Chronic hyperkalemia in non-dialysis CKD: controversial issues in nephrology practice

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

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

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.

RAASi Therapy Attenuates the Association between 24-h Urinary Potassium Excretion and Dietary Potassium Intake in CKD Patients

The aim of this study was to evaluate urinary potassium (K) excretion as a reliable marker of dietary K intake, in a cohort of CKD patients with or without Renin-Angiotensin-Aldosterone System (RAAS) inhibitor therapy. One hundred and thirty-eight consecutive out-patients (51 f and 87 m) aged 60 ± 13 years and affected by CKD stage 3-4, who were metabolically and nutritionally stable, entered the study between November 2021 and October 2022. No difference was observed between patients with (n = 85) or without (n = 53) RAAS inhibitor therapy, regarding dietary intakes, blood biochemistry, and 24-h urine excretion parameters. Considering all patients, urinary K showed a weak relationship with eGFR (r = 0.243, p < 0.01), and with dietary K intake (r = 0.184, p < 0.05). Serum K was not associated with dietary K intake, but an inverse relationship was observed with eGFR (r = -0.269, p < 0.01). When patients were examined depending on whether they were receiving RAAS inhibitor therapy, the weak inverse relationship between serum K and eGFR was maintained in both groups. Conversely, urinary K excretion remained positively associated with dietary K intake only in the no RAAS inhibitor group. In conclusion, 24-h urine K excretion may be used as a surrogate of K intake, but RAAS inhibitor therapy reduces the association between 24-h urine K excretion and dietary K intake in CKD patients.

Outcomes in patients with cardiometabolic disease who develop hyperkalemia while treated with a renin-angiotensin-aldosterone system inhibitor

BACKGROUND

Many patients with indications for renin-angiotensin-aldosterone system inhibitor (RAASi) therapy are not receiving these medications. Concern about hyperkalemia is thought to contribute to this lack of evidence-based therapy.

METHODS

A retrospective cohort study included adult patients in primary care practices affiliated with an integrated health care delivery system treated with RAASi between 2000 and 2019 for any of the following indications: (a) coronary artery disease (CAD); (b) heart failure (HF) with a left ventricle ejection fraction ≤ 40%; (c) diabetes mellitus (DM) with proteinuria; or (d) chronic kidney disease (CKD) with proteinuria. Relationship between hyperkalemia (K > 5.0 mEg/L) over the first 12 months of follow-up and a composite end point of cardiovascular events, renal dysfunction, and all-cause mortality was evaluated.

RESULTS

Among 82,732 study patients, 7,727 (9.34%) developed hyperkalemia. Patients with hyperkalemia were older (69.0 vs 64.6) and more likely to have CAD (57.8 vs 53.7%), CKD (57.3 vs 51.1%), HF (19.3 vs 9.7%), and DM (45.3 vs 33.3%) (P < .001 for all). Five-year cumulative risk of the primary outcome was higher in patients who did (63.9%; 95% CI: 62.8%-65.1%) versus did not (37.2%; 95% CI: 36.8%-37.6%) develop hyperkalemia. Five-year cumulative risk of ED visit or hospitalization for hyperkalemia was 15.6% (14.7%-16.6%) for patients with versus 2.7% (95% CI: 2.6-2.9) for patients without hyperkalemia, rising to 25.9% (95% CI: 22.4-29.9) for patients with severe (K > 6.0 mEq/dL) hyperkalemia. Patients who experienced hyperkalemia were more likely (34.4%) than patients who did not (29.2%) to deintensify RAASi therapy (P < .001). Five-year cumulative risk of the primary outcome was higher in patients who lowered RAASi dose (50.4%; 95% CI: 48.5%-52.4%) or stopped RAASi therapy completely (49.3%; 95% CI: 48.5%-50.1%), compared to patients who continued RAASi therapy (36.1%; 95% CI: 25.7-36.5). Similar findings were observed in multivariable analyses and for individual components of the primary outcome.

CONCLUSIONS

Hyperkalemia is a common complication of RAASi therapy and is associated with an increased risk of multiple adverse outcomes. Patients who have their RAASi medications deintensified after a hyperkalemic event have higher incidence of cardiovascular events, renal dysfunction and death.

