Prevalence and economic burden of hyperkalemia in the United States Medicare population

Potassium-Based Sodium Substitutes Impact the Sodium and Potassium Content of Foods

OBJECTIVE

Potassium-based sodium substitutes (PBSS) can be used to replace sodium during food processing. How potassium and sodium content is associated with PBSS is not known. The objectives of the study were to describe the prevalence of PBSS by sodium content claim category and describe how PBSS are associated with sodium and potassium concentrations by sodium level.

DESIGN AND METHODS

This cross-sectional analysis used the July 2018 version of the United States Department of Agriculture's Branded Food Products Database. Products were divided into sodium content claim category and were analyzed for the presence of PBSS. Products with nonmissing values for sodium and potassium were grouped by sodium level and analyzed for the prevalence of PBSS to explore potassium and sodium concentration. Column proportion z-test with the Bonferroni correction was used to explore the occurrence of PBSS by sodium content claim category. Mann-Whitney U-test was used to assess differences in potassium and sodium concentrations across sodium levels and within levels by the presence/absence of PBSS.

RESULTS

The prevalence of PBSS in the categories "without a sodium content claim" (2.4%), "lightly salted" (0.5%), and "unsalted" claims (0.6%) were statistically significantly lower than prevalence of PBSS in the "sodium free" (9.5%), "low sodium" (10.3%), and "reduced sodium" claim categories (23.3%; all P < .01). Among the group of products with serving sizes more than 30 g containing PBSS, there was a 357 mg per serving higher median sodium concentration and a 160 mg per serving higher median potassium concentration compared to the group without PBSS (both P < .01).

CONCLUSION

In the "reduced sodium" claim category, a higher prevalence of PBSS was found compared to other sodium claim categories. The presence of PBSS was associated with higher potassium and sodium concentrations in foods.

Hyperkalemia Recurrence Following Medical Nutrition Therapy in Patients with Stage 3-4 Chronic Kidney Disease: The REVOLUTIONIZE I Real-World Study

INTRODUCTION

The REVOLUTIONIZE I study aimed to characterize the relationships between medical nutrition therapy (MNT) and hyperkalemia recurrence in patients with stage 3-4 chronic kidney disease (CKD) and hyperkalemia who received MNT in real-world clinical practice.

METHODS

This observational cohort study used de-identified electronic health record data from patients aged ≥ 18 years with stage 3-4 CKD who received MNT between January 2019 and October 2022 and had hyperkalemia (serum potassium > 5.0 mmol/L) within 30 days before MNT. Patients were followed for 6 months or until the first censoring event (death, prescription of outpatient potassium binder, or study end). The primary outcome was the percentage of patients with ≥ 1 hyperkalemia recurrence during follow-up. Secondary outcomes included the number of hyperkalemia recurrences per patient, time to each recurrence, and hyperkalemia-related healthcare resource utilization. Exploratory outcomes included all-cause healthcare resource utilization and mortality.

RESULTS

The final cohort comprised 2048 patients; 1503 (73.4%) patients remained uncensored after 6 months. During the 6-month follow-up period, 56.0% of patients had ≥ 1 hyperkalemia recurrence and 37.4% had ≥ 1 recurrence within the first month. Patients with ≥ 1 hyperkalemia recurrence during follow-up had a mean ± standard deviation (SD) of 2.6 ± 2.2 recurrences. The mean ± SD time to first hyperkalemia recurrence was 45 ± 46 days; the time between recurrences decreased with subsequent episodes. Hyperkalemia-related hospitalizations and emergency department visits were recorded for 13.7% and 1.5% of patients, respectively. Sensitivity analyses showed that results were consistent across patient subgroups, including those with comorbid heart failure and patients receiving renin-angiotensin-aldosterone system inhibitor therapy at baseline.

CONCLUSION

Most patients with stage 3-4 CKD had hyperkalemia recurrence, and MNT alone was inadequate to prevent recurrence. These patients may require additional long-term treatment, such as novel potassium binders, to maintain normokalemia and prevent hyperkalemia recurrence following MNT. Infographic available for this article. INFOGRAPHIC.

Acquired hyperkalaemia leading to periodic paralysis: an emergency department perspective

Hyperkalaemia is one of the common electrolyte imbalances dealt with in the emergency department and is caused by extracellular accumulation of potassium ions above normal limits usually greater than 5.0-5.5 mmol/L. It is found in a total of 1-10% of hospitalised patients usually associated with chronic kidney disease and heart failure. The presentation can range from being asymptomatic to deadly arrhythmias. The appearance of symptoms depends on the rate of change rather than just the numerical values. The rare presentation includes periodic paralysis characterised by the sudden onset of short-term muscle weakness, stiffness or paralysis. Management goals are directed towards reducing potassium levels in emergency settings and later on avoiding the triggers for future attacks. In this case, we present a man in his 50s with the generalised weakness later on diagnosed as hyperkalaemic periodic paralysis secondary to tumour lysis syndrome. Emergency physicians dealing with common electrolyte imbalances should keep a sharp eye on their rare presentation and their precipitating factors and should act accordingly.

