC to relax dietary potassium restriction in CKD has not been examined.

METHODS

We conducted a retrospective chart review of patients 6 months to 18 years of age with CKD stage 4-5 or on dialysis (5D) administered SZC for sustained hyperkalemia (potassium ≥ 5.5 mEq/L, three consecutive values). Patients received SZC (0.5-10 g per dose; age-based) either short-term (< 30 days) or long-term (> 30 days).

RESULTS

Twenty patients with median age 10.8 (inter-quartile range 3.9, 13.4) years were treated with SZC. Short-term SZC, for 5 (3, 19) days, was associated with safe management of dialysis catheter insertions (n = 5) and access dysfunction (n = 4), and was useful during palliative care (n = 1). Serum potassium levels decreased from 6.7 (6.1, 6.9) to 4.4 (3.7, 5.2) mEq/L (P < 0.001). Long-term SZC for 5.3 (4.2, 10.1) months achieved decline in serum potassium from 6.1 (5.8, 6.4) to 4.8 (4.2, 5.4) mEq/L (P < 0.001). SZC use was associated with liberalization of diet (n = 6) and was useful in patients with poor adherence to dietary restriction (n = 3). Adverse events or edema were not observed; serum sodium and blood pressure remained stable.

CONCLUSIONS

SZC was safe and effective for the management of acute and chronic hyperkalemia in children with CKD4-5/5D. Its use was associated with relaxation of dietary potassium restriction. Studies to examine its routine use to improve diet and nutritional status in children with CKD are required.

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.

Recommendations for the management of hyperkalemia in patients receiving renin-angiotensin-aldosterone system inhibitors

Hyperkalemia is common in clinical practice and can be caused by medications used to treat cardiovascular diseases, particularly renin-angiotensin-aldosterone system inhibitors (RAASis). This narrative review discusses the epidemiology, etiology, and consequences of hyperkalemia, and recommends strategies for the prevention and management of hyperkalemia, mainly focusing on guideline recommendations, while recognizing the gaps or differences between the guidelines. Available evidence emphasizes the importance of healthcare professionals (HCPs) taking a proactive approach to hyperkalemia management by prioritizing patient identification and acknowledging that hyperkalemia is often a long-term condition requiring ongoing treatment. Given the risk of hyperkalemia during RAASi treatment, it is advisable to monitor serum potassium levels prior to initiating these treatments, and then regularly throughout treatment. If RAASi therapy is indicated in patients with cardiorenal disease, HCPs should first treat chronic hyperkalemia before reducing the dose or discontinuing RAASis, as reduction or interruption of RAASi treatment can increase the risk of adverse cardiovascular and renal outcomes or death. Moreover, management of hyperkalemia should involve the use of newer potassium binders, such as sodium zirconium cyclosilicate or patiromer, as these agents can effectively enable optimal RAASi treatment. Finally, patients should receive education regarding hyperkalemia, the risks of discontinuing their current treatments, and need to avoid excessive dietary potassium intake.

Randomised, blinded, cross-over evaluation of the palatability of and preference for different potassium binders in participants with chronic hyperkalaemia in the USA, Canada and Europe: the APPETIZE study

OBJECTIVES

Traditional potassium (K+) binders for treating hyperkalaemia are unpalatable and poorly tolerated. Newer K+ binders are reportedly better tolerated; however, no published data describe their palatability, a determinant of long-term adherence. This study evaluated the palatability of and preference for three K+ binders: sodium and calcium polystyrene sulfonate (S/CPS), sodium zirconium cyclosilicate (SZC) and calcium patiromer sorbitex (patiromer).

DESIGN

Phase 4, randomised, participant-blinded, cross-over study. Participants were randomised to one of six taste sequences and, using a 'sip and spit' approach, tasted each K+ binder before completing a survey.

SETTING

17 centres across the USA, Canada and European Union.

PARTICIPANTS

144 participants with chronic kidney disease, hyperkalaemia and no recent use of K+ binders.

MAIN OUTCOME MEASURES

For the primary (USA) and key secondary (Canada and European Union) endpoints, participants rated palatability attributes (taste, texture, smell and mouthfeel) and willingness to take each K+ binder on a scale of 0-10 (rational evaluation). Feelings about each attribute, and the idea of taking the product once daily, were evaluated using a non-verbal, visual measure of emotional response. Finally, participants ranked the K+ binders according to palatability.

RESULTS

In each region, SZC and patiromer outperformed S/CPS on overall palatability (a composite of taste, texture, smell and mouthfeel), based on rational evaluation and emotional response. Taking the product once daily was more appealing for SZC and patiromer, creating greater receptivity than the idea of taking S/CPS. The emotional response to mouthfeel had the strongest influence on feelings about taking each product. In each region, a numerically greater proportion of participants ranked SZC as the most preferred K+ binder versus patiromer or S/CPS.

