Clinical factors associated with hyperkalemia in patients with congestive heart failure1

Nonsteroidal Mineralocorticoid Receptor Antagonists: Exploring Role in Cardiovascular Disease

ABSTRACT

Aldosterone, a mineralocorticoid hormone, plays a role in the pathophysiology of many cardiovascular disease states. Mineralocorticoid receptor antagonists (MRAs) have been shown to improve clinical outcomes in select patient populations. However, use of available steroidal receptor antagonists, eplerenone and spironolactone, is often limited by the risk or development of hyperkalemia. Nonsteroidal MRAs have been designed to overcome this limitation. The nonsteroidal MRAs have been studied in patients with heart failure with reduced ejection fraction, hypertension, and to lower the risk of cardiac and renal outcomes in those with type 2 diabetes and renal disease. In this review, the pharmacology of the MRAs is compared, the data evaluating the use of nonsteroidal MRAs are examined, and the place of this new generation of therapy is discussed. At this time, it seems that there could be a future role for nonsteroidal MRAs to reduce the risk of renal outcomes in high-risk individuals.

Eplerenone: The Multifaceted Drug in Cardiovascular Pharmacology

Conventionally, rennin-angiotensin-aldosterone system (RAAS) inhibition has focused on angiotensin-converting enzyme (ACE) inhibitors, angiotensin receptor blockers and angiotensin receptor-neprilysin inhibitors (ARNI) are the latest addition to this armamentarium. However, mineralocorticoid receptor antagonists (MRAs) also constitute an integral part of this anti-RAAS brigade, which are perceived more often as diuretics and are often under prescribed in heart failure (HF) despite being universally advocated by all major guidelines. Apart from HF, they have also shown promise in the management of hypertension, post-myocardial infarction, and hyperaldosteronism. Eplerenone, Food and Drug Administration (FDA) approved in 2002, is an acceptable alternative to spironolactone due to its sparing androgenic effects. In two big pivotal trials in heart failure (EMPHASIS -HF) and post-myocardial infarction (EPHESUS), the drug has firmly shown a reduction in adverse cardiovascular events. It has an established place in the management of resistant hypertension too. In this article, we will discuss the role of RAAS and its pathophysiology, pitfalls of spironolactone, which led to success of its congener, eplerenone, major studies conducted on eplerenone, current role of eplerenone, and comparison of the two MRAs.

Medication as a risk factor for hospitalization due to heart failure and shock: a series of case-crossover studies in Swiss claims data

Purpose

Heart failure is among the leading causes for hospitalization in Europe. In this study, we evaluate potential precipitating factors for hospitalization for heart failure and shock.

Methods

Using Swiss claims data (2014–2015), we evaluated the association between hospitalization for heart failure and shock, and prescription of oral potassium supplements, non-steroidal anti-inflammatory drugs (NSAIDs), and amoxicillin/clavulanic acid. We conducted case-crossover analyses, where exposure was compared for the hazard period and the primary control period (e.g., 1–30 days before hospitalization vs. 31–60 days, respectively). Conditional logistic regression was applied and subsequently adjusted for addressing potential confounding by disease progression. Sensitivity analyses were conducted and stratification for co-medication was performed.

Results

We identified 2185 patients hospitalized with heart failure or shock. Prescription of potassium supplements, NSAIDs, and amoxicillin/clavulanic acid was significantly associated with an increased risk for hospitalization for heart failure and shock with crude odds ratios (OR) of 2.04 for potassium (95% CI 1.24–3.36, p = 0.005, 30 days), OR 1.8 for NSAIDs (95% CI 1.39–2.33, p < 0.0001, 30 days), and OR 3.25 for amoxicillin/clavulanic acid (95% CI 2.06–5.14, p < 0.0001, 15 days), respectively. Adjustment attenuated odds ratios, while the significant positive association remained (potassium OR 1.70 (95% CI 1.01–2.86, p = 0.046), NSAIDs OR 1.50 (95% CI 1.14–1.97, p = 0.003), and amoxicillin/clavulanic acid OR 2.26 (95% CI 1.41–3.62, p = 0.001).

Conclusion

Prescription of potassium supplements, NSAIDs, and amoxicillin/clavulanic acid is associated with increased risk for hospitalization. Underlying conditions such as pain, electrolyte imbalances, and infections are likely contributing risk factors. Physicians may use this knowledge to better identify patients at risk and adapt patient management.

Electronic supplementary material

The online version of this article (10.1007/s00228-020-02835-x) contains supplementary material, which is available to authorized users.

Incident Hyperkalemia, Hypokalemia, and Clinical Outcomes During Spironolactone Treatment of Heart Failure With Preserved Ejection Fraction: Analysis of the TOPCAT Trial

BACKGROUND

In patients with heart failure and preserved ejection fraction (HF-PEF) randomized in the Americas as part of the Treatment of Preserved Cardiac Function Heart Failure with an Aldosterone Antagonist (TOPCAT) trial, treatment with spironolactone enhanced the risk of hyperkalemia but reduced the risk of hypokalemia. We examined the clinical correlates and prognostic implications of incident hypo- and hyperkalemia during study follow-up.