Epidemiology and risk factors for hyperkalaemia in heart failure

Patients with heart failure (HF), particularly those with impaired renal function receiving renin-angiotensin-aldosterone system inhibitors (RAASis), are at risk of hyperkalaemia; when hyperkalaemia is severe, this can have serious clinical consequences. The incidence, prevalence, and risk factors for hyperkalaemia reported in randomized trials of RAASis may not reflect clinical practice due to exclusion of patients with elevated serum potassium (sK+ ) or severe renal impairment: information on patients managed in routine clinical care is important to understanding the actual burden of hyperkalaemia. This paper reviews the available clinical epidemiology data on hyperkalaemia in HF and considers areas requiring further research. Observational studies published since 2017 that focused on hyperkalaemia, included patients with HF, and had ≥1000 participants were considered. Hyperkalaemia occurrence in HF varied widely from 7% to 39% depending on the setting, HF severity, follow-up length, and concomitant medications. Rates were lowest in patients with newly diagnosed HF and highest in patients with greater disease severity; comorbidities, such as chronic kidney disease and diabetes, and RAASi use, reflected commonly identified risk factors for hyperkalaemia in patients with HF. Hyperkalaemia was most often mild; however, from the limited data available, persistence of mild hyperkalaemia was associated with an increased risk of mortality and major adverse cardiovascular events. There were also limited data available on the progression of hyperkalaemia. Recurrence was common, occurring in one-quarter to two-fifths of hyperkalaemia cases. Despite HF guidelines recommending close monitoring of sK+ , 55-93% of patients did not receive appropriate testing before or after initiation of RAASi or in follow-up to moderate/severe hyperkalaemia detection. Many of the observational studies were retrospective and from a single country. There is a need for international, prospective, longitudinal, observational studies, such as the CARE-HK in HF study (NCT04864795), to understand hyperkalaemia's prevalence, incidence, and severity; to identify and characterize cases that persist, progress, and recur; to highlight the importance of sK+ monitoring when using RAASi; and to assess the impact of newer HF therapies and potassium binders in clinical practice. Data from both clinical trials and observational studies with adjustments for confounding variables will be needed to assess the contribution of hyperkalaemia to clinical outcomes.

Dietary Sodium Reduction Is Best for Reducing Blood Pressure: Controversies in Hypertension

The global burden of cardiovascular disease (CVD) continues to grow, as does the incidence of hypertension, one of the most important modifiable risk factors of CVD. Non-pharmacologic, population level interventions are critically needed to halt the hypertension pandemic, but there is an ongoing debate as to whether public policy efforts should focus more on dietary sodium reduction or increasing potassium. In this commentary, we summarize arguments in favor of policy geared towards reduced sodium intake. Recognizing increasing dietary sodium as one of the drivers of the hypertension pandemic is critical to developing public policy to reduce population level sodium exposure and blood pressure. We draw from a robust field of evidence to show that reducing sodium intake improves blood pressure in a linear fashion, across the lifespan, at an individual level and a population level, and may even reduce CVD events. While potassium plays an important role in blood pressure regulation, potassium interventions are less effective at reducing blood pressure, carry risk of hyperkalemia in select populations, and are more logistically challenging. There is an urgent need for nation-wide policies to reduce sodium intake to help stem the hypertension pandemic and prevent CVD.

Effect of low sodium and high potassium diet on lowering blood pressure and cardiovascular events

Incorporating aggressive lifestyle modifications along with antihypertensive medication therapy is a crucial treatment strategy to enhance the control rate of hypertension. Dietary modification is one of the important lifestyle interventions for hypertension, and it has been proven to have a clear effect. Among food ingredients, sodium and potassium have been found to have the strongest association with blood pressure. The blood pressure-lowering effect of a low sodium diet and a high potassium diet has been well established, especially in hypertensive population. A high intake of potassium, a key component of the Dietary Approaches to Stop Hypertension (DASH) diet, has also shown a favorable impact on the risk of cardiovascular events. Additionally, research conducted with robust measurement methods has shown cardiovascular benefits of low-sodium intake. In this review, we aim to discuss the evidence regarding the relationship between the low sodium and high potassium diet and blood pressure and cardiovascular events.

Evaluation of longer- vs short-term use of patiromer on health care resource utilization in the patiromer longer-term use evaluation (VALUE) study

BACKGROUND

Studies suggest that continuous long-term use of patiromer by patients with hyperkalemia is associated with less health care resource utilization compared with not using potassium binders.

OBJECTIVE

To retrospectively evaluate health care resource utilization and costs with longer-term adherent vs short-term use of patiromer.

METHODS

Time-restricted extracts from Optum's de-identified Clinformatics® Data Mart Database (CDM; January 2016-May 2019) and Symphony Health (SHA; January 2016-September 2018) deidentified databases were analyzed. Both include participants enrolled in commercial and privatized public insurance programs (SHA includes some government programs). Both integrate health care claims data from medical and pharmacy claims. Patients aged 18 years or older with hyperkalemia and an index patiromer prescription were selected. Patiromer use was identified as short-term (<2 months) and any fill quantity or adherent longer-term with claims for at least 2 consecutive months and fill quantities of at least 80% of the total days. Groups were matched on multiple categorical covariates to control for demographic variables, baseline characteristics, and markers of disease severity. Random sampling without replacement was performed 50 times to identify 50 sets of patients matched from the short-term cohort to the longer-term cohort. Health care costs/charges and encounters were compared for a 6-month post-index period using t-tests.

