Hyperkalemia across the Continuum of Kidney Function

Consensus statement on the management of hyperkalaemia-An Asia-Pacific perspective

Hyperkalaemia is an electrolyte imbalance that impairs muscle function and myocardial excitability, and can potentially lead to fatal arrhythmias and sudden cardiac death. The prevalence of hyperkalaemia is estimated to be 6%-7% worldwide and 7%-10% in Asia. Hyperkalaemia frequently affects patients with chronic kidney disease, heart failure, and diabetes mellitus, particularly those receiving treatment with renin-angiotensin-aldosterone system (RAAS) inhibitors. Both hyperkalaemia and interruption of RAAS inhibitor therapy are associated with increased risks for cardiovascular events, hospitalisations, and death, highlighting a clinical dilemma in high-risk patients. Conventional potassium-binding resins are widely used for the treatment of hyperkalaemia; however, caveats such as the unpalatable taste and the risk of gastrointestinal side effects limit their chronic use. Recent evidence suggests that, with a rapid onset of action and improved gastrointestinal tolerability, novel oral potassium binders (e.g., patiromer and sodium zirconium cyclosilicate) are alternative treatment options for both acute and chronic hyperkalaemia. To optimise the care for patients with hyperkalaemia in the Asia-Pacific region, a multidisciplinary expert panel was convened to review published literature, share clinical experiences, and ultimately formulate 25 consensus statements, covering three clinical areas: (i) risk factors of hyperkalaemia and risk stratification in susceptible patients; (ii) prevention of hyperkalaemia for at-risk individuals; and (iii) correction of hyperkalaemia for at-risk individuals with cardiorenal disease. These statements were expected to serve as useful guidance in the management of hyperkalaemia for health care providers in the region.

Determination of trace elements and electrolyte levels in kidney tissue of simvastatin-treated septic rats

Trace elements are cofactors in various enzymes in the antioxidant defense and cell homeostasis required in the tissue during inflammation. In acute kidney injury induced by lipopolysaccharide (LPS), renal cells are affected by cytotoxicity. Renal evacuation and gastrointestinal absorption rates are important in regulating plasma levels of trace elements. Simvastatin is a widely used anti-lipidemic drug with known anti-inflammatory effects. This study aimed to examine the effect of simvastatin on trace elements and electrolyte levels in kidney tissue in rats with LPS-induced sepsis. Adult male Wistar albino rats were divided into four groups: control, LPS (20 mg/kg, i.p., single dose), simvastatin (20 mg/kg, o.p., 5 days), and LPS + Simvastatin (LPS + Sim). Sodium, potassium, calcium, magnesium, selenium, zinc, copper, and histological structural changes were examined in kidney tissue samples 4 h after LPS execution. The inductively coupled plasma optical emission spectroscopy technique (ICP-OES) was used to determine the tissue trace element levels. In rats with sepsis-induced LPS, selenium, calcium, sodium, and magnesium levels significantly decreased while copper, potassium, and zinc levels significantly increased compared to other experimental groups. In sepsis treated with the simvastatin (LPS + Simvastatin) group, trace elements and electrolyte levels are like the control groups, apart from selenium levels. Selenium levels were significantly decreased in the LPS + Simvastatin group compared to the controls. As a result of examining the kidney tissues under a light microscope, simvastatin improved tissue damage caused by LPS-induced acute kidney injury. LPS-induced renal injury and simvastatin caused significant changes in the oxidant/antioxidant system. In septic rats, simvastatin was shown to balance some trace element levels, and it may improve damage in the kidney tissue.

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.

Protective effects of safranal on kidney tissue in a rat model of distant ischemia-reperfusion injury with infrarenal aortic occlusion

Background/aim

Ischemia-reperfusion (IR) injury to a part of the body can cause damage to distant organs such as the kidney and heart. This study investigated the protective effects of safranal against IR-induced renal injury.

Materials and methods

Used in this study were 24 Wistar Albino male rats, which were divided into 3 equal and randomised groups. The sham group underwent laparotomy only. In the IR group, the infrarenal aorta was clamped for 1 h, and then reperfused for 2 h. In the IR-safranal group, safranal was administered 30 min before the procedure and IR injury was induced in the same way as in the IR group. After the procedure, blood and tissue samples were collected from the rats for biochemical and histopathological analyses. Antioxidant capacity and proinflammatory cytokine analyses were performed on the blood samples. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining was performed to determine the number of cells undergoing apoptosis in the kidney tissue.

Results

The estimated glomerular filtration rate, an indicator of renal function, was lower in the IR group (p1 = 0.024 vs. p3 = 0.041, respectively) compared to the other groups, while creatinine levels were higher in the IR group compared to the other groups (p1 = 0.032 vs. p2 = 0.044, respectively). The blood urea nitrogen level was higher in the IR group than in the other groups (p1 = 0.001vs p2 = 0.035, respectively). The total antioxidant and total oxidant status, indicating tissue oxidative stress, did not differ between groups (p = 0.914 vs. p = 0.184, respectively). Among the proinflammatory cytokines, the interleukin-1β (IL-1β) and IL-6 levels were significantly higher in the IR group (p = 0.034 vs. p = 0.001, respectively), but the tumour necrosis factor-α (p = 0.19), and interferon-γ (p = 0.311) levels did not differ between groups. Histopathological examination showed significantly less damage to glomerular and tubular cells in the IR-safranal group (p < 0.001). The number of TUNEL-positive cells was higher in the IR group compared to the other groups (p < 0.001).