METHODS

We defined the region-specific incidence of hypokalemia (potassium [K⁺] <3.5 mmol/l) and hyperkalemia (K⁺ ≥5.5 mmol/l) among both placebo- and spironolactone-assigned patients in TOPCAT. Factors associated with incident hypokalemia and hyperkalemia and the relationship between incident K⁺ abnormalities and the risk of subsequent mortality were analyzed in multivariable regression models restricted to the Americas.

RESULTS

In the Americas, assignment to spironolactone increased risk for hyperkalemia (hazard ratio 3.21, 95% confidence interval 2.46-4.20, P < .001) and reduced risk of hypokalemia (hazard ratio 0.43, 95% confidence interval 0.34-0.55, P < .001). Assignment to spironolactone, lower estimated glomerular filtration rate, higher baseline K⁺, diabetes, and lower hemoglobin were associated with incident hyperkalemia, whereas assignment to placebo, lower K⁺, younger age, lower estimated glomerular filtration rate, and use of diuretics at baseline were associated with hypokalemia. The combination of spironolactone and an angiotensin-converting enzyme inhibitor or angiotensin receptor blocker was associated with incremental risk for hyperkalemia and protection from hypokalemia. Independent of region, both hypokalemia and hyperkalemia, were associated with higher risk for cardiovascular and all-cause mortality in multivariable-adjusted Cox regression models.

CONCLUSIONS

Both hyperkalemia and hypokalemia are associated with heightened risk for mortality in HF-PEF. Use of spironolactone in this population requires careful laboratory surveillance of K⁺ and creatinine, particularly in high-risk groups.

Treatment of Hyperkalemia in Heart Failure

PURPOSE OF REVIEW

The aim of this paper is to discuss strategies for prevention and management of hyperkalemia in patients with heart failure, including the role of novel therapies.

RECENT FINDINGS

Renin-angiotensin-aldosterone system (RAAS) antagonists, including angiotensin-converting enzyme inhibitors (ACEI), angiotensin receptor blockers (ARB), and mineralocorticoid receptor antagonists (MRA) decrease mortality and morbidity in heart failure but increase the risk of hyperkalemia, especially when used in combination. Prevention of hyperkalemia and its associated complications requires careful patient selection, counseling regarding dietary potassium intake, awareness of drug interactions, and regular laboratory surveillance. Recent data suggests that the risk of hyperkalemia may be further moderated through the use of combined angiotensin-neprilysin inhibitors, novel MRAs, and novel potassium binding agents. Clinicians should be mindful of the risk of hyperkalemia when prescribing RAAS inhibitors to patients with heart failure. In patients at highest risk, such as those with diabetes, the elderly, and advanced chronic kidney disease, more intensive laboratory surveillance of potassium and creatinine may be required. Novel therapies hold promise for reducing the risk of hyperkalemia and enhancing the tolerability of RAAS antagonists.

Use of Mineralocorticoid Receptor Antagonists in Patients With Heart Failure and Comorbid Diabetes Mellitus or Chronic Kidney Disease

BACKGROUND

Perceived risks of hyperkalemia and acute renal insufficiency may limit use of mineralocorticoid receptor antagonist (MRA) therapy in patients with heart failure, especially those with diabetes mellitus or chronic kidney disease.

METHODS AND RESULTS

Using clinical registry data linked to Medicare claims, we analyzed patients hospitalized with heart failure between 2005 and 2013 with a history of diabetes mellitus or chronic kidney disease. We stratified patients by MRA use at discharge. We used inverse probability-weighted proportional hazards models to assess associations between MRA therapy and 30-day, 1-year, and 3-year mortality, all-cause readmission, and readmission for heart failure, hyperkalemia, and acute renal insufficiency. We performed interaction analyses for differential effects on 3-year outcomes for reduced, borderline, and preserved ejection fraction. Of 16 848 patients, 12.3% received MRA therapy at discharge. Higher serum creatinine was associated with lower odds of MRA use (odds ratio, 0.66; 95% confidence interval, 0.61-0.71); serum potassium was not (odds ratio, 1.00; 95% confidence interval, 0.90-1.11). There was no mortality difference between groups. MRA therapy was associated with greater risks of readmission for hyperkalemia and acute renal insufficiency and lower risks of long-term all-cause readmission. Patients on MRA therapy with borderline or preserved ejection fraction had greater risks of readmission for hyperkalemia (P=0.02) and acute renal insufficiency (P<0.001); patients with reduced ejection fraction did not.

CONCLUSIONS

Among patients with heart failure and diabetes mellitus or chronic kidney disease, MRA use was associated with lower risk of all-cause readmission despite greater risk of hyperkalemia and acute renal insufficiency.

Incidence of and Risk Factors for Severe Adverse Events in Elderly Patients Taking Angiotensin-Converting Enzyme Inhibitors or Angiotensin II Receptor Blockers after an Acute Myocardial Infarction

STUDY OBJECTIVE

To assess the incidence of and risk factors associated with severe adverse events in elderly patients who used angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin II receptor blockers (ARBs) after an acute myocardial infarction (AMI).

DESIGN

Retrospective cohort study.

DATA SOURCES

Centers for Medicare & Medicaid Services Chronic Conditions Data Warehouse (Medicare service claims database), American Community Survey of the U.S. Census Bureau, and Multum Lexicon Drug database.