RESULTS

Of the CDM patients, 1,267 (40.2%) vs 1,887 (59.8%) and of the SHA patients, 2,234 (35.1%) vs 4,132 (64.9%) experienced longer-term vs short-term patiromer use, respectively. Patient sampling selected 242 and 485 patient-matched pairs from CDM and SHA databases, respectively. At 6 months post-index in longer-term vs short-term patiromer groups (P < 0.0001 for all differences shown), respective mean medical and prescription costs/charges were $42,000 vs $54,311 (-$12,311) and $6,816 vs $4,786 (+$2,030), respectively, for CDM patients and $75,147 vs $84,414 (-$9,267) and $4,689 vs $3,736 (+$953) for SHA patients. In the CDM database, medical costs were lower for longer-term vs short-term cohorts for end-stage renal disease services charges ($10,342 vs $14,976 [-$4,634]), inpatient charges ($15,789 vs $21,473 [-$5,684]), and office visit charges ($10,152 vs $13,152 [-$3,000]). Patient out-of-pocket costs ($658 vs $420 [+$238]) and total prescription charges ($6,158 vs $4,366 [+$1,792]) were higher for the longer-term cohort of CDM patients, with similar findings in the SHA dataset.

CONCLUSIONS

Adherent, longer-term use of patiromer is associated with significantly lower medical costs offsetting higher prescription costs, driven by the largest changes in inpatient and clinic services at CDM and SHA, respectively. This illustrates an economic value of longer-term adherence to patiromer.

Exploring kidney dialysis costs in the United States: a scoping review

AIMS

The increasing prevalence of end-stage renal disease (ESRD) in the United States (US) represents a considerable economic burden due to the high cost of dialysis treatment. This review examines data from real-world studies to identify cost drivers and explore areas where dialysis costs could be reduced.

METHODS

We identified and synthesized evidence published from 2016-2023 reporting direct dialysis costs in adult US patients from a comprehensive literature search of MEDLINE, Embase, and grey literature sources (e.g. US Renal Data System reports).

RESULTS

Most identified data related to Medicare expenditures. Overall Medicare spending in 2020 was $29B for hemodialysis and $2.8B for peritoneal dialysis (PD). Dialysis costs accounted for almost 80% of total Medicare expenditures on ESRD beneficiaries. Private insurance payers consistently pay more for dialysis; for example, per person per month spending by private insurers on outpatient dialysis was estimated at $10,149 compared with Medicare spending of $3,364. Dialysis costs were higher in specific high-risk patient groups (e.g. type 2 diabetes, hepatitis C). Spending on hemodialysis was higher than on PD, but the gap in spending between PD and hemodialysis is closing. Vascular access costs accounted for a substantial proportion of dialysis costs.

LIMITATIONS

Insufficient detail in the identified studies, especially related to outpatient costs, limits opportunities to identify key drivers. Differences between the studies in methods of measuring dialysis costs make generalization of these results difficult.

CONCLUSIONS

These findings indicate that prevention of or delay in progression to ESRD could have considerable cost savings for Medicare and private payers, particularly in patients with high-risk conditions such as type 2 diabetes. More efficient use of resources is needed, including low-cost medication, to improve clinical outcomes and lower overall costs, especially in high-risk groups. Widening access to PD where it is safe and appropriate may help to reduce dialysis costs.

Impact of Sodium Zirconium Cyclosilicate Plus Renin-Angiotensin-Aldosterone System Inhibitor Therapy on Short-Term Medical Costs in Hyperkalemia: OPTIMIZE II Real-World Study

INTRODUCTION

Patients receiving cardiorenal-protective renin-angiotensin-aldosterone system inhibitors (RAASis) are at increased risk of developing hyperkalemia, which is associated with increased medical costs. The aim of this study was to evaluate the impact of adding sodium zirconium cyclosilicate (SZC) therapy on 3-month medical costs in patients who experienced hyperkalemia while receiving RAASi therapy.

METHODS

The retrospective OPTIMIZE II study used medical and pharmacy claims data from IQVIA PharMetrics® Plus. Patients aged ≥ 18 years who received SZC (≥ 60 day supply over 3 months' follow-up) and continued RAASi between July 2019 and December 2021 (Continue RAASi + SZC cohort) were 1:1 exact and propensity score matched with patients who discontinued RAASi after hyperkalemia diagnosis and did not receive SZC (Discontinue RAASi + no SZC cohort). The primary outcome was hyperkalemia-related medical costs to payers over 3 months; all-cause medical and pharmacy costs were also analyzed.

RESULTS

In the Continue RAASi + SZC (n = 467) versus Discontinue RAASi + no SZC (n = 467) cohort, there were significant reductions in mean per-patient hyperkalemia-related medical costs (reduction of $2216.07; p = 0.01) and all-cause medical costs (reduction of $6102.43; p < 0.001); mean hyperkalemia-related inpatient medical costs and all-cause inpatient and emergency department medical costs were significantly reduced. The reduction in all-cause medical cost in the Continue RAASi + SZC cohort offset an increase in the mean per-patient all-cause pharmacy cost (increase of $3117.71; p < 0.001).

