Clinical and Economic Burden of Hyperkalemia: A Nationwide Hospital-Based Cohort Study in Japan

Economic burden of recurrent hyperkalemia in patients with chronic kidney disease

BACKGROUND

Hyperkalemia is a common complication of chronic kidney disease (CKD) and can become recurrent in half of cases. However, the incremental economic burden associated with recurrent hyperkalemia is unknown.

OBJECTIVE

To evaluate all-cause health care resource utilization (HRU) and medical costs in patients with stage 3/4 CKD with recurrent hyperkalemia vs normokalaemia and vs nonrecurrent hyperkalemia.

METHODS

Data were from Optum's de-identified Market Clarity Data (January 1, 2016, to August 1, 2022). This retrospective observational cohort study compared patients with stage 3/4 CKD with recurrent hyperkalemia (≥2 hyperkalemia events within 1 year [hyperkalemia event: hyperkalemia diagnosis or potassium [K+]>5 mmol/l]; index was the first hyperkalemia event) with an exact- and propensity score-matched cohort of patients with normokalemia (K+ ≥3.5 to ≤5 mmol/l; random K+ as index) and separately with a matched cohort of patients with nonrecurrent hyperkalemia (1 hyperkalemia event within 1 year; index was hyperkalemia event). Patient characteristics, medication use, HRU, and medical costs were compared between cohorts using standardized mean differences during the 12-month baseline period. All-cause HRU and medical costs during the 12-month follow-up were compared using Wilcoxon rank sum tests for continuous variables and McNemar tests for categorical variables. Substudies of recurrent hyperkalemia vs normokalemia were conducted for patients with Medicare coverage and renin-angiotensin-aldosterone system inhibitor (RAASi) use.

RESULTS

The recurrent hyperkalemia vs normokalemia sample comprised 4,549 matched pairs (Medicare substudy: 3,151; RAASi substudy: 3,535) and the recurrent hyperkalemia vs nonrecurrent hyperkalemia sample comprised 1,599 matched pairs. Baseline characteristics, HRU, and medical costs of the cohorts were similar after matching. During follow-up, patients with recurrent hyperkalemia had a mean of 11.2 more health care encounters (0.5 more inpatient admissions, 0.3 more emergency department visits, and 7.2 more outpatient visits) than patients with normokalemia. Patients with recurrent hyperkalemia also had double the total annual medical costs vs normokalemia ($34,163 vs $15,175; P < 0.001), mainly driven by inpatient costs ($21,250 vs $7,392), which accounted for 62.2% and 48.7% of total costs, respectively. Results were similar in the RAASi and Medicare substudies. Recurrent hyperkalemia was associated with a mean 4.3 more all-cause health care encounters and $14,057 higher medical costs (both P < 0.001) than nonrecurrent hyperkalemia.

CONCLUSIONS

Recurrent hyperkalemia in patients with stage 3/4 CKD was associated with higher all-cause HRU and medical costs compared with normokalemia (including in patients with Medicare coverage and RAASi use) and nonrecurrent hyperkalemia. Research is needed to understand if long-term treatment strategies aimed at preventing hyperkalemia recurrence may alleviate this economic burden.

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

INTRODUCTION

Our model was conducted from Kuwaiti payer's perspective to provide evidence on the cost-effectiveness of Sodium zirconium cyclosilicate (SZC) versus patiromer to correct and maintain serum potassium (K+) in combination with renin-angiotensin-aldosterone system inhibitors (RAASis) with different dose titration in patients with chronic kidney disease/heart failure (CKD/HF) with/without renal replacement therapy (RRT).

METHODOLOGY

The model was developed as a patient-level, fixed-time increment stochastic simulation to simulate the complexity of disease, including multiple coexisting and competing conditional risks. This model was established to compare SZC versus patiromer as a treatment for hyperkalemia (HK) among adult populations with underlying conditions of advanced CKD stages 3a-5 or HF to correct and maintain serum K + over a lifetime horizon. The clinical outcomes of SZC and patiromer were demonstrated through arm-specific K + trajectories extracted from the HARMONIZE trial and OPAL-HK trial, respectively. The utility data was captured from different studies. Direct medical cost was captured from local data from Kuwaiti hospitals. Sensitivity analyses were conducted to assess the uncertainty in the model.

RESULTS

Within different scenarios of CKD/HF, SZC was a cost-saving option, with/without RRT, whether one-off administration or repeated administration, except for one-off treatment administration among the HF cohort, which generated an incremental cost effectiveness ratio of KWD 331/quality adjusted life year (QALY). The incremental QALY of SZC ranged from 0.007 to 0.202. In addition, the savings observed with SZC fall within a range of KWD -60 to KWD -1,235 at serum K+ ≥ 5.1 mmol/L.

CONCLUSION

The evidence generated by our model recommends the inclusion of SZC as a treatment option to correct HK and maintain normal serum K + level for CKD/HF patients within the Kuwaiti healthcare system. The costs saved from reducing frequent HK episodes, RAASis discontinuation/down titration, major cardiovascular events, and hospitalization offset the drug acquisition cost of SZC.

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.