PATIENTS

A total of 101,588 eligible Medicare fee-for-service beneficiaries 66 years or older, who were hospitalized for AMI between January 1, 2008, and December 31, 2009, and used ACEIs or ARBs within 30 days after discharge.

MEASUREMENTS AND MAIN RESULTS

Primary outcomes were hospitalizations for acute renal failure (ARF) and hyperkalemia. The secondary outcome was discontinuation or suspension of ACEI/ARB therapy after a visit to a health care provider. The primary risk factors of interest were age, sex, race/ethnicity, and chronic kidney disease (CKD). Cumulative incidence curves and multivariable Fine-Gray proportional hazards models with 95% confidence intervals (CIs) were used with death as a competing risk in both intention-to-treat (ITT) and as-treated (AT) analyses. In the study cohort, 2.8% experienced ARF, 0.5% experienced hyperkalemia, and 63.7% discontinued ACEI/ARB therapy within 1 year after hospital discharge. Approximately half of the incidence of ARF and hyperkalemia occurred within 6 months after hospital discharge, but the cumulative incidence increased after 6 months. Patients older than 85 years had a higher rate of ARF (ITT hazard ratio [HR] 1.15, 95% CI 1.04-1.28) and hyperkalemia (ITT HR 1.33, 95% CI 1.05-1.68) compared with those aged 65-74 years. Patients with baseline CKD had higher rates of ARF (ITT HR 1.61, 95% CI 1.42-1.82), hyperkalemia (ITT HR 1.41, 95% CI 1.11-1.77), and ACEI/ARB therapy discontinuation or suspension (ITT HR 1.05, 95% CI 1.02-1.09).

CONCLUSION

We found a low incidence of ARF and hyperkalemia in elderly patients treated with ACEIs or ARBs after AMI hospitalization. However, a high rate of treatment discontinuation might prevent a higher rate of occurrence of these events. Long-term careful monitoring of severe adverse events and timely discontinuation of ACEIs or ARBs among elderly patients with advancing age and CKD after an AMI is warranted in clinical practice.

Elevated baseline potassium level within reference range is associated with worse clinical outcomes in hospitalised patients

The clinical significance of elevated baseline serum potassium (K⁺) levels in hospitalised patients is rarely described. Hence, we performed a retrospective study assessing the significance of elevated K⁺ levels in a one-year admission cohort. Adult patients without hypokalaemia or end-stage renal disease were included. Adverse outcomes were all-cause mortality, hospital-acquired acute kidney injury, and events of arrhythmia. In total, 17,777 patients were included in the study cohort, and a significant difference (P < 0.001) was observed in mortality according to baseline serum K⁺ levels. The adjusted hazard ratios (HRs) and associated 95% confidence intervals (CIs) of all-cause mortality for K⁺ levels above the reference range of 3.6–4.0 mmol/L were as follows: 4.1–4.5 mmol/L, adjusted HR 1.075 (95% CI 0.981–1.180); 4.6–5.0 mmol/L, adjusted HR 1.261 (1.105–1.439); 5.1–5.5 mmol/L, adjusted HR 1.310 (1.009–1.700); >5.5 mmol/L, adjusted HR 2.119 (1.532–2.930). Moreover, the risks of in-hospital acute kidney injury and arrhythmia were higher in patients with serum K⁺ levels above 4.0 mmol/L and 5.5 mmol/L, respectively. In conclusion, increased serum K⁺ levels, including mild elevations may be related to worse prognosis. Close monitoring and prompt correction of underlying causes or hyperkalaemia itself is warranted for admitted patients.

Serum Potassium Levels and Outcome in Acute Heart Failure (Data from the PROTECT and COACH Trials)

Serum potassium is routinely measured at admission for acute heart failure (AHF), but information on association with clinical variables and prognosis is limited. Potassium measurements at admission were available in 1,867 patients with AHF in the original cohort of 2,033 patients included in the Patients Hospitalized with acute heart failure and Volume Overload to Assess Treatment Effect on Congestion and Renal FuncTion trial. Patients were grouped according to low potassium (<3.5 mEq/l), normal potassium (3.5 to 5.0 mEq/l), and high potassium (>5.0 mEq/l) levels. Results were verified in a validation cohort of 1,023 patients. Mean age of patients was 71 ± 11 years, and 66% were men. Low potassium was present in 115 patients (6%), normal potassium in 1,576 (84%), and high potassium in 176 (9%). Potassium levels increased during hospitalization (0.18 ± 0.69 mEq/l). Patients with high potassium more often used angiotensin-converting enzyme inhibitors and mineralocorticoid receptor antagonists before admission, had impaired baseline renal function and a better diuretic response (p = 0.005), independent of mineralocorticoid receptor antagonist usage. During 180-day follow-up, a total of 330 patients (18%) died. Potassium levels at admission showed a univariate linear association with mortality (hazard ratio [log] 2.36, 95% confidence interval 1.07 to 5.23; p = 0.034) but not after multivariate adjustment. Changes of potassium levels during hospitalization or potassium levels at discharge were not associated with outcome after multivariate analysis. Results in the validation cohort were similar to the index cohort. In conclusion, high potassium levels at admission are associated with an impaired renal function but a better diuretic response. Changes in potassium levels are common, and overall levels increase during hospitalization. In conclusion, potassium levels at admission or its change during hospitalization are not associated with mortality after multivariate adjustment.