CONCLUSIONS

Preference for more palatable K+ binders such as SZC and patiromer may provide an opportunity to improve adherence to long-term treatment of hyperkalaemia.

TRIAL REGISTRATION NUMBER

NCT04566653.

Potassium homeostasis and therapeutic intervention with sodium zirconium cyclosilicate: A model-informed drug development case study

Potassium (K+ ) is the main intracellular cation in the body. Elevated K+ levels (hyperkalemia) increase the risk of life-threatening arrhythmias and sudden cardiac death. However, the details of K+ homeostasis and the effects of orally administered K+ binders, such as sodium zirconium cyclosilicate (SZC), on K+ redistribution and excretion in patients remain incompletely understood. We built a fit-for-purpose systems pharmacology model to describe K+ homeostasis in hyperkalemic subjects and capture serum K+ (sK+ ) dynamics in response to acute and chronic administration of SZC. The resulting model describes K+ distribution in the gastrointestinal (GI) tract, blood, and extracellular and intracellular spaces of tissue, renal clearance of K+ , and K+ -SZC binding and excretion in the GI tract. The model, which was fit to time-course sK+ data for individual patients from two clinical trials, accounts for bolus delivery of K+ in meals and oral doses of SZC. The virtual population of patients derived from fitting the model to these trials was then modified to predict the SZC dose-response and inform clinical trial design in two new applications: emergency lowering of sK+ in severe hyperkalemia and prevention of hyperkalemia between dialysis sessions in patients with end-stage chronic kidney disease. In both cases, the model provided novel and useful insight that was borne out by the now completed clinical trials, providing a concrete case study of fit-for-purpose, model-informed drug development after initial approval of a drug.

Mortality and hyperkalaemia-associated hospitalisation in patients with chronic kidney disease: comparison of sodium zirconium cyclosilicate and sodium/calcium polystyrene sulfonate

Background

Sodium zirconium cyclosilicate (SZC), a novel drug used for treating hyperkalaemia, is effective in reducing serum potassium levels. The effects of potassium adsorbents on the mortality and hyperkalaemia-associated hospitalisation rates remain unclear. We aimed to examine how mortality and hyperkalaemia-associated hospitalisation rates vary with usage of various potassium adsorbents.

Methods

This retrospective study used patients' data between April 2008 and August 2021 obtained from a large-scale Japanese medical claims database. Consecutive patients with chronic kidney disease (CKD) prescribed potassium adsorbents were enrolled and divided into three groups according to the adsorbent type [SZC, calcium polystyrene sulfonate (CPS), and sodium polystyrene sulfonate (SPS)] and were observed for 1 year. The primary outcome was a composite of mortality and hyperkalaemia-associated hospitalisation.

Results

In total, 234, 54 183, and 18 692 patients were prescribed SZC, CPS, and SPS, respectively. The SZC group showed a higher event-free survival rate than the other two groups. The hazard ratio for the primary outcome in the CPS and SPS groups was similar in the analyses of the subgroups of patients who did not receive renal replacement therapy and those who received haemodialysis. The SZC group had a higher renin-angiotensin-aldosterone system inhibitors (RAASi) continuation rate compared to CPS and SPS groups, the difference being especially significant for SPS.

Conclusions

This real-world study demonstrated the therapeutic effect of SZC in reducing mortality and hyperkalaemia-associated hospitalisations. The high RAASi continuation rate in the SZC group might be a contributing factor for improvement of the primary outcome.

Effects of Patiromer and Sodium Zirconium Cyclosilicate on Blood Pressure in Rats with Chronic Kidney Disease

BACKGROUND

Potassium-binders patiromer and sodium zirconium cyclosilicate (SZC) are approved to treat hyperkalaemia, which is frequently observed in chronic kidney disease (CKD). Elevated blood pressure (BP) is common in CKD, due in part to impaired sodium excretion. The effect of patiromer, which exchanges calcium for potassium and SZC, which exchanges sodium or hydrogen for potassium, on BP was assessed in a CKD rat model.

METHODS

Thirty-six Sprague Dawley rats with 5/6 nephrectomy were randomised to three groups (n = 12/group) to receive 4 g/kg/day patiromer or SZC, or vehicle treatment, for 8 weeks. BP was determined by radiotelemetry and urinary protein and electrolytes were measured.

RESULTS

At Week 8, systolic BP (sBP) increased in all groups; however, patiromer led to a lower mean (standard deviation) sBP than vehicle or SZC (141 [2.9] vs 158 [5.2] or 162 [6.1] mm Hg, respectively, both p < 0.001), with no difference in sBP between vehicle and SZC (p = 0.08). Similar results were observed for diastolic BP. Serum potassium levels fell with SZC (p < 0.02), but not vehicle or patiromer. Urine potassium decreased with both patiromer and SZC versus vehicle (p < 0.01); urine sodium increased with SZC (p < 0.01); and urine calcium increased with patiromer (p < 0.01). Urine phosphorus decreased with patiromer (p < 0.01) but increased with SZC (p < 0.01). Patiromer resulted in less proteinuria than vehicle or SZC (both p < 0.017).

