Hyperkalaemia in diabetes: prevalence and associations

Risk of hyperkalaemia in patients with type 2 diabetes mellitus prescribed with SGLT2 versus DPP-4 inhibitors

AIMS

To investigate the risk of hyperkalaemia in new users of sodium-glucose cotransporter 2 (SGLT2) inhibitors vs. dipeptidyl peptidase-4 (DPP-4) inhibitors among patients with type 2 diabetes mellitus (T2DM).

METHODS AND RESULTS

Patients with T2DM who commenced treatment with an SGLT2 or a DPP-4 inhibitor between 2015 and 2019 were collected. A multivariable Cox proportional hazards analysis was applied to compare the risk of central laboratory-determined severe hyperkalaemia, hyperkalaemia, hypokalaemia (serum potassium ≥6.0, ≥5.5, and <3.5 mmol/L, respectively), and initiation of a potassium binder in patients newly prescribed an SGLT2 or a DPP-4 inhibitor. A total of 28 599 patients (mean age 60 ± 11 years, 60.9% male) were included after 1:2 propensity score matching, of whom 10 586 were new users of SGLT2 inhibitors and 18 013 of DPP-4 inhibitors. During a 2-year follow-up, severe hyperkalaemia developed in 122 SGLT2 inhibitor users and 325 DPP-4 inhibitor users. Use of SGLT2 inhibitors was associated with a 29% reduction in incident severe hyperkalaemia [hazard ratio (HR) 0.71, 95% confidence interval (CI) 0.58-0.88] compared with DPP-4 inhibitors. Risk of hyperkalaemia (HR 0.81, 95% CI 0.71-0.92) and prescription of a potassium binder (HR 0.74, 95% CI 0.67-0.82) were likewise decreased with SGLT2 inhibitors compared with DPP-4 inhibitors. Occurrence of incident hypokalaemia was nonetheless similar between those prescribed an SGLT2 inhibitor and those prescribed a DPP-4 inhibitor (HR 0.90, 95% CI 0.81-1.01).

CONCLUSION

Our study provides real-world evidence that compared with DPP-4 inhibitors, SGLT2 inhibitors were associated with lower risk of hyperkalaemia and did not increase the incidence of hypokalaemia in patients with T2DM.

New Treatment Options for Hyperkalemia in Patients with Chronic Kidney Disease

Hyperkalemia may cause life-threatening cardiac and neuromuscular alterations, and it is associated with high mortality rates. Its treatment includes a multifaceted approach, guided by potassium levels and clinical presentation. In general, treatment of hyperkalemia may be directed towards stabilizing cell membrane potential, promoting transcellular potassium shift and lowering total K+ body content. The latter can be obtained by dialysis, or by increasing potassium elimination by urine or the gastrointestinal tract. Until recently, the only therapeutic option for increasing fecal K+ excretion was represented by the cation-exchanging resin sodium polystyrene sulfonate. However, despite its common use, the efficacy of this drug has been poorly studied in controlled studies, and concerns about its safety have been reported. Interestingly, new drugs, namely patiromer and sodium zirconium cyclosilicate, have been developed to treat hyperkalemia by increasing gastrointestinal potassium elimination. These medications have proved their efficacy and safety in large clinical trials, involving subjects at high risk of hyperkalemia, such as patients with heart failure and chronic kidney disease. In this review, we discuss the mechanisms of action and the updated data of patiromer and sodium zirconium cyclosilicate, considering that the availability of these new treatment options offers the possibility of improving the management of both acute and chronic hyperkalemia.

Hyperkalemia in ambulant postcardiac surgery patients during combined therapy with angiotensin-converting enzyme inhibitor, spironolactone, and diet rich in potassium: A report of two cases and review of literature

Introduction:

Potassium is the most abundant cation in intracellular compartment. A deficiency or excess of its serum concentration can be deleterious to the one suffering from a cardiac ailment. Post cardiac surgery patients are often on multiple drugs like angiotensin receptor blockers (ARBs), angiotensin converting enzyme inhibitors (ACEI), diuretics including potassium sparing diuretics which are known to predispose for hyperkalemia. We report two postoperative cases who developed life threatening hyperkalemia despite normal renal function due to a combination of factors like treatment with ACEI, potassium sparing diuretics, high dietary intake of potassium and we also discuss renal handling of potassium in this review of literature.