CONCLUSION

RAASi therapy has well-established cardiorenal benefits. In OPTIMIZE II, management of RAASi-induced hyperkalemia with SZC was associated with lower hyperkalemia-related and all-cause medical costs than RAASi discontinuation without SZC, demonstrating medical cost savings with maintaining RAASi therapy with SZC.

Medical Costs in Patients with Hyperkalemia on Long-Term Sodium Zirconium Cyclosilicate Therapy: The RECOGNIZE II Study

Purpose

Hyperkalemia, defined as abnormally high serum potassium levels of ≥5.1 mmol/L, is associated with increased medical costs. This real-world study evaluated the impact of long-term sodium zirconium cyclosilicate (SZC) therapy on medical costs in patients with hyperkalemia.

Patients and Methods

This retrospective, comparative study used claims data from IQVIA PharMetrics® Plus. Patients aged ≥18 years with hyperkalemia who had outpatient SZC fills (>3-month supply over 6 months) between July 2019 and December 2021 and continuous insurance coverage 6 months before and 6 months after the first SZC fill were included. These patients (SZC cohort) were 1:1 exact- and propensity score-matched on baseline variables with patients with hyperkalemia who did not receive SZC (non-SZC cohort). The primary endpoint was hyperkalemia-related medical costs to payers over 6 months.

Results

Each cohort included 661 matched patients. Mean per-patient hyperkalemia-related medical costs were reduced by 49.5% ($3728.47) for the SZC versus non-SZC cohort ($3798.04 vs $7526.51; P<0.001), whereas mean all-cause medical costs were reduced by 21.0% ($5492.20; $20,722.23 vs $26,214.43; P<0.01). A 39.8% ($3621.03) increase in all-cause pharmacy costs ($12,727.20 vs $9106.17; P<0.01) was offset by the medical cost savings.

Conclusion

This study demonstrated that long-term (>3 months) outpatient treatment with SZC was associated with medical cost savings compared with no SZC therapy.

Admission plasma potassium and length of hospital stay: a meta-analysis

OBJECTIVE

Hypokalaemia and hyperkalaemia ('dyskalaemia') are commonly seen in patients requiring emergency hospital admission. The adverse effect of dyskalaemia on mortality is well described but there are few data for the effect on hospital length of stay. We sought to determine the association of serum potassium concentration with in-hospital length of stay.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

A structured search of MEDLINE, PubMed and SCOPUS databases to 19 March 2021.

ELIGIBILITY CRITERIA

Observational cohort studies defining exposure of interest as serum potassium levels (at admission or within the first 72 hours) and with outcome of interest as length of hospital stay. Studies had to provide estimates of length of stay as a comparison between normokalaemia and defined ranges of hyperkalaemia or hypokalaemia.

DATA EXTRACTION AND SYNTHESIS

We identified 39 articles published to March 2021 that met the inclusion and exclusion criteria. Study selection, data extraction and quality assessment were carried out by two reviewers working independently and in duplicate, to assessed eligibility and risk of bias, and extract data from eligible studies. Random effects models were used to pool estimates across the included studies. Meta-analyses were performed using Cochrane-RevMan.

RESULTS

Five studies were included in the meta-analysis. Compared with the reference group (3.5-5.0 mmol/L), the pooled raw differences of medians were 4.45 (95% CI 2.71 to 6.91), 1.99 (95% CI 0.03 to 3.94), 0.98 (95% CI 0.91 to 1.05), 1.51 (95% CI 1.03 to 2.0), 1 (95% CI 0.75 to 1.25) and 2.76 (95% CI 1.24 to 4.29) for patients with potassium levels of <2.5, 2.5 to <3.0, 3.0 to <3.5, <5 to 5.5, <5.5 to 6 and >6.0 mmol/L, respectively.

CONCLUSION

Hospital length of stay follows a U-shaped distribution, with duration of admission being twofold greater at the extremes of the potassium range.

Rationale and design of CONTINUITY: a Phase 4 randomized controlled trial of continued post-discharge sodium zirconium cyclosilicate treatment versus standard of care for hyperkalemia in chronic kidney disease

Background

Individuals with chronic kidney disease (CKD) hospitalized with hyperkalemia are at risk of hyperkalemia recurrence and re-hospitalization. We present the rationale and design of CONTINUITY, a study to examine the efficacy of continuing sodium zirconium cyclosilicate (SZC)-an oral, highly selective potassium (K⁺) binder-compared with standard of care (SoC) on maintaining normokalemia and reducing re-hospitalization and resource utilization among participants with CKD hospitalized with hyperkalemia.

Methods

This Phase 4, randomized, open-label, multicenter study will enroll adults with Stage 3b-5 CKD and/or estimated glomerular filtration rate <45 mL/min/1.73 m², within 3 months of eligibility screening, hospitalized with a serum potassium (sK⁺) level of >5.0-≤6.5 mmol/L, without ongoing K⁺ binder treatment. The study will include an in-hospital phase, where participants receive SZC for 2-21 days, and an outpatient (post-discharge) phase. At discharge, participants with sK⁺ 3.5-5.0 mmol/L will be randomized (1:1) to SZC or SoC and monitored for 180 days. The primary endpoint is the occurrence of normokalemia at 180 days. Secondary outcomes include incidence and number of hospital admissions or emergency department visits both with hyperkalemia as a contributing factor, and renin-angiotensin-aldosterone system inhibitor down-titration. The safety and tolerability of SZC will be evaluated.Ethics approval has been received from all relevant ethics committees. Enrollment started March 2022 and the estimated study end date is December 2023.