CONCLUSIONS

After 8 weeks, treatment with patiromer resulted in lower BP in rats than vehicle or SZC. Further studies are needed to determine the mechanism of the differential effect of potassium binders on rat BP.

Therapeutic update on oral potassium exchange resin use in chronic kidney disease patients: a systematic review of randomized controlled clinical trials

Hyperkalemia is a common electrolyte disorder in patients with chronic kidney disease (CKD) that increases in prevalence with the decline of glomerular fltration rate (GFR). Another risk of hyperkalemia is the use of renin-angiotensin-aldosterone system inhibitors (RAASi) and/or mineralocorticoid receptor antagonists (MRAs) in managing CKD and proteinuria. The treatment of chronic hyperkalemia is challenging especially for outpatients. Treatment options for hyperkalemia include the potassium exchange resins of which two new potassium binders, Patiromer Sorbitex Calcium, and Sodium Zirconium Cyclosilicate (SZC) have demonstrated their clinical efficacy in reducing serum potassium with a positive safety profile. The old potassium exchange resin sodium polystyrene sulfonate (Kayexalate™) has some negative side effects including colonic necrosis, hypomagnesemia, and hypernatremia. In this review and literature search, we compare the available oral potassium exchange resins, highlight their advantages and disadvantages and comment on efficacy and safety parameters specifically in CKD patients.

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.

Economic impact of the use of patiromer in chronic kidney disease or heart failure for the treatment of chronic hyperkalemia in Spain

INTRODUCTION

Chronic hyperkalemia has negative consequences in the medium and long term, and determines the suspension of nephro and cardioprotective drugs, such as renin-angiotensin-aldosterone system inhibitors (RAASi). There is an alternative to the suspension or dose reduction of these treatments: the administration of potassium chelators. The aim of this study is to estimate the economic impact of the use of patiromer in patients with chronic kidney disease (CKD) or heart failure (HF) and hyperkalemia in Spain.

MATERIALS AND METHOD

The annual economic impact of the use of patiromer has been estimated from the perspective of the Spanish society. Two scenarios were compared: patients with CKD or HF and hyperkalemia treated with and without patiromer. The costs have been updated to 2020 euros, using the Health Consumer Price Index. Direct healthcare costs related to the use of resources (treatment with RAASi, CKD progression, cardiovascular events and hospitalization due to hyperkalemia), direct non-healthcare costs (informal care: costs derived from time dedicated by patient's relatives), the indirect costs (productivity loss), as well as an intangible cost (due to premature mortality) were considered. A deterministic sensitivity analysis was performed to validate the robustness of the study results.

RESULTS

The mean annual cost per patient in the scenario without patiromer is €9,834.09 and €10,739.37 in CKD and HF, respectively. The use of patiromer would lead to cost savings of over 30% in both diseases. The greatest savings in CKD come from the delay in the progression of CKD. While in the case of HF, 80.1% of these savings come from premature mortality reduction. The sensitivity analyses carried out show the robustness of the results, obtaining savings in all cases.

CONCLUSIONS

The incorporation of patiromer allows better control of hyperkalemia and, as a consequence, maintain treatment with RAASi in patients with CKD or HF. This would generate a 32% of annual savings in Spain (€3,127 in CKD; €3,466 in HF). The results support the positive contribution of patiromer to health cost in patients with only CKD or in patients with only HF.

Consensus document on the management of hyperkalemia

Hyperkalaemia is a common electrolyte imbalance with potentially serious short-, medium- and long-term consequences on morbidity and mortality rates and the use of national health service resources. The fact that different medical specialities can manage hyperkalaemia makes it important to have a unified approach, and the recent availability of new specific drug treatments means that the approach needs to be updated. This consensus document from the scientific societies most directly involved in the management of hyperkalaemia (Sociedad Española de Cardiología [Spanish Society of Cardiology], Sociedad Española de Endocrinología y Nutrición [Spanish Society of Endocrinology and Nutrition], Sociedad Española de Medicina Interna [Spanish Society of Internal Medicine], Sociedad Española de Medicina de Urgencias y Emergencias [Spanish Society of Accident and Emergency Medicine] and Sociedad Española de Nefrología [Spanish Society of Nephrology]) first of all reviews basic aspects of potassium balance and blood potassium. Then it goes on to focus on the concept, epidemiology, pathophysiology and diagnostic and therapeutic approaches to hyperkalaemia. The available evidence and the main published studies have been reviewed with the aim of providing a useful tool in the multidisciplinary approach to patients with hyperkalaemia.