Methodology:

We present a case series of two cases of cardiac surgery, who presented in the emergency department with hyperkalemia, managed conservatively and detailed history revealed that patient were also on very high nutritional potassium.

Result:

Both the patients responded to conservative management and there was no recurrence of such episodes once the dose of diuretics was adjusted and diet modification advised.

Conclusion:

In India, many patients are from a low socioeconomic background and often resort to cheap and filling food items like bananas. This dietary factor should be kept in mind while prescribing patients with these medications and adequate counseling regarding diet should be done.

Hyperkalaemia in people with diabetes: occurrence, risk factors and outcomes in a Danish population-based cohort study

AIMS

To examine the incidence, risk factors and clinical outcomes of hyperkalaemia in people with diabetes in a real-world setting.

METHODS

Using Danish health registries, we identified a population-based cohort of people with first-time drug-treated diabetes, in the period 2000-2012. First, the cumulative incidence of hyperkalaemia, defined as first blood test with potassium level >5.0 mmol/l after diabetes treatment initiation, was ascertained. Second, in a case-control analysis, risk factors were compared in people with vs without hyperkalaemia. Third, clinical outcomes were assessed among individuals with hyperkalaemia in a before-after analysis, and among people with and without hyperkalaemia in a matched cohort analysis.

RESULTS

Of 68 601 individuals with diabetes (median age 62 years, 47% women), 16% experienced hyperkalaemia (incidence rate 40 per 1000 person-years) during a mean follow-up of 4.1 years. People who developed hyperkalaemia had a higher prevalence of chronic kidney disease [prevalence ratio 1.74 (95% CI 1.68-1.81)], heart failure [prevalence ratio 2.35 (95% CI 2.18-2.54)], use of angiotensin-converting enzyme inhibitors [prevalence ratio 1.24 (95% CI 1.20-1.28)], use of spironolactone [prevalence ratio 2.68 (95% CI 2.48-2.88)] and potassium supplements [prevalence ratio 1.59 (95% CI 1.52-1.67)]. In people with diabetes who developed hyperkalaemia, 31% were acutely hospitalized within 6 months before hyperkalaemia, increasing to 50% 6 months after hyperkalaemia [before-after risk ratio 1.67 (95% CI 1.61-1.72)]. The 6-month mortality rate after hyperkalaemia was 20%. Compared with matched individuals without hyperkalaemia, the hazard ratio for death was 6.47 (95% CI 5.81-7.21).

CONCLUSIONS

One in six newly diagnosed people with diabetes experienced a hyperkalaemic event, which was associated with severe clinical outcomes and death.

Mineralocorticoid receptor antagonists for heart failure: a real-life observational study

Aims

Mineralocorticoid receptor antagonists (MRAs) have been demonstrated to improve outcomes in reduced ejection fraction heart failure (HFrEF) patients. However, MRAs added to conventional treatment may lead to worsening of renal function and hyperkalaemia. We investigated, in a population‐based analysis, the long‐term effects of MRA treatment in HFrEF patients.

Methods and results

We analysed data of 6046 patients included in the Metabolic Exercise Cardiac Kidney Index score dataset. Analysis was performed in patients treated (n = 3163) and not treated (n = 2883) with MRA. The study endpoint was a composite of cardiovascular death, urgent heart transplantation, or left ventricular assist device implantation. Ten years' survival was analysed through Kaplan–Meier, compared by log‐rank test and propensity score matching.

At 10 years' follow‐up, the MRA‐untreated group had a significantly lower number of events than the MRA‐treated group (P < 0.001). MRA‐treated patients had more severe heart failure (higher New York Heart Association class and lower left ventricular ejection fraction, kidney function, and peak VO₂). At a propensity‐score‐matching analysis performed on 1587 patients, MRA‐treated and MRA‐untreated patients showed similar study endpoint values.