Potassium Bioaccessibility in Uncooked and Cooked Plant Foods: Results from a Static In Vitro Digestion Methodology

Hyperkalemia is a major concern in chronic kidney disease and in end-stage renal disease, representing a predictor of hospitalization and mortality. To prevent and treat hyperkalemia, dietary management is of great clinical interest. Currently, the growing use of plant-based diets causes an increasing concern about potassium load in renal patients. The aim of this study was to assess the bioaccessibility of potassium in vegetables, concerning all aspects of the plants (fruit, flower, root, tuber, leaf and seed) and to what extent different boiling techniques affect potassium content and bioaccessibility of plant-based foods. Bioaccessibility was evaluated by an in vitro digestion methodology, resembling human gastro-intestinal tract. Potassium content was higher in seeds and leaves, despite it not being possible to define a common “rule” according to the type of organ, namely seed, leaf or fruit. Boiling reduced potassium content in all vegetables excluding carrot, zucchini, and cauliflower; boiling starting from cold water contributed to a greater reduction of the potassium content in potato, peas, and beans. Bioaccessibility after in vitro digestion ranged from 12 (peas) to 93% (tomato) regardless of species and organs. Higher bioaccessibility was found in spinach, chicory, zucchini, tomato, kiwi, and cauliflower, and lower bioaccessibility in peas. Potassium from leaf resulted in the highest bioaccessibility after digestion; as a whole potassium bioaccessibility in the fruits and vegetables studied was 67% on average, with differences in relation to the different organs and species. Further, considering the method of boiling to reduce potassium content, these data indicate that the effective potassium load from plant-based foods may be lower than originally expected. This supports the clinical advices to maintain a wide use of plant-based food in the management of renal patients.

Low variability of plant protein intake in the CKiD cohort does not demonstrate changes in estimated GFR nor electrolyte balance

BACKGROUND

Vegetable or plant-based sources of protein may confer health benefits in children with progressive kidney disease. Our aims were to understand the effect of the proportion of vegetable protein intake on changes in estimated GFR and to understand the effect of the proportion of vegetable protein intake on serum levels of bicarbonate, phosphorus, and potassium.

METHODS

Children with baseline eGFR between 30 and 90 mL/min/1.73 m² were recruited from 59 centers across North America as part of the chronic kidney disease in children (CKiD) study. The percentage of dietary vegetable protein (VP%) was gathered from annual Food Frequency Questionnaires. We performed longitudinal linear mixed models to determine the effect of VP% on eGFR and longitudinal logistic mixed models to determine the effect of VP% on electrolyte balance (potassium, phosphorus, bicarbonate).

RESULTS

Two thousand visits from 631 subjects. Across all dichotomized groups of children (sex, African American race, Hispanic ethnicity, glomerular etiology of CKD, hypertension, anemia, hyperkalemia, hyperphosphatemia, acidosis, BMI < 95th percentile), the median VP% was 32-35%. The longitudinal mixed model analysis did not show any effect of VP% on eGFR electrolyte (bicarbonate, phosphorus, and potassium) abnormalities (p > 0.1).

CONCLUSIONS

A diverse cohort of children with CKD has a narrow and homogeneous intake of vegetable protein. Due to the low variability of plant-based protein in the cohort, there were no associations between the percentage of plant protein intake and changes in eGFR nor electrolyte balance. A higher resolution version of the Graphical abstract is available as Supplementary information.

Hyperkalemia and Metabolic Acidosis Occur at a Higher eGFR in Sickle Cell Disease

Background

People with sickle cell disease (SCD) have an elevated estimated glomerular filtration rate (eGFR) compared with the general population, and this may alter the usual creatinine-based eGFR cutoffs for which physiologic evidence of kidney dysfunction is apparent. This study aimed to identify eGFR thresholds for hyperkalemia and metabolic acidosis in patients with SCD.

Methods

This was a cross-sectional analysis of 733 patients with severe (hemoglobin SS or Sβ ⁰-thalassemia) SCD genotype, 238 patients with moderate (hemoglobin SC or Sβ ⁺-thalassemia) SCD genotype, and 1333 age- and sex-matched African Americans from the National Health and Nutrition Examination Survey (NHANES). The prevalence rates of hyperkalemia and metabolic acidosis were compared by eGFR category. Cutoffs for hyperkalemia and metabolic acidosis were determined using generalized additive models.

Results

Hyperkalemia and metabolic acidosis were more common in those with severe SCD genotype (13% and 21%, respectively) compared with the NHANES (0.3% and 5%, respectively); the prevalence rates in the moderate SCD genotype were intermediate for hyperkalemia (3%) and metabolic acidosis (11%). The proportion of patients with hyperkalemia and metabolic acidosis progressively increased with lower eGFR category in both SCD genotype groups. The eGFR thresholds for hyperkalemia and metabolic acidosis were higher in the severe (85 and 91 ml/min per 1.73 m², respectively) and moderate (52 and 102 ml/min per 1.73 m², respectively) SCD genotypes compared with the NHANES (34 and 46 ml/min per 1.73 m²).