Conclusions

This study will assess the potential of SZC versus SoC in managing people with CKD and hyperkalemia post-discharge.

Trial registration

ClinicalTrials.gov identifier: NCT05347693; EudraCT: 2021-003527-14, registered on 19 October 2021.

Predicting hyperkalemia in patients with advanced chronic kidney disease using the XGBoost model

BACKGROUND

Hyperkalemia is a common complication of chronic kidney disease (CKD). Hyperkalemia is associated with mortality, CKD progression, hospitalization, and high healthcare costs in patients with CKD. We developed a machine learning model to predict hyperkalemia in patients with advanced CKD at an outpatient clinic.

METHODS

This retrospective study included 1,965 advanced CKD patients between January 1, 2010, and December 31, 2020 in Taiwan. We randomly divided all patients into the training (75%) and testing (25%) datasets. The primary outcome was to predict hyperkalemia (K⁺ > 5.5 mEq/L) in the next clinic vist. Two nephrologists were enrolled in a human-machine competition. The area under the receiver operating characteristic curves (AUCs), sensitivity, specificity, and accuracy were used to evaluate the performance of XGBoost and conventional logistic regression models with that of these physicians.

RESULTS

In a human-machine competition of hyperkalemia prediction, the AUC, PPV, and accuracy of the XGBoost model were 0.867 (95% confidence interval: 0.840-0.894), 0.700, and 0.933, which was significantly better than that of our clinicians. There were four variables that were chosen as high-ranking variables in XGBoost and logistic regression models, including hemoglobin, the serum potassium level in the previous visit, angiotensin receptor blocker use, and calcium polystyrene sulfonate use.

CONCLUSIONS

The XGBoost model provided better predictive performance for hyperkalemia than physicians at the outpatient clinic.

The Increased Clinical and Economic Burden of Hyperkalemia in Medicare Patients Admitted to Long-Term Care Settings

INTRODUCTION

Older patients are at increased risk for hyperkalemia (HK). This study describes the prevalence, recurrence, and clinical and economic burden of HK in Medicare patients admitted to a long-term care (LTC) setting.

METHODS

Retrospective cohort study using 100% Medicare Fee-for-Service (FFS) claims identified patients aged ≥ 65 years with index admission between 2017 and 2019 to a LTC setting (skilled nursing, home health, inpatient rehabilitation, or long-term acute care). Beneficiaries were required to have 12 months continuous medical and pharmacy coverage prior to index LTC admission and ≥ 30 days after LTC discharge (follow-up). Patient characteristics, healthcare resource utilization, and costs were assessed. HK was defined as ICD-10 diagnosis code E87.5 in any claim position or Medicare Part D fill for oral potassium binder.

RESULTS

Of 4,562,231 patients with a LTC stay, the prevalence of HK was 14.7% over the full study period (pre-index, index stay, and follow-up). Excluding those with HK only during the follow-up period resulted in 4,081,103 patients. Of these, 290,567 (7.1%) had HK and 3,790,536 (92.9%) did not have HK during or within 14 days prior to index LTC stay. The HK recurrence rate during index stay and follow-up was 48.3%. Unmatched HK versus non-HK patients were more often male (43.0% vs. 35.4%), Black (13.5% vs. 8.0%), dual eligible for Medicaid (34.2% vs. 25.0%), with higher mean Charlson Comorbidity Index scores (6.2 vs. 3.9) (all p < 0.0001). After propensity matching, HK patients were 2.2 times more likely to be hospitalized, with higher mortality (30.8% vs. 21.5%) and higher total healthcare costs during both index stay (US$26,520 vs. $18,021; p < 0.0011) and follow-up ($57,948 vs. $41,744 (p < 0.0011) versus matched non-HK patients.

CONCLUSION

Prevalence and recurrence of HK was high among LTC patients, and HK was associated with significantly greater clinical and economic burden during and post-LTC.

Impact on hospitalizations of long-term versus short-term therapy with sodium zirconium cyclosilicate during routine outpatient care of patients with hyperkalemia: the recognize I study

BACKGROUND

Hyperkalemia is associated with increased healthcare resource utilization (HRU). This study evaluated the impact of sodium zirconium cyclosilicate (SZC) use on HRU in outpatients with hyperkalemia.

RESEARCH DESIGN AND METHODS

A retrospective noncomparative study using claims data from the HealthVerity warehouse, which included outpatients in the United States who initiated SZC between January and December 2019 (index date) with ≥6 months' continuous coverage before (baseline) and after (follow-up) the index date (total coverage of 12 months). The study aimed to describe HRU with long-term and short-term SZC (defined as >90 and ≤90 days' supply, respectively, during 180 days' follow-up) and identify characteristics associated with long-term versus short-term therapy.

