Calcineurin inhibitor-related hyperkalemia is caused by hyporeninemic hypoaldosteronism and fludrocortisone is an effective treatment: Report of a case series and review of the literature.

INTRODUCTION: Calcineurin inhibitors (CNIs) are widely used in transplantation. Although CNI-related hyperkalemia is common (10%-60.6%), the underlying pathogenetic mechanism is not well-elucidated and may lead to dose adjustment or treatment withdrawal. OBJECTIVE: The aim of this study is to describe CNI-related hyperkalemia due to hyporeninemic hypoaldosteronism in pediatric transplant recipients who were successfully treated with fludrocortisone. METHOD: In a total of 55 hematopoietic stem cell (HSCT) and 35 kidney transplant recipients followed according to institutional immunosuppression protocols, recipients diagnosed with CNI-related hyperkalemia were reviewed. Recipients who were receiving intravenous fluid, potassium, or were diagnosed with hemolysis, acute graft rejection, or had an eGFR < 30 mL/min/1.73m2, were excluded. A detailed analysis of clinical history as well as biochemical studies was carried out to reveal possible pathophysiology. RESULTS: Three pediatric transplant recipients (one HSCT, two kidney transplantation) with findings of hyperkalemia, hyponatremia, and a mild elevation in blood urea nitrogen while on CNIs were recruited. Urinary potassium excretion was diminished while sodium excretion was increased. Plasma aldosterone levels were low, and renin was not increased in response. Primary adrenal insufficiency was ruled out, and hyporeninemic hypoaldosteronism was diagnosed. CNI-related hyperkalemia was detected earlier in case 1, who had HSCT (22 days), than in the second and third cases, who had kidney transplantation (24 and 30 months post-transplantation, respectively). The discrepancy was hypothesized to be explained by higher overall CNI dose due to higher serum target CNI used in HSCT than kidney transplantation. Electrolyte imbalance was reversed upon administration of physiologic dose fludrocortisone (0.05 mg, daily), while fludrocortisone was ceased after CNI withdrawal in case 1, which is additional evidence for the etiological association of CNIs and hyporeninemic hypoaldosteronism. CONCLUSION: Our three cases strengthen the premise that CNI-related hyperkalemia may be due to hyporeninemic hypoaldosteronism, and the timing and severity may be related to CNI dose. Fludrocortisone is a safe and effective treatment in CNI-related hyperkalemia, providing maintenance of CNIs, which are one of the essential therapeutic agents for pediatric transplantation.

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.

Managing hyperkalemia in patients with heart failure on guideline-directed medical therapy: challenges and opportunities.

Heart failure is a chronic and invalidating syndrome that affects tens of millions of people worldwide with significant socio-economic ramifications for the health care systems. Significant progress in the understanding of the pathophysiology of heart failure has allowed the gradual introduction of several drug classes for the management of such patients. Beta-blockers, mineralocorticoid receptor antagonists, angiotensin receptor neprilysin inhibitors, and sodium-glucose-cotransporter 2 inhibitors are all considered pillars of the guideline-directed medical therapy for heart failure. Despite remarkable improvements in the morbidity and mortality of heart failure, however, many patients still develop clinically significant hyperkalemia during combined treatment with those four pharmacological pillars. The consequence is often a down-titration or discontinuation of one or more crucial drugs, which in turns leads to a considerable increase in the risk of cardiovascular events, dialysis, and all-cause mortality. This paper will explore novel approaches for the management of hyperkalemia in heart failure, including closer monitoring of potassium levels, early review of drugs that might increase the risk of hyperkalemia, and pharmacological treatment of hyperkalemia, with a special emphasis on sodium-glucose-cotransporter 2 inhibitors and potassium-binding agents, including patiromer and sodium zirconium cyclosilicate.

Impact of a Hyperkalemia Protocol Tailored to Glucose Concentration and Renal Function on Insulin-Induced Hypoglycemia in Patients with Low Pretreatment Glucose.