Conclusions

We demonstrate that hyperkalemia and metabolic acidosis are more common and occur at higher eGFR values in patients with SCD compared with age- and sex-matched African Americans, including in eGFR ranges considered to be normal. Future studies using redefined creatinine-based eGFR thresholds for abnormal kidney function may identify high-risk patients for earlier intervention strategies and referral for specialized renal care in SCD.

Finerenone in Predominantly Advanced CKD and Type 2 Diabetes With or Without Sodium-Glucose Cotransporter-2 Inhibitor Therapy

INTRODUCTION

FIDELIO-DKD (FInerenone in reducing kiDnEy faiLure and dIsease prOgression in Diabetic Kidney Disease) investigated the nonsteroidal, selective mineralocorticoid receptor (MR) antagonist finerenone in patients with CKD and type 2 diabetes (T2D). This analysis explores the impact of use of sodium-glucose cotransporter-2 inhibitor (SGLT-2i) on the treatment effect of finerenone.

METHODS

Patients (N = 5674) with T2D, urine albumin-to-creatinine ratio (UACR) of 30 to 5000 mg/g and estimated glomerular filtration rate (eGFR) of 25 to <75 ml/min per 1.73 m2 receiving optimized renin-angiotensin system (RAS) blockade were randomized to finerenone or placebo. Endpoints were change in UACR and a composite kidney outcome (time to kidney failure, sustained decrease in eGFR ≥40% from baseline, or renal death) and key secondary cardiovascular outcomes (time to cardiovascular death, nonfatal myocardial infarction, nonfatal stroke, or hospitalization for heart failure) (ClinicalTrials.gov, NCT02540993).

RESULTS

Of 5674 patients, 259 (4.6%) received an SGLT-2i at baseline. Reduction in UACR with finerenone was found with or without use of SGLT-2i at baseline, with ratio of least-squares means of 0.69 (95% CI = 0.66-0.71) and 0.75 (95% CI -= 0.62-0.90), respectively (P interaction = 0.31). Finerenone also significantly reduced the kidney and key secondary cardiovascular outcomes versus placebo; there was no clear difference in the results by SGLT-2i use at baseline (P interaction = 0.21 and 0.46, respectively) or at any time during the trial. Safety was balanced with or without SGLT-2i use at baseline, with fewer hyperkalemia events with finerenone in the SGLT-2i group (8.1% vs. 18.7% without).

CONCLUSION

UACR improvement was observed with finerenone in patients with CKD and T2D already receiving SGLT-2is at baseline, and benefits on kidney and cardiovascular outcomes appear consistent irrespective of use of SGLT-2i.

Medication Optimization for New Initiators of Empagliflozin for Diabetic Kidney Disease

Sodium-glucose cotransporter 2 (SGLT2) inhibitors are recommended agents for the treatment of diabetic kidney disease (DKD). Additionally, SGLT2 inhibitors lower blood glucose, decrease blood pressure, and can be useful for volume management. For these reasons, we hypothesized that initiating SGLT2 inhibitor therapy may be associated with deprescribing of other medications in patients with DKD. We compared medication lists at SGLT2 inhibitor initiation and 6 months post-initiation in 21 patients with DKD who were followed in our interprofessional outpatient nephrology clinic to evaluate deprescribing patterns in diabetes, hypertension, and diuretic medications. Six months of SGLT2 inhibitor therapy in patients with DKD was associated with deprescribing of high-risk diabetes agents, antihypertensives, and loop diuretics with minimal changes in A1C and fewer adverse events.

Prevalence of Metabolic Acidosis Among Patients with Chronic Kidney Disease and Hyperkalemia

INTRODUCTION

Although hyperkalemia and metabolic acidosis often co-occur in patients with chronic kidney disease (CKD), the prevalence of metabolic acidosis among patients with CKD and hyperkalemia is understudied. Therefore, we used medical record data from the Research Action for Health Network to estimate this prevalence.

METHODS

Adult patients with CKD stage 3-5, ≥ 1 outpatient potassium value > 5.0 mEq/l, and ≥ 1 outpatient bicarbonate value available were identified. Patients with end stage kidney disease (ESKD) in the prior year were excluded. The prevalence of metabolic acidosis in each calendar year from 2014 to 2017 among patients with CKD and hyperkalemia was estimated using two definitions of hyperkalemia (potassium > 5.0 mEq/l and > 5.5 mEq/l) and metabolic acidosis (bicarbonate < 18 mEq/l and < 22 mEq/l).