RESULTS

Of 1153 patients, 748 (64.9%) received short-term and 405 (35.1%) received long-term therapy. During follow-up, lower proportions of patients on long-term versus short-term therapy had hyperkalemia-related hospitalizations (10.1% vs 15.1%; P < 0.05) and all-cause hospitalizations (22.5% vs 29.3%; P < 0.05). Hyperkalemia-related and all-cause hospitalization proportions were 33.0% and 23.3% lower, respectively. Predictors of long-term therapy included stage 3 chronic kidney disease.

CONCLUSIONS

Approximately one-third of patients with hyperkalemia received long-term SZC therapy. Hyperkalemia-related and all-cause hospitalization proportions were lower with long-term therapy, although further confirmatory studies are needed.

A New Perspective to Longstanding Challenges with Outpatient Hyperkalemia: A Narrative Review

Purpose of Review

Outpatient hyperkalemia is a common problem with potentially deadly consequences. Potassium level thresholds to treat outpatient hyperkalemia are unstandardized and variable, leaving health care providers to rely on their own clinical judgment. This narrative review highlights the challenges of outpatient hyperkalemia management and includes recommendations for future studies that may standardize treatment, improve patient outcomes, and optimize health care utilization.

Sources of Information

PubMed, Google Scholar, and the reference lists of identified articles were used to include English, peer-reviewed studies and guidelines for this review.

Methods

This narrative review examines outpatient hyperkalemia from both a laboratory and clinical perspective. In addition to peer-reviewed literature, guidelines and expert consensus statements were included to highlight the inconsistencies and paucity of evidence that health care providers rely on to make clinical decisions.

Key Findings

There are multiple reasons why outpatient hyperkalemia management is both challenging and sub-optimal. Clinicians must discern if the potassium level result is accurate and, if so, does the result warrant referral to the emergency department. Factitious hyperkalemia, or falsely elevated potassium level results due to analytical errors, occurs frequently, but there are no ways to identify it other than for hemolyzed samples. Additionally, guidelines and expert panels are inconsistent on the thresholds for treatment and the management of hyperkalemia. Finally, there are inconsistencies between laboratories as to when and how providers are notified of results, and the suggested thresholds for urgent management. A study that integrates the expertise of clinical biochemists and clinicians is needed to inform evidence-based guidelines for the management of outpatient hyperkalemia.

Limitations

This was a comprehensive review of what is known and what still needs to be understood for the management of outpatient hyperkalemia. A formal tool to assess the quality of the included studies was not used and selection bias may have occurred.

Impact of chronic potassium binder treatment on the clinical outcomes in patients with hyperkalemia: Results of a nationwide hospital-based cohort study

Introduction: Hyperkalemia (HK) is a common disorder in patients with heart failure or chronic kidney disease, and potassium binders (PBs) are recommended to control serum potassium (S-K) levels. Although HK is often a chronic condition, short-term and intermittent PBs treatment has been largely applied to control S-K levels, and little is known about the impact of long-term and chronic PBs treatment on clinical outcomes. Method: This retrospective cohort study was conducted using a Japanese claims database (April 2008-September 2018). HK was defined as at least two S-K ≥5.1 mmol/L within a 12-month(M) interval. The index date was defined as the initial PB prescription date, and the S-K values were examined at 3M, 6M, and 12M after the index. The medication possession ratio (MPR) was used to evaluate the length of the prescribed period of PB, as prescription refill was not allowed in Japan. Clinical outcomes were analyzed by comparing MPR <80% to MPR ≥80% using Cox proportional hazards regression. Results: We found 4,321 patients with HK and were on initial PB treatments, and 993 and 3,328 patients were categorized in the MPR <80% and MPR ≥80% groups, respectively. The mean prescription days ±SD in the MPR <80% and MPR ≥80% groups were 114.7 ± 9.1 and 1151.2 ± 22.5, respectively. S-K value with adjustment by covariates in MPR <80% and MPR ≥80% groups were 5.62 (95% CI: 5.57-5.68) and 5.72 (95% CI: 5.68-5.76) at index followed by 4.65 (95% CI: 4.58-4.71) and 4.57 (95% CI: 4.51-4.62) at 3M, respectively. The hazard ratios of incidence rates in hospitalization was 1.41 (p < 0.001), introduction of renal replacement therapy was 1.25 (p < 0.003), recurrent HK was 1.67 (p < 0.001), and decreased eGFR was 1.41 (p < 0.001), respectively. Conclusion: These results indicate a higher risk of adverse outcomes when PBs were not prescribed chronically, whereas S-K levels were similarly controlled. Chronic control with continued PBs rather than temporary treatment may be associated with the reduction of adverse clinical outcomes in patients with HK.