BACKGROUND: Hyperkalemia is a common electrolyte abnormality that requires urgent treatment. Insulin is an effective treatment for hyperkalemia, but risk factors for developing insulin-induced hypoglycemia exist (e.g., low pretreatment glucose or renal impairment). OBJECTIVE: This study evaluated the impact of a hyperkalemia protocol tailored to glucose concentration and renal function on insulin-induced hypoglycemia. METHODS: This was a retrospective cohort study of emergency department patients with glucose ≤ 100 mg/dL treated with insulin for hyperkalemia. The primary outcome was incidence of hypoglycemia in patients treated prior to (July 1, 2018-June 30, 2019) vs. after (January 1, 2020-December 31, 2020) the protocol update, which individualized insulin and dextrose doses by glucose concentration and renal function. Secondary outcomes included change in potassium and protocol safety. We assessed factors associated with hypoglycemia using multiple logistic regression. RESULTS: We included 202 total patients (preimplementation: 114, postimplementation: 88). Initial insulin dose was lower in the postimplementation group (p < 0.001). We found a nonsignificant reduction in hypoglycemia in the postimplementation group (42.1% vs. 30.7%, p = 0.10). Degree of potassium reduction was similar in patients who received insulin 5 units vs. 10 units (p = 0.72). Higher pretreatment glucose (log odds ratio [OR] -0.05, 95% confidence interval [CI] -0.08 to -0.02) and additional insulin administration (log OR -1.55, 95% CI -3.01 to -0.25) were associated with reduced risk of developing hypoglycemia. CONCLUSION: A hyperkalemia protocol update was not associated with a significant reduction in hypoglycemia, and the incidence of hypoglycemia remained higher than anticipated. Future studies attempting to optimize treatment in this high-risk population are warranted.

Population Pharmacodynamic Dose-Response Analysis of Serum Potassium Following Dosing with Sodium Zirconium Cyclosilicate.

BACKGROUND: Sodium zirconium cyclosilicate (SZC) is an approved oral treatment for hyperkalemia that selectively binds potassium (K+) in the gastrointestinal tract and removes K+ from the body through increased fecal excretion. Here, we describe the population pharmacodynamic (PopPD) response of serum K+ concentration in patients with hyperkalemia who are treated with SZC, estimate the impact of patients' intrinsic and extrinsic factors, and compare predicted serum K+ responses between 5 g alternate daily (QOD) and 2.5 g once daily (QD) maintenance doses. METHODS: PopPD analysis was based on pooled data from seven phase II and III clinical trials for SZC. A semi-mechanistic longitudinal mixed-effects (base) model was used to characterize serum K+ concentration after SZC dosing. Indirect-response, virtual pharmacokinetics-pharmacodynamics (PK-PD) modeling was used to mimic the drug exposure compartment. Full covariate modeling was used to assess covariate impact on the half-maximal effective concentration of drug (EC50), placebo response, and Kout. Models were evaluated using goodness-of-fit plots, relative standard errors, and visual predictive checks, and data were stratified to optimize model performance across subgroups. Covariate effects were evaluated based on the magnitude of change in serum K+ between baseline and end of correction phase dosing (48 h, SZC 10 g three times a day) and maintenance phase dosing (28 days, SZC 10 g QD) using a reference subject. RESULTS: The analysis data set included 2369 patients and 25,764 serum K+ observations. The mean (standard deviation) patient age was 66.0 (12) years, 61% were male, 68% were White, 34% had congestive heart failure, and 62% had diabetes. Mean (standard deviation) serum K+ at baseline was 5.49 (0.43) mmol/L. Both the base and full covariance models adequately described observed data. In the final model, there was a sigmoid exposure response on Kin, with EC50 of 32.8 g and a Hill coefficient of 1.36. The predicted placebo-adjusted dose-responses of serum K+ change appeared nearly linear in the correction and maintenance phases. No clinically meaningful difference in placebo-adjusted serum K+ change from baseline at 28 days was observed between maintenance regimens of SZC 5 g QOD and 2.5 g QD. A greater SZC treatment response was associated with high serum K+ at baseline, advanced age, lower body weight, lower estimated glomerular filtration rate, and Black/African American and Asian race, compared with the reference patient. The impact of heart failure status and diabetes status was only minor. CONCLUSIONS: The PopPD model of SZC adequately described changes in serum K+ concentration during correction and maintenance phase dosing. A greater treatment response was associated with various covariates, but the impact of each was modest. Overall, these findings suggest that no adjustment in SZC dose is needed for any of the covariates evaluated.