RESULTS

In the 2017 patient cohort and among patients with CKD and hyperkalemia, patients with metabolic acidosis were younger (69 versus 74 years), more likely to have advanced CKD (35% versus 13%), and use oral sodium bicarbonate (21% versus 4%) than patients without metabolic acidosis. The prevalence of metabolic acidosis (< 22 mEq/l) ranged from 25 to 29% when hyperkalemia was defined by potassium > 5.0 mEq/l and ranged from 33 to 39% when hyperkalemia was defined by potassium > 5.5 mEq/l.

CONCLUSION

Results demonstrated that prevalence estimates of metabolic acidosis varied based on the definition of hyperkalemia and metabolic acidosis utilized.

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.

Chronic kidney disease measures for cardiovascular risk prediction

Chronic kidney disease (CKD) affects 15-20% of adults globally and causes various complications, one of the most important being cardiovascular disease (CVD). CKD has been associated with many CVD subtypes, especially severe ones like heart failure, independent of potential confounders such as diabetes and hypertension. There is no consensus in major clinical guidelines as to how to incorporate the two key measures of CKD (glomerular filtration rate and albuminuria) for CVD risk prediction. This is a critical missed opportunity to appropriately refine predicted risk and personalize prevention therapies according to CKD status, particularly since these measures are often already evaluated in clinical care. In this review, we provide an overview of CKD definition and staging, the subtypes of CVD most associated with CKD, major pathophysiological mechanisms, and the current state of CKD as a predictor of CVD in major clinical guidelines. We will introduce the novel concept of a "CKD Add-on", which allows the incorporation of CKD measures in existing risk prediction models, and the implications of taking into account CKD in the management of CVD risk.

Binding Potassium to Improve Treatment With Renin-Angiotensin-Aldosterone System Inhibitors: Results From Multiple One-Stage Pairwise and Network Meta-Analyses of Clinical Trials

This manuscript presents findings from the first dichotomous data pooling analysis on clinical trials (CT) regarding the effectiveness of binding potassium. The results emanated from pairwise and network meta-analyses aiming evaluation of response to commercial potassium-binding polymers, that is, to achieve and maintain normal serum potassium (n = 1,722), and the association between this response and an optimal dosing of renin-angiotensin-aldosterone system inhibitors (RAASi) needing individuals affected by heart failure (HF) or resistant hypertension, who may be consuming other hyperkalemia-inducing drugs (HKID) (e.g., β-blockers, heparin, etc.), and frequently are affected by chronic kidney disease (CKD) (n = 1,044): According to the surface under the cumulative ranking area (SUCRA), sodium zirconium cyclosilicate (SZC) (SUCRA >0.78), patiromer (SUCRA >0.58) and sodium polystyrene sulfonate (SPS) (SUCRA <0.39) were different concerning their capacity to achieve normokalemia (serum potassium level (sK+) 3.5-5.0 mEq/L) or acceptable kalemia (sK+ ≤ 5.1 mEq/L) in individuals with hyperkalemia (sK+ >5.1 mEq/L), and, when normokalemia is achieved, patiromer 16.8-25.2 g/day (SUCRA = 0.94) and patiromer 8.4-16.8 g/day (SUCRA = 0.41) can allow to increase the dose of spironolactone up to 50 mg/day in subjects affected by heart failure (HF) or with resistant hypertension needing treatment with other RAASi. The potential of zirconium cyclosilicate should be explored further, as no data exists to assess properly its capacity to optimize dosing of RAASi, contrarily as it occurs with patiromer. More research is also necessary to discern between benefits of binding potassium among all type of hyperkalemic patients, for example, patients with DM who may need treatment for proteinuria, patients with early hypertension, etc. Systematic Review Registration:https://www.crd.york.ac.uk/PROSPERO/, identifier: CRD42020185614, CRD42020185558, CRD42020191430.

Randomized Trial on the Effects of Dietary Potassium on Blood Pressure and Serum Potassium Levels in Adults with Chronic Kidney Disease

In the general population, an increased potassium (K) intake lowers blood pressure (BP). The effects of K have not been well-studied in individuals with chronic kidney disease (CKD). This randomized feeding trial with a 2-period crossover design compared the effects of diets containing 100 and 40 mmol K/day on BP in 29 adults with stage 3 CKD and treated or untreated systolic BP (SBP) 120–159 mmHg and diastolic BP (DBP) <100 mmHg. The primary outcome was 24 h ambulatory systolic BP. The higher-versus lower-K diet had no significant effect on 24 h SBP (−2.12 mm Hg; p = 0.16) and DBP (−0.70 mm Hg; p = 0.44). Corresponding differences in clinic BP were −4.21 mm Hg for SBP (p = 0.054) and −0.08 mm Hg for DBP (p = 0.94). On the higher-K diet, mean serum K increased by 0.21 mmol/L (p = 0.003) compared to the lower-K diet; two participants had confirmed hyperkalemia (serum K ≥ 5.5 mmol/L). In conclusion, a higher dietary intake of K did not lower 24 h SBP, while clinic SBP reduction was of borderline statistical significance. Additional trials are warranted to understand the health effects of increased K intake in individuals with CKD.