Hyperkalemia: Prevalence, Predictors and Emerging Treatments

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

Optimizing Therapies in Heart Failure: The Role of Potassium Binders

Heart failure (HF) is a worrisome cardiac pandemic with a negative prognostic impact on the overall survival of individuals. International guidelines recommend up-titration of standardized therapies in order to reduce symptoms, hospitalization rates, and cardiac death. Hyperkalemia (HK) has been identified in 3–18% of HF patients from randomized controlled trials and over 25% of HF patients in the “real world” setting. Pharmacological treatments and/or cardio-renal syndrome, as well as chronic kidney disease may be responsible for HK in HF patients. These conditions can prevent the upgrade of pharmacological treatments, thus, negatively impacting on the overall prognosis of patients. Potassium binders may be the best option in patients with HK in order to reduce serum concentrations of K⁺ and to promote correct upgrades of therapies. In addition to the well-established use of sodium polystyrene sulfonate (SPS), two novel drugs have been recently introduced: sodium zirconium cyclosilicate (SZC) and patiromer. SZC and patiromer are gaining a central role for the treatment of chronic HK. SZC has been shown to reduce K⁺ levels within 48 h, with guaranteed maintenance of normokalemia for up to12 months. Patiromer has resulted in a statistically significant decrease in serum potassium for up to 52 weeks. Therefore, long-term results seemed to positively promote the implementation of these compounds in clinical practice due to their low rate side effects. The aim of this narrative review is to delineate the impact of new potassium binders in the treatment of patients with HF by providing a critical reappraisal for daily application of novel therapies for hyperkalemia in the HF setting.

Cost of End-of-Life Inpatient Encounters in Patients with Chronic Kidney Disease in the United States: A Report from the DISCOVER CKD Retrospective Cohort

Introduction

Real-world data reporting healthcare resource utilisation and costs associated with end-of-life care for patients with chronic kidney disease (CKD) are limited. We examined length of hospitalisation and costs associated with end-of-life inpatient encounters using retrospective data from DISCOVER CKD.

Methods

Data on inpatient encounters for patients with CKD aged ≥ 18 years between January 2016 and March 2020 were extracted from the US Premier Hospital Database. Encounters ending in death were identified and grouped by reason for the encounter, using the International Classification of Diseases, Tenth Revision, and by their insurance coverage. Encounters were evaluated overall and stratified according to cardiovascular (CV), kidney failure and infection-related reasons, and by their coverage by commercial, Medicaid, Medicare or other insurers. Length of hospitalisation and total costs were calculated for encounters.

Results

Among 237,734 encounters ending in death, the mean [standard deviation (SD)] age was 74.2 (12.4) years, and 45.3% of patients were female. In total, 25,118, 4210 and 76,307 encounters were classified as relating to CV reasons, kidney failure and infection, respectively. Among all encounters, the mean (SD) length of hospitalisation ranged from 9.1 (11.2) (Medicare) to 12.8 (18.4) (Medicaid) days. Across insurers, encounters related to kidney failure were associated with the longest hospitalisations compared with CV and infection [mean range (days): 10.7–15.9 vs. 7.5–10.5 and 8.7–12.7, respectively]. The median [interquartile range (IQR)] total cost of any inpatient encounter was $17,057 ($8040–35,873). Kidney failure-related encounters had higher costs compared with CV and infection [median (IQR), $18,469 ($8673–38,315) vs. $17,503 ($7766–39,693) and $16,403 ($7762–34,910), respectively]. Medicaid-covered encounters had the highest costs of all insurers [median (IQR), $16,189 ($7725–33,443)].

Conclusions

Among patients with CKD, end-of-life encounters were most frequently related to infection. Encounters relating to kidney failure incurred the highest costs.

Trial registration

ClinicalTrials.gov identifier: NCT04034992.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s12325-021-02010-3.

The prevalence of predialysis hyperkalemia and associated characteristics among hemodialysis patients: The RE-UTILIZE study

Introduction

Hyperkalemia (HK), defined as serum potassium (K⁺) >5.0 mEq/L, is an independent predictor of mortality in patients on maintenance hemodialysis (HD). This study investigated the annual prevalence of HK and examined patient characteristics potentially associated with a higher annual HK prevalence.

Methods

This retrospective observational cohort study used Dialysis Outcomes and Practice Patterns Study (DOPPS) survey data from US patients undergoing in‐center HD thrice weekly from 2018 to 2019. The primary endpoint was the proportion of patients with any predialysis HK (K⁺ >5.0 mEq/L) within 1 year from the index date (date of DOPPS enrollment), using the first hyperkalemic K⁺ value. Secondary endpoints were the proportion of patients with moderate‐to‐severe (K⁺ >5.5 mEq/L) or severe (K⁺ >6.0 mEq/L) HK.

Findings

Overall, 9347 patients on HD were included in this analysis (58% male and 49% aged >66 years). Any predialysis HK (K⁺ >5.0 mEq/L) occurred in 74% of patients within 1 year of the index date, 52% within 3 months, and 38% within 1 month. The annual prevalence of moderate‐to‐severe and severe HK was 43% and 17%, respectively. Recurrent HK (at least two K⁺ >5.0 mEq/L within 1 year) occurred in 60% of patients, and 2.8% of patients were prescribed an oral K⁺ binder. Multivariable logistic regression analysis showed younger age, female sex, Hispanic ethnicity, and renin–angiotensin–aldosterone system inhibitor use were significantly associated with a higher annual prevalence of any predialysis HK, while Black race, obesity, recent initiation of HD, and dialysate K⁺ bath concentration ≥3 mEq/L were associated with a lower prevalence of HK.

Discussion

The annual prevalence of predialysis HK and recurrence were high among US patients on HD, whereas oral K⁺ binder use was low. Further studies are needed to understand the impact of dialysate K⁺ bath concentrations on predialysis HK among patients on HD.