Myelotoxicity and kidney dysfunction related to the use of trimethoprim-sulfamethoxazole for the treatment of Pneumocystis jirovecii pneumonia: a case report of severe adverse events with a common drug.

Trimethoprim-sulfamethoxazole (TMP-SMX) is the primary therapeutic option for Pneumocystis jirovecii pneumonia (PCP). Gastrointestinal symptoms and cutaneous rash are common side effects, with hyperkalemia being uncommon in patients without kidney dysfunction, and myelotoxicity being even rarer. We present the case of a male patient with hypertension and a recent diagnosis of non-Hodgkin lymphoma, undergoing rituximab treatment for two months. He was admitted to the intensive care unit due to dyspnea, tachypnea, and pleuritic pain, requiring mechanical ventilation. Chest computed tomography showed bilateral and multilobed ground-glass opacities, compromising more than 80% of the lung parenchyma. Pulmonary tuberculosis and COVID-19 were ruled out. An angiotomography and Doppler ultrasound revealed an extensive pulmonary thrombus and deep venous thrombosis. Empiric treatment with TMP-SMX for PCP was initiated, but within four days, the patient experienced metabolic acidosis and severe hyperkalemia, necessitating hemodialysis. He also presented with progressive pancytopenia and critical levels of leukopenia and thrombocytopenia. The hypothesis of TMP-SMX-induced myelotoxicity was suspected. Considering the unavailability of an alternative treatment, it was opted to continue TMP-SMX and initiate a granulocyte-colony-stimulating factor. However, the patient maintained medullary deterioration, becoming refractory to the transfusion of blood derivates. On the 17th day of treatment, a clinical decision was made to suspend TMP-SMX, leading to improvements within 48 hours in marrow and kidney functions, metabolic acidosis, and hyperkalemia. Despite all efforts, the patient died after 35 days of hospitalization due to hospital-acquired infections. This case highlights the importance of clinicians recognizing potential myelotoxicity with TMP-SMX and promptly discontinuing the drug if necessary.

Effectiveness and safety of early treatment with spironolactone for new-onset acute heart failure.

BACKGROUND: The effectiveness and safety of mineralocorticoid receptor antagonists (MRA) in acute heart failure (HF) is uncertain. We sought to describe the prescription of spironolactone during acute HF and whether early treatment is effective and safe in a real-world setting. METHODS: We performed a retrospective cohort study of adult (≥18 years) nonpregnant patients hospitalized with new-onset HF with reduced ejection fraction (HFrEF, defined by ejection fraction ≤40%) within 15 Kaiser Permanente Southern California medical centers between 2016 and 2021. Early treatment was defined by spironolactone prescription at discharge. The primary effectiveness outcome was a composite of HF readmission or all-cause mortality at 180 days. Safety outcomes were hypotension and hyperkalemia at 90 days. RESULTS: Among 2318 HFrEF patients, 368 (15.9%) were treated with spironolactone at discharge. After 1:2 propensity score matching, 354 early treatment and 708 delayed/no treatment patients were included in the analysis. The median age was 63 (IQR: 52-74) years; 61.6% were male, and 38.6% were White. By 90 days, ~20% had crossed over in the two groups. Early treatment was not associated with the composite outcome at 180 days (HR [95% CI]: 0.81 [0.56-1.17]), but a trend towards benefit by 365 days that did not reach statistical significance (0.78 [0.58-1.06]). Early treatment was also associated with hyperkalemia (subdistribution HR [95% CI]: 2.33 [1.30-4.18]) but not hypotension (0.93 [0.51-1.72]). CONCLUSIONS: Early treatment with spironolactone at discharge for new-onset HFrEF in a real-world setting did not reduce the risk of HF readmission or mortality in the first year after discharge. The risk of hyperkalemia was increased.

Cost-effectiveness analysis of sodium zirconium cyclosilicate for hyperkalemia among patients with chronic kidney disease or heart failure in Kuwait.