Multicentre, observational, retrospective cohort of hyperkalaemia burden at haemodialysis facility-level in China: the Visualize-HD study protocol

OBJECTIVES

Hyperkalaemia is a potentially life-threatening disorder in patients undergoing haemodialysis (HD). Excess mortality and hospitalisation have been associated with hyperkalaemia (HK) after the long (2-day) interdialytic interval (LIDI) in patients on thrice a week HD compared with the short (1-day) interdialytic interval. Moreover, not much research has been conducted in China on the descriptive epidemiology and management of HK among different HD centres. The aim of this study is to address this evidence gap by investigating the risk factors associated with HK clinical burden at the HD facility level, current HD centres management patterns, serum potassium management patterns, as well as the risk factors associated with crude mortality in China.

DESIGN

Multicentre, observational, retrospective cohort study.

SETTING

This study plans to enrol 300 HD centres across China. Haemodialysis centres having ≥100 patients on maintenance HD within 3 years before study initiation, with participation willingness, routine blood collection post-LIDI and death records will be included.

PARTICIPANTS

Patients aged ≥18 years and on chronic HD for ≥3 months will be considered eligible. Summary data about serum potassium, characteristics of patients, facility practice patterns will be collected at HD facility level and death records will be at the patient level.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome will be to examine the association between suspected risk factors and HK prevalence at HD facility level. Suspected risk factors include dialysis prescriptions and serum potassium testing frequency, characteristics of patients and related medication usage. The secondary outcome will be to determine the HK prevalence, serum potassium management pattern and risk factors associated with crude mortality. The primary and secondary outcomes will be analysed using regression models. Exploratory outcomes will further investigate the risk factors associated with serum potassium ≥6.0 and ≥6.5 mmol/L.

CONCLUSION

The study is expected to provide insights to improve dialysis practice patterns and understand the clinical burden of HK.

ETHICS AND DISSEMINATION

This study protocol was reviewed and approved by the Institutional Review Boards and Ethics Committee of Peking University People's Hospital (Approval number: 2020PHB324-01). The results will be disseminated through national and international presentations and peer-reviewed publications.

TRIAL REGISTRATION NUMBER

NCT05020717.

Comparison of effectiveness and safety of sodium polystyrene sulfonate and sodium zirconium cyclosilicate for treatment of hyperkalemia in hospitalized patients

PURPOSE

Potassium binders are frequently utilized for the treatment of hyperkalemia in hospitalized patients; however, there is limited data directly comparing individual agents. The purpose of this study was to compare the effectiveness and safety of sodium polystyrene sulfonate (SPS) and sodium zirconium cyclosilicate (SZC) for hyperkalemia treatment in hospitalized patients.

METHODS

This retrospective cohort study evaluated adult patients who were admitted within a 7-hospital health system and received SPS or SZC for a serum potassium level greater than 5.0 mEq/L. Patients receiving dialysis prior to SPS/SZC administration, those receiving other potassium-lowering medications within 6 hours prior to blood sampling for a repeat potassium level, and those started on kidney replacement therapy prior to sampling for a repeat potassium level were excluded.

RESULTS

Following evaluation of 3,903 patients, the mean reduction in serum potassium 4 to 24 hours after binder administration was 0.96 mEq/L with SPS and 0.78 mEq/L with SZC (P < 0.0001). The median dose of SPS was 30 g (interquartile range [IQR], 15-30 g) while the median (IQR) dose of SZC was 10 g (10-10 g). Resolution of hyperkalemia within 24 hours was achieved in a higher percentage of patients with use of SPS (74.9%) versus SZC (68.8%) (P < 0.001).

CONCLUSION

One of the largest comparisons of SPS and SZC conducted to date, this study demonstrated the effectiveness and safety of both agents. While a statistically greater reduction in serum potassium was observed with use of SPS, there was significant dosing variability among agents that limited the ability to directly compare specific doses. Further investigation is needed to determine the optimal dose of each agent for acute hyperkalemia management. This data will inform clinical decisions about the choice of potassium binder for acute hyperkalemia.

A Real-World Experience of Hyperkalemia Management Using Sodium Zirconium Cyclosilicate in Chronic Hemodialysis: A Multicenter Clinical Audit

INTRODUCTION

 Hyperkalemia, a common condition among hemodialysis (HD) patients, is associated with adverse health outcomes. Evidence of the safety and efficacy of a potassium-binder, sodium zirconium cyclosilicate (SZC), has been limited among Asian (HD) patients beyond phase 3 trials. This article demonstrates real-world evidence of SZC usage in an Asian cohort of HD patients.