Dispelling myths and misconceptions about the treatment of acute hyperkalemia

Hyperkalemia represents a widespread and potentially lethal condition that affects millions of people across their lives. Despite the prevalence and severity of the condition, there are no consensus guidelines on the treatment of hyperkalemia or even a standard definition. Herein, we provide a succinct review of what we believe to be the most significant misconceptions encountered in the emergency care of hyperkalemia, examine current available literature, and discuss practical points on several modalities of hyperkalemia treatment. Additionally, we review the pathophysiology of the electrocardiographic effects of hyperkalemia and how intravenous calcium preparations can antagonize these effects. We conclude each section with recommendations to aid emergency physicians in making safe and efficacious choices for the treatment of acute hyperkalemia.

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.

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.

Inpatient management and post-discharge outcomes of hyperkalemia

OBJECTIVES

Patients with hyperkalemia are commonly treated in the inpatient setting; however, real-world evidence is limited. The purpose of this study was to describe the inpatient management and post-discharge outcomes among patients with hyperkalemia.

METHODS

Electronic medical record data (2012-2018) were used to analyze US adult patients with an inpatient stay with hyperkalemia (≥1 potassium value >5.0mEq/L). Patient characteristics, treatments, and monitoring six months prior to and during the inpatient stay, and hyperkalemia recurrence and inpatient readmissions post-discharge were summarized and compared among patients with mild (>5.0-5.5mEq/L), moderate (>5.5-6.0), and severe (>6.0) hyperkalemia.

RESULTS

Of the 21,793 patients, 69.2% had mild, 19.0% had moderate, and 11.8% had severe hyperkalemia during inpatient care. The most common inpatient treatments were temporizing agents (mild: 28.9%; moderate: 46.0%; severe: 73.0%), diuretics (32.7%; 37.1%; 34.6%), and sodium-polystyrene sulfonate (11.7%; 27.8%; 45.3%). Almost no patients (0.1%) received a potassium binder at discharge. Most patients (86.8%) had their potassium levels return to ≤5.0mEq/L during the inpatient stay. Death during the inpatient stay occurred in 12.3% of mild, 15.5% of moderate, and 19.5% of severe hyperkalemic patients. Within 30 days of discharge, hyperkalemia recurred in 13.3%, 15.4%, and 18.4% of patients with mild, moderate, and severe hyperkalemia, respectively. Additionally, 19.7%, 21.5%, and 19.6% of patients were readmitted to inpatient care within 30 days post-discharge.

CONCLUSION

Among patients with hyperkalemia in the inpatient setting, treatment and normalization of serum potassium levels were common. However, death, readmission, and hyperkalemia recurrence were also fairly common across all cohorts. Future studies examining measures to reduce inpatient death, readmission, and hyperkalemia recurrence among patients with hyperkalemia in inpatient care are warranted.

Healthcare utilization and expenditures associated with hyperkalemia management: a retrospective study of Medicare Advantage patients

AIMS

This study aimed to estimate the association of patiromer exposure vs. no potassium (K⁺) binder (NoKb) exposure with healthcare utilization and expenditures among a cohort of Medicare Advantage patients with hyperkalemia (HK).

METHODS

Using Optum's Clinformatics Data Mart (study period 2016-2019), the authors assessed propensity score-matched patients (1:1) with a serum K⁺ concentration ≥5.0 mmol/L and an HK diagnosis that were exposed to patiromer or NoKb on baseline characteristics. The following outcomes were compared: (1) inpatient/emergency department (ED) encounters, (2) inpatient costs greater than or equal to mean Medicare Advantage inpatient cost (i.e. $14,900), and (3) the relative healthcare spending rate. Logistic regression and zero-inflated negative binomial regression were used to analyze the outcomes.

RESULTS

The study cohort included 1,539 patiromer and NoKb matched pairs. Baseline characteristics were (patiromer/NoKb): age 74/75 years; female 42/40%; serum K⁺ 5.6/5.6 mmol/L; eGFR rate 36/36 mL/min/1.73 m²; low-income subsidy 42/41%, chronic kidney disease 96/96%; end-stage renal disease 12/12%; and congestive heart failure 37/36%. A total of 253 matched pairs (506 patients) remained uncensored and were analyzed at 6 months. Inpatient/ED encounters were observed for 25% (patiromer) and 37% (NoKb) (odds ratio [OR] 0.58, 95% confidence interval [CI]: 0.38-0.89). The relative odds of having inpatient costs ≥$14,900 were ∼50% less for patients exposed to patiromer vs. NoKb (OR [95% CI]: 0.47 [0.25-0.89]). The relative total healthcare spending rate (including inpatient, outpatient, ED, and pharmacy costs) was 19% less for patients exposed to patiromer vs. NoKb (spending rate ratio [95% CI]: 0.81 [0.67-0.98]).

CONCLUSION AND LIMITATIONS

Among Medicare Advantage patients with HK, patiromer exposure (vs. NoKb) was associated with statistically significant reductions in the proportion with inpatient/ED encounters, inpatient costs ≥$14,900, and lower total healthcare spending. Further research, with larger sample size, is warranted to fully validate these findings.