Conclusion

Safranal may have protective effects against kidney damage caused by distant ischemia-reperfusion injury.

Daptomycin-Induced Severe Hyperkalemia With Normal Creatine Kinase in a Patient With Methicillin-Resistant Staphylococcus aureus Osteomyelitis

We report a case of an asymptomatic 60-year-old female who presented to the emergency department due to a home health measured serum potassium of 7.7 mmol/L (normal range: 3.6-5.0 mmol/L) and was admitted for severe hyperkalemia. She was recently started on a low dose of daily intravenous daptomycin to treat methicillin-resistant Staphylococcus aureus (MRSA) osteomyelitis of her sacral decubitus ulcers. Laboratory results showed normal creatine kinase (CK). Her elevated serum potassium levels reversed throughout her hospital stay and remained within normal range after daptomycin discontinuation, establishing a temporal relationship between daptomycin and hyperkalemia. To our knowledge, no other cases report daptomycin-induced severe hyperkalemia in the absence of rhabdomyolysis. Our case emphasizes the importance of considering hyperkalemia as an adverse effect of daptomycin, especially in elderly hospitalized patients.

Impact of Hyperkalemia in Heart Failure and Reduced Ejection Fraction: A Retrospective Study

(1) Background: Hyperkalemia is a common finding in patients with heart failure and reduced ejection fraction (HFrEF), though its prognostic significance is controversial. There is no consensus on optimal potassium levels in these patients. The primary endpoint of this study was to determine the 5-year incidence of hyperkalemia in a cohort of patients with HFrEF. Secondary endpoints were to determine predictors of hyperkalemia and its impact on overall 5-year mortality; (2) Methods: retrospective, longitudinal, single-center observational study of patients with HFrEF followed-up in a specialized unit between 2011 and 2019. Hyperkalemia was considered as potassium concentration > 5.5 mEq/L; (3) Results: Hyperkalemia was observed in 170 (16.8%) of the 1013 patients. The 5-year hyperkalemia-free survival rate was 82.1%. Hyperkalemia was more frequent at the beginning of follow-up. Factors associated with hyperkalemia in the multivariate analysis were baseline potassium (HR 3.13, 95%CI 2.15-4.60; p < 0.001), creatinine clearance (HR 0.99, 95%CI 0.98-0.99; p = 0.013), right ventricular function (HR 0.95, 95%CI 0.91-0.99; p = 0.016) and diabetes mellitus (HR 1.40, 95%CI 1.01-1.96; p = 0.047). The overall survival rate at 5 years was 76.4%. Normal-high potassium levels (5-5.5 mEq/L) were inversely associated with mortality (HR 0.60, 95%CI 0.38-0.94; p = 0.025); (4) Conclusions: Hyperkalemia is a common finding in patients with HFrEF with an impact on the optimization of neurohormonal treatment. In our retrospective study, potassium levels in the normal-high range seem to be safe and are not associated with increased mortality.

Assessing patiromer utilization and associated serum potassium changes in US veterans with prior sodium polystyrene sulfonate exposure

Untreated chronic hyperkalemia is associated with an increased risk of mortality. Novel potassium binders (e.g., patiromer) are new additions to the clinician's armamentarium. Prior to their approval, clinicians often considered trialing sodium polystyrene sulfonate. The study objective was to assess patiromer utilization and associated changes in serum potassium (K+) in US veterans with prior sodium polystyrene sulfonate exposure. This was a real-world observational study of US veterans with chronic kidney disease and a baseline K+ ≥ 5.1 mEq/L, initiated on patiromer between January 1, 2016, and February 28, 2021. The primary endpoints were patiromer utilization (dispensations and treatment courses), and K+ change at 30-, 91-, and 182-day follow-up (FU) intervals. Patiromer utilization was described using Kaplan-Meier probabilities and the proportion of days covered. Descriptive changes in population average K+ were obtained from a pre-post design using single-arm within-patient pre-post lab pairs and paired t tests. Two hundred five veterans met the study criteria. We observed an average of 1.25 (95% CI, 1.19-1.31) treatment courses and a median treatment duration of 64 days. Fifty veterans (24.4%) had >1 course, and 17.6% of patients remained on their initial patiromer treatment course until the end of the 180-day FU. The mean K+ value was 5.73 mEq/L (5.66-5.79) at baseline, 4.95 mEq/L (95% CI, 4.86-5.05) at the 30-day interval, 4.93 mEq/L (95% CI, 4.84-5.03) at the 91-day interval, and 4.9 mEq/L (95% CI, 4.8-4.99) at the 182-day interval. Novel potassium binders (e.g., patiromer) are newer chronic hyperkalemia management tools for clinicians. The average population K+ decreased to <5.1 mEq/L at all follow-up intervals. Patiromer appeared to be well tolerated with nearly 18% of patients remaining on their initial treatment course during the entire 180-day FU period. The median treatment duration was 64 days and approximately 24% of patients initiated a second course during FU.

Development and Validation of a Food Frequency Questionnaire to Assess Potassium Intake of Patients on Hemodialysis

OBJECTIVE

To develop and to validate a food frequency questionnaire (FFQ) to assess potassium intake of patients on hemodialysis.