METHODS

 A retrospective clinical audit was conducted among 293 patients who received maintenance HD at community-based dialysis centers in Singapore. Patients received SZC for either management of hyperkalemia or hyperkalemia prevention during anticipated disruption to dialysis, such as during traveling. Among patients treated for hyperkalemia (N = 147), serum potassium (K+) prior to SZC initiation and at the endpoint was compared using a paired Student's t-test. Changes in K+ from baseline to endpoint were compared across various categories within each demographic and health-related variables using either Student's t-test or one-way ANOVA. Patients who experienced adverse events after SZC initiation or were deceased during the audit were reviewed to provide a descriptive account.

RESULTS

 Among patients who received SZC for hyperkalemia treatment, SZC use was associated with a significant reduction of 0.812 mmol/L in serum potassium. Patients with ethnicities other than Chinese, Malay, or Indian had a nominal reduction in K+ of 0.7 mmol/L and this can be accounted for the small sample size of this sub-group. The three main ethnicities which represented more than 95% of the sample showed a significant reduction in K+ levels (all three p<0.001). This is consistent with other studies with SZC which showed efficacy across various ethnicities. Patients who received SZC for hyperkalemia treatment or prevention had a significant lowering of mortality rate. This mortality reduction may have inherent biases and confounders, due to the retrospective clinical audit study design.  Conclusions: Overall, SZC was safe and effective among the audited patients. The efficacy in the real-world setting was similar to previous trials. The novel use of SZC to manage serum potassium when HD sessions are missed, such as during traveling, warrants further investigation due to potentially significant life-saving implications.

Hyperkalemia in chronic kidney disease: a focus on potassium lowering pharmacotherapy

INTRODUCTION

Hyperkalemia is one of the most common electrolyte disorders in chronic kidney disease (CKD) and is associated with serious adverse outcomes. Hyperkalemia risk is even greater when CKD patients also have additional predisposing conditions such as diabetes or heart failure. Renin-angiotensin-aldosterone-system blockers are first-line treatments for cardio- and nephroprotection, but their use is often limited due to K+ elevation, resulting in high rates of discontinuation.

AREAS COVERED

This article provides an overview of factors interfering with K+ homeostasis and discusses recent data on newer therapeutic agents used for the treatment of hyperkalemia. A detailed literature search was performed in two major databases (PubMed/MEDLINE and Scopus) up to April 2023.

EXPERT OPINION

Major clinical trials have tested new and promising kidney protective therapies such as sodium/glucose-cotransporter-2 inhibitors and mineralocorticoid-receptor-antagonists, with promising results. Until recently, the only treatment option for hyperkalemia was the cation-exchanging resin sodium-polystyrene-sulfonate. However, despite its common use, the efficacy and safety data of this drug in the long-term management of hyperkalemia are scarce. During the last decade, two novel orally administered K+-exchanging compounds (patiromer and sodium-zirconium-cyclosilicate) have been approved for the treatment of adults with hyperkalemia, as they both effectively reduce elevated serum K+ and maintain chronically K+ balance within the normal range with an excellent tolerability and no serious adverse events.

Hyperkalaemia prevalence and dialysis patterns in Chinese patients on haemodialysis: an interim analysis of a prospective cohort study (PRECEDE-K)

BACKGROUND

Hyperkalaemia is a known risk factor for cardiac arrhythmia and mortality in patients on haemodialysis. Despite standard adequate haemodialysis, hyperkalaemia is common in patients with end-stage renal disease (ESRD) at interdialytic intervals. Data on hyperkalaemia burden and its effects on dialysis patterns and serum potassium (sK) fluctuations in patients on haemodialysis in China remain limited. The prospective, observational cohort study (PRECEDE-K; NCT04799067) investigated the prevalence, recurrence, and treatment patterns of hyperkalaemia in Chinese patients with ESRD on haemodialysis.

METHODS

Six hundred adult patients were consecutively enrolled from 15 secondary and tertiary hospitals in China. In this interim analysis, we report the baseline characteristics of the cohort, the prevalence of predialysis hyperkalaemia (sK > 5.0 mmol/L), and the trends in serum-dialysate potassium gradient and intradialytic sK shift at Visit 1 (following a long interdialytic interval [LIDI]).

RESULTS

At baseline, most patients (85.6%) received three-times weekly dialysis; mean duration was 4.0 h. Mean urea reduction ratio was 68.0% and Kt/V was 1.45; 60.0% of patients had prior hyperkalaemia (previous 6 months). At Visit 1, mean predialysis sK was 4.83 mmol/L, and 39.6% of patients had hyperkalaemia. Most patients (97.7%) received a dialysate potassium concentration of 2.0 mmol/L. The serum-dialysate potassium gradient was greater than 3 mmol/L for over 40% of the cohort (1- < 2, 2- < 3, 3- < 4, and ≥ 4 mmol/L in 13.6%, 45.1%, 35.7%, and 5.2% of patients, respectively; mean: 2.8 mmol/L). The intradialytic sK reduction was 1- < 3 mmol/L for most patients (0- < 1, 1- < 2, 2- < 3, and ≥ 3 mmol/L in 24.2%, 62.2%, 12.8%, and 0.9% of patients, respectively; mean: 1.4 mmol/L).