Mechanism of Action and Pharmacology of Patiromer, a Nonabsorbed Cross-Linked Polymer That Lowers Serum Potassium Concentration in Patients With Hyperkalemia

Hyperkalemia is a potentially life-threatening condition, and patients who have chronic kidney disease, who are diabetic, or who are taking renin-angiotensin-aldosterone system inhibitors are at increased risk. Therapeutic options for hyperkalemia tend to have limited effectiveness and can be associated with serious side effects. Colonic potassium secretion can increase to compensate when urinary potassium excretion decreases in patients with renal impairment, but this adaptation is insufficient and hyperkalemia still results. Patiromer is a novel, spherical, nonabsorbed polymer designed to bind and remove potassium, primarily in the colon, thereby decreasing serum potassium in patients with hyperkalemia. Patiromer has been found to decrease serum potassium in patients with hyperkalemia having chronic kidney disease who were on renin-angiotensin-aldosterone system inhibitors. Results of nonclinical studies and an early phase clinical study are reported here. Two studies with radiolabeled drug, one in rats and the other in dogs, confirmed that patiromer was not absorbed into the systemic circulation. Results of an in vitro study showed that patiromer was able to bind 8.5 to 8.8 mEq of potassium per gram of polymer at a pH similar to that found in the colon and had a much higher potassium-binding capacity compared with other resins, including polystyrene sulfonate. In a study in hyperkalemic rats, a decrease in serum potassium was observed via an increase in fecal potassium excretion. In a clinical study in healthy adult volunteers, a significant increase in fecal potassium excretion and a significant decrease in urinary potassium excretion were observed. Overall, patiromer is a high-capacity potassium binder, and the chemical and physical characteristics of patiromer may lead to good clinical efficacy, tolerability, and patient acceptance.

Effect of the SGLT2 Inhibitor Dapagliflozin on Potassium Levels in Patients with Type 2 Diabetes Mellitus: A Pooled Analysis

INTRODUCTION

Hyperkalemia risk is increased in diabetes, particularly in patients with renal impairment or those receiving angiotensin-converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs) or potassium-sparing diuretics. Conversely, other diuretics can increase hypokalemia risk. We assessed the effects of the sodium glucose co-transporter 2 (SGLT2) inhibitor dapagliflozin on serum potassium levels in a pooled analysis of clinical trials in patients with type 2 diabetes mellitus (T2DM).

METHODS

Fourteen randomized, placebo-controlled, double-blind T2DM studies were analyzed: pooled data from 13 studies of ≤24 weeks' duration (dapagliflozin 10 mg, N = 2360; placebo, N = 2295); and one 52-week moderate renal impairment study in patients with baseline eGFR ≥30 to <60 mL/min/1.73 m(2) (dapagliflozin 10 mg, N = 85; placebo, N = 84). Central laboratory serum potassium levels were determined at each study visit.

RESULTS

No clinically relevant mean changes from baseline in serum potassium ≤24 weeks were reported for dapagliflozin 10 mg [-0.05 mmol/L; 95% confidence interval (CI) -0.07, -0.03] versus placebo (-0.02 mmol/L; 95% CI -0.04, 0.00) in the pooled population or in the renal impairment study (-0.03 mmol/L; 95% CI -0.14, 0.08 vs. -0.02 mmol/L; 95% CI -0.13, 0.09, respectively). The incidence rate ratio for serum potassium ≥5.5 mmol/L over 24 weeks for dapagliflozin 10 mg versus placebo was 0.90 (95% CI 0.74, 1.10) in the pooled population; with no increased risk in patients receiving ARBs/ACE inhibitors, or potassium-sparing diuretics, or in those with moderate renal impairment. Slightly more patients receiving dapagliflozin 10 mg had serum potassium ≤3.5 mmol/L versus placebo (5.2% vs. 3.6%); however, no instances of serum potassium ≤2.5 mmol/L were reported.

CONCLUSION

Dapagliflozin is not associated with an increased risk of hyperkalemia or severe hypokalemia in patients with T2DM.

FUNDING

Bristol-Myers Squibb and AstraZeneca.

Hyperkalemia among hospitalized patients and association between duration of hyperkalemia and outcomes

INTRODUCTION

The aim of the study was to investigate predictors of mortality in patients hospitalized with hyperkalemia.

MATERIAL AND METHODS

Data among hospitalized patients with hyperkalemia (serum potassium ≥ 5.1 mEq/l) were collected. Patients with end-stage renal disease on dialysis were excluded.

RESULTS

Of 15,608 hospitalizations, 451 (2.9%) episodes of hyperkalemia occurred in 408 patients. In patients with hyperkalemia, chronic kidney disease, hypertension, diabetes, coronary artery disease and heart failure were common comorbidities. Acute kidney injury (AKI) and metabolic acidosis were common metabolic abnormalities, and 359 patients (88%) were on at least one drug associated with hyperkalemia. Mean duration to resolution of hyperkalemia was 12 ±9.9 h. Nonsteroidal anti-inflammatory drugs (HR = 1.59), highest potassium level (HR = 0.61), tissue necrosis (HR = 0.61), metabolic acidosis (HR = 0.77), and AKI (HR = 0.77) were significant independent determinants of duration prior to hyperkalemia resolution. Tissue necrosis (OR = 4.55), potassium supplementation (OR = 5.46), metabolic acidosis (OR = 4.84), use of calcium gluconate for treatment of hyperkalemia (OR = 4.62), AKI (OR = 3.89), and prolonged duration of hyperkalemia (OR = 1.06) were significant independent predictors of in-hospital mortality.