Conclusions

In conclusion, MRA treatment does not affect the composite of cardiovascular death, urgent heart transplantation or left ventricular assist device implantation in a real‐life setting. A meticulous patient follow‐up, as performed in trials, is likely needed to match the positive MRA‐related benefits observed in clinical trials.

How to Improve Adherence to Life-saving Heart Failure Treatments with Potassium Binders

Medications that affect the renin-angiotensin-aldosterone system (RAAS) form the mainstay of current heart failure (HF) therapy in patients with reduced ejection fraction. Concerns about the risk of hyperkalaemia have created a significant barrier to optimal RAAS inhibitor therapy in patients with HF, however, and many patients are discontinuing or receiving suboptimal doses of these lifesaving therapies. This has serious health and economic implications due to adverse renal and cardiovascular events. There is therefore an important unmet need for novel therapeutic options for the long-term management of patients with, and at risk for, hyperkalaemia. Two new potassium-binding agents, patiromer and ZS-9, have been shown to be effective and safe for the treatment of hyperkalaemia, as well as the maintenance of normokalaemia, without dose reduction or discontinuation of RAAS inhibitors. In addition, the fast onset of ZS-9 action suggests that it may be useful in the treatment of acute hyperkalaemia. These agents may allow for dose optimisation of RAAS inhibitors for the long-term maintenance and protection of the renal and cardiovascular system.

Compared effects of calcium and sodium polystyrene sulfonate on mineral and bone metabolism and volume overload in pre-dialysis patients with hyperkalemia

BACKGROUND

Hyperkalemia is prevalent in end-stage renal disease patients, being involved in life-threatening arrhythmias. Although polystyrene sulfonate (PS) is commonly used for the treatment of hyperkalemia, direct comparison of effects between calcium and sodium PS (CPS and SPS) on mineral and bone metabolism has not yet been studied.

METHODS

In a randomized and crossover design, 20 pre-dialysis patients with hyperkalemia (>5 mmol/l) received either oral CPS or SPS therapy for 4 weeks.

RESULTS

After 4-week treatments, there was no significant difference of changes in serum potassium (K) from the baseline (ΔK) between the two groups. However, SPS significantly decreased serum calcium (Ca) and magnesium (Mg) and increased intact parathyroid hormone (iPTH) values, whereas CPS reduced iPTH. ΔiPTH was inversely correlated with ΔCa and ΔMg (r = -0.53 and r = -0.50, respectively). Furthermore, sodium (Na) and atrial natriuretic peptide (ANP) levels were significantly elevated in patients with SPS, but not with CPS, whereas ΔNa and ΔANP were significantly correlated with each other in all the patients. We also found that ΔNa and Δ(Na to chloride ratio) were positively correlated with ΔHCO₃^-. In artificial colon fluid, CPS increased Ca and decreased Na. Furthermore, SPS greatly reduced K, Mg, and NH₃.

CONCLUSION

Compared with SPS, CPS may be safer for the treatment of hyperkalemia in pre-dialysis patients, because it did not induce hyperparathyroidism or volume overload.

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.

Risk of hyperkalemia in patients with moderate chronic kidney disease initiating angiotensin converting enzyme inhibitors or angiotensin receptor blockers: a randomized study

Background

Angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers are renoprotective but both may increase serum potassium concentrations in patients with chronic kidney disease (CKD). The proportion of affected patients, the optimum follow-up period and whether there are differences between drugs in the development of this complication remain to be ascertained.

Methods

In a randomized, double-blind, phase IV, controlled, crossover study we recruited 30 patients with stage 3 CKD under restrictive eligibility criteria and strict dietary control. With the exception of withdrawals, each patient was treated with olmesartan and enalapril separately for 3 months each, with a 1-week wash-out period between treatments. Patients were clinically assessed on 10 occasions via measurements of serum and urine samples. We used the Cochran–Mantel–Haenszel statistics for comparison of categorical data between groups. Comparisons were also made using independent two-sample t-tests and Welch’s t-test. Analysis of variance (ANOVA) was performed when necessary. We used either a Mann–Whitney or Kruskal-Wallis test if the distribution was not normal or the variance not homogeneous.