CONCLUSIONS

Hyperkalaemia after a LIDI was common in this real-world cohort of Chinese patients despite standard adequate haemodialysis, and led to large serum-dialysate potassium gradients and intradialytic sK shifts. Previous studies have shown hyperkalaemia and sK fluctuations are highly correlated with poor prognosis. Effective potassium-lowering treatments should be evaluated for the improvement of long-term prognosis through the control of hyperkalaemia and sK fluctuations.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT04799067.

Hyperkalemia in CKD: an overview of available therapeutic strategies

Hyperkalemia (HK) is a life-threatening condition that often occurs in patients with chronic kidney disease (CKD). High serum potassium (sKsK) is responsible for a higher risk of end-stage renal disease, arrhythmias and mortality. This risk increases in patients that discontinue cardio-nephroprotective renin-angiotensin-aldosterone system inhibitor (RAASi) therapy after developing HK. Hence, the management of HK deserves the attention of the clinician in order to optimize the therapeutic strategies of chronic treatment of HK in the CKD patient. The adoption in clinical practice of the new hypokalaemic agents patiromer and sodium zirconium cyclosilicate (SZC) for the prevention and chronic treatment of HK could allow patients, suffering from heart failure and chronic renal failure, to continue to benefit from RAASi therapy. We have updated a narrative review of the clear variables, correct definition, epidemiology, pathogenesis, etiology and classifications for HK among non-dialysis CKD (ND CKD) patients. Furthermore, by describing the prognostic impact on mortality and on the progression of renal damage, we want to outline the strategies currently available for the control of potassium (K+) plasma levels.

DIALIZE China: A Phase IIIb, Randomized, Placebo-Controlled Study to Reduce Predialysis Hyperkalemia With Sodium Zirconium Cyclosilicate in Chinese Patients

PURPOSE

The DIALIZE China study (Reduce Incidence of Pre-Dialysis Hyperkalaemia With Sodium Zirconium Cyclosilicate in Chinese Subjects) (NCT04217590) evaluated sodium zirconium cyclosilicate (SZC) for the management of hyperkalemia in Chinese patients undergoing hemodialysis.

METHODS

In the double-blind, Phase IIIb DIALIZE China study, Chinese adults with kidney failure and predialysis hyperkalemia (predialysis serum potassium [sK+] concentration >5.4 mmol/L after the long interdialytic interval [LIDI] and >5.0 mmol/L after ≥1 short interdialytic interval) who were receiving hemodialysis 3 times weekly were randomized to placebo or SZC 5 g once daily on nondialysis days. Doses were titrated towards maintaining normokalemia for 4 weeks (titration period) in 5-g increments up to 15 g. Primary efficacy was the proportion of responders during the 4-week evaluation period following the titration period (ie, those with a predialysis sK+ of 4.0-5.0 mmol/L for at least 3 of 4 hemodialysis visits following the LIDI) who did not require urgent rescue therapy.

FINDINGS

Overall, 134 adults (mean [SD] age, 55 [11.3] years) were randomized to SZC or placebo (n = 67 each). There were significantly more responders with SZC (37.3%) versus placebo (10.4%; estimated odds ratio [OR] = 5.10; 95% CI, 1.90-15.12; P < 0.001). The probability of all predialysis sK+ concentrations being 3.5 to 5.5 mmol/L was significantly higher with SZC versus placebo (estimated OR = 6.41; 95% CI, 2.71-15.12; P < 0.001). A greater proportion of patients achieved an sK+ of 3.5 to 5.5 mmol/L on at least 3 of 4 LIDI visits during evaluation with SZC (73.1%) versus placebo (29.9%). Serious adverse events occurred in 9.1% and 11.9% of patients in the SZC and placebo groups, respectively.

IMPLICATIONS

SZC treatment for predialysis hyperkalemia is effective and well tolerated in Chinese patients with kidney failure receiving hemodialysis.

CLINICALTRIALS

gov identifier: NCT04217590.

Managing Hyperkalemia in the Modern Era: A Case-Based Approach

The last decade has seen tremendous advances in the prevention and treatment of recurrent hyperkalemia. In this narrative review, we aim to highlight contemporary data on key areas in the epidemiology and management of hyperkalemia. Focusing on drug-induced hyperkalemia (the implications of renin-angiotensin-aldosterone system inhibitors [RAASi] discontinuation and the role of mineralocorticoid receptor antagonists), newer concurrent therapies that modify potassium handling (sodium-glucose transporter 2 inhibitors [SGLT2i]), the introduction of new treatment agents (oral potassium binding agents), and the controversial role of dietary potassium restriction, we apply recent research findings and review the evidence in a case-based format.