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.

Management of Chronic Hyperkalemia in Patients With Chronic Kidney Disease: An Old Problem With News Options

Hyperkalemia is one of the main electrolyte disorders in patients with chronic kidney disease (CKD). The prevalence of hyperkalemia increases as the Glomerular Filtration Rate (GFR) declines. Although chronic hyperkalemia is not a medical emergency, it can have negative consequences for the adequate cardio-renal management in the medium and long term. Hyperkalemia is common in patients on renin-angiotensin-aldosterone system inhibitors (RAASi) or Mineralocorticoid Receptor Antagonists (MRAs) and can affect treatment optimization for hypertension, diabetes mellitus, heart failure (HF), and CKD. Mortality rates are higher with suboptimal dosing among patients with CKD, diabetes or HF compared with full RAASi dosing, and are the highest among patients who discontinue RAASis. The treatment of chronic hyperkalemia is still challenging. Therefore, in the real world, discontinuation or reduction of RAASi therapy may lead to adverse cardiorenal outcomes, and current guidelines differ with regard to recommendations on RAASi therapy to enhance cardio and reno-protective effects. Treatment options for hyperkalemia have not changed much since the introduction of the cation exchange resin over 50 years ago. Nowadays, two new potassium binders, Patiromer Sorbitex Calcium, and Sodium Zirconium Cyclosilicate (SZC) already approved by FDA and by the European Medicines Agency, have demonstrated their clinical efficacy in reducing serum potassium with a good safety profile. The use of the newer potassium binders may allow continuing and optimizing RAASi therapy in patients with hyperkalemia keeping the cardio-renal protective effect in patients with CKD and cardiovascular disease. However, further research is needed to address some questions related to potassium disorders (definition of chronic hyperkalemia, monitoring strategies, prediction score for hyperkalemia or length for treatment).

Practical guidance for the use of potassium binders in the management of hyperkalaemia in patients with heart failure and/or chronic kidney disease

Given the critical physiological role of potassium, it is understandable that the development of severe hyperkalaemia requires effective management to reduce its effects, which include muscle weakness, paralysis and cardiac arrhythmias. Hyperkalaemia most often results from the failure of renal adaptation to potassium imbalance. Patients who are most susceptible to the development of hyperkalaemia include those with chronic kidney disease and those with heart failure. These patients are often treated with renin-angiotensin-aldosterone system (RAAS) inhibitors, such as angiotensin-converting enzyme inhibitors and angiotensin II-receptor blockers, but the development of hyperkalaemia can require down-titration or cessation of RAAS inhibitors. This presents a significant challenge to nephrologists, cardiologists and healthcare professionals treating these patients as this can prevent them from receiving maximum guideline-directed RAAS inhibitor therapy. Panellists in this roundtable discussion shared their clinical experiences of using potassium binders to manage hyperkalaemia in patients with chronic kidney disease and patients with heart failure (illustrated with case studies) in Northern Ireland and considered recommendations for the implementation and maintenance of chronic potassium-lowering treatment.

Current Management of Hyperkalemia in Non-Dialysis CKD: Longitudinal Study of Patients Receiving Stable Nephrology Care

Background: No study has explored the limitations of current long-term management of hyperkalemia (HK) in outpatient CKD clinics. Methods: We evaluated the association between current therapeutic options and control of serum K (sK) during 12-month follow up in ND-CKD patients stratified in four groups by HK (sK ≥ 5.0 mEq/L) at baseline and month 12: Absent (no-no), Resolving (yes-no), New Onset (no-yes), Persistent (yes-yes). Results: We studied 562 patients (age 66.2 ± 14.5 y; 61% males; eGFR 39.8 ± 21.8 mL/min/1.73 m², RAASI 76.2%). HK was “absent” in 50.7%, “resolving” in 15.6%, “new onset” in 16.6%, and “persistent” in 17.1%. Twenty-four hour urinary measurements testified adherence to nutritional recommendations in the four groups at either visit. We detected increased prescription from baseline to month 12 of bicarbonate supplements (from 5.0 to 14.1%, p < 0.0001), K-binders (from 2.0 to 7.7%, p < 0.0001), and non-K sparing diuretics (from 34.3 to 41.5%, p < 0.001); these changes were consistent across groups. Similar results were obtained when using higher sK level (≥5.5 mEq/L) to stratify patients. Mixed-effects regression analysis showed that higher sK over time was associated with eGFR < 60, diabetes, lower serum bicarbonate, lower use of non-K sparing diuretics, bicarbonate supplementation, and K-binder use. Treatment-by-time interaction showed that sK decreased in HK patients given bicarbonate (p = 0.003) and K-binders (p = 0.005). Conclusions: This observational study discloses that one-third of ND-CKD patients under nephrology care remain with or develop HK during a 12-month period despite low K intake and increased use of sK-lowering drugs.