Long-term outcomes of add-on direct renin inhibition in igA nephropathy: a propensity score-matched cohort study

INTRODUCTION

The long-term clinical outcomes in biopsy proven IgAN patients treated with aliskiren on top of a maximally tolerated dose of ACEi/ARB remain unknown.

METHODS

Patients with IgAN treated with a direct renin inhibitor and ACEi/ARB for at least 6 months were compared with a 1:1 propensityscore-matched cohort (including MEST-C score and the 12-months pre-exposure slope of eGFR matching) who received ACEi/ARB without aliskiren exposure to compute the hazard ratio of reaching the primary endpoint of a composite of 40% reduction in eGFR, initiation of KRT and all-cause mortality. Secondary outcome measures included changes in mean UPCR, blood pressure, eGFR, incidence of hyperkalemia and other adverse events during follow-up.

RESULTS

After a median follow-up of 2.5 years, 8/36 (22.2%) aliskiren-treated patients and 6/36 (16.7%) control patients reached the primary composite outcome (HR = 1.60; 95% CI 0.52-4.88; P = 0.412). Aliskiren treatment increased the risk of ≥ 40% eGFR decline (HR = 1.60; 95% CI 0.52-4.88; P = 0.412), and hyperkalemia (HR = 8.60; 95% CI 0.99-73.64; P = 0.050). At 10.8 years, renal composite outcome was reached in 69.4% vs 58.3% (HR = 2.16; 95% CI 1.18-3.98; P = 0.013) of patients in the aliskiren and control groups, respectively. The mean UPCR reduction between treatment and control was not statistically different (52.7% vs 42.5%; 95% CI 0.63-2.35; P = 0.556). The mean intergroup difference in eGFR decline over 60 months was 7.75 ± 3.95 ml/min/1.73 m² greater in the aliskiren group (12.83 vs 5.08; 95% CI - 0.17 to 15.66; P = 0.055).

CONCLUSION

Among patients with IgAN, add-on aliskiren was associated with less favorable long-term kidney outcomes despite an initial anti-proteinuric effect.

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.

Compared effectiveness of sodium zirconium cyclosilicate and calcium polystyrene sulfonate on hyperkalemia in patients with chronic kidney disease

Hyperkalemia is a well-recognized electrolyte abnormality in patients with chronic kidney disease (CKD). Potassium binders are often used to prevent and treat hyperkalemia. However, few studies have evaluated the difference in serum potassium (K⁺) level-lowering effect during the post-acute phase between the novel potassium binder, sodium zirconium cyclosilicate (ZSC), and conventional agents. This retrospective study included patients who received potassium binders (either ZSC or calcium polystyrene sulfonate [CPS]) in our hospital between May 2020 and July 2022. The patients were divided into the ZSC and CPS groups. After propensity score matching, we compared changes from baseline to the first follow-up point, at least 4 weeks after initiating potassium binders, in electrolytes including K⁺ level between the two groups. Of the 132 patients, ZSC and CPS were administered in 48 and 84 patients, respectively. After matching, 38 patients were allocated to each group. The ZSC group showed greater reduction in K⁺ levels than did the CPS group (P < 0.05). Moreover, a significant increase in serum sodium minus chloride levels, a surrogate marker for metabolic acidosis, was observed in the ZSC group (P < 0.05). Our results demonstrated that ZSC could potentially improve hyperkalemia and metabolic acidosis in patients with CKD.

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.

JE, Wang J, Onishi Y, Yajima T, Sada K, Yamamoto Y, Shibagaki Y. Validation of a new instrument for measuring disease-specific quality of life: A pilot study among patients with chronic kidney disease and hyperkalemia

BACKGROUND

To prepare for a longitudinal study of the effects of potassium-lowering treatment on quality of life (QOL), we quantified the validity of a new disease-specific instrument for measuring QOL, using data from patients who had hyperkalemia (HK) due to chronic kidney disease (CKD) or chronic heart failure, and were also being treated with potassium binders (PBs).

METHODS

In this cross-sectional study, the participants were 98 patients at five outpatient clinics in Japan. The outcome measures were the Medical Outcomes Study 36-item short-form (SF-36), a widely used generic measure of QOL, and the Quality of Life Disease-specific Impact Scale (QDIS-7), a recently-developed disease-specific measure of QOL. Internal-consistency reliability was quantified, and factor analysis was done to confirm hypothesized QOL dimensions. Validation tests used two external criteria: CKD stage, and PB formulation. PB formulation was used because different formulations are associated with different degrees of patients' burden. Using a previously-described method, we computed the relative validity (RV) of the two measures.

RESULTS

Two factor scoring of the SF-36 and one factor scoring of the QDIS-7, as standardized from previous studies, were confirmed. The RVs showed that the QDIS-7 was much more valid than the SF-36, for discriminating between groups defined clinically (by CKD stage), and also between groups defined by PB formulation. Reliability was satisfactory: 0.73-0.95 for the SF-36 and 0.86 for the QDIS-7.

CONCLUSIONS

The QDIS-7 with CKD or PB attributions was more valid than the SF-36 for measuring the effects of CKD and of PB formulation on QOL.