CONCLUSIONS

Tissue necrosis, potassium supplementation, metabolic acidosis, calcium gluconate for treatment of hyperkalemia, AKI and prolonged duration of hyperkalemia are independent predictors of in-hospital mortality.

Severe hyperkalemia requiring hospitalization: predictors of mortality

Introduction

Severe hyperkalemia, with potassium (K⁺) levels ≥ 6.5 mEq/L, is a potentially life-threatening electrolyte imbalance. For prompt and effective treatment, it is important to know its risk factors, clinical manifestations, and predictors of mortality.

Methods

An observational cohort study was performed at 2 medical centers. A total of 923 consecutive Korean patients were analyzed. All were 19 years of age or older and were hospitalized with severe hyperkalemia between August 2007 and July 2010; the diagnosis of severe hyperkalemia was made either at the time of admission to the hospital or during the period of hospitalization. Demographic and baseline clinical characteristics at the time of hyperkalemia diagnosis were assessed, and clinical outcomes such as in-hospital mortality were reviewed, using the institutions' electronic medical record systems.

Results

Chronic kidney disease (CKD) was the most common underlying medical condition, and the most common precipitating factor of hyperkalemia was metabolic acidosis. Emergent admission was indicated in 68.6% of patients, 36.7% had electrocardiogram findings typical of hyperkalemia, 24.5% had multi-organ failure (MOF) at the time of hyperkalemia diagnosis, and 20.3% were diagnosed with severe hyperkalemia at the time of cardiac arrest. The in-hospital mortality rate was 30.7%; the rate was strongly correlated with the difference between serum K⁺ levels at admission and at their highest point, and with severe medical conditions such as malignancy, infection, and bleeding. Furthermore, a higher in-hospital mortality rate was significantly associated with the presence of cardiac arrest and/or MOF at the time of diagnosis, emergent admission, and intensive care unit treatment during hospitalization. More importantly, acute kidney injury (AKI) in patients with normal baseline renal function was a strong predictor of mortality, compared with AKI superimposed on CKD.

Conclusions

Severe hyperkalemia occurs in various medical conditions; the precipitating factors are similarly diverse. The mortality rate is especially high in patients with severe underlying disease, coexisting medical conditions, and those with normal baseline renal function.

What is the risk of hyperkalaemia in heart failure?

INTRODUCTION

Chronic heart failure (CHF) is the only major cardiovascular disease whose prevalence and incidence are thought to be increasing. Potassium balance may be lost both through the neurohormonal mechanisms involved in cardiovascular diseases and through the drugs used in their treatment. Avoiding both hypo- and hyperkalemia is difficult but beneficial in CHF.

AREAS COVERED

Aldosterone production is decreased in the elderly, diabetic patients, and those receiving drugs that block the production or action of renin and angiotensin II. As a result, these groups, as well as those with already impaired potassium excretion due to progressive age or disease-related decline in glomerular filtration rate, are particularly vulnerable to the development of hyperkalemia.

EXPERT OPINION

Evidence from several studies suggests that, in patients with CHF, serum potassium should be maintained between 4.0 and 5.5 mEq/L. To gain the maximum benefit from aldosterone antagonists it is necessary to individualize their use; it is also necessary to carefully monitor electrolytes.

Life-threatening drug-associated hyperkalemia: a retrospective study from laboratory signals

PURPOSE

Life-threatening hyperkalemia may be induced by drugs and preventable in at-risk patients. This study was designed to describe cases of 'serious' drug-associated hyperkalemia.

METHODS

Adult subjects with a serum potassium concentration above 6.5 mmol/L detected at admission or during hospital stay in nephrology, cardiology, geriatric, emergency or intensive care units were identified by biology laboratories of hospitals and clinics located in Midi-Pyrenees (southwest France). Patients dialyzed for end-stage kidney disease were excluded. Data were collected from medical files. Hyperkalemia was defined as drug-associated if at least one drug known to increase serum potassium concentration was taken when hyperkalemia occurred (among drugs taken in outpatient care for hyperkalemia detected at admission and among drugs taken in outpatient care and continued at hospital and drugs introduced from admission for hyperkalemia detected during hospital stay).

RESULTS

Of 168 hyperkalemia cases, 102 (60.7%) were classified as drug-associated. They concerned elderly patients (mean age: 76.1 years) often having arterial hypertension and/or cardiac diseases (88.2%). Risk factors, mainly acute kidney failure, were observed in almost all cases (98.0%). Drugs predominantly involved were angiotensin-converting enzyme inhibitors (47.1%), spironolactone (41.2%), angiotensin II receptor antagonists (23.5%) and potassium supplements (23.5%). In 10% of cases, death could be attributed to hyperkalemia.

CONCLUSIONS

Laboratory databases allowed an exhaustive identification of hyperkalemia cases. The frequency of drug-related hyperkalemia and their characteristics suggest that treatment with drugs known to increase serum potassium concentration can be inappropriate, especially regarding associations or indications, and is highly risky for predisposed patients.