INTRODUCTION: Our model was conducted from Kuwaiti payer's perspective to provide evidence on the cost-effectiveness of Sodium zirconium cyclosilicate (SZC) versus patiromer to correct and maintain serum potassium (K+) in combination with renin-angiotensin-aldosterone system inhibitors (RAASis) with different dose titration in patients with chronic kidney disease/heart failure (CKD/HF) with/without renal replacement therapy (RRT). METHODOLOGY: The model was developed as a patient-level, fixed-time increment stochastic simulation to simulate the complexity of disease, including multiple coexisting and competing conditional risks. This model was established to compare SZC versus patiromer as a treatment for hyperkalemia (HK) among adult populations with underlying conditions of advanced CKD stages 3a-5 or HF to correct and maintain serum K + over a lifetime horizon. The clinical outcomes of SZC and patiromer were demonstrated through arm-specific K + trajectories extracted from the HARMONIZE trial and OPAL-HK trial, respectively. The utility data was captured from different studies. Direct medical cost was captured from local data from Kuwaiti hospitals. Sensitivity analyses were conducted to assess the uncertainty in the model. RESULTS: Within different scenarios of CKD/HF, SZC was a cost-saving option, with/without RRT, whether one-off administration or repeated administration, except for one-off treatment administration among the HF cohort, which generated an incremental cost effectiveness ratio of KWD 331/quality adjusted life year (QALY). The incremental QALY of SZC ranged from 0.007 to 0.202. In addition, the savings observed with SZC fall within a range of KWD -60 to KWD -1,235 at serum K+ ≥ 5.1 mmol/L. CONCLUSION: The evidence generated by our model recommends the inclusion of SZC as a treatment option to correct HK and maintain normal serum K + level for CKD/HF patients within the Kuwaiti healthcare system. The costs saved from reducing frequent HK episodes, RAASis discontinuation/down titration, major cardiovascular events, and hospitalization offset the drug acquisition cost of SZC.

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.

Acute Hyperkalemia Management in the Emergency Department.

Acute hyperkalemia is characterized by high concentrations of potassium in the blood that can potentially lead to life-threatening arrhythmias that require emergent treatment. Therapy involves the utilization of a constellation of different agents, all targeting different goals of care. The first, and most important step in the treatment of severe hyperkalemia with electrocardiographic (ECG) changes, is to stabilize the myocardium with calcium in order to resolve or mitigate the development of arrythmias. Next, it is vital to target the underlying etiology of any ECG changes by redistributing potassium from the extracellular space with the use of intravenous regular insulin and inhaled beta-2 agonists. Finally, the focus should shift to the elimination of excess potassium from the body through the use of intravenous furosemide, oral potassium-binding agents, or renal replacement therapy. Multiple nuances and controversies exist with these therapies, and it is important to have a robust understanding of the underlying support and recommendations for each of these agents to ensure optimal efficacy and minimize the potential for adverse effects and medication errors.

The role of a novel mineralocorticoid receptor antagonist, finerenone, in chronic kidney disease: mechanisms and clinical advances.

BACKGROUND: Chronic kidney disease (CKD) poses a significant health risk in contemporary society. Current CKD treatments primarily involve renin-angiotensin-aldosterone system inhibitors and mineralocorticoid receptor antagonists, albeit associated with hyperkalemia risks. A novel selective mineralocorticoid receptor antagonist, finerenone, offers a promising, safer alternative for CKD therapy. This review comprehensively assesses the role and efficacy of finerenone in CKD treatment by analyzing clinical and animal studies. Emerging evidence consistently supports finerenone's ability to effectively slow the progression of CKD. By targeting the mineralocorticoid receptor, finerenone not only mitigates renal damage but also exhibits a favorable safety profile, minimizing hyperkalemia concerns. CONCLUSION: Finerenone emerges as a valuable addition to CKD therapy, demonstrating potential benefits in delaying CKD progression while minimizing side effects. Nevertheless, further clinical trials are necessary to provide a comprehensive understanding of its safety and efficacy.

Novel potassium binders to optimize RAASi therapy in heart failure: A systematic review and meta-analysis.