Results

Enalapril and olmesartan increased serum potassium levels similarly (0.3 mmol/L and 0.24 mmol/L respectively). The percentage of patients presenting hyperkalemia higher than 5 mmol/L did not differ between treatments: 37% for olmesartan and 40% for enalapril. The mean e-GFR ranged 46.3 to 48.59 ml/mint/1.73 m² in those treated with olmesartan and 46.8 to 48.3 ml/mint/1.73 m² in those with enalapril and remained unchanged at the end of the study. The decreases in microalbuminuria were also similar (23% in olmesartan and 29% in enalapril patients) in the 4 weeks time point. The percentage of patients presenting hyperkalemia, even after a two month period, did not differ between treatments. There were no appreciable changes in sodium and potassium urinary excretion.

Conclusions

Disturbances in potassium balance upon treatment with either olmesartan or enalapril are frequent and without differences between groups. The follow-up of these patients should include control of potassium levels, at least after the first week and the first and second month after initiating treatment.

Trial registration

The trial EudraCT “2008-002191-98”.

Hyperkalaemia in the age of aldosterone antagonism

Hyperkalaemia is well recognized as a medical emergency. However, with the publication of trials showing benefit with renin-aldosterone axis suppression in heart failure, the epidemiology of patients presenting with hyperkalaemia has changed. The reported incidence of rate of serious hyperkalaemia (>6.0 mEq/l of potassium) ranges from 6 to 12% in patients on spironolactone with congestive cardiac failure (CCF). A rational choice of therapy based on present evidence is different from the traditionally used algorithm, given our understanding of the physiology relevant to this patient group. This article discusses the changing face of hyperkalaemia and the present evidence and discusses options in treatment of hyperkalaemia.

Clinical factors affecting serum potassium concentration in cardio-renal decompensation syndrome

BACKGROUND

Renin-angiotensin-aldosterone system (RAAS) inhibitors are currently indispensable for the treatment of heart failure. It is well known that hyperkalemia is likely to occur in renal failure; however, it has not yet been clarified how the serum potassium concentration changes as heart failure progresses. Currently, the cardio-renal decompensation syndrome holds that the serum potassium concentration is altered similarly by both heart failure and renal failure; however, there are no definitive reports on this. In order to use RAAS inhibitors more safely and effectively in heart failure, it is necessary to understand the factors affecting serum potassium concentration in the clinical setting.

METHODS AND RESULTS

We examined the clinical factors affecting serum potassium concentration in 1035 consecutive patients with cardiovascular disease who were hospitalized in our institution. Multiple regression analysis showed that the independent factors associated with an elevated serum potassium concentration were renal insufficiency evaluated by estimated glomerular filtration rate (eGFR) (P<0.0001), diabetes mellitus evaluated by HbA(1c) (P=0.0005) and the use of RAAS inhibitors (P=0.0010). The independent factors associated with a decreased serum potassium concentration were mean blood pressure (P<0.0001), heart failure evaluated by log BNP (P=0.0164) and the use of diuretics (P=0.0232).

CONCLUSIONS

The serum potassium concentration decreases with the severity of heart failure if renal function is preserved. From the perspective of potassium homeostasis, we could use the RAAS inhibitors more aggressively in patients with heart failure who do not have renal failure.

Combining neuroendocrine inhibitors in heart failure: reflections on safety and efficacy

Neuroendocrine activation in heart failure has become the major target of pharmacotherapy for this growing epidemic. Agents targeting the renin-angiotensin-aldosterone and sympathetic nervous systems have shown cardiovascular and survival benefits in clinical trials. Beta-blockers and angiotensin-converting enzyme (ACE) inhibitors remain the mainstream initial therapy. The benefits of aldosterone antagonists have been demonstrated in advanced heart failure (spironolactone) and after myocardial infarction complicated by left ventricular dysfunction and heart failure (eplerenone). Emerging clinical evidence demonstrated that angiotensin receptor blockers may be a reasonable alternative to ACE inhibitors in patients with heart failure (candesartan) and following myocardial infarction complicated by heart failure or left ventricular dysfunction (valsartan). Angiotensin receptor blockers (candesartan) also provided incremental benefits when added to ACE inhibitors in chronic heart failure. Thus, combining neuroendocrine inhibitors in heart failure appears both biologically plausible and evidence-based. However, this approach raised concerns about side effects, such as hypotension, renal insufficiency, hyperkalemia, and others. Close follow-up and implementation of evidence-based medicine (ie, using agents and doses proven beneficial in clinical trials) should therefore be undertaken when combining neuroendocrine inhibitors.