The positive predictive value of a hyperkalemia diagnosis in automated health care data

PURPOSE

Our objectives were to determine performance of coded hyperkalemia diagnosis at identifying (1) clinically evident hyperkalemia and (2) serum potassium>6 mmol/L.

METHODS

This retrospective observational study included 8722 patients with diabetes within an integrated healthcare system who newly initiated an angiotensin converting enzyme inhibitor, angiotensin receptor blocker, or spironolactone. The primary outcome was first hyperkalemia-associated event (hospitalization, emergency department visit or death within 24 hours of coded diagnosis and/or potassium≥6 mmol/L) during the first year of therapy. Medical records were reviewed.

RESULTS

Among a random sample of 99 patients not coded as having hyperkalemia, none had hyperkalemia upon record review. Among all 64 patients identified as having hyperkalemia, all had hospitalization or emergency department visit associated with coded diagnosis or elevated potassium. Of 55 with coded diagnosis, 42 (PPV 76%) had clinically evident hyperkalemia; 32 (PPV 58%) had potassium≥6. Of 9 identified using only potassium≥6, 7 (PPV 78%) had clinically evident hyperkalemia.

CONCLUSIONS

Nearly one-fourth of patients with coded diagnosis do not have clinically evident hyperkalemia and nearly one-half do not have potassium≥6. Because both false positives and negatives occur with coded diagnoses, medical record validation of hyperkalemia-associated outcomes is necessary.

Spironolactone use in heart failure patients with end-stage renal disease on hemodialysis: is it safe?

BACKGROUND

Spironolactone is used in the treatment of cardiovascular disease, but is contraindicated in renal dysfunction due to the risk of hyperkalemia. It is not known if patients with end-stage renal disease (ESRD) on hemodialysis are at the same risk for hyperkalemia. The objective of this study was to systematically review the evidence evaluating the incidence of hyperkalemia with spironolactone use in ESRD patients on hemodialysis.

HYPOTHESIS

Spironolactone use in ESRD patients on hemodialysis may not lead to greater incidence of hyperkalemia.

METHODS

We searched the MEDLINE, Embase, CINAHL, Cochrane, and PubMed databases up to January 2010 for English-language, human-subject clinical trials that evaluated the rate of hyperkalemia with spironolactone use in ESRD patients on hemodialysis. Search terms included were "spironolactone," "eplerenone," "aldosterone antagonist," "heart failure," "kidney failure," "hemodialysis," "dialysis," and "renal replacement therapy."

RESULTS

Six prospective trials demonstrated that spironolactone use was safe in ESRD patients on hemodialysis. The incidence of hyperkalemia with spironolactone treatment in these studies was similar to control groups. The studies involved a small population of compliant subjects who were at low risk for hyperkalemia.

CONCLUSIONS

Small pilot studies demonstrated that spironolactone treatment in ESRD patients on hemodialysis did not result in higher hyperkalemia rates. Larger studies are needed to confirm these preliminary results before spironolactone is routinely considered in hemodialysis patients.

Diabetes and drug-associated hyperkalemia: effect of potassium monitoring

BACKGROUND

Renin-angiotensin-aldosterone system (RAAS) inhibitors are associated with hyperkalemia, but there is little evidence demonstrating patients who receive potassium monitoring have a lower rate of hyperkalemia.

OBJECTIVE

To evaluate the association between potassium monitoring and serious hyperkalemia-associated adverse outcomes among patients with diabetes newly initiating RAAS inhibitor therapy.

DESIGN

Retrospective observational study.

PARTICIPANTS

Patients with diabetes without end-stage renal disease initiating RAAS inhibitor therapy between 2001 and 2006 at three integrated health care systems.

MEASUREMENTS

Potassium monitoring and first hyperkalemia-associated adverse event during the initial year of therapy. Hyperkalemia-associated adverse events included hospitalizations, emergency department visits or deaths within 24 h of hyperkalemia diagnosis and/or diagnostic potassium >or=6 mmol/l. Incidence rates were calculated in person-years (p-y). We used inverse probability propensity score weighting to adjust for differences between patients with and without monitoring; Poisson regression was used to obtain adjusted relative risks.

RESULTS

A total of 19,391 of 27,355 patients (71%) received potassium monitoring. Serious hyperkalemia-associated events occurred at an incidence rate of 10.2 per 1,000 p-y. Compared to patients without monitoring, adjusted relative risk of hyperkalemia-associated adverse events among all patients with monitoring was 0.50 (0.37, 0.66); in the subset of patients who also had chronic kidney disease (n = 2,176), adjusted relative risk was 0.29 (0.18, 0.46).

CONCLUSIONS

Patients prescribed RAAS inhibitors who have both diabetes and chronic kidney disease and receive potassium monitoring are less likely to experience a serious hyperkalemia-associated adverse event compared to similar patients who did not receive potassium monitoring. This evidence supports existing consensus-based guidelines.

Association of aldosterone concentration and mineralocorticoid receptor genotype with potassium response to spironolactone in patients with heart failure

STUDY OBJECTIVE

To identify patient-specific factors associated with spironolactone-induced potassium level elevation in patients with heart failure.

DESIGN

Prospective cohort study.

SETTING

Two adult heart failure clinics.