Evaluation of the effect of sodium zirconium cyclosilicate on arrhythmia-related cardiovascular outcomes in patients receiving chronic haemodialysis with hyperkalaemia: protocol for the multicentre, randomised, controlled DIALIZE-Outcomes study

INTRODUCTION

Patients with kidney failure receiving chronic haemodialysis have elevated risk of arrhythmias potentially increasing the likelihood of sudden cardiac death, stroke and hospitalisation. The DIALIZE study (NCT03303521) demonstrated that sodium zirconium cyclosilicate (SZC) was an efficacious and well-tolerated treatment for predialysis hyperkalaemia in patients undergoing haemodialysis. The DIALIZE-Outcomes study evaluates the effect of SZC on sudden cardiac death and arrhythmia-related cardiovascular outcomes in patients receiving chronic haemodialysis with recurrent hyperkalaemia.

METHODS AND ANALYSIS

International, multicentre, randomised, double-blind, placebo-controlled study conducted at 357 study sites across 25 countries. Adults (≥18 years) receiving chronic haemodialysis three times per week with recurrent predialysis serum potassium (K+) ≥5.5 mmol/L post long interdialytic interval (LIDI) are eligible. Patients (~2800) will be randomised 1:1 to SZC or placebo, starting at 5 g orally once daily on non-dialysis days and titrated weekly in 5 g increments (maximum 15 g) to target predialysis serum K+ 4.0-5.0 mmol/L post LIDI. The primary objective is to evaluate efficacy of SZC versus placebo in reducing occurrence of the primary composite endpoint of sudden cardiac death, stroke or arrhythmia-related hospitalisation, intervention or emergency department visit. Secondary endpoints include efficacy of SZC versus placebo in maintaining normokalaemia (serum K+ 4.0-5.5 mmol/L post LIDI) at the 12-month visit, preventing severe hyperkalaemia (serum K+ ≥6.5 mmol/L post LIDI) at the 12-month visit and reducing the incidence of individual cardiovascular outcomes. Safety of SZC will be evaluated. The study is event driven, with participants remaining in the study until 770 primary endpoint events have occurred. Average time in the study is expected to be ~25 months.

ETHICS AND DISSEMINATION

Approval was obtained from the relevant institutional review board/independent ethics committee from each participating site (approving bodies in supplementary information). The results will be submitted to a peer-reviewed journal.

TRIAL REGISTRATION NUMBERS

EudraCT 2020-005561-14 and clinicaltrials.gov identifier NCT04847232.

Evaluation of safety, effectiveness and treatment patterns of sodium zirconium cyclosilicate in management of hyperkalaemia in China: a real-world study protocol

INTRODUCTION

Hyperkalaemia (HK) is a potentially life-threatening electrolyte imbalance associated with several adverse clinical outcomes. The efficacy and negative effects of currently existing treatment options have made HK management questionable. Sodium zirconium cyclosilicate (SZC), a novel highly selective potassium binder, is approved for the treatment of HK. The present study will be aimed to assess the safety, effectiveness and treatment patterns of SZC in Chinese patients with HK in a real-world clinical setting as it is required by China's drug review and approval process.

METHODS AND ANALYSIS

This is a multicentre, prospective cohort study which plans to enrol 1000 patients taking SZC or willing to take SZC from approximately 40 sites in China. Patients ≥18 years of age at the time of signing the written informed consent and with documented serum potassium levels ≥5.0 mmol/L within 1 year before study enrolment day will be included. Eligible patients will receive SZC treatment and will be followed up for 6 months from enrolment day. The primary objective will be to evaluate the safety of SZC for the management of HK in Chinese patients in terms of adverse events (AEs), serious AEs as well as discontinuation of SZC. The secondary objectives will include understanding the SZC dosage information in terms of its effectiveness and treatment patterns under real-world clinical practice and assessing effectiveness of SZC during the observational period.

ETHICS AND DISSEMINATION

This study protocol was approved by the Ethics Committee of the First Affiliated Hospital of Dalian Medical University (approval number: YJ-JG-YW-2020). All the participating sites have received the ethics approval. Results will be disseminated through national and international presentations and peer-reviewed publications.

TRIAL REGISTRATION NUMBER

NCT05271266.

Hyperkalemia: Prevalence, Predictors and Emerging Treatments

It is well established that an elevated potassium level (hyperkalemia) is associated with a risk of adverse events including morbidity, mortality and healthcare system cost. Hyperkalemia is commonly encountered in many chronic conditions including kidney disease, diabetes and heart failure. Furthermore, hyperkalemia may result from the use of renin-angiotensin-aldosterone system inhibitors (RAASi), which are disease-modifying treatments for these conditions. Therefore, balancing the benefits of optimizing treatment with RAASi while mitigating hyperkalemia is crucial to ensure patients are optimally treated. In this review, we will briefly discuss the definition, causes, epidemiology and consequences of hyperkalemia. The majority of the review will be focused on management of hyperkalemia in the acute and chronic setting, emphasizing contemporary approaches and evolving data on the relevance of dietary restriction and the use of novel potassium binders.