METHODS

This is a cross-sectional study that included 41 patients in the FFQ development step and 53 patients in the FFQ validation step. In the FFQ development step, the patients completed a 3-day food record (used as a reference method). Total potassium intake and potassium from each food item were calculated. Food items that contributed up to 90% of the total potassium intake were considered to be included in the FFQ food list. Then the FFQ was applied in person through the google-forms platform. The result of potassium intake obtained by the FFQ was compared with that obtained by the 3-day food record.

RESULTS

A total of 94 patients were included: 53.2% women; age 55.7 ± 15.0 years; 47.9% had diabetes; body mass index 25.0 ± 4.5 kg/m²; and dialysis vintage 34.5 (17.0-68.2) months. Demographic, clinical, and laboratory parameters did not differ between the development and validation groups. From the 255 registered food items, 85 comprised the FFQ. The standardized Cronbach's alpha obtained was 0.71. No difference was found between the potassium intake obtained by the FFQ and by the 3-day food record (1,438.5 ± 659.4 mg/d vs. 1,464.8 ± 529.4 mg/d; P = .753, respectively) with an intraclass correlation coefficient of 0.66 (P = .001). No systematic bias or proportionality bias between the methods was observed in the Bland-Altman graphical analysis.

CONCLUSION

The quantitative FFQ presented strong relative validity and may constitute a practical tool in the analysis of potassium intake of patients on hemodialysis.

Justification for initiating patiromer when restricted by prior authorization and clinical guidance in a US health care system

BACKGROUND: In the Veterans Health Administration, patiromer is a formulary medication restricted by prior authorization and criteria-for-use (CFU). Historically, patiromer approval was restricted by step therapy, requiring prescribers to trial sodium polystyrene sulfonate (SPS). OBJECTIVE: To describe clinical scenarios leading to patiromer initiation by characterizing patient experience with primary hyperkalemia treatment modalities, especially SPS. METHODS: All veterans who initiated patiromer between January 1, 2016, and February 28, 2021, with chronic kidney disease and dispensed SPS during the 3 months preceding patiromer were included. A structured chart-review process was used to abstract prior authorization drug request notes to characterize patiromer approval and patient experience with primary pharmacotherapy. Results were reported with descriptive frequencies and proportions. RESULTS: Three hundred thirty-one veterans met inclusion criteria. Primary justification for patiromer initiation included continuation of patiromer initiated outside the Veterans Health Administration or during inpatient stay (5.7%) and SPS inventory shortage (25.4%). CFU justification was mentioned in 83.7% of notes and, among those with CFU justification, SPS treatment was documented in 68.7%. Clinician statements indicating that SPS was ineffective occurred in 65 (41.7%) and statements of safety concerns (either observed or potential) in 37 (23.7%) veterans. CONCLUSIONS: Patiromer approval is multifactorial, and clinicians often opted to avoid long-term SPS use because of safety concerns, lack of consistent availability, and concerns about its appropriateness for longterm hyperkalemia management. DISCLOSURES: Drs Patel and Sauer received funding from Otsuka Canada Pharmaceutical Inc. to study the use of patiromer in the VHA. This material is the result of work supported with resources and the use of facilities at the VA Salt Lake City Health Care System. The views expressed in this manuscript are those of the authors and do not necessarily reflect the position or policy of the Department of Veterans Affairs or the US government. Drs Qualls and Pinnell are supported by the VA Advanced Fellowship Program in Medical Informatics with the Office of Academic Affiliations. This work was funded through a partnered research mechanism. Otsuka Canada Pharmaceutical Inc. was not involved in development or review of this manuscript.

Lactated Ringer's solution and risk of hyperkalemia in patients with reduced kidney function

BACKGROUND

Emerging evidence supports the superiority of balanced crystalloids such as Lactated Ringer's (LR) compared to normal saline but concerns for the development of hyperkalemia have limited its use. Although LR inherently contains potassium, there exists a paucity of evidence to suggest that LR could potentiate hyperkalemia. To address this, we evaluated the effect of LR on serum potassium in patients with reduced kidney function who are at risk of developing hyperkalemia.

METHODS

We conducted a single-center, retrospective cohort-based observational clinical study that included 293 clinical encounters who were hospitalized with an estimated glomerular filtration rate (eGFR) of < 30 ml/min/1.73m², at the time of hospital admission. Subjects must have received a minimum of 500 ml of LR continuously during the admission. Only those with a minimum of one lab report within 24 hours prior to-, and post-LR administration that reported serum measurements of potassium, glucose, and bicarbonate levels were included. Other potential risk factors for developing hyperkalemia including medication, tube feeds, potassium supplements, and red blood cell transfusion during or within 24 hours after LR administration were recorded.

RESULTS

Serum potassium prior to LR use was highly correlated and predictive of the serum potassium after LR use [P < 0.0001; Odds Ratio 6.77 (3.73 - 12.28)]. Sixteen encounters (5%) developed de-novo hyperkalemia following LR use. No significant positive correlation between the amount of LR administered and the development of hyperkalemia was found.

CONCLUSIONS

LR use was not independently associated with the development of hyperkalemia in patients with reduced kidney function.

Potassium management with finerenone: Practical aspects

INTRODUCTION

Finerenone, a selective nonsteroidal mineralocorticoid receptor antagonist, has favourable effects on cardiorenal outcomes in patients with mild-to-severe chronic kidney disease with increased albuminuria and type 2 diabetes.