PATIENTS

Sixty-two adult (mean +/- SD age 54 +/- 16 yrs) aldosterone antagonist-naïve patients with heart failure.

INTERVENTION

Patients received spironolactone 12.5 mg/day, titrated to 25 mg/day if tolerated.

MEASUREMENTS AND MAIN RESULTS

Blood samples were obtained at baseline, 1 week after spironolactone initiation, and 1 week after spironolactone dose titration for assessment of baseline aldosterone level, serum chemistry, and angiotensinogen (AGT) c.-6G>A and p.M268T and mineralocorticoid receptor (NR3C2) c.215C>G and p.I180V genotypes. Patient characteristics, laboratory values, and genotypes were compared between those whose potassium levels increased by more than 0.5 mEq/L (15 patients) and those with lower potassium level elevations (47 patients) after spironolactone initiation and dose titration. Patients with a greater potassium level elevation had a higher mean +/- SD aldosterone concentration (178 +/- 92 vs 102 +/- 57 pg/ml, p=0.007) and NR3C2 215G allele frequency (50% vs 22%, p<0.01). Aldosterone concentrations positively correlated with diuretic dose (r=0.313, p=0.014) and negatively correlated with serum potassium level (r= -0.319, p=0.012). On regression analysis, factors predictive of potassium level increases greater than 0.5 mEq/L with spironolactone were aldosterone level greater than 150 pg/ml (odds ratio [OR] 30, 95% confidence interval [CI] 3.2-287] and NR3C2 215G carrier status (OR 17, 95% CI 1.6-167).

CONCLUSION

Our data suggest that potassium should be monitored with particular caution when spironolactone is started in patients with heart failure who have evidence of elevated aldosterone levels, such as high diuretic requirements, or the NR3C2 215G allele.

Increasingly restrictive definitions of hyperkalemia outcomes in a database study: effect on incidence estimates

PURPOSE

To determine the incidence of hyperkalemia-associated adverse outcomes among ambulatory patients with diabetes newly initiating renin-angiotensin-aldosterone system (RAAS) inhibitor therapy and to examine to what extent increasingly restrictive definitions of hyperkalemia-associated outcomes influenced incidence estimates.

METHODS

Retrospective cohort study of 27 355 individuals with diabetes who were new users of RAAS inhibitors at three integrated healthcare systems.

RESULTS

Using the least restrictive definition of hyperkalemia-associated outcome, an ambulatory visit (AV), inpatient hospitalization (IP), or emergency department (ED) visit co-occurring within 7 days of coded hyperkalemia diagnosis and/or potassium concentration of > or =5.5 mmol/L, the incidence rate of hyperkalemia was 30.1 per 1000 person-years (p-y). Restricting to only IP or ED visits co-occurring within 24 hours of coded diagnosis and/or potassium > or =6 mmol/L, the incidence rate was 10.2 per 1000 p-y. When this latter definition was further restricted by removing available potassium laboratory values, the incidence rate declined to 9.5 per 1000 p-y.

CONCLUSIONS

Modifying the definition of hyperkalemia-associated outcome resulted in up to threefold differences in incidence rate estimates. Our results demonstrate the value of including potassium laboratory results and AVs in identifying hyperkalemia from electronic data. Comparing incidence estimates across published studies requires consideration of differences in outcome definitions.

Incidence of risk factors for developing hyperkalemia when using ACE inhibitors in cardiovascular diseases

STUDY OBJECTIVE

To determine the incidence of and the risk factors associated with hyperkalemia, induced by ACEI-drug interactions among cardiac patients.

SETTING

Five medical and cardiology wards of a tertiary care center in Malaysia.

SUBJECTS

Five hundred cardiac inpatients, who received ACEIs concomitantly with other interacting drugs.

METHOD

This was a prospective cohort study of 500 patients with cardiovascular diseases admitted to Penang Hospital between January to August 2006, who received ACEIs concomitantly with other interacting drugs. ACEI-drug interactions of clinical significance were identified using available drug information resources. Drug Interaction Probability Scale (DIPS) was used to assess the causality of association between ACEI-drug interactions and the adverse outcome (hyperkalemia).

MAIN OUTCOME MEASURE

Hyperkalemia as an adverse clinical outcome of the interaction was identified from laboratory investigations.

RESULTS

Of the 489 patients included in the analysis, 48 (9.8%) had hyperkalemia thought to be associated with ACEI-drug interactions. Univariate analysis using binary logistic regression revealed that advanced age (60 years or more), and taking more than 15 medications were independent risk factors significantly associated with hyperkalemia. However, current and previous smoking history appeared to be a protective factor. Risk factors identified as predictors of hyperkalemia secondary to ACEI-drug interactions by multi-logistic regression were: advanced age (adjusted OR 2.3, CI 1.07-5.01); renal disease (adjusted OR 4.7, CI 2.37-9.39); hepatic disease (adjusted OR 5.2, CI 1.08-25.03); taking 15-20 medications (adjusted OR 4.4, CI 2.08-9.19); and taking 21-26 medications (adjusted OR 9.0, CI 1.64-49.74).

CONCLUSION

Cardiac patients receiving ACEIs concomitantly with potentially interacting drugs are at high risk of experiencing hyperkalemia. Old age, renal disease, hepatic disease, and receiving large number of medications are factors that may significantly increase their vulnerability towards this adverse outcome; thus, frequent monitoring is advocated.