Prevalence and management of hyperkalemia in chronic kidney disease and heart failure patients in the Gulf Cooperation Council (GCC)

Hyperkalemia is a frequent complication in patients with chronic kidney disease (CKD) or heart failure (HF) and associated with neuromuscular manifestations, changes in the electrocardiogram, and increased risk of mortality. While data on the prevalence and management of hyperkalemia in the gulf region are scarce, risk factors such as preference for potassium-rich foods (e.g., dates and dried fruits/vegetables), periods of intense fasting (e.g., Ramadan), and diabetes (an ancestor of CKD and HF) are common. Therefore, a panel of nephrologists and cardiologists from countries of the Gulf Cooperation Council (GCC) convened to collate and review available data on the prevalence, regional drivers, and current practice in the management of hyperkalemia in the region. Eventually, this review provides consensus recommendations on a balanced utilization of dietary and pharmacological options including new potassium binders for achieving and sustainably maintaining desirable serum potassium levels in countries of the GCC region. Alignment with regional habits and practice was a key aspect to facilitate the uptake of the recommendations into physicians' practice and patients' lives.

An evaluation of sodium zirconium cyclosilicate: a new treatment option for hyperkalaemia in China

INTRODUCTION

Hyperkalemia is a common complication of chronic kidney disease (CKD), diabetes mellitus (DM), and heart failure (HF) that can lead to severe arrhythmias and sudden death and is associated with a higher risk of mortality. Therefore, the prevention and treatment of hyperkalemia is important. Sodium zirconium cyclosilicate (SZC), a new oral potassium-lowering drug, has offered an additional treatment option for Chinese patients with hyperkalemia since its launch in China in late 2019, and some experience has been accumulated regarding its efficacy and safety.

AREAS COVERED

In this review, the authors summarize the epidemiological features of hyperkalemia in China and review the clinical data regarding the use of sodium zirconium cyclosilicate in Chinese patients.

EXPERT OPINION

The prevalence of hyperkalemia is particularly high in Chinese patients with chronic kidney disease and heart failure. In China, recent clinical studies have shown that SZC rapidly reduces serum potassium, maintains normal potassium concentration, and is well tolerated and safe. Two Chinese expert consensus statements have recommended the use of SZC for the acute correction and chronic maintenance of potassium concentration.

Sodium zirconium cyclosilicate and metabolic acidosis: Potential mechanisms and clinical consequences

Metabolic acidosis is frequent in chronic kidney disease (CKD) and is associated with accelerated progression of CKD, hypercatabolism, bone disease, hyperkalemia, and mortality. Clinical guidelines recommend a target serum bicarbonate ≥ 22 mmol/L, but metabolic acidosis frequently remains undiagnosed and untreated. Sodium zirconium cyclosilicate (SZC) binds potassium in the gut and is approved to treat hyperkalemia. In clinical trials with a primary endpoint of serum potassium, SZC increased serum bicarbonate, thus treating CKD-associated metabolic acidosis. The increase in serum bicarbonate was larger in patients with more severe pre-existent metabolic acidosis, was associated to decreased serum urea and was maintained for over a year of SZC therapy. SZC also decreased serum urea and increased serum bicarbonate after switching from a potassium-binding resin in normokalemic individuals. Mechanistically, these findings are consistent with SZC binding the ammonium ion (NH₄⁺) generated from urea by gut microbial urease, preventing its absorption and, thus, preventing the liver regeneration of urea and promoting the fecal excretion of H⁺. This mechanism of action may potentially result in benefits dependent on corrected metabolic acidosis (e.g., improved well-being, decreased catabolism, improved CKD mineral bone disorder, better control of serum phosphate, slower progression of CKD) and dependent on lower urea levels, such as decreased protein carbamylation. A roadmap is provided to guide research into the mechanisms and clinical consequences of the impact of SZC on serum bicarbonate and urate.

Oral sorbents for small, charged uremic toxins, and carbon block for regeneration of dialysate: Fourth down and long

Complexities of sorbent regeneration of dialysate led me to look at other ways to use sorbents to remove uremic toxins. An oral sorbent containing cation and anion exchangers showed effective binding of potassium, phosphate, sodium, hydrogen, and ammonium (from urea) in vitro. Animal studies are ongoing. Carbon block columns can effectively bind organic and middle molecules toxins from the dialysate. Together, these two technologies have the potential to greatly simplify dialysis for end-stage renal disease patients.