METHODS

Two large, randomized trials have evaluated the effects of finerenone on clinical outcomes. The first trial (FIDELIO-DKD) investigated renal outcomes, and the second (FIGARO-DKD) cardiovascular outcomes.

RESULTS

Patients in the two studies had a high intrinsic risk of hyperkalemia due to type 2 diabetes, treatment with optimized doses of an inhibitor of the renin-angiotensin system, and, in some patients, their advanced chronic kidney disease. This was reflected in the incidence of hyperkalemia in the placebo group during the trials. Patients on finerenone had a significantly higher incidence of hyperkalemia compared with patients on placebo, but treatment discontinuation due to hyperkalemia was low, and no patients experienced death attributable to hyperkalemia. Structured routine potassium monitoring with temporary treatment interruption and dose reduction, as used in the two trials, should ensure the safe use of finerenone to protect the kidneys and cardiovascular system of patients with albuminuric chronic kidney disease and type 2 diabetes.

CONCLUSIONS

The aim of this document is to highlight the routine potassium management required when using finerenone and to provide practical recommendations.

The effects of angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers in critically ill patients with acute kidney injury: An observational study using the MIMIC database

Background: The safety of prescribing angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) during acute kidney injury (AKI) remains unclear. We aimed to investigate the associations of ACEI/ARB therapy in AKI with the risk of mortality, acute kidney disease (AKD), and hyperkalemia.

Methods: We conducted a retrospective monocentric study, which included patients in Massachusetts between 2008 and 2019 from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database. Propensity score matching was performed for the endpoint analysis. The association between ACEI/ARB therapy and mortality was assessed using Cox proportional hazards regression models. Logistic regression was used to assess the risk of AKD and hyperkalemia.

Results: Among the 19,074 individuals with AKI admitted to the intensive care unit (ICU), 3,244 (17.0%) received ACEI/ARBs, while 15,830 (83.0%) did not. In the propensity score-matched sample of 6,358 individuals, we found a decreased risk of mortality in those who received ACEI/ARBs compared to those who did not (hazard ratio [HR] for ICU mortality: 0.34, 95% confidence interval [CI]: 0.27–0.42); HR for in-hospital mortality: 0.47, 95% CI: 0.39–0.56; HR for 30-day mortality: 0.47, 95% CI: 0.40–0.56; HR for 180-day mortality: 0.53, 95% CI: 0.45–0.62). However, the use of ACEI/ARBs was associated with a higher risk of AKD (risk ratio [RR]: 1.81; 95% CI: 1.55–2.12). There was no significant association between ACEI/ARBs and an increased risk of hyperkalemia (RR: 1.21; 95% CI: 0.96–1.51).

Conclusions: ACEI/ARB treatment during an episode of AKI may decrease all-cause mortality, but increases the risk of AKD. Future randomized controlled trials are warranted to validate these findings.

A quantitative systems pharmacology model of plasma potassium regulation by the kidney and aldosterone

Plasma potassium regulation within a narrow range is vital for life. The risk for hyperkalemia increases when kidney function is impaired and with therapeutic interventions such as mineralocorticoid receptor antagonists (MRAs). The kidney maintains potassium homeostasis by matching potassium intake and excretion, in part through the action of aldosterone. A mechanistic mathematical model was developed and used to investigate the effect of renal impairment and MRAs on plasma potassium levels. The model describes renal potassium filtration, reabsorption, and secretion along the nephron; potassium-aldosterone regulatory feedbacks; whole body potassium balance; and the pharmacologic effects of MRAs. The model was calibrated by fitting (1) the plasma potassium and aldosterone response to potassium infusion in humans on high/low potassium diets, and (2) the acute potassium excretion response to spironolactone. The model was validated by predicting steady-state plasma potassium with sustained spironolactone treatment in hyperaldosteronism patients. The model was then used to demonstrate that (1) declining renal function alone has a small effect on plasma potassium for GFR > 30 ml/min, but an increasing effect as GFR approaches end stage renal disease (GFR ~ 15 ml/min) (2) the effect of increasing potassium intake has minimal effect at normal GFRs but increasing effect on plasma potassium as GFR declines, and 3) MRAs have a minor effect on plasma potassium when GFR is normal, but cause larger increases as GFR falls below 60 ml/min. This model provides a quantitative framework for investigating integrated impacts of diseases and therapies in this complex system.

Hyperkalemia Risk with Finerenone: Results from the FIDELIO-DKD Trial

BACKGROUND

Finerenone reduced risk of cardiorenal outcomes in patients with CKD and type 2 diabetes in the FIDELIO-DKD trial. We report incidences and risk factors for hyperkalemia with finerenone and placebo in FIDELIO-DKD.

METHODS

This post hoc safety analysis defined hyperkalemia as ≥mild or ≥moderate based on serum potassium concentrations of >5.5 or >6.0 mmol/L, respectively, assessed at all regular visits. Cumulative incidences of hyperkalemia were based on the Aalen-Johansen estimator using death as competing risk. A multivariate Cox proportional hazards model identified significant independent predictors of hyperkalemia. Restricted cubic splines assessed relationships between short-term post-baseline changes in serum potassium or eGFR and subsequent hyperkalemia risk. During the study, serum potassium levels guided drug dosing. Patients in either group who experienced ≥mild hyperkalemia had the study drug withheld until serum potassium was ≤5.0 mmol/L; then the drug was restarted at the 10 mg daily dose. Placebo-treated patients underwent sham treatment interruption and downtitration.

RESULTS

Over 2.6 years' median follow-up, 597 of 2785 (21.4%) and 256 of 2775 (9.2%) patients treated with finerenone and placebo, respectively, experienced treatment-emergent ≥mild hyperkalemia; 126 of 2802 (4.5%) and 38 of 2796 (1.4%) patients, respectively, experienced moderate hyperkalemia. Independent risk factors for ≥mild hyperkalemia were higher serum potassium, lower eGFR, increased urine albumin-creatinine ratio, younger age, female sex, β-blocker use, and finerenone assignment. Diuretic or sodium-glucose cotransporter-2 inhibitor use reduced risk. In both groups, short-term increases in serum potassium and decreases in eGFR were associated with subsequent hyperkalemia. At month 4, the magnitude of increased hyperkalemia risk for any change from baseline was smaller with finerenone than with placebo.

CONCLUSIONS

Finerenone was independently associated with hyperkalemia. However, routine potassium monitoring and hyperkalemia management strategies employed in FIDELIO-DKD minimized the impact of hyperkalemia, providing a basis for clinical use of finerenone.

Hyperkalemia management in the emergency department: An expert panel consensus

Hyperkalemia is a common electrolyte abnormality identified in the emergency department (ED) and potentially fatal. However, there is no consensus over the potassium threshold that warrants intervention or its treatment algorithm. Commonly used medications are at best temporizing measures, and the roles of binders are unclear in the emergent setting. As the prevalence of comorbid conditions altering potassium homeostasis rises, hyperkalemia becomes more common, and hence there is a need to standardize management. A panel was assembled to synthesize the available evidence and identify gaps in knowledge in hyperkalemia treatment in the ED. The panel was composed of 7 medical practitioners, including 5 physicians, a nurse, and a clinical pharmacist with collective expertise in the areas of emergency medicine, nephrology, and hospital medicine. This panel was sponsored by the American College of Emergency Physicians with a goal to create a consensus document for managing acute hyperkalemia. The panel evaluated the evidence on calcium for myocyte stabilization and potassium shifting and excretion. This article summarizes information on available therapies for hyperkalemia and proposes a hyperkalemia treatment algorithm for the ED practitioner based on the currently available literature and highlights diagnostic pitfalls and evidence gaps.

Prevalence and clinical correlates of hyperkalemia in stable kidney transplant recipients

Although hyperkalemia (HK) is often associated with adverse clinical outcomes in renal patients, few studies are available in the setting of kidney transplantation. Therefore, we evaluated prevalence and clinical correlates of HK in stable kidney transplant recipients (KTRs) on standard of care immunosuppressive therapy. We studied 160 stable KTRs (post-transplant vintage 46.6 ± 16.6 months), most of whom (96.2%) on calcineurin inhibitor (CNI)-based immunosuppressive therapy. HK was defined as plasma potassium levels above 5 mEq/L, confirmed in two consecutive samples. Office blood pressure was measured, and renal graft function was expressed by estimated glomerular filtration rate (eGFR), calculated according to the CKD-EPI formula. HK prevalence was 8.8%, and plasma K above 5.5 mEq/L was found in 2.5% of all KTRs. In the univariate logistic regression analysis HK was significantly associated with serum urea concentration (OR 1.03, 95% CI 1.01-1.05 for each 1 mg/dL increase), tCO₂ (OR 0.77, 95% CI 0.66-0.90 for each 1 mmol/L increase), the presence of arterial hypertension (OR 4.01, 95% CI 1.3-12.64), the use of RAAS inhibitors (OR 5.26, 95% CI 1.6-17.7), and eGFR less than 30 ml/min/1.73 m² (OR 7.51, 95% CI 2.37-23.77). By multivariable backward stepwise regression analysis, the presence of metabolic acidosis (OR 0.83, 95% CI 0.69-0.99, P = 0.04), arterial hypertension (OR 4.65 95% CI 1.01-17.46 P = 0.03), and to be administered RAAS inhibitors (OR 6.11, 95% CI 1.03-25.96 P = 0.03) remained significantly associated with HK. We conclude that in stable KTRs the prevalence of HK is about 9%, slightly lower than previously reported. Moreover, it is not associated with eGFR, but with metabolic acidosis, arterial hypertension, and the use of RAAS inhibitors.

Association between hyperkalemia, RAASi non-adherence and outcomes in chronic kidney disease

Background

Hyperkalemia is relatively frequent in CKD patients treated with renin-angiotensin-aldosterone-system inhibitors (RAASi).

Aim

The aim of the present study was to estimate the increased risk of cardiovascular events and mortality due to sub-optimal adherence to RAASi in CKD patients with hyperkalemia.

Methods

An observational retrospective cohort study was conducted, based on administrative and laboratory databases of five Local Health Units. Adult patients discharged from the hospital with a diagnosis of CKD, who were prescribed RAASi between January 2010 and December 2017, were included. We evaluated the appearance of documented episodes of hyperkalemia, RAASi therapy adherence and the effects of these two variables on cardiovascular events, death and dialysis inception for study patients.