The Impact of Hyperkalemia on Mortality and Healthcare Resource Utilization Among Patients With Chronic Kidney Disease: A Matched Cohort Study in China

Objectives

This study aimed to estimate the impact of hyperkalemia on 1-year survival and all-cause healthcare resource utilization among patients with chronic kidney disease in China.

Methods

Adult new-onset chronic kidney disease patients were identified between 2012 and 2016, among which the hyperkalemia and non-hyperkalemia cohorts were further selected and matched. Survival and all-cause healthcare resource utilization during a 12 month period were compared using Kaplan-Meier curves with log-rank test, Cox proportional hazard model, and Kaplan-Meier sample average method.

Results

Among 1,003 pairs of patients (mean age 67.2 ± 14.3 years), the 1-year all-cause mortality was 5.39-times higher in the hyperkalemia cohort than the non-hyperkalemia cohort (hazard ratio = 5.39, P &lt; 0.001). The mean costs and number of healthcare services among the hyperkalemia patients were significantly higher (P &lt; 0.05) in each follow-up month. An annual increase cost of ¥38,479 was observed in the hyperkalemia cohort, largely due to the sharp increase in inpatient costs during the first month after hyperkalemia events (¥22,204 vs. 1,032, P &lt; 0.001). Medication costs were the most important cost component for both cohorts [¥26,786 (45%) vs. ¥12,378(60%)]. However, hyperkalemia patients spent more on non-medication treatment [¥13,410(23%) vs. ¥2,335(11%)] including nursing, monitoring, etc. Hyperkalemia patients had more annual inpatient admissions (1.9 vs. 0.7) and length of stays (28.6 vs. 8.7), while the number of outpatient visits (36.8 vs. 36.4) were similar.

Conclusions

In Chinese chronic kidney disease patients, hyperkalemia is associated with substantially increased clinical and economic burdens that are driven by the short period following the hyperkalemia events, which strengthens calls for sufficient supervision and management of serum potassium.

Phase I Study of the Pharmacodynamics and Safety of Sodium Zirconium Cyclosilicate in Healthy Chinese Adults

Sodium zirconium cyclosilicate (SZC) is an effective potassium binder for patients with hyperkalemia. This single‐center, open‐label, phase I study (NCT03283267) characterized the pharmacodynamics and safety of SZC in Chinese individuals. Twenty‐two healthy Chinese adults (mean age, 33.5 years) randomized 1:1 received daily oral SZC 5 or 10 g for 4 days, following 4 days on a low‐sodium, high‐potassium diet (continued throughout the study). End points were mean change from baseline in 24‐hour urinary potassium (primary) and sodium excretion, and serum potassium concentration. Urinary potassium excretion significantly decreased with SZC 5 g (mean change [mmol], –13.0; P < .001) and 10 g (–15.4; P < .001). Although urinary sodium excretion decreased significantly with SZC 5 g (–11.5; P = .030), there was no significant change with SZC 10 g (–5.1; P = .299). Serum potassium concentrations decreased significantly with SZC 5 g (–0.14; P = .031) and 10 g (–0.20; P = .002). All treatment‐emergent adverse events were mild, and none were considered causally related to SZC. Over 4 days, the pharmacodynamics and safety of SZC were consistent in healthy Chinese adults with global studies and patients of Japanese ethnicity.

Characterization and selection of Japanese electronic health record databases used as data sources for non-interventional observational studies

BACKGROUND

Interventional studies are the fundamental method for obtaining answers to clinical questions. However, these studies are sometimes difficult to conduct because of insufficient financial or human resources or the rarity of the disease in question. One means of addressing these issues is to conduct a non-interventional observational study using electronic health record (EHR) databases as the data source, although how best to evaluate the suitability of an EHR database when planning a study remains to be clarified. The aim of the present study is to identify and characterize the data sources that have been used for conducting non-interventional observational studies in Japan and propose a flow diagram to help researchers determine the most appropriate EHR database for their study goals.

METHODS

We compiled a list of published articles reporting observational studies conducted in Japan by searching PubMed for relevant articles published in the last 3 years and by searching database providers' publication lists related to studies using their databases. For each article, we reviewed the abstract and/or full text to obtain information about data source, target disease or therapeutic area, number of patients, and study design (prospective or retrospective). We then characterized the identified EHR databases.

RESULTS

In Japan, non-interventional observational studies have been mostly conducted using data stored locally at individual medical institutions (663/1511) or collected from several collaborating medical institutions (315/1511). Whereas the studies conducted with large-scale integrated databases (330/1511) were mostly retrospective (73.6%), 27.5% of the single-center studies, 47.6% of the multi-center studies, and 73.7% of the post-marketing surveillance studies, identified in the present study, were conducted prospectively. We used our findings to develop an assessment flow diagram to assist researchers in evaluating and choosing the most suitable EHR database for their study goals.

CONCLUSIONS

Our analysis revealed that the non-interventional observational studies were conducted using data stored local at individual medical institutions or collected from collaborating medical institutions in Japan. Disease registries, disease databases, and large-scale databases would enable researchers to conduct studies with large sample sizes to provide robust data from which strong inferences could be drawn.