AIMS: Hyperkalemia often occurs among heart failure (HF) patients, particularly when treated with renin-angiotensin-aldosterone system inhibitors (RAASi). Even modest potassium levels variations raise the risk of mortality and prompt patients to discontinue disease-modifying treatment, as RAASi. Novel potassium binders (NPB), patiromer and sodium zirconium cyclosilicate, are effective in reducing potassium levels and are approved for the treatment of hyperkalemia in HF, but whether their use results in a real optimization of HF treatment remains to be seen. The aim of the present meta-analysis was to assess the efficacy of NPB on the optimization of RAASi therapy in HF patients. METHODS AND RESULTS: PubMed, Web of Science and Clinicaltrial.gov were searched without restrictions from inception to 06 August 2022 to identify valuable articles. The studies that met the inclusion criteria were analyzed. The prespecified primary outcome was the optimization of RAASi therapy in HF patients, defined as the proportion of patients on RAASi at the end of follow-up. Secondary outcomes were hyperkalemia events, reduction in potassium levels, and adverse drugs reactions. Six studies with a total of 1390 patients were included. NPB improved RAASi therapy optimization in HF by 14% (95% CI: 4-26%), decreased hyperkalemia events by 29% (95% CI: 55-92%), and reduced potassium levels by 0.31 mEq/L (95% CI: 0.18-0.44) compared to placebo, maintaining a good safety profile. CONCLUSION: NPB are effective in allowing RAASi therapy optimization in patients affected by HF, in reducing hyperkalemia events and potassium levels. SYSTEMATIC REVIEW REGISTRATION: CRD42022351811 URL: https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=351811.

Sodium zirconium cyclosilicate reconciles management of hyperkalemia and continuity of renin-angiotensin-aldosterone system inhibitors: a retrospective observational study.

BACKGROUND: Sodium zirconium cyclosilicate, a non-absorbed non-polymer zirconium silicate, is a new potassium binder for hyperkalemia. A previous report showed that administering sodium zirconium cyclosilicate to patients with hyperkalemia allows a higher continuation rate of renin-angiotensin-aldosterone system inhibitors. However, no studies have compared sodium zirconium cyclosilicate with existing potassium binders for renin-angiotensin-aldosterone system inhibitor continuity. The purpose of this study was to evaluate the effect of sodium zirconium cyclosilicate on angiotensin-converting enzyme inhibitor /angiotensin receptor blocker continuation in patients with hyperkalemia compared to that of calcium polystyrene sulfonate. METHODS: Patients on angiotensin-converting enzyme inhibitors/angiotensin receptor blockers who were newly prescribed sodium zirconium cyclosilicate or calcium polystyrene sulfonate to treat hyperkalemia at a tertiary referral hospital between August 2020 and April 2022 were enrolled in this single-center, retrospective observational study. The primary outcome measure was angiotensin-converting enzyme inhibitor/angiotensin receptor blocker prescription three months after initiating potassium binders. RESULTS: In total, 174 patients on angiotensin-converting enzyme inhibitors/angiotensin receptor blockers who were newly administered sodium zirconium cyclosilicate (n = 62) or calcium polystyrene sulfonate (n = 112) were analyzed. The prescription rate of angiotensin-converting enzyme inhibitors /angiotensin receptor blockers at 3 months was significantly higher in the sodium zirconium cyclosilicate group than in the calcium polystyrene sulfonate group (89 vs. 72%). Multivariate logistic regression models showed that sodium zirconium cyclosilicate was independently associated with the primary outcome (odds ratio 2.66, 95% confidence interval 1.05-7.43). The propensity score-matched comparison also showed a significant association between sodium zirconium cyclosilicate and the primary outcome. CONCLUSIONS: Our study suggests that administering sodium zirconium cyclosilicate to patients with hyperkalemia allows for a higher continuation rate of angiotensin-converting enzyme inhibitors/angiotensin receptor blockers than calcium polystyrene sulfonate. These findings suggest that sodium zirconium cyclosilicate has potential benefits for patients with chronic kidney disease receiving renin-angiotensin-aldosterone system inhibitors.

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.

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.

The efficacy and safety of new potassium binders on renin-angiotensin-aldosterone system inhibitor optimization in heart failure patients: a systematic review and meta-analysis.