Prevalence and correlates of hyperkalemia in a renal nutrition clinic

Hyperkalemia (HK) is a frequent complication of chronic kidney disease (CKD). Vegetable-based renal diets are considered at risk due to the high potassium (K) content. The aim of this study was to describe the prevalence and correlates of chronic hyperkalemia (HK) in CKD patients on nutritional care, and in particular, the risk of HK in patients on plant-based versus animal-based low-protein diets. We recruited adult patients affected by CKD not on dialysis, afferent to our renal nutrition clinic from November 2014 to May 2019. We evaluated a total of 870 accesses in 219 patients (172 m, 47 f, age 67 ± 13 years). HK was defined as mild when K serum level was 5.1-5.9 mEq/l, moderate when K serum level was 6.0-6.9 mEq/l, and severe HK when K serum level was ≥ 7 mEq/l. Biochemical, anthropometric data and medications were recorded. The prevalence of HK in all the renal nutrition visits was 26.1%; all but six cases were mild HK, whereas no severe HK was observed. The prevalence of HK was associated with decreased eGFR, up to 36.5% for eGFR < 20 ml/min. Medications were similar in hyperkalemic and normokalemic patients, RAASi being present in up to 85% of patients. In a follow-up of 40 ± 14 months, no association was found between HK and mortality, whereas HK, at the start of follow-up, showed a trend to increased ESRD risk. Serum potassium levels and prevalence of HK were not different between patients on animal-based low-protein diet and plant-based low-protein diet. In conclusion, chronic HK is quite prevalent in a renal nutrition clinic, especially when eGFR falls down below 60 ml/min, thereby reaching the highest prevalence in CKD stage 4. Hyperkalemia is mostly mild, being moderate to severe HK quite infrequent. Hyperkalemia was not associated with higher risk of mortality, whereas a trend, although not statistically significant, was observed for lower ESRD-free survival. Plant-based low-protein diet is not associated with significant higher prevalence of HK with respect to animal-based LPD at the same residual kidney function.

Real-World Epidemiology of Potassium Derangements Among Chronic Cardiovascular, Metabolic and Renal Conditions: A Population-Based Analysis

BACKGROUND

The aims of the present analysis are to estimate the prevalence of five key chronic cardiovascular, metabolic and renal conditions at the population level, the prevalence of renin-angiotensin-aldosterone system inhibitor (RAASI) medication use and the magnitude of potassium (K+) derangements among RAASI users.

METHODS AND RESULTS

We used data from more than 375,000 individuals, 55 years of age or older, included in the population-based healthcare database of the Catalan Institute of Health between 2015 and 2017. The conditions of interest were chronic heart failure (CHF), chronic kidney disease (CKD), diabetes mellitus, ischemic heart disease and hypertension. RAASI medications included angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, mineralocorticoid receptor antagonists (MRAs) and renin inhibitors. Hyperkalemia was defined as K+ levels >5.0 mEq/L and hypokalemia as K+ <3.5 mEq/L. The prevalence of chronic cardiovascular, metabolic and renal conditions was high, and particularly that of hypertension (prevalence ranging from 48.2% to 48.9%). The use of at least one RAASI medication was almost ubiquitous in these patients (75.2-77.3%). Among RAASI users, the frequency of K+ derangements, mainly of hyperkalemia, was very noticeable (12% overall), particularly in patients with CKD or CHF, elderly individuals and users of MRAs. Hypokalemia was less frequent (1%).

CONCLUSION

The high prevalence of K+ derangements, and particularly hyperkalemia, among RAASI users highlights the real-world relevance of K+ derangements, and the importance of close monitoring and management of K+ levels in routine clinical practice. This is likely to benefit a large number of patients, particularly those at higher risk.