Is routine electrolyte testing necessary for diabetic patients who present to the emergency department with moderate hyperglycemia?

OBJECTIVES

No consensus standard is established for the workup of diabetic patients with moderate hyperglycemia [fingerstick glucose of 11.00-33.00 mmol/l (200-600 mg/dl)]. We measured the incidence of serious electrolyte abnormalities in patients with moderate hyperglycemia and attempted to identify a subset of these patients who can safely forego routine electrolyte testing.

METHODS

Prospective cohort study in two affiliated emergency departments.

INCLUSION CRITERIA

Moderate hyperglycemia.

EXCLUSION CRITERIA

new onset diabetes or renal failure. The composite outcome was defined as an abnormal potassium K >5.00 or <3.50 mmol/l or diabetic ketoacidosis. Univariate analyses were performed using t-test and Fisher's exact test (alpha=0.05, two-tails). Logistic regression models were generated to identify variables that could predict the composite outcome.

RESULTS

Three hundred and ninety-nine adults were enrolled (294 type II, 38% men). Mean age was 59+/-15 (20-97 years) years. The incidence of the composite outcome was 22% (95% confidence interval, 17.8-26.0%, n=86). The univariate analysis identified potassium-altering medications and insulin use as risk factors for the composite outcome. Logistic regression analysis identified potassium-altering medications as an increased risk (relative risk: 1.64, 95% confidence interval, 1.14-2.37) and use of oral hypoglycemics as a decreased risk (relative risk: 0.62, 95% confidence interval, 0.43-0.90) of the composite outcome. Cross-validation of the model demonstrated poor sensitivity (76%) and even worse accuracy (51%).

CONCLUSION

We failed to identify any subgroup of patients with moderate hyperglycemia who can be safely excluded from routine electrolyte testing. We recommend routine electrolyte testing for all moderate hyperglycemia patients in the emergency department.

Laboratory evaluation of potassium and creatinine among ambulatory patients prescribed spironolactone: are we monitoring for hyperkalemia?

BACKGROUND

Serum potassium and creatinine evaluation is recommended in patients prescribed spironolactone, yet the proportion of ambulatory patients chronically dispensed spironolactone receiving evaluation is not well understood.

OBJECTIVE

To estimate the rate of potassium and creatinine evaluation and identify factors associated with conducting these tests among ambulatory patients dispensed spironolactone.

METHODS

A retrospective cohort study was designed to evaluate patients at 10 health maintenance organizations with ongoing spironolactone dispensing for one year (N = 2257). Potassium and creatinine evaluation were determined from administrative data. Associations between patient characteristics and laboratory testing were assessed, using logistic regression modeling.

RESULTS

Serum creatinine and potassium were evaluated in 72.3% of patients during a 13 month period. The likelihood of potassium and creatinine monitoring was greater among patients who were older (OR 1.28; 95% CI 1.17 to 1.41 per decade of life); male (OR 1.25; 95% CI 1.01 to 1.54); had diabetes (OR 1.63; 95% CI 1.31 to 2.03); received concomitant therapy with angiotensin-converting enzyme inhibitors/angiotensin receptor blockers (OR 2.23; 95% CI 1.74 to 2.87), potassium supplements (OR 1.96; 95% CI 1.51 to 2.54), or digoxin (OR 2.10 95% CI 1.48 to 2.98); or had more outpatient visits (OR 1.31; 95% CI 1.19 to 1.44). Among patients with heart failure (n = 790), factors associated with the incidence of laboratory testing were diabetes (OR 1.64, 95% CI 1.14 to 2.34), outpatient visits (OR 1.20; 95% CI 1.02 to 1.41), and digoxin therapy (OR 2.26; 95% CI 1.38 to 3.69).