Guideline-directed medical therapy (GDMT) has improved outcomes in patients with heart failure, including the use of renin-angiotensin-aldosterone system inhibitors, which can hinder the excretion of potassium, resulting in hyperkalaemia. New potassium binders (NPBs) can prevent this adverse effect; however, the efficacy and safety of NPB for this indication have not been fully established. We conducted a systematic review and meta-analysis synthesizing randomized controlled trials (RCTs), which were retrieved by systematically searching PubMed, Web of Science, Scopus, and Cochrane through 26 April 2023. The risk of bias assessment was conducted, following Cochrane's updated Risk of Bias 2 assessment tool. We used the fixed-effects model to pool dichotomous data using risk ratio (RR) and continuous data using mean difference (MD), with a 95% confidence interval (CI) (PROSPERO ID: CRD42023426113). We included six RCTs with a total of 1432 patients. NPB was significantly associated with successful mineralocorticoid receptor antagonist (MRA) optimization [RR: 1.13 with 95% CI (1.02-1.25), P = 0.02], decreased patients with MRA at less than the target dose [RR: 0.72 with 95% CI (0.57-0.90), P = 0.004], and decreased hyperkalaemic episodes [RR: 0.42 with 95% CI (0.24-0.72), P = 0.002]. However, there was no difference between NPB and placebo regarding angiotensin-converting enzyme inhibitor (ACEi)/angiotensin receptor blocker (ARB)/angiotensin receptor/neprilysin inhibitor (ANRi) optimization [RR: 1.02 with 95% CI (0.89-1.17), P = 0.76] and serum potassium change [MD: -0.31 with 95% CI (-0.61 to 0.00), P = 0.05], with an acceptable safety profile except for the increased incidence of hypokalaemia with NPB [RR: 1.57 with 95% CI (1.12-2.21), P = 0.009]. NPB has been shown to improve GDMT outcomes by enhancing MRA optimization and reducing hyperkalaemic episodes. However, there are limited data on the effects of NPB on ACEi/ARB/ANRi optimization. Future RCTs should investigate ACEi/ARB/ANRi optimization and conduct head-to-head comparisons of NPB (patiromer and sodium zirconium cyclosilicate).

Potassium-lowering effects of sodium zirconium cyclosilicate in the early post-transplant period.

PROBLEM: Hyperkalemia is a serious condition among intra-abdominal transplant recipients, and the safety and efficacy of sodium zirconium cyclosilicate (SZC) for its management during the early post-transplant period are not well-established. METHODS: Adults who received at least one 10-g dose of SZC within 14 days after an intra-abdominal transplant between January 2020 and July 2022 were included in our study. The primary outcome was the change in potassium (K+) levels following the first SZC dose. Other analyses explored adjunctive potassium-lowering therapies, potential gastrointestinal complications, and patient subgroups based on therapy and transplant type. RESULTS: Among the recipients (n = 46), 11 were kidney recipients, 26 were liver recipients, seven were simultaneous liver/kidney recipients, and two were simultaneous pancreas/kidney recipients. The mean time to first dose post-transplant was 7.6 (±4) days, and the mean change in serum K+ after the initial SZC dose was -.27 mEq (p = .001). No gastrointestinal complications were observed following the SZC dose. The mean increase in serum bicarbonate was .58 mEq (p = .41) following the first dose of SZC. Four kidney recipients required dialysis following the SZC dose. CONCLUSION: This study represents the largest investigation on the use of SZC in transplant recipients. A single 10-g dose of SZC reduced serum K+ levels in all subgroups, while the use of adjunctive K+-lowering therapies did not provide additional reduction beyond the effects of SZC. Importantly, no gastrointestinal complications were observed. These findings suggest that SZC may be a safe and promising therapeutic option for hyperkalemia management following solid organ transplantation.

Sodium Bicarbonate and Calcium Chloride for the Treatment of Hyperkalemia-Induced Cardiac Arrest: A Randomized, Blinded, Placebo-Controlled Animal Study.