Impact on clinical outcomes and health costs of deranged potassium levels in patients with chronic cardiovascular, metabolic, and renal conditions

INTRODUCTION AND OBJECTIVES

Potassium derangements are frequent among patients with chronic cardiovascular conditions. Studies on the associations between potassium derangements and clinical outcomes have yielded mixed findings, and the implications for health care expenditure are unknown. We assessed the population-based associations between hyperkalemia, hypokalemia and clinical outcomes and health care costs, in patients with chronic heart failure, chronic kidney disease, diabetes mellitus, hypertension, and ischemic heart disease.

METHODS

Population-based, longitudinal study including up to 36 269 patients from a health care area with at least one of the above-mentioned conditions. We used administrative, hospital and primary care databases. Participants were followed up between 2015 and 2017, were aged ≥ 55 years and had at least 1 potassium measurement. Four analytic designs were used to evaluate prevalent and incident cases and the use of renin-angiotensin-aldosterone system inhibitors.

RESULTS

Hyperkalemia was twice as frequent as hypokalemia. On multivariable-adjusted analyses, hyperkalemia was robustly and significantly associated with an increased risk of all-cause death (HR from Cox regression models ranging from 1.31-1.68) and with an increased odds of a yearly health care expenditure >85th percentile (OR, 1.21-1.29). Associations were even stronger in hypokalemic patients (HR for all-cause death, 1.92-2.60; OR for health care expenditure> percentile 85th, 1.81-1.85).

CONCLUSIONS

Experimental studies are needed to confirm whether the prevention of potassium derangements reduces mortality and health care expenditure in these chronic conditions. Until then, our findings provide observational evidence on the potential importance of maintaining normal potassium levels.

Plant-based diets to manage the risks and complications of chronic kidney disease

Traditional dietary recommendations for patients with chronic kidney disease (CKD) focus on the quantity of nutrients consumed. Without appropriate dietary counselling, these restrictions can result in a low intake of fruits and vegetables and a lack of diversity in the diet. Plant nutrients and plant-based diets could have beneficial effects in patients with CKD: increased fibre intake shifts the gut microbiota towards reduced production of uraemic toxins; plant fats, particularly olive oil, have anti-atherogenic effects; plant anions might mitigate metabolic acidosis and slow CKD progression; and as plant phosphorus has a lower bioavailability than animal phosphorus, plant-based diets might enable better control of hyperphosphataemia. Current evidence suggests that promoting the adoption of plant-based diets has few risks but potential benefits for the primary prevention of CKD, as well as for delaying progression in patients with CKD G3-5. These diets might also help to manage and prevent some of the symptoms and metabolic complications of CKD. We suggest that restriction of plant foods as a strategy to prevent hyperkalaemia or undernutrition should be individualized to avoid depriving patients with CKD of these potential beneficial effects of plant-based diets. However, research is needed to address knowledge gaps, particularly regarding the relevance and extent of diet-induced hyperkalaemia in patients undergoing dialysis.

Cost-analysis of persistent hyperkalaemia in non-dialysis chronic kidney disease patients under nephrology care in Italy

AIM

In patients with chronic kidney disease (CKD), hyperkalaemia (HK) (potassium level ≥ 5.0 mEq/L) is associated with poor clinical outcomes. This study provides novel insights by comparing management costs of CKD patients with normokalaemia vs those with persistent HK regularly followed in renal clinics in Italy.

METHODS

To this aim, a Markov model over life-time horizon was developed. Time to end-stage renal disease (ESRD) and time to death in CKD patients were derived from an observational multi-centre database including 1665 patients with non-dialysis CKD stage 1-5 under nephrology care in Italy (15 years follow-up). Resource use for CKD and HK management was obtained from the observational database, KDIGO international guidelines, and clinical expert opinion.

RESULTS

Results showed that patients with normokalaemia vs persistent HK brought an average per patient lifetime cost-saving of €16 059 besides delayed onset of ESRD by 2.29 years and increased survival by 1.79 years with increment in total survival and dialysis-free survival in normokalaemia that decreased from early to advanced disease. Cost-saving related to normokalaemia increased at more advanced CKD; however, it was already evident at early stage (3388.97€ at stage 1-3a). OWSA confirmed cost-saving associated with normokalaemia across all parameter variations.

DISCUSSION AND CONCLUSION

This model is the first to simulate the impact of HK in non-dialysis CKD patients on economic and clinical outcomes using real-world data from nephrology clinics. In these patients, persistent HK results into higher lifetime costs, besides poorer clinical outcomes, that are evident since the early stages of CKD. Maintaining normokalaemia should therefore be of main concern in CKD treatment planning to improve long-term economic and clinical outcomes.

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.

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.