CONCLUSIONS

Three-fourths of ambulatory patients dispensed spironolactone receive recommended laboratory evaluation, with monitoring more likely to be completed in patients prescribed concomitant therapy with drugs that increase hyperkalemia risk, older patients, and those with diabetes.

Analysis of factors causing hyperkalemia

OBJECTIVE

Patients with impaired renal function or diabetes are considered to be prone to hyperkalemia. Furthermore, hyperkalemia is an adverse drug reaction of inhibitors of the renin-angiotensin system (RAS) that are established to be efficacious in these patients. However, the current status of hyperkalemia in the clinical setting remains obscure.

METHODS

A total of 9,117 patients treated at Toranomon Hospital between January and October 2005, who had serum creatinine levels below 5 mg/dL were studied. Patients on dialysis and patients using cation exchange resin or diuretics that lower serum potassium were excluded.

RESULTS

Serum potassium increased significantly accompanying the increase in serum creatinine, and was significantly elevated in diabetic patients compared to non-diabetic patients. Serum potassium also increased significantly with the administration of angiotensin-II receptor blockers (ARB), angiotensin-converting-enzyme inhibitors (ACEI) or beta-blockers. A combination of diabetes and RAS inhibitor administration significantly increased serum potassium compared to each factor alone in patients with a serum creatinine level below 1.5 mg/dL but not in those with a higher serum creatinine level. According to step-wise multiple regression analyses, an elevated serum creatinine level had the strongest positive correlation with the serum potassium level, followed by diabetes, ACEI use, ARB use, and age.

CONCLUSION

Lowered renal function, diabetes, use of RAS inhibitors and old age are independent factors that increase the serum potassium level. Caution should be exercised when using RAS inhibitors in diabetic patients even if their renal function is relatively preserved. In selected patients with diabetes or impaired renal function, however, RAS inhibitors can be used without hyperkalemia.

Quantification of the risk and predictors of hyperkalemia in patients with left ventricular dysfunction: a retrospective analysis of the Studies of Left Ventricular Dysfunction (SOLVD) trials

BACKGROUND

Limited data are available to predict the occurrence of hyperkalemia. Risk assessment is complicated by the lack of consistency of definition between trials.

METHODS

We conducted a retrospective analysis of the SOLVD to evaluate the incidence of hyperkalemia and the value of several baseline characteristics as predictors of hyperkalemia in patients with left ventricular dysfunction.

RESULTS

The incidence of hyperkalemia was 6.0% and 1.1% using a definition of > or = 5.5 and > or = 6.0 mmol/L, respectively. Independent predictors of hyperkalemia (> or = 5.5 mmol/L) were randomization to enalapril, baseline serum creatinine, serum potassium, New York Heart Association functional class III or IV, a history of diabetes, and atrial fibrillation (all P < .05). The use of loop diuretics was also associated with an increased risk of hyperkalemia but only in patients included in the SOLVD prevention trial. Similar results were obtained when renal function was evaluated using the estimated creatinine clearance.

CONCLUSIONS

The definition of hyperkalemia is important when evaluating its incidence in clinical trials. Renal dysfunction, baseline serum potassium, diabetes, atrial fibrillation, New York Heart Association functional class, and treatment with an angiotensin-converting enzyme inhibitor are factors associated with the development of hyperkalemia in patients with left ventricular dysfunction. More specifically, our results suggests that before initiating drugs that can cause hyperkalemia in patients with heart failure, a strong consideration should be given to calculate creatinine clearance and that patients with a creatinine clearance < 60 mL/min should undergo a close monitoring of their serum potassium to prevent the development of hyperkalemia.

Clinical factors associated with hyperkalemia in patients with congestive heart failure1

BACKGROUND

Patients with congestive heart failure (CHF) are at risk for hyperkalemia because of coexisting comorbidities and use of multiple medications that impair potassium (K) excretion such as angiotensin converting enzyme (ACE) inhibitors.

OBJECTIVE

To identify clinical factors associated with hