Treatment of hyperkalemia: something old, something new

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.

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.

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.

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.

Hyperkalemia and Electrocardiogram Manifestations in End-Stage Renal Disease

Hyperkalemia is one of the more common acute life-threatening metabolic emergencies. The aim of our study is to determine the correlation and accuracy of abnormal ECG parameters as a function of serum potassium concentration in the end-stage renal disease (ESRD) population. We performed a retrospective chart review of emergency department patients presenting with ESRD and receiving emergent hemodialysis treatment. A total of 96 patients, each with five independent ED visits, provided 480 sets of ECGs and electrolytes. Of these, four ECGs were excluded for inability to interpret, leaving a total of 476 patient encounters that met all inclusion criteria. Linear regression analysis on the limited data set for serum potassium versus T/R in V2, V3, and V4, PR, and QRS found weak correlations (r2 = 0.02 to 0.12) with statistical significance <0.05 level for T/R in V2, V3, and V4. In summary, we found that a QRS duration of 120 ms or greater is most predictive of hyperkalemia in the ESRD population. On the other hand, T/R ratio, PR interval and QRS duration have poor correlations with serum potassium and are not predictive of hyperkalemia in patients with ESRD.

The gut–liver axis in sepsis: interaction mechanisms and therapeutic potential

Sepsis is a potentially fatal condition caused by dysregulation of the body's immune response to an infection. Sepsis-induced liver injury is considered a strong independent prognosticator of death in the critical care unit, and there is anatomic and accumulating epidemiologic evidence that demonstrates intimate cross talk between the gut and the liver. Intestinal barrier disruption and gut microbiota dysbiosis during sepsis result in translocation of intestinal pathogen-associated molecular patterns and damage-associated molecular patterns into the liver and systemic circulation. The liver is essential for regulating immune defense during systemic infections via mechanisms such as bacterial clearance, lipopolysaccharide detoxification, cytokine and acute-phase protein release, and inflammation metabolic regulation. When an inappropriate immune response or overwhelming inflammation occurs in the liver, the impaired capacity for pathogen clearance and hepatic metabolic disturbance can result in further impairment of the intestinal barrier and increased disruption of the composition and diversity of the gut microbiota. Therefore, interaction between the gut and liver is a potential therapeutic target. This review outlines the intimate gut–liver cross talk (gut–liver axis) in sepsis.

Effects of different potassium-lowering regimens on acute hyperkalemia in hemodialysis patients: a real-world, retrospective study

Background

Hyperkalemia is a common and potentially life-threatening electrolyte disorder in maintenance hemodialysis (MHD) patients. This study aimed to evaluate the efficacy and safety of potassium-lowering regimens during treatment of acute hyperkalemia in MHD patients.

Methods

This retrospective real-world study (RWS) was conducted among 139 MHD patients. They were given different potassium-lowering regimens, viz. the insulin and glucose (IG) intravenous administration group (IG, 46 patients), the sodium polystyrene sulfonate group (SPS, 33 patients), the sodium zirconium cyclosilicate group (SZC, 38 patients), the IG + SZC group (22 patients). The primary efficacy end point was the rate of serum potassium decline at 2 h. The rates of adverse events were also compared.

Results

At 2 h, the mean ± SE change of serum potassium level was − 0.71 ± 0.32 mmol per liter (mmol/L) in IG group, − 0.43 ± 0.38 mmol/L in SPS group, − 0.64 ± 0.36 mmol/L in SZC group, − 1.43 ± 0.38 mmol/L in IG + SZC group (P < 0.01). The serum potassium level in IG + SZC group decreased more than that in the other three groups (P < 0.01), while the serum potassium level in SPS group decreased less than that in the other three groups (P < 0.05). There was no significant difference on the decrease of the serum potassium level between IG group and the SZC group (P = 0.374). The IG group and the IG + SZC group had higher rates of symptomatic hypoglycemia. The SPS group had significant decreases of serum calcium and serum magnesium after treatment.

Conclusions

Among MHD patients with acute hyperkalemia, SZC had similar potassium-lowering efficacy with IG intravenous administration at 2 h and superior on convenience and side-effects.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03530-4.

Predicting hypoglycemia after treatment of hyperkalemia with insulin and glucose (Glu-K60 score)

Background

Hyperkalemia can lead to fatal cardiac arrhythmias. Ten units of intravenous (IV) regular insulin with 25 g of glucose is the mainstay for treating hyperkalemia. However, the most important complication of this treatment is hypoglycemia. We aimed to develop a scoring model to predict hypoglycemia after the treatment of hyperkalemia.

Methods

A retrospective study was conducted at a university-based hospital between January 2013 and June 2021. We included the hyperkalemic patients (> 5.3 mmol/L) who were ≥ 18 years old and treated with 10 units of IV regular insulin with 25 g of glucose. Incomplete data on posttreatment blood glucose, pregnancy, and diabetes mellitus were excluded. Endpoint was posttreatment hypoglycemia (≤ 70 mg/dL or ≤ 3.9 mmol/L). Multivariable logistic regression was used to establish a full model and a subsequently reduced model using the backward elimination method. We demonstrated the model performance using the area under the receiver operating characteristic curve (AuROC), calibration plot, and Hosmer–Lemeshow goodness-of-fit test. Internal validation was done with a bootstrap sampling procedure with 1000 replicates. Model optimism was estimated.

Results

Three hundred and eighty-five patients were included, with 97 posttreatment hypoglycemia (25.2%). The predictive model comprised the following three criteria: age > 60 years old, pretreatment blood glucose ≤ 100 mg/dL (≤ 5.6 mmol/L), and pretreatment potassium > 6 mmol/L. The AuROC of this model was 0.671 (95% confidence interval [CI] 0.608 to 0.735). The calibration plot demonstrated consistency with the original data. Hosmer–Lemeshow goodness-of-fit test showed no evidence of lack-of-fit (p 0.792); therefore, the model was also fit to the original data. Internal validation via bootstrap sampling showed a consistent AuROC of 0.670 (95% CI 0.660 to 0.670) with minimal model optimism. A high risk for posttreatment hypoglycemia was indicated if the patient met at least one of those criteria. Sensitivity and specificity were 95.9% and 14.9%, respectively.

Conclusion

High risk was indicated when at least one of the criteria was met: age > 60 years old, pretreatment blood glucose ≤ 100 mg/dL (≤ 5.6 mmol/L), and pretreatment potassium > 6 mmol/L. Blood glucose levels should frequently check in the high-risk group.

Trial registration

TCTR20210225002 (www.thaiclinicaltrials.org).

Hypoglycaemia due to insulin therapy for the management of hyperkalaemia in hospitalised adults: A scoping review

Introduction

Hyperkalaemia is a very common electrolyte disorder encountered in hospitalised patients. Although hypoglycaemia is a frequent complication of insulin therapy, it is often under-appreciated. We conducted a scoping review of this important complication, and of other adverse effects, of the treatment of hyperkalaemia in hospitalised adults to map existing research on this topic and to identify any knowledge gaps.

Materials and methods

We followed the PRISMA-ScR guidelines. Studies were eligible for inclusion if they reported on any adverse effects in hospitalised patients ≥18-years-old, with hyperkalaemia receiving treatment that included insulin. All eligible research from 1980 to 12 October 2021 were included. We searched Medline (PubMed), Embase (Ovid), the Cochrane Library, CINHAL, Africa-Wide Information, Web of Science Core Collection, LILACS and Epistemonikos. The protocol was prospectively registered with the Open Science Framework (https://osf.io/x8cs9).

Results

Sixty-two articles were included. The prevalence of hypoglycaemia by any definition was 17.2% (95% CI 16.6–17.8%). The median timing of hypoglycaemia was 124 minutes after insulin administration (IQR 102–168 minutes). There were no differences in the prevalence of hypoglycaemia when comparing insulin dose (<10 units vs. ≥10 units), rate of insulin administration (continuous vs. bolus), type of insulin (regular vs. short-acting) or timing of insulin administration relative to dextrose. However, lower insulin doses were associated with a reduced prevalence of severe hypoglycaemia (3.5% vs. 5.9%, P = 0.02). There was no difference regarding prevalence of hypoglycaemia by dextrose dose (≤25 g vs. >25 g); however, prevalence was lower when dextrose was administered as a continuous infusion compared with bolus administration (3.3% vs. 19.5%, P = 0.02). The most common predictor of hypoglycaemia was the pre-treatment serum glucose concentration (n = 13 studies), which ranged from < 5.6–7.8 mmol/L.

Conclusion

This is the first comprehensive review of the adverse effects following insulin therapy for hyperkalaemia. Hypoglycaemia remains a common adverse effect in hospitalised adults. Future randomised trials should focus on identifying the optimal regimen of insulin therapy to mitigate the risk of hypoglycaemia.

Hyperkalemia in Diabetes Mellitus Setting

Diabetes mellitus is a global health problem that affects 9.3% of the worldwide population and is associated with a series of comorbidities such as heart failure (HF) and chronic kidney disease (CKD). Diabetic patients, especially those with associated CKD, are more susceptible to present potassium disorders, in particular hyperkalemia due to kidney disease progression or use of renin-angiotensin-aldosterone blockers. Hyperkalemia is a potentially life-threatening condition that increases the risk of cardiac arrhythmia episodes and sudden death, making the management of potassium levels a challenge to reduce the mortality rate in this population. This review aims to briefly present the potassium physiology and discuss the main conditions that lead to hyperkalemia in diabetic individuals, the main signs, symptoms, and exams for the diagnosis of hyperkalemia, and the steps that should be followed to manage patients with this potentially life-threatening condition.

Determinants of Hyperkalemia Progression Among Patients with Mild Hyperkalemia

Introduction

The progression of mild hyperkalemia and the predictors of progression have not been well characterized. In this study we aimed to characterize the progression of hyperkalemia and identify the risk factors for hyperkalemia progression.

Methods

Adults with mild hyperkalemia (at least one serum potassium measure > 5.0 and ≤ 5.5 mEq/L) were identified using electronic medical records from the Research Action for Health Network (2012–2018). Progression to moderate-to-severe and progression to severe hyperkalemia were defined as the first occurrences of a serum potassium measure > 5.5 and > 6.0 mEq/L, respectively. Kaplan–Meier analyses were conducted to estimate progression rates for all patients and by pre-specified patient subgroups. Hazard ratios (HR) of moderate-to-severe and severe hyperkalemia progression were estimated using Cox models.

Results

Of 35,369 patients with mild hyperkalemia, 16.9% and 8.7% progressed to moderate-to-severe and severe hyperkalemia, respectively. Rates of hyperkalemia progression elevated with the severity of chronic kidney disease (CKD). The highest progression rates were seen in patients with CKD stage 5 (stage 5 vs. no CKD: moderate-to-severe, 50.2% vs. 12.0%; severe, 31.3% vs. 3.9%; p < 0.001). Higher progression rates were also observed in patients with heart failure, hypertension, and type II diabetes compared with patients without those conditions (all p < 0.001). The most prominent risk factors were CKD stage 5 (HR of progression to moderate-to-severe hyperkalemia, 3.32 [95% CI 3.03–3.64]; severe, 4.08 [3.55–4.69]), CKD stage 4 (2.19 [1.97–2.43], 2.28 [1.92–2.71]), CKD stage 3 (1.57 [1.46–1.68], 1.65 [1.46–1.87]), type I diabetes (1.37 [1.18–1.61], 1.54 [1.23–1.93]), and serum potassium (1.12 [1.10–1.15], 1.13 [1.10–1.17] per 0.1 mEq/L increase) (all p values < 0.05).

Conclusion

Hyperkalemia progression rates increased significantly with CKD stage and were also higher among patients with higher baseline potassium level, heart failure, hypertension, and diabetes.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12325-021-01925-1.

External validation and update of the early detection rule for severe hyperkalemia among patients with symptomatic bradycardia

OBJECTIVE

Chon et al. suggested a high prevalence of severe hyperkalemia (serum potassium ≥ 6.0 mEq/L with electrocardiographic [ECG] changes) among patients with symptomatic or extreme bradycardia. Despite the urgent need to detect and treat severe hyperkalemia, serum potassium result may be available too late and is often spuriously high. Meanwhile, the traditional, descriptive ECG findings of severe hyperkalemia have shown unsatisfactory diagnostic powers. To overcome these diagnostic problems, they outlined the following quantitative rules to facilitate its early detection: Maximum precordial T wave ≥ 8.5 mV (2), atrial fibrillation/junctional bradycardia (1), heart rate (HR) ≤ 42/min (1) with (original rule)/without (ECG-only rule) diltiazem medication (2), and diabetes mellitus (1). Here we report on our external validation of these rules and the resulting updates.

METHODS

This retrospective, cross-sectional study included all adults with symptomatic (HR ≤ 50/min with syncope/pre-syncope/dizziness, altered mentality, chest pain, dyspnea, general weakness, oliguria, or shock) or extreme (HR ≤ 40/min) bradycardia who visited a university emergency department from 2014 to 2019. After validating the abovementioned rules externally, we selected risk factors of severe hyperkalemia among the ECG findings and easy-to-assess clinical variables by multiple logistic regression analysis. After modelling the updated 'ECG-only' and 'ECG-plus' indices, we internally validated the better of the two by bootstrapping with 1000 iterations.

RESULTS

Among 455 symptomatic/extreme bradycardia cases (70.3 ± 13.1 years; 213 females [46.8%]), 70 (15.4%) had severe hyperkalemia. The previous ECG-only rule showed a c-statistic of 0.765 (95% CI: 0.706-0.825), Hosmer-Lemeshow test of p < 0.001, and a calibration slope of 0.719 (95% CI: 0.401-1.04). On updating, the ECG-plus index summing junctional bradycardia/atrial fibrillation (1), maximum precordial T wave≥8.0 mV (2), general weakness as the chief complaint (2), oxygen demand (1), and dialysis (2) outperformed the ECG-only index (c-statistic, 0.832; 95% CI, 0.785-0.880 vs. 0.764; 95% CI, 0.700-0.828; p = 0.011). On bootstrapping, the c-statistic was 0.832 (95% CI: 0.786-0.878). For scores ≥ 3 (positive likelihood ratio ≥ 5.0), the sensitivity and specificity were 0.514 and 0.901, respectively. For scores ≤ 1, negative likelihood ratio was ≤0.2.

CONCLUSIONS

Previous rules showed less satisfactory calibration but fair discrimination to detect severe hyperkalemia in patients with symptomatic or extreme bradycardia. We propose the ECG-plus index as the optimum tool to facilitate its early detection.

Hyperkalemia with RAAS inhibition: Mechanism, clinical significance, and management

Renin-angiotensin-aldosterone system (RAAS) inhibitors are evidence-based treatments for a number of conditions including hypertension, diabetes mellitus, chronic kidney disease, and congestive heart failure. Among the most common adverse effects of RAAS inhibitors is hyperkalemia which results from either reduced secretion of aldosterone or increased resistance to aldosterone. Many of the conditions for which RAAS inhibitors are recommended further amplify the risk for hyperkalemia in and of themselves. RAAS inhibitor-related hyperkalemia is associated with an increased risk for cardiovascular events, hospitalizations, and death. Yet discontinuation of RAAS inhibitors for patients with chronic kidney disease and congestive heart failure is also associated with an increased risk for cardiovascular events, hospitalizations, and death. Therefore, clinicians are often left to struggle with the dilemma of the best management approach to RAAS inhibitor-related hyperkalemia. The ideal solution involves pharmacotherapies that are safe and effective in mitigating hyperkalemia and allow patients to continue to receive the beneficial effects from RAAS inhibitors. In this regard, modern pharmacologic agents such as patiromer and zirconium cyclosilicate are providing a mechanism whereby physicians are better equipped to maintain their patients on RAAS inhibitors.

A Rare Case of Patiromer Induced Hypercalcemia

Patiromer is a calcium (Ca)-potassium (K) exchange resin approved for the treatment of hyperkalemia. Disorders of Ca or acid base balance were not reported in pre-approval clinical trials. We present a case of a patient with chronic kidney disease (CKD) with an unusual picture of hypercalcemia, metabolic alkalosis and hypokalemia upon intensification of patiromer dosing. A 56-year-old white man with CKD stage 4 (baseline creatinine 2.8 mg/dL) due to type 1 diabetes mellitus, proteinuria (1.5 g/g) and persistently high serum potassium 5.9 mEq/L attributed to type 4 renal tubular acidosis was evaluated in clinic. Due to high risk of CKD progression, patiromer 8.4 g daily, followed by 16.8 g daily was prescribed to enable renin angiotensin aldosterone system (RAAS) inhibitor. After 5 months of being on patiromer 16.8 g daily, routine laboratory tests revealed serum potassium 2.5 mEq/L, serum calcium 12.8 mg/dL and carbon dioxide 34 mEq/L. Patiromer was discontinued and thorough investigation held was negative for other causes of hypercalcemia. Five days after patiromer discontinuation, serum calcium returned to normal. The role of secondary hyperparathyroidism in this case remains unclear. We, therefore recommend cautious vigilance of patients receiving patiromer and undergoing dose escalation.

Risk of Intestinal Necrosis With Sodium Polystyrene Sulfonate: A Systematic Review and Meta-analysis

BACKGROUND

Reports of severe gastrointestinal side effects associated with sodium polystyrene sulfonate (SPS), particularly intestinal necrosis, have led some to recommend costlier alternative medications. No prior systematic review has included studies with controls reporting intestinal necrosis rates associated with SPS.

METHODS

A systematic literature search was conducted using Cochrane Library, Embase, Medline, Google Scholar, PubMed, Scopus, and Web of Science Core Collection from database inception through October 4, 2020. We included any clinical trial, cohort, or case-control study reporting an association between SPS and intestinal necrosis or severe gastrointestinal side effects.

RESULTS

Six studies including 26,716 patients treated with SPS with controls met inclusion criteria. The pooled odds ratio (OR) of intestinal necrosis was 1.43 (95% CI, 0.39-5.20). The pooled hazard ratio (HR) for intestinal necrosis from the two studies that performed survival analysis was 2.00 (95% CI, 0.45-8.78). The pooled HR for the composite outcome of severe gastrointestinal adverse events was 1.46 (95% CI, 1.01-2.11).

CONCLUSION

Based on our review of six studies, the risk of intestinal necrosis with SPS is not statistically greater than controls, although there was a statistically significantly increased risk for the composite outcome of severe gastrointestinal side effects based on two studies. Because of the risk of bias from potential confounding and selective reporting, the overall strength of evidence to support an association between SPS and intestinal necrosis or other severe gastrointestinal side effects is low. PROSPERO registration CRD42020213119.

Treatment of Mild Hyperkalemia in Hospitalized Patients: An Unnecessary Practice?

Background

Sodium polystyrene sulfonate (SPS) is one of the most commonly used treatments for mild hyperkalemia. Other treatments include insulin, sodium bicarbonate, and salbutamol, which may be given alone or in combination. The results of research examining treatment effectiveness for mild hyperkalemia (e.g., the ability of SPS to achieve normokalemia) thus far have been inconsistent. Given that the effectiveness of treatment for mild hyperkalemia is debatable, new research is needed.

Objective

To determine whether treatment of hospitalized patients with mild hyperkalemia (using SPS or another approach, relative to no treatment) was associated with achievement of normokalemia (serum potassium < 5.1 mmol/L).

Methods

For this retrospective, quasi-experimental study, hospitalized patients with index serum potassium level between 5.1 and 6.4 mmol/L were identified. Post-index serum potassium level within 24 hours was dichotomized (< 5.1 or ≥ 5.1 mmol/L). Pre-index serum creatinine and serum potassium levels were recorded as the average of the first 5 values immediately before the index potassium value. For each patient, treatment was categorized as no treatment, SPS treatment, or other treatment strategy.

Results

Among the 1944 patients included in the analysis, the average age was 66.8 (standard deviation 13.5) years; 605 (31.1%) of the patients were women and 1339 (68.9%) were men. Logistic regression results indicated that patients who were female and/or had higher pre-index serum potassium were less likely to return to normokalemia within 24 hours after the time of the index serum potassium value. Treatment category was not a statistically significant predictor of the achievement of normokalemia. Most patients with mild hyperkalemia (> 74.5% in each treatment category) achieved normokalemia, whether or not they received treatment.

Conclusions

The findings of this study suggest that although follow-up is required for mild hyperkalemia in hospitalized patients, active treatment may be unnecessary.

Hyperkalemia excursions are associated with an increased risk of mortality and hospitalizations in hemodialysis patients

BACKGROUND

Hyperkalemia is common among hemodialysis (HD) patients and has been associated with adverse clinical outcomes. Previous studies considered a single serum potassium (K) measurement or time-averaged values, but serum K excursions out of the target range may be more reflective of true hyperkalemia events. We assessed whether hyperkalemia excursions lead to an elevated risk of adverse clinical outcomes.

METHODS

Using data from 21 countries in Phases 4-6 (2009-18) of the Dialysis Outcomes and Practice Patterns Study (DOPPS), we investigated the associations between peak serum K level, measured monthly predialysis, over a 4-month period ('peak K') and clinical outcomes over the subsequent 4 months using Cox regression, adjusted for potential confounders.

RESULTS

The analysis included 62 070 patients contributing a median of 3 (interquartile range 2-6) 4-month periods. The prevalence of hyperkalemia based on peak K was 58% for >5.0, 30% for >5.5 and 12% for >6.0 mEq/L. The all-cause mortality hazard ratio for peak K (reference ≤5.0 mEq/L) was 1.15 [95% confidence interval (CI) 1.09, 1.21] for 5.1-5.5 mEq/L, 1.19 (1.12, 1.26) for 5.6-6.0 mEq/L and 1.33 (1.23, 1.43) for >6.0 mEq/L. Results were qualitatively consistent when analyzing hospitalizations and a cardiovascular composite outcome.

CONCLUSIONS

Among HD patients, we identified a lower K threshold (peak K 5.1-5.5 mEq/L) than previously reported for increased risk of hospitalization and mortality, with the implication that a greater proportion (>50%) of the HD population may be at risk. A reassessment of hyperkalemia severity ranges is needed, as well as an exploration of new strategies for effective management of chronic hyperkalemia.

Hyperkalaemia in Heart Failure

Hyperkalaemia has become an increasingly prevalent finding in patients with heart failure (HF), especially with renin–angiotensin–aldosterone system (RAAS) inhibitors and angiotensin–neprilysin inhibitors being the cornerstone of medical therapy. Patients living with HF often have other comorbidities, such as diabetes and chronic kidney disease, which predispose to hyperkalaemia. Until now, we have not had any reliable or tolerable therapies for the treatment of hyperkalaemia to facilitate implementation or achievement of target doses of RAAS inhibition. Patiromer sorbitex calcium and sodium zirconium cyclosilicate are two novel potassium-binding resins that have shown promise in the management of patients predisposed to developing recurrent hyperkalaemia, and their use may allow for further optimisation of guideline directed medical therapy.

Adverse gastrointestinal events with sodium polystyrene sulphonate and calcium polystyrene sulphonate use in dialysis patients: a nationwide registry study

INTRODUCTION

Sodium polystyrene sulphonate (SPS) and calcium polystyrene sulphonate (CPS) are commonly used cation-exchange resins for the treatment and control of hyperkalaemia. However, their use (particularly SPS) has been limited by reports of adverse gastrointestinal (GI) events. The safety of these compounds in patients undergoing dialysis requires larger investigation.

AIMS

To study the occurrence of adverse GI events (occlusion, perforation, thrombosis/ischaemia) in the periods of SPS or CPS exposition versus the periods without exposition in dialysis patients.

METHODS

Dialysis patients were extracted from the French National Registry and merged with the French hospital discharge database (between 2006 and 2017). For our primary analysis, we used patients who had any claim of SPS use (n = 43 771). Time-varying Cox models, negative binomial regression and pre- versus post-treatment average treatment effects.

RESULTS

The mean age was 66 ± 15 years, 37% were female and 92% were undergoing haemodialysis. Over a 1-year follow-up, patients on periods with SPS (on-SPS) did not present an increased risk of adverse GI events versus the periods without SPS (off-SPS):  incidence rate (IR) (per 1000 person years) = 7.4 (6.4-8.7) versus 9.5 (8.1-11.0); adjusted hazard ratio (HR) (95% CI) = 0.81 (0.60-1.09), P = 0.17. Patients exposed to SPS did not experience a higher rate of adverse GI events in the year after SPS initiation versus the year before SPS initiation; P-value for parallel trend = 0.87. Patients on-CPS also did not show an increased risk of adverse GI events versus off-CPS: IR (per 1000 py) = 8.6 (5.1-11.9) versus 7.8 (5.1-11.9); adjusted HR (95% CI) = 0.76 (0.31-1.80), P = 0.52. The rates of adverse GI events in the periods on and off exposure were also similar over a follow-up of 5 years.

CONCLUSION

Our large, nationwide study shows that the incidence of adverse GI events in patients undergoing dialysis was low and that neither the use of SPS nor CPS was associated with increased GI events risk.

The pharmacotherapeutic management of hyperkalemia in patients with cardiovascular disease

Introduction: Patients with cardiovascular diseases (CVD) are at increased risk of hyperkalemia, particularly when treated with renin-angiotensin-aldosterone inhibitors (RAASIs). Because the occurrence or fear of hyperkalemia, RAASIs are frequently down-titrated or discontinued in patients with CVD, with consequent worse outcomes than patients who remain on maximum doses.Areas covered: This article reviews potassium homeostasis, epidemiology, risk factors, and outcomes of hyperkalemia, and efficacy and safety of the drugs used for acute and chronic treatment of hyperkalemia. A literature search was carried out using the PubMed and guidelines for the management of hyperkalemia.Expert opinion: The emergency treatment of hyperkalemia is not supported by high-quality evidence and clinical trials did not report drug effects on clinical outcomes. Two potassium binders, patiromer and sodium zirconium cyclosilicate, represent a new approach in the treatment of chronic hyperkalemia as they may allow the titration and maintenance of guidelines-recommended doses of RAASIs in patients with CVD who otherwise would not tolerate them due to the risk of hyperkalemia.Further studies are needed to evaluate the safety and efficacy of drug therapy and support the development of guidelines for acute and chronic hyperkalemia.

Effects of estimated glomerular filtration rate and diabetes mellitus on the effect of insulin for treating hyperkalemia during anesthesia

PURPOSE

We analyzed the effectiveness of insulin for treating hyperkalemia (≥ 5 mEq/L) during anesthesia and the effects of the estimated glomerular filtration rate (eGFR) and diabetes mellitus (DM) on the insulin treatment.

METHODS

Patients 18 years of age and older who received intravenous insulin lispro for hyperkalemia under general anesthesia between January 2010 and March 2020 were enrolled. We performed three propensity score matching analyses according to eGFR stages (eGFR ≥ 60 vs. 30 ≤ eGFR < 60 and eGFR ≥ 60 vs. eGFR < 30 mL/min/1.73 m²) and DM status.

RESULTS

The study included 475 patients. For patients with hyperkalemia during surgery, the odds ratios [ORs] of failure to decrease potassium (K⁺) after insulin treatment were higher in patients with eGFR < 30 mL/min/1.73 m² (adjusted OR 3.24; 95% confidence interval 1.38-7.64; P = 0.007) than in patients with eGFR ≥ 60 mL/min/1.73 m². There was no significant difference in the ORs of patients with 30 ≤ eGFR < 60 mL/min/1.73 m² and DM.

CONCLUSION

The patients with a low eGFR had a higher incidence of K⁺ not decreasing after insulin treatment. Periodic assessment of K⁺ may be required during anesthesia.

Kayexalate-Induced Esophageal Ulceration in a Patient with Decompensated Cirrhosis: A Review of the Literature

Hyperkalemia is one of the most common electrolyte abnormalities encountered in clinical practice. The treatment of hyperkalemia includes removal of excess potassium from the body using cation exchange resins, e.g., sodium polystyrene sulfonate (Kayexalate) is one of the most practiced modalities in clinical medicine. Colonic mucosal necrosis and perforation are the serious gastrointestinal side effects associated with sodium polystyrene sulfonate (SPS) use, which have been reported with or without concomitant use of sorbitol. However, the catastrophic bleeding esophageal ulcer has been rarely described in our literature search. Due to the risk of colonic necrosis, the FDA has issued a warning to avoid concomitant sorbitol use with Kayexalate. We present an individual with acute hematemesis due to bleeding esophageal ulcer immediately after treatment with Kayexalate therapy. Though the exact mechanism by which Kayexalate causes esophageal ulcer to be elucidated, nonetheless it is worthwhile to be vigilant about its potential adverse effects. Our case highlights the rare but certainly the life-threatening complication of Kayexalate therapy.

Ambulatory Treatments for RAAS Inhibitor-Related Hyperkalemia and the 1-Year Risk of Recurrence

BACKGROUND AND OBJECTIVE

The optimal ambulatory management of renin-angiotensin-aldosterone system inhibitor (RAASi)-related hyperkalemia to reduce the risk of recurrence is unknown. We examined the risk of hyperkalemia recurrence on the basis of outpatient pharmacologic changes following an episode of RAASi-related hyperkalemia.

DESIGN

We performed a population-based, retrospective cohort study of older adults (n=49,571; mean age 79 years) who developed hyperkalemia (potassium ≥5.3 mEq/L) while on a RAASi and were grouped as follows: no intervention, RAASi discontinuation, RAASi dose decrease, new diuretic, diuretic dose increase, or sodium polystyrene sulfonate within 30 days. The primary outcome was hyperkalemia recurrence, with secondary outcomes of cardiovascular events and all-cause mortality within 1 year.

RESULTS

Among patients who received a pharmacologic intervention (23% of the cohort), RAASi discontinuation was the most commonly prescribed strategy (74%), followed by RAASi decrease (15%), diuretic increase (7%), new diuretic (3%), and sodium polystyrene sulfonate (1%). A total of 16,977 (34%) recurrent hyperkalemia events occurred within 1 year. Compared with no intervention (35%, referent), the cumulative incidence of recurrent hyperkalemia was lower with RAASi discontinuation (29%; hazard ratio, 0.82; 95% confidence interval, 0.78 to 0.85), whereas there was no difference with RAASi dose decrease (36%; hazard ratio, 0.94; 95% confidence interval, 0.86 to 1.02), new diuretic (32%; hazard ratio, 0.95; 95% confidence interval, 0.78 to 1.17), or diuretic increase (38%; hazard ratio, 0.99; 95% confidence interval, 0.87 to 1.12) and a higher incidence with sodium polystyrene sulfonate (55%; hazard ratio, 1.30; 95% confidence interval, 1.04 to 1.63). RAASi discontinuation was not associated with a higher risk of 1-year cardiovascular events (hazard ratio, 0.96; 95% confidence interval, 0.91 to 1.02) or all-cause mortality (hazard ratio, 1.05; 95% confidence interval, 0.96 to 1.15) compared with no intervention.

CONCLUSIONS

Among older adults with RAASi-related hyperkalemia, RAASi discontinuation is associated with the lowest risk of recurrent hyperkalemia, with no apparent increase in short-term risks for cardiovascular events or all-cause mortality.

A narrative review on the potential of tomato and lycopene for the prevention of Alzheimer's disease and other dementias

Oxidative stress is a major factor in aging and is implicated in the pathogenesis of tumors, diabetes mellitus, cardiovascular and neurodegenerative diseases, including Alzheimer Disease (AD). Bioactive constituents of tomato as polyphenols and carotenoids, among which lycopene (LYC) are effective in reducing markers of oxidative stress, and appear to have a protective modulator role on the pathogenetic mechanisms, cognitive symptoms and behavioral manifestations of these diseases in cell cultures and animal models. Epidemiological evidence indicates a consistent association between the intake of tomatoes and reduced cardiovascular and neoplastic risk. LYC deficiency is common in elders and AD patients and it is strongly predictive of mortality and poor cardiovascular (CV) outcomes. Dietary intake of tomatoes seems to be more effective than tomato/LYC supplementation. Limited evidence from human intervention trials suggests that increasing tomato intake, besides improving CV markers, enhances cognitive performances. In this narrative review, we analyze the existing evidence on the beneficial effects of tomatoes on AD-related processes or risk factors. Results support the development of promising nutritional strategies to increase the levels of tomato consumption for the prevention or treatment of AD and other dementias. Extensive well-structured research, however, is mandatory to confirm the neuroprotective effects of tomato/LYC in humans.

An Evidence-Based Narrative Review of the Emergency Department Management of Acute Hyperkalemia

BACKGROUND

The normal range for potassium is within narrow limits. Hyperkalemia is an electrolyte disorder that frequently affects patients in the emergency department (ED), and can result in significant morbidity and mortality if not identified and treated rapidly.

OBJECTIVE

This article provides an evidence-based narrative review of the management of hyperkalemia, with focused updates for the emergency clinician.

METHODS

We searched in MEDLINE, EMBASE, Web of Science, and Scopus databases for articles in English published in peer-reviewed journals and indexed up until May 2020. We used multiple search terms, including hyperkalemia, potassium, acute hyperkalemia, emergency department, dyskalemia, potassium disorders, kidney disease, epidemiology, electrolyte disturbance, severe hyperkalemia, and emergency management.

DISCUSSION

In the ED, interventions aimed to protect patients from the immediate dangers of elevated serum potassium are divided into the following: stabilizing cardiac membrane potentials, reducing serum potassium levels through shift from the extracellular fluid to intracellular fluid, and elimination of potassium through excretion via urinary or fecal excretion. Calcium is widely recommended to stabilize the myocardial cell membrane, but additional research is necessary to establish criteria for use, dosages, and preferred solutions. Redistribution of potassium ions from the bloodstream into the cells is based on intravenous insulin or nebulized β2-agonists.

CONCLUSIONS

Hyperkalemia is a frequent electrolyte disorder in the ED. Because of the risk of fatal dysrhythmia due to cardiac membrane instability, hyperkalemia is a medical emergency. There is a lack of scientific evidence on the optimal management of hyperkalemia and more research is needed to establish optimal strategies to manage acute hyperkalemia in the emergency department.

The Effect of Patient Factors and Cotreatments on the Magnitude of Potassium Lowering with Insulin-Glucose Treatment in Patients with Hyperkalemia

The management of hyperkalemia with insulin-glucose/dextrose treatment (IDT) may be influenced by patient factors and cotreatments. We aimed to determine the magnitude of potassium lowering by IDT while considering patient factors and cotreatments. We observed the change in serum potassium in 410 patients with a mean serum potassium of 6.6 mmol/L (SD, 0.6 mmol/L) treated with IDT at three major metropolitan hospitals. Mean potassium lowering was 1.4 mmol/L (SD, 0.8 mmol/L) and 53% achieved normokalemia. Cotreatment with sodium polystyrene sulfonate, salbutamol, or sodium bicarbonate occurred in 64%, 12%, and 10% of patients, respectively. In multiple linear regression analysis, cotreatment with sodium polystyrene sulfonate or sodium bicarbonate was not associated with any significant reduction in serum potassium beyond that achieved by IDT, within the initial 6 h of treatment. We observed an additional lowering of serum potassium with salbutamol of 0.3 mmol/L (95% CI: 0.1 to 0.6 mmol/L; p = 0.009) but the clinical significance was unclear as the proportion of patients achieving normokalemia was not affected by cotreatment within the initial 6 h after IDT. We also found evidence that the potassium-lowering effect of IDT was dependent on the pre-treatment serum potassium. For every 1 mmol/L increase in pre-treatment serum potassium over 6.0 mmol/L, there was an associated 0.7 mmol/L increase in the potassium-lowering effect of IDT, on average, which was independent of any cotreatment. There was no significant impact of acute kidney injury or chronic kidney disease status on the efficacy of IDT.

ENaC expression correlates with the acute furosemide-induced K+ excretion

BACKGROUND

In the aldosterone-sensitive distal nephron (ASDN), epithelial sodium channel (ENaC)-mediated Na+ absorption drives K+ excretion. K+ excretion depends on the delivery of Na+ to the ASDN and molecularly activated ENaC. Furosemide is known as a K+ wasting diuretic as it greatly enhances Na+ delivery to the ASDN. Here, we studied the magnitude of acute furosemide-induced kaliuresis under various states of basal molecular ENaC activity.

METHODS

C57/Bl6J mice were subjected to different dietary regimens that regulate molecular ENaC expression and activity levels. The animals were anesthetized and bladder-catheterized. Diuresis was continuously measured before and after administration of furosemide (2 µg/g BW) or benzamil (0.2 µg/g BW). Flame photometry was used to measure urinary [Na+ ] and [K+ ]. The kidneys were harvested and, subsequently, ENaC expression and cleavage activation were determined by semiquantitative western blotting.

RESULTS

A low K+ and a high Na+ diet markedly suppressed ENaC protein expression, cleavage activation, and furosemide-induced kaliuresis. In contrast, furosemide-induced kaliuresis was greatly enhanced in animals fed a high K+ or low Na+ diet, conditions with increased ENaC expression. The furosemide-induced diuresis was similar in all dietary groups.

CONCLUSION

Acute furosemide-induced kaliuresis differs greatly and depends on the a priori molecular expression level of ENaC. Remarkably, it can be even absent in animals fed a high Na+ diet, despite a marked increase of tubular flow and urinary Na+ excretion. This study provides auxiliary evidence that acute ENaC-dependent K+ excretion requires both Na+ as substrate and molecular activation of ENaC.

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.

The Association of Insulin-dextrose Treatment with Hypoglycemia in Patients with Hyperkalemia

Treatment of hyperkalemia with intravenous insulin-dextrose is associated with a risk of hypoglycemia. We aimed to determine the factors associated with hypoglycemia (glucose < 3.9 mmol/L, or < 70 mg/dL) and the critical time window with the highest incidence. In a retrospective cohort study in a tertiary hospital network, we included 421 adult patients with a serum potassium ≥ 6.0 mmol/L who received insulin-dextrose treatment. The mean age was 70 years with 62% male predominance. The prevalence of diabetes was 60%, and 70% had chronic kidney disease (eGFR < 60 ml/min/1.73 m²). The incidence of hypoglycemia was 21%. In a multivariable logistic regression model, the factors independently associated with hypoglycemia were: body mass index (per 5 kg/m², OR 0.85, 95% CI: 0.69–0.99, P = 0.04), eGFR < 60 mL/min/1.73 m² (OR 2.47, 95% CI: 1.32–4.63, P = 0.005), diabetes (OR 0.57, 95% CI 0.33–0.98, P = 0.043), pre-treatment blood glucose (OR 0.84, 95% CI: 0.77–0.91, P < 0.001), and treatment in the emergency department compared to other locations (OR 2.53, 95% CI: 1.49–4.31, P = 0.001). Hypoglycemia occurred most frequently between 60 and 150 min, with a peak at 90 min. Understanding the factors associated with hypoglycemia and the critical window of risk is essential for the development of preventive strategies.

Hyperkalemia in heart failure

Hyperkalemia is increasingly prevalent in the heart failure population as more people live with heart failure and comorbid conditions such as diabetes and chronic kidney disease. Furthermore, renin–angiotensin–aldosterone (RAAS) inhibitors are a key component of clinical therapy in these populations. Until now, we have not had any reliable or tolerable therapies for treatment of hyperkalemia resulting in inability to implement or achieve target doses of RAAS inhibition. This review will focus on two new therapies for hyperkalemia: patiromer and sodium zirconium cyclosilicate (SZC).

Insulin glucose infusion versus nebulised salbutamol versus combination of salbutamol and insulin glucose in acute hyperkalaemia in the emergency room: protocol for a randomised, multicentre, controlled study (INSAKA)

INTRODUCTION

Hyperkalaemia is a common electrolyte disorder and can be life-threatening. In the emergency room (ER), interventions aim to protect patients from the immediate dangers of elevated serum potassium by redistributing potassium ions from the bloodstream into the cells via intravenous insulin or nebulised beta2-agonists. However, to date, evidence for acute management of hyperkalaemia is limited. The aim of this randomised controlled trial is therefore to compare three strategies, namely insulin/glucose intravenous infusion, nebulised salbutamol or a combination of nebulised salbutamol and insulin/glucose intravenous infusion to reduce serum potassium concentration at 60 min as a first-line treatment in patients admitted to the ER with serum potassium concentrations superior or equal to 6 mmol/L.

METHODS AND ANALYSIS

INSAKA is a prospective, multicentre, controlled, open-label, parallel-group, randomised in a 1:1:1 ratio clinical trial. Patients will be eligible for randomisation if they have serum potassium concentrations superior or equal to 6 mmol/L measured in the ER. Patients will receive either: (1) 10 mg of nebulised salbutamol, (2) 10 units of short-acting insulin in an intravenous bolus with 500 mL of 10% glucose or (3) 10 units of short-acting insulin in an intravenous bolus with 500 mL of 10% glucose combined with 10 mg of nebulised salbutamol. The primary endpoint will be the mean change in the absolute serum potassium level from baseline to 60 min measured in mmol/L. We plan to include 525 patients.

ETHICS AND DISSEMINATION

The INSAKA trial will be conducted in accordance with the International Council on Harmonization Good Clinical Practices. All trial documents and procedures have been reviewed and approved by the Ethics Committee Sud Méditerranée III (approval ID number: 19.07.16.36428). The results will be actively disseminated through peer-reviewed journals, conference presentations, social media, broadcast media, print media and the internet.

TRIAL REGISTRATION

EudraCT number: 2019-002710-39, Clinicaltrials.gov identifier: NCT04012138.

Hyperkalemia and Hypertension Post Organ Transplantation - A Management Challenge

Potassium is the most important intracellular cation and the kidneys play a pivotal role in potassium homeostasis. Potassium disorder is a common electrolyte abnormality and it increases the risk of death from any cause, particularly cardiovascular events. Hyperkalemia is a common electrolyte abnormality encountered post organ transplantation. The etiology is multifactorial, and includes drugs such as calcineurin inhibitors. In certain regards, the clinical picture of post-transplantation hyperkalemia and hypertension resembles that of Gordon syndrome or familial hyperkalemic hypertension, a disorder characterized by over activity of thiazide-sensitive sodium chloride cotransporter. Effective and safe management of chronic hyperkalemia can be challenging in this special patient population. Despite the significant short-term and long-term side effects, fludrocortisone (a potent synthetic oral mineralocorticoid receptor agonist) has emerged as the default drug of choice for treatment of refractory hyperkalemia in many organ transplant recipients. However, the long-term efficacy and safety of fludrocortisone for management of hyperkalemia in organ transplant recipients remains unknown. This review discusses potassium homeostasis, including the role of the kidneys, and focuses on calcineurin inhibitor-induced hyperkalemia and on the under-appreciated role of thiazide-type diuretic use in management of hyperkalemia and hypertension. We present an illustrative case of post-transplantation hyperkalemia and hypertension with relevant literature.

Regulation of the Renal NaCl Cotransporter and Its Role in Potassium Homeostasis

Daily dietary potassium (K+) intake may be as large as the extracellular K+ pool. To avoid acute hyperkalemia, rapid removal of K+ from the extracellular space is essential. This is achieved by translocating K+ into cells and increasing urinary K+ excretion. Emerging data now indicate that the renal thiazide-sensitive NaCl cotransporter (NCC) is critically involved in this homeostatic kaliuretic response. This suggests that the early distal convoluted tubule (DCT) is a K+ sensor that can modify sodium (Na+) delivery to downstream segments to promote or limit K+ secretion. K+ sensing is mediated by the basolateral K+ channels Kir4.1/5.1, a capacity that the DCT likely shares with other nephron segments. Thus, next to K+-induced aldosterone secretion, K+ sensing by renal epithelial cells represents a second feedback mechanism to control K+ balance. NCC’s role in K+ homeostasis has both physiological and pathophysiological implications. During hypovolemia, NCC activation by the renin-angiotensin system stimulates Na+ reabsorption while preventing K+ secretion. Conversely, NCC inactivation by high dietary K+ intake maximizes kaliuresis and limits Na+ retention, despite high aldosterone levels. NCC activation by a low-K+ diet contributes to salt-sensitive hypertension. K+-induced natriuresis through NCC offers a novel explanation for the antihypertensive effects of a high-K+ diet. A possible role for K+ in chronic kidney disease is also emerging, as epidemiological data reveal associations between higher urinary K+ excretion and improved renal outcomes. This comprehensive review will embed these novel insights on NCC regulation into existing concepts of K+ homeostasis in health and disease.

Case report: Patiromer-induced hypercalcemia

Patiromer is a novel potassium-binding compound which has recently received FDA approval. This ion exchange resin releases calcium when it binds potassium. We describe the development of hypercalcemia after initiation of patiromer. The calcium levels fell when the drug was stopped but recurred when it was later resumed. Patiromer was again discontinued, and the serum calcium level fell back into the normal range. We believe this patient manifested patiromer-induced hypercalcemia.

Treating potassium disturbances: kill the killers but avoid overkill

OBJECTIVES

In this publication, we review the definitions, symptoms, causes, differential diagnoses and therapies of hypokalemia and hyperkalemia.

METHODS

Comprehensive tables and diagnostic algorithms are provided when appropriate.

RESULTS AND CONCLUSIONS

Although both hypokalemia and hyperkalemia may be life-threatening, this is essentially the case with severe changes (serum potassium < 2.5 or > 6.5 mmol/L), the presence of symptoms or electrocardiographic deviations, the association with aggravating factors (e.g. digitalis intake) and/or rapid acute changes. Only these truly need an emergency therapeutic approach. In all other cases, a careful consideration of the causes and their correction should prevail over additional approaches to modify serum potassium concentration. Although most therapeutic approaches to both hypokalemia and hyperkalemia have been well established since many years, recently two new intestinal potassium binders have been introduced on the market. It remains to be elucidated whether these drugs truly have an additional role on top of the existing treatments.

Management of hyperkalemia in patients with kidney disease: a position paper endorsed by the Italian Society of Nephrology

Hyperkalemia (HK) is the most common electrolyte disturbance observed in patients with kidney disease, particularly in those in whom diabetes and heart failure are present or are on treatment with renin-angiotensin-aldosterone system inhibitors (RAASIs). HK is recognised as a major risk of potentially life threatening cardiac arrhythmic complications. When an acute reduction of renal function manifests, both in patients with chronic kidney disease (CKD) and in those with previously normal renal function, HK is the main indication for the execution of urgent medical treatment and the recourse to extracorporeal replacement therapies. In patients with end-stage renal disease, the presence of HK not responsive to medical therapy is an indication at the beginning of chronic renal replacement therapy. HK can also be associated indirectly with the progression of CKD, because the finding of high potassium values leads to withdrawal of treatment with RAASIs, which constitute the first choice nephro-protective treatment. It is therefore essential to identify patients at risk of developing HK, and to implement therapeutic interventions aimed at preventing and treating this dangerous complication of kidney disease. Current strategies aimed at the prevention and treatment of HK are still unsatisfactory, as evidenced by the relatively high prevalence of HK also in patients under stable nephrology care, and even in the ideal setting of randomized clinical trials where optimal treatment and monitoring are mandatory. This position paper will review the main therapeutic interventions to be implemented for the prevention, detection and treatment of HK in patients with CKD on conservative care, in those on dialysis, in patients in whom renal disease is associated with diabetes, heart failure, resistant hypertension and who are on treatment with RAASIs, and finally in those presenting with severe acute HK.

Dietary Approaches to Stop Hypertension (DASH): potential mechanisms of action against risk factors of the metabolic syndrome

The metabolic syndrome is a cluster of disorders dominated by abdominal obesity, hypertriacylglycerolaemia, low HDL-cholesterol, high blood pressure and high fasting glucose. Diet modification is a safe and effective way to treat the metabolic syndrome. Dietary Approaches to Stop Hypertension (DASH) is a dietary pattern rich in fruits, vegetables and low-fat dairy products, and low in meats and sweets. DASH provides good amounts of fibre, K, Ca and Mg, and limited quantities of total fat, saturated fat, cholesterol and Na. Although DASH was initially designed for the prevention or control of hypertension, using a DASH diet has other metabolic benefits. In the present review, the effect of each dietary component of DASH on the risk factors of the metabolic syndrome is discussed. Due to limited fat and high fibre and Ca content, individuals on the DASH diet are less prone to overweight and obesity and possess lower concentrations of total and LDL-cholesterol although changes in TAG and HDL-cholesterol have been less significant and available evidence in this regard is still inconclusive. Moreover, high amounts of fruit and vegetables in DASH provide great quantities of K, Mg and fibre, all of which have been shown to reduce blood pressure. K, Mg, fibre and antioxidants have also been effective in correcting glucose and insulin abnormalities. Evidence is provided from cross-sectional investigations, cohort studies and randomised controlled trials, and, where available, from published meta-analyses. Mechanisms are described according to human studies and, in the case of a lack of evidence, from animal and cell culture investigations.

Pharmacologic Treatment of Chronic Hyperkalemia in Patients with Chronic Kidney Disease

Hyperkalemia is frequently complicated in patients with advanced chronic kidney disease (CKD) because kidney is the major route of potassium excretion. Urinary potassium excretion is reduced according to the decline in glomerular filtration rate, and the risk of hyperkalemia is increased in patients with high potassium intake, advanced age, diabetes mellitus, congestive heart failure, and medications such as renin-angiotensin-aldosterone system(RAAS) blockades. On the other hand, the benefits of RAAS blockades and a high-potassium diet should be considered in CKD patients. To overcome these contradictory treatment strategies, potassium binders have emerged as new options to enhance fecal potassium excretion. In different regions of the world, four types of potassium binders are preferentially used. Whereas sodium polystyrene sulfonate (SPS) exchanges sodium for potassium, calcium polystyrene sulfonate (CPS) has the advantage of avoiding hypervolemia because it exchanges calcium for potassium. SPS was first introduced in the 1950s and used for a long time in western countries, and CPS is currently prescribed in Asia including South Korea. In contrast with the paucity of clinical studies using SPS or CPS, the recent randomized, controlled trials reported that two newer potassium binders, patiromer and sodium zirconium cyclosilicate (ZS-9), effectively and safely reduce serum potassium levels in CKD patients taking RAAS blockades. Our experiences showed that the long-term administration of a small dose of CPS was also effective and safe in treatment of chronic hyperkalemia. Further comparative trials among patiromer, ZS-9, and CPS are required to provide guides to cost-effective management of hyperkalemia in CKD patients.

Heart failure in chronic kidney disease: conclusions from a Kidney Disease: Improving Global Outcomes (KDIGO) Controversies Conference

The incidence and prevalence of heart failure (HF) and chronic kidney disease (CKD) are increasing, and as such a better understanding of the interface between both conditions is imperative for developing optimal strategies for their detection, prevention, diagnosis, and management. To this end, Kidney Disease: Improving Global Outcomes (KDIGO) convened an international, multidisciplinary Controversies Conference titled Heart Failure in CKD. Breakout group discussions included (i) HF with preserved ejection fraction (HFpEF) and nondialysis CKD, (ii) HF with reduced ejection fraction (HFrEF) and nondialysis CKD, (iii) HFpEF and dialysis-dependent CKD, (iv) HFrEF and dialysis-dependent CKD, and (v) HF in kidney transplant patients. The questions that formed the basis of discussions are available on the KDIGO website http://kdigo.org/conferences/heart-failure-in-ckd/, and the deliberations from the conference are summarized here.

Boosting the Limited Use of Mineralocorticoid Receptor Antagonists Through New Agents for Hyperkalemia

Background:

Hyperkalemia is an important clinical problem that is associated with significant lifethreatening complications. Several conditions are associated with increased risk for hyperkalemia such as chronic kidney disease, diabetes mellitus, heart failure, and the use of renin-angiotensin-aldosterone system (RAAS) inhibitors.

Objective:

The purpose of this review is to present and critically discuss treatment options for the management of hyperkalemia.

Method:

A comprehensive review of the literature was performed to identify studies assessing the drug-induced management of hyperkalemia.

Results:

The management of chronic hyperkalemia seems to be challenging and includes a variety of traditional interventions, such as restriction in the intake of the dietary potassium, loop diuretics or sodium polystyrene sulfonate. In the last few years, several new agents have emerged as promising options to reduce potassium levels in hyperkalemic patients. Patiromer and sodium zirconium cyclosilicate 9 (ZS-9) have been examined in hyperkalemic patients and were found to be efficient and safe. Importantly, the efficacy of these novel drugs might allow the continuation of the use of RAAS inhibitors, morbidity- and mortality-wise beneficial class of drugs in the setting of chronic kidney disease and heart failure.

Conclusion:

Data support that the recently emerged patiromer and ZS-9 offer significant hyperkalemia-related benefits. Larger trials are needed to unveil the impact of these drugs in other patients’ subpopulations, as well.

Can physicians detect hyperkalemia based on the electrocardiogram?

OBJECTIVE

Although there is no consensus on how to use an electrocardiogram (ECG) in patients with hyperkalemia, physicians often obtain it in the acute setting when diagnosing and treating hyperkalemia. The objective of this study is to evaluate if physicians are able to detect hyperkalemia based on the ECG.

METHODS

The study was conducted at a large county hospital with a population of end stage renal disease (ESRD) patients who received hemodialysis (HD) solely on an emergent basis. Five hundred twenty eight ECGs from ESRD patients were evaluated. The prevalence of hyperkalemia was approximately 60% in this cohort, with at least half of them in the severe hyperkalemia range (K ≥ 6.5 mEq/L).

RESULTS

The mean sensitivity and specificity of the emergency physicians detecting hyperkalemia were 0.19 (± 0.16) and 0.97(± 0.04) respectively. The mean positive predictive value of evaluators for detecting hyperkalemia was 0.92 (±0.13) and the mean negative predictive value was 0.46 (± 0.05). In severe hyperkalemia (K ≥ 6.5 mEq/L), the mean sensitivity improved to 0.29 (± 0.20), while specificity decreased to 0.95 (±0.07).

CONCLUSION

An ECG is not a sensitive method of detecting hyperkalemia and should not be relied upon to rule it out. However, the ECG has a high specificity for detecting hyperkalemia and could be used as a rule in test.

Prise en charge de l’hyperkaliémie aux urgences

L’hyperkaliémie est l’un des désordres hydroélectrolytiques les plus fréquemment rencontrés aux urgences. Les étiologies principales sont l’insuffisance rénale aiguë ou chronique, le diabète et l’insuffisance cardiaque. L’hyperkaliémie aiguë peut être une urgence vitale, car elle est potentiellement létale du fait du risque d’arythmie cardiaque. Sa prise en charge aux urgences manque actuellement de recommandations claires en ce qui concerne le seuil d’intervention et les thérapeutiques à utiliser. Les thérapeutiques couramment appliquées sont fondées sur un faible niveau de preuve, et leurs effets secondaires sont mal connus. Des études supplémentaires sont nécessaires pour évaluer l’utilisation de ces traitements et celle de nouveaux traitements potentiellement prometteurs. Nous faisons ici une mise au point sur les données connues en termes d’épidémiologie, de manifestations cliniques et électrocardiographiques, et des différentes thérapeutiques qui peuvent être proposées dans la prise en charge de l’hyperkaliémie aux urgences.

Gut microbiota: novel therapeutic target for nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is one of the most common and increasing liver diseases worldwide with a prevalence of 20-33%. NAFLD may progress to fibrosis, compensated cirrhosis, advanced cirrhosis, or hepatocellular carcinoma. Despite the increasing prevalence of NAFLD, definitive medical treatment has not been established, with the exception of lifestyle modification with exercise. Because of the direct connection via portal vein between the intestines and the liver (gut-gut microbiota-liver axis), gut microbiota and associated dysbiosis have been known as regulators in the pathophysiology of NAFLD. Area covered: New therapeutic approaches for modulation of gut microbiota have been proposed and the effectiveness of new therapies including probiotics, prebiotics, synbiotics, bile acid regulation, absorbent, and fecal microbiota transplantation have been demonstrated in recent several studies. This review focuses on the available evidences for new therapies modulating gut microbiota in the management and the prevention of NAFLD. Expert commentary: Gut-gut microbiota-liver axis may play an important role in the etiology of many liver diseases, including NAFLD. It is logical to seek the manipulation of this axis, and further studies are required to understand the underlying precise mechanisms of microbiota-modulation on NAFLD.