New mineralocorticoid receptor antagonists: update on their use in chronic kidney disease and heart failure

Aldosterone is a mineralocorticoid hormone with a well-known effect on the renal tubule leading to water retention and potassium reabsorption. Other major effects of the hormone include the induction of proinflammatory activity that leads to progressive fibrotic damage of the target organs, heart and kidney. Blocking the aldosterone receptor therefore represents an important pharmacological strategy to avoid the clinical conditions deriving from heart failure (CHF) and chronic kidney disease (CKD). However, steroidal mineralocorticoid receptor antagonists (MRA) have a low safety profile, especially in CKD patients due to the high incidence of hyperkalemia. A new generation of nonsteroidal MRA has recently been developed to obtain a selective receptor block avoiding side-effects like hyperkalemia and thereby making the drugs suitable for administration to CKD patients. This review summarizes the results of published preclinical and clinical studies on the nonsteroidal MRA, apararenone esaxerenone and finerenone. The trials showed a better safety profile with maintained drug efficacy compared with steroidal MRA. For this reason, nonsteroidal MRA represent an interesting new therapeutic approach for the prevention of CHF and CKD progression. Some basic research findings also yielded interesting results in acute clinical settings such as myocardial infarction and acute kidney injury.

Efficacy and safety of the pharmacotherapy used in the management of hyperkalemia: a systematic review

BACKGROUND

Although the management of hyperkalemia follows expert guidelines, treatment approaches are based on traditionally accepted practice standards. New drugs have been assessed such as sodium zirconium cyclosilicate and patiromer; however, their safety and efficacy or effectiveness have not yet been compared to traditional pharmacotherapy.

OBJECTIVE

The present systematic review had the purpose to evaluate the efficacy, effectiveness, and safety of hyperkalemia pharmacotherapies.

METHODS

PubMed, LILACS, Cochrane Library, and ClinicalTrials were searched through November 2018. Clinical trial, cohort and case-control were searched. The risk of bias (RoB v2.0 and ROBINS-I) and quality of evidence (GRADE) at the level of outcomes were assessed.

RESULTS

Sixteen clinical trials and one retrospective cohort were identified regarding efficacy and safety of 24 different alternatives. The management of hyperkalemia remains empirical and off-label, since sodium zirconium cyclosilicate and patiromer are not available in several countries and further studies are required to assess efficacy, effectiveness and safety. Sodium or calcium polystyrene sulfonate (moderate confidence), sodium zirconium cyclosilicate (moderate confidence), and insulin plus dextrose (moderate confidence) showed superior efficacy to, respectively, placebo, no treatment, placebo, and dextrose. Other therapies (low confidence) showed similar efficacy compared to active or inactive alternatives. Most of the adverse events reported were nonspecific, so it was not possible to assign the cause and to classify as defined or probable.

CONCLUSIONS

Comparative cohort and case-control studies are need to evaluate the safety and effectiveness of new and traditional pharmacotherapies to support the development of guidelines about acute and chronic hyperkalemia, with high-quality evidence.

Competing-Risk Analysis of Death and End Stage Kidney Disease by Hyperkalaemia Status in Non-Dialysis Chronic Kidney Disease Patients Receiving Stable Nephrology Care

Hyperkalaemia burden in non-dialysis chronic kidney disease (CKD) under nephrology care is undefined. We prospectively followed 2443 patients with two visits (referral and control with 12-month interval) in 46 nephrology clinics. Patients were stratified in four categories of hyperkalaemia (serum potassium, sK ≥ 5.0 mEq/L) by sK at visit 1 and 2: Absent (no-no), Resolving (yes-no), New Onset (no-yes), Persistent (yes-yes). We assessed competing risks of end stage kidney disease (ESKD) and death after visit 2. Age was 65 ± 15 years, eGFR 35 ± 17 mL/min/1.73 m², proteinuria 0.40 (0.14–1.21) g/24 h. In the two visits sK was 4.8 ± 0.6 and levels ≥6 mEq/L were observed in 4%. Hyperkalaemia was absent in 46%, resolving 17%, new onset 15% and persistent 22%. Renin-angiotensin-system inhibitors (RASI) were prescribed in 79% patients. During 3.6-year follow-up, 567 patients reached ESKD and 349 died. Multivariable competing risk analysis (sub-hazard ratio-sHR, 95% Confidence Interval-CI) evidenced that new onset (sHR 1.34, 95% CI 1.05–1.72) and persistent (sHR 1.27, 95% CI 1.02–1.58) hyperkalaemia predicted higher ESKD risk versus absent, independently from main determinants of outcome including eGFR change. Conversely, no effect on mortality was observed. Results were confirmed by testing sK as continuous variable. Therefore, in CKD under nephrology care, mild-to-moderate hyperkalaemia status is common (37%) and predicts per se higher ESKD risk but not mortality.