The management of hyperkalemia in patients with cardiovascular disease

The development of hyperkalemia is common in patients with cardiac and kidney disease who are administered drugs that antagonize the renin-angiotensin-aldosterone system (RAAS). As the results of large-scale clinical trials in hypertension, chronic kidney disease, and congestive heart failure demonstrate benefits of RAAS blockade alone or, in some cases, in combination therapies, the incidence of hyperkalemia has increased in clinical practice. Although there is potential for adverse events in the presence of hyperkalemia, there also are potential benefits of RAAS blockers that support their use in high-risk patient populations. Management of hyperkalemia may be improved by identifying the levels of potassium that may potentially induce harm and using appropriate strategies to avert the levels that may be dangerous or life threatening.

Cardiorenal syndrome

The term cardiorenal syndrome (CRS) increasingly has been used without a consistent or well-accepted definition. To include the vast array of interrelated derangements, and to stress the bidirectional nature of heart-kidney interactions, we present a new classification of the CRS with 5 subtypes that reflect the pathophysiology, the time-frame, and the nature of concomitant cardiac and renal dysfunction. CRS can be generally defined as a pathophysiologic disorder of the heart and kidneys whereby acute or chronic dysfunction of 1 organ may induce acute or chronic dysfunction of the other. Type 1 CRS reflects an abrupt worsening of cardiac function (e.g., acute cardiogenic shock or decompensated congestive heart failure) leading to acute kidney injury. Type 2 CRS comprises chronic abnormalities in cardiac function (e.g., chronic congestive heart failure) causing progressive chronic kidney disease. Type 3 CRS consists of an abrupt worsening of renal function (e.g., acute kidney ischemia or glomerulonephritis) causing acute cardiac dysfunction (e.g., heart failure, arrhythmia, ischemia). Type 4 CRS describes a state of chronic kidney disease (e.g., chronic glomerular disease) contributing to decreased cardiac function, cardiac hypertrophy, and/or increased risk of adverse cardiovascular events. Type 5 CRS reflects a systemic condition (e.g., sepsis) causing both cardiac and renal dysfunction. Biomarkers can contribute to an early diagnosis of CRS and to a timely therapeutic intervention. The use of this classification can help physicians characterize groups of patients, provides the rationale for specific management strategies, and allows the design of future clinical trials with more accurate selection and stratification of the population under investigation.

Risk factors associated with a high velocity of the development of hyperkalaemia in hospitalised patients

BACKGROUND/OBJECTIVE

Drugs have been recognised as a primary or contributing cause of hyperkalaemia, especially when administered to patients with underlying risk factors. The objective of this study was to analyse the influence of the known risk factors for hyperkalaemia on the velocity of the development of hyperkalaemia.

STUDY DESIGN/METHODS

Clinical characteristics, laboratory data and medication profiles of patients developing hyperkalaemia (serum potassium>or=5.0 mmol/L) hospitalised between 2000 and 2004 in the University Hospital Basel, Switzerland, were recorded. Factors associated with a high velocity of the development of hyperkalaemia were detected using a multiple logistic regression model. Subsequently, the velocity during a defined observation period was compared between patients with one risk factor and patients with two or more risk factors. Finally, the dose effects of drugs identified as risk factors for a high velocity of the development of hyperkalaemia were analysed using two sample comparisons.

RESULTS

A random sample of 551 hospitalised patients was analysed. Compared with the drug treatment at entry, significantly more patients during the hospitalisation were treated with drugs associated with hyperkalaemia, such as heparins (p<0.001), ACE inhibitors or angiotensin receptor blockers (ARBs) [p=0.002], potassium supplements (p<0.001), potassium-sparing diuretics (p<0.001) and/or NSAIDs or selective cyclo-oxygenase (COX)-2 inhibitors (p<0.001). Risk factors associated with a high velocity of the development of hyperkalaemia were use of potassium supplements (adjusted odds ratio [OR] 3.386; 95% CI 2.251, 5.091), severe renal impairment (OR 3.119; 95% CI 2.007, 4.850), use of ACE inhibitors or ARBs (OR 2.642; 95% CI 1.742, 4.006), use of potassium-sparing diuretics (OR 2.065; 95% CI 1.310, 3.254), and diabetes mellitus (OR 1.525; 95% CI 1.005, 2.313). The velocity of the development of hyperkalaemia significantly increased in patients with two or more risk factors. Dose effects could be found for potassium supplements (p=0.006) and potassium-sparing diuretics (p=0.007), but not for ACE inhibitors or ARBs (p=0.289). In contrast, the use of kaliuretics (loop diuretics or thiazides) was associated with a decreased velocity of the development of hyperkalaemia in patients with serious renal impairment (p=0.016) and in patients treated with two or more drug classes associated with a high velocity of the development of hyperkalaemia (p=0.001).

CONCLUSIONS

Risk factors associated with a high velocity of the development of hyperkalaemia are use of potassium supplements>severe renal impairment>use of ACE inhibitors or ARBs>use of potassium-sparing diuretics>diabetes mellitus. The presence of two or more of these risk factors is associated with an even faster development of hyperkalaemia. Clinicians should be aware of these risk factors in order to avoid a rapid development of potentially life-threatening hyperkalaemia.