OBJECTIVES: Current international guidelines recommend administrating calcium chloride and sodium bicarbonate to patients with hyperkalemia-induced cardiac arrest, despite limited evidence. The aim of this study was to evaluate the efficacy of calcium chloride and sodium bicarbonate on return of spontaneous circulation (ROSC) in a pig model of hyperkalemia-induced cardiac arrest. DESIGN: A randomized, blinded, placebo-controlled experimental pig study. Hyperkalemia was induced by continuous infusion of potassium chloride over 45 minutes followed by a bolus. After a no flow period of 7 minutes, pigs first received 2 minutes of basic cardiopulmonary resuscitation and subsequently advanced life support. The first intervention dose was administered after the fifth rhythm analysis, followed by a defibrillation attempt at the sixth rhythm analysis. A second dose of the intervention was administered after the seventh rhythm analysis if ROSC was not achieved. In case of successful resuscitation, pigs received intensive care for 1 hour before termination of the study. SETTING: University hospital laboratory. SUBJECTS: Fifty-four female Landrace/Yorkshire/Duroc pigs (38-42 kg). INTERVENTIONS: The study used a 2 × 2 factorial design, with calcium chloride (0.1 mmol/kg) and sodium bicarbonate (1 mmol/kg) as the interventions. MEASUREMENTS AND MAIN RESULTS: Fifty-two pigs were included in the study. Sodium bicarbonate significantly increased the number of animals achieving ROSC (24/26 [92%] vs. 13/26 [50%]; odds ratio [OR], 12.0; 95% CI, 2.3-61.5; p = 0.003) and reduced time to ROSC (hazard ratio [HR] 3.6; 95% CI, 1.8-7.5; p < 0.001). There was no effect of calcium chloride on the number of animals achieving ROSC (19/26 [73%] vs. 18/26 [69%]; OR, 1.2; 95% CI, 0.4-4.0; p = 0.76) or time to ROSC (HR, 1.5; 95% CI, 0.8-2.9; p = 0.23). CONCLUSIONS: Administration of sodium bicarbonate significantly increased the number of animals achieving ROSC and decreased time to ROSC. There was no effect of calcium chloride on the number of animals achieving ROSC or time to ROSC.

Sacubitril/valsartan compared to ramipril in high-risk post-myocardial infarction patients stratified according to use of mineralocorticoid receptor antagonists: Insight from the PARADISE MI trial.

AIM: It is unknown whether safety and clinical endpoints by use of sacubitril/valsartan (an angiotensin receptor-neprilysin inhibitor [ARNI]) are affected by mineralocorticoid receptor antagonists (MRA) in high-risk myocardial infarction (MI) patients. The aim of this study was to examine whether MRA modifies safety and clinical endpoints by use of sacubitril/valsartan in patients with a MI and left ventricular systolic dysfunction (LVSD) and/or pulmonary congestion. METHODS AND RESULTS: Patients (n = 5661) included in the PARADISE MI trial (Prospective ARNI vs. ACE Inhibitor Trial to Determine Superiority in Reducing Heart Failure Events After MI) were stratified according to MRA. Primary outcomes in this substudy were worsening heart failure or cardiovascular death. Safety was defined as symptomatic hypotension, hyperkalaemia >5.5 mmol/L, or permanent drug discontinuation. A total of 2338 patients (41%) were treated with MRA. Safety of ARNI compared to ramipril was not altered significantly by ± MRA, and both groups had similar increase in symptomatic hypotension with ARNI. In patients taking MRA, the risk of hyperkalaemia or permanent drug discontinuation was not significantly altered by ARNI (p > 0.05 for all comparisons). The effect of ARNI compared with ramipril was similar in those who were and were not taking MRA (hazard ratio [HR]MRA 0.96, 95% confidence interval [CI] 0.77-1.19 and HRMRA- 0.87, 95% CI 0.71-1.05, for the primary endpoint; p = 0.51 for interaction [Clinical Endpoint Committee adjudicated]); similar findings were observed if investigator-reported endpoints were evaluated (p = 0.61 for interaction). CONCLUSIONS: Use of a MRA did not modify safety or clinical endpoints related to initiation of ARNI compared to ramipril in the post-MI setting in patients with LVSD and/or congestion.