Results

Of the 9241 selected patients, 4451 met all the criteria for study inclusion. Among them, 1071 had at least one documented episode of hyperkalemia, while 3380 did not. After propensity score matching based on several variables we obtained 2 groups of patients. The appearance of hyperkalemia caused treatment discontinuation in 21.8% of patients previously on RAASi therapy, and sub-optimal adherence (proportion of days covered  < 80%) in 33.6% of them. Non-adherence to RAASi therapy among hyperkalemia patients was associated with a higher risk of cardiovascular events (hazard ratio [HR] 1.45, confidence interval [CI] 1.02–2.08; p < 0.05). Moreover, in non-adherent hyperkalemia patients, the risk of death increased by 126% (HR 2.26, CI 1.62–3.15; p < 0.001) compared with adherent patients.

Conclusions

In a large cohort of CKD patients treated with RAASi, we observed that following hyperkalemia onset, non-adherence to RAASi medication can result in an increased risk of cardiovascular events and death.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s40620-021-01070-6.

Clinical Management of Hyperkalemia

Hyperkalemia is an electrolyte abnormality with potentially life-threatening consequences. Despite various guidelines, no universally accepted consensus exists on best practices for hyperkalemia monitoring, with variations in precise potassium (K⁺) concentration thresholds or for the management of acute or chronic hyperkalemia. Based on the available evidence, this review identifies several critical issues and unmet needs with regard to the management of hyperkalemia. Real-world studies are needed for a better understanding of the prevalence of hyperkalemia outside the clinical trial setting. There is a need to improve effective management of hyperkalemia, including classification and K⁺ monitoring, when to reinitiate previously discontinued renin-angiotensin-aldosterone system inhibitor (RAASi) therapy, and when to use oral K⁺-binding agents. Monitoring serum K⁺ should be individualized; however, increased frequency of monitoring should be considered for patients with chronic kidney disease, diabetes, heart failure, or a history of hyperkalemia and for those receiving RAASi therapy. Recent clinical studies suggest that the newer K⁺ binders (patiromer sorbitex calcium and sodium zirconium cyclosilicate) may facilitate optimization of RAASi therapy. Enhancing the knowledge of primary care physicians and internists with respect to the safety profiles of these newer K⁺ binders may increase confidence in managing patients with hyperkalemia. Lastly, the availability of newer K⁺-binding agents requires further study to establish whether stringent dietary K⁺ restrictions are needed in patients receiving K⁺-binder therapy. Individualized monitoring of serum K⁺ among patients with an increased risk of hyperkalemia and the use of newer K⁺-binding agents may allow for optimization of RAASi therapy and more effective management of hyperkalemia.

Moringa oleifera ethanolic extract attenuates tilmicosin-induced renal damage in male rats via suppression of oxidative stress, inflammatory injury, and intermediate filament proteins mRNA expression

Tilmicosin (Til) is a popular macrolide antibiotic, widely used in veterinary practice. The present study was designed to address the efficacy of Moringa oleifera ethanolic extract (MOE) in protecting against Tilmicosin (Til) - induced nephrotoxicity in Sprague Dawley rats. Animals were treated once with Til (75 mg/kg bw, subcutaneously), and/or MOE for 7 days (400 or 800 mg/kg bw, by oral gavage). Til-treatment was associated with significantly increased serum levels of creatinine, urea, sodium, potassium and GGT activity, as well as decreased total protein and albumin concentrations. Renal tissue hydrogen peroxide (H2O2) and malondialdehyde (MDA) levels were elevated, while the activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx) enzymes were diminished. The levels of renal tumor necrosis factor alpha (TNF-α) and interleukin-1 beta (IL-1β) and the mRNA expression of intermediate filament protein encoding genes (desmin, nestin and vimentin) in the kidney were up- regulated with histopathological alterations in renal glomeruli, tubules and interstitial tissue. These toxic effects were markedly ameliorated by co-treatment of MOE with Til, in a dose dependent manner. Taken together, these results indicate that MO at 800 mg/kg protects against Til-induced renal injury, likely by its potent antioxidant and anti-inflammatory properties, which make it suitable to be used as a protective supplement with Til therapy.

Novel approaches to management of hyperkalaemia in kidney transplantation

PURPOSE OF REVIEW

Medications used frequently after kidney transplantation, including calcineurin inhibitors, angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, beta blockers and antimicrobials, are considered the leading culprit for posttransplant hyperkalaemia in recipients with a well functioning allograft. Other risk factors include comorbidities such as diabetes, hypertension and heart failure; and consumption of a potassium-enriched diet. We review the mechanisms for hyperkalaemia following kidney transplantation that are addressed using nonpharmacological and pharmacological interventions. We also discuss emerging therapeutic approaches for the management of recurrent hyperkalaemia in solid organ transplantation, including newer potassium binding therapies.

RECENT FINDINGS

Patiromer and sodium zirconium cyclosilicate are emerging potassium binders approved for the treatment of hyperkalaemia. Patiromer is a polymer that exchanges potassium for calcium ions. In contrast, sodium zirconium cyclosilicate is a nonpolymer compound that exchanges potassium for sodium and hydrogen ions. Both agents are efficacious in the treatment of chronic or recurrent hyperkalaemia and may result in fewer gastrointestinal side effects than older potassium binders such as sodium polystyrene sulfonate and calcium polystyrene sulfonate. Large-scale clinical studies have not been performed in kidney transplant patients. Patiromer may increase serum concentrations of tacrolimus, but not cyclosporine. Sodium zirconium cyclosilicate does not appear to compromise tacrolimus pharmacokinetics, although it may have a higher sodium burden.

SUMMARY

Patiromer and sodium zirconium cyclosilicate may be well tolerated options to treat asymptomatic hyperkalaemia and have the potential to ease potassium dietary restrictions in kidney transplant patients by maintaining a plant-dominant, heart-healthy diet. Their efficacy, better tolerability and comparable cost with respect to previously available potassium binders make them an attractive therapeutic option in chronic hyperkalaemia following kidney transplantation.

Hyperkalemia Among Hospitalized Patients and Association Between Duration of Hyperkalemia and Outcomes

Background Hyperkalemia is a serious life-threatening condition that leads to significant morbidity and mortality. Objectives The aim of this study is to investigate the association between the duration and outcomes in patients hospitalized with hyperkalemia, as well as associated risk factors and drug-induced hyperkalemia. Methods A three-year retrospective chart review study was conducted at a tertiary hospital at King Abdulaziz Medical City, Riyadh, Saudi Arabia, between January 2016 and April 2019. We included all hospitalized adults and patients with hyperkalemia. Pediatric patients and dialysis patients with end-stage renal failure were excluded. Results Out of a total of 300 hospitalized patients who were screened for hyperkalemia, only 142 patients were included. The majority of cases were males (56.3%), whereas 43.7% were females. Most patients were above 55 years old. Regarding comorbidities in patients with hyperkalemia, most of them suffered from high blood pressure or diabetes. The mean serum potassium value was 5.7 ± 0.51 mEq. The most frequent medications used in the study population were azole antifungal medication followed by nonsteroidal anti-inflammatory drugs, beta-blockers, and angiotensin-converting enzyme inhibitors. Around 54 patients were not treated with medication and were monitored for spontaneous correction of hyperkalemia. Insulin was the most used medication for the treatment of hyperkalemia. The mean duration for the resolution of hyperkalemia was 12 ±9.4 hours. Out of 142 patients, only 10 (7%) patients died with hyperkalemia. Conclusions Hospitalized patients are at risk of hyperkalemia. In our study, we found that patients who had hyperkalemia were significantly likely to have acute kidney injury or cardiovascular diseases, and azole antifungals and beta-blockers were the most commonly used medications.

Evolution of Patiromer Use: a Review

PURPOSE OF REVIEW

The purpose of this review is to present data from clinical trials that resulted in the key data supporting the use of patiromer as a potassium binder in clinical practice today.

RECENT FINDINGS

In addition to trials that support the current Food and Drug Administration label and published over the past 3 years, the recently published Spironolactone With Patiromer in the Treatment of Resistant Hypertension in Chronic Kidney Disease (AMBER) trial provides clear benefits of patiromer use in a group of resistant hypertension patients. The AMBER was a phase 2, multicenter, randomized, double-blind, parallel-group, placebo-controlled study that evaluated 295 participants stratified by local serum potassium measurement (4.3 to < 4.7 mmol/L vs 4.7 to 5.1 mmol/L) and history of diabetes and chronic kidney disease. The focus was on enabling participants with resistant hypertension to achieve blood pressure goals by using spironolactone. Additionally, the ongoing Patiromer for the Management of Hyperkalemia in Subjects Receiving RAASi Medications for the Treatment of Heart Failure (DIAMOND) trial is designed to demonstrate how patiromer is an "enabler" of therapies that are needed to either control resistant hypertension or reduce mortality in heart failure but generate hyperkalemia. These and other studies are discussed in detail. Patiromer is one of two new potassium binders that are far better tolerated than the previous agent and can be given chronically to participants who need life-saving therapies but have elevations of potassium into a dangerous range as a consequence.

Hyperkalemia: pathophysiology, risk factors and consequences

There have been significant recent advances in our understanding of the mechanisms that maintain potassium homoeostasis and the clinical consequences of hyperkalemia. In this article we discuss these advances within a concise review of the pathophysiology, risk factors and consequences of hyperkalemia. We highlight aspects that are of particular relevance for clinical practice. Hyperkalemia occurs when renal potassium excretion is limited by reductions in glomerular filtration rate, tubular flow, distal sodium delivery or the expression of aldosterone-sensitive ion transporters in the distal nephron. Accordingly, the major risk factors for hyperkalemia are renal failure, diabetes mellitus, adrenal disease and the use of angiotensin-converting enzyme inhibitors, angiotensin receptor blockers or potassium-sparing diuretics. Hyperkalemia is associated with an increased risk of death, and this is only in part explicable by hyperkalemia-induced cardiac arrhythmia. In addition to its well-established effects on cardiac excitability, hyperkalemia could also contribute to peripheral neuropathy and cause renal tubular acidosis. Hyperkalemia-or the fear of hyperkalemia-contributes to the underprescription of potentially beneficial medications, particularly in heart failure. The newer potassium binders could play a role in attempts to minimize reduced prescribing of renin-angiotensin inhibitors and mineraolocorticoid antagonists in this context.

Hyperchloremic normal gap metabolic acidosis

Metabolic acidosis is defined as a pathologic process that, when unopposed, increases the concentration of hydrogen ions (H+) in the body and reduces the bicarbonate (HCO3-) concentration. Metabolic acidosis can be of a kidney origin or an extrarenal cause. Assessment of urinary ammonium excretion by calculating the urine anion gap or osmolal gap is a useful method to distinguish between these two causes. Extrarenal processes include increased endogenous acid production and accelerated loss of bicarbonate from the body. Metabolic acidosis of renal origin is due to a primary defect in renal acidification with no increase in extrarenal hydrogen ion production. This situation can occur because either the renal input of new bicarbonate is insufficient to regenerate the bicarbonate lost in buffering endogenous acid as with distal renal tubular acidosis (RTA) or the RTA of renal insufficiency, or the filtered bicarbonate is lost by kidney wasting as in proximal RTA. In either condition, because of loss of either NaHCO3 (proximal RTA) or NaA (distal RTA), effective extracellular volume is reduced and as a result the avidity for chloride reabsorption derived from the diet is increased and results in a hyperchloremic normal gap metabolic acidosis. The RTA of renal insufficiency is also characterized by a normal gap acidosis, however, with severe reductions in the glomerular filtration rate an anion gap metabolic acidosis eventually develops.

Epidemiology of hyperkalemia in chronic kidney disease

BACKGROUND

Hyperkalaemia is a significant electrolyte imbalance in chronic kidney disease (CKD). Renin-angiotensin-aldosterone system inhibitors (RAASi) have beneficial cardio-renal properties, although they can often cause hyperkalaemia.

OBJECTIVE

To examine the prevalence of hyperkalaemia in CKD, identify factors associated with its appearance and the relationship between hyperkalaemia and mortality.

PATIENTS AND METHODS

Retrospective observational study on patients with CKD in the period 1971-2017. The population was categorised into 3groups: Group 1, patients with CKD without renal replacement therapy; Group 2, patients on haemodialysis; and Group 3, patients on continuous ambulatory peritoneal dialysis.

RESULTS

A total of 2,629 patients were evaluated. The prevalence observed in the different groups was: 9.6%, 16.4% and 10.6%, respectively. Risk factors related to the appearance of hyperkalaemia in the CKD group were glomerular filtration rate (GFR) (P<.001), plasma creatinine (P<.001), plasma sodium (P<.001), haemoglobin (P=.028), diastolic blood pressure (P=.012), intake of ACE inhibitors and/or angiotensin ii receptor blockers (P=.008), treatment with metformin (P<.001) and diabetes (P=.045). Treatment with RAASi significantly increased hyperkalaemia as GFR decreased, as well as in patients with diabetes or heart failure.

CONCLUSIONS

Hyperkalaemia is a frequent metabolic alteration in CKD patients that increases in the presence of drugs with beneficial cardio-renal properties (RAASi), which means that patients often lose the benefit associated with these drugs. New, recently-appearing non-absorbable compounds, which bind to potassium in the gastrointestinal tract, enhancing faecal excretion and thus maintaining the cardio-renal benefit of the RAASi, could be relevant in the progress of patients with CKD.

Chronic Kidney Disease and Dietary Measures to Improve Outcomes

Chronic kidney disease is an ongoing deterioration of renal function that often progresses to end-stage renal disease. Management goals in children include slowing disease progression, prevention and treatment of complications, and optimizing growth, development, and quality of life. Nutritional management is critically important to achieve these goals. Control of blood pressure, proteinuria, and metabolic acidosis with dietary and pharmacologic measures may slow progression of chronic kidney disease. Although significant progress in management has been made, further research is required to resolve many outstanding controversies. We review recent developments in pediatric chronic kidney disease, focusing on dietary measures to improve outcomes.

Dialysate Potassium and Mortality in a Prospective Hemodialysis Cohort

BACKGROUND

Studies examining the association of dialysate potassium concentration and mortality in hemodialysis patients show conflicting findings. We hypothesized that low dialysate potassium concentrations are associated with higher mortality, particularly in patients with high pre-dialysis serum potassium concentrations.

METHODS

We evaluated 624 hemodialysis patients from the prospective Malnutrition, Diet, and Racial Disparities in Kidney Disease study recruited from 16 outpatient dialysis facilities over 2011-2015 who underwent protocolized collection of dialysis treatment characteristics every 6 months. We examined the association of dialysate potassium concentration, categorized as 1, 2, and 3 mEq/L, with all-cause mortality risk in the -overall cohort, and stratified by pre-dialysis serum potassium (< 5 vs. ≥5 mEq/L) using case-mix adjusted Cox models.

RESULTS

In baseline analyses, dialysate potassium concentrations of 1 mEq/L were associated with higher mortality, whereas concentrations of 3 mEq/L were associated with similar mortality in the overall cohort (reference: 2 mEq/L): adjusted hazard ratios (aHRs; 95% CI) 1.70 (1.01-2.88) and 0.95 (0.64-1.39), respectively. In analyses stratified by serum potassium, baseline dialysate potassium concentrations of 1 mEq/L were associated with higher mortality in patients with serum potassium ≥5 mEq/L but not in those with serum potassium < 5 mEq/L: aHRs (95% CI) 2.87 (1.51-5.46) and 0.74 (0.27-2.07), respectively (p interaction = 0.04). These findings were robust with incremental adjustment for serum potassium, potassium-binding resins, and potassium-modifying medications.

CONCLUSION

Low (1 mEq/L) dialysate potassium -concentrations were associated with higher mortality, particularly in hemodialysis patients with high pre-dialysis serum potassium. Further studies are needed to identify therapeutic strategies that mitigate inter-dialytic serum potassium accumulation and subsequent high dialysate serum potassium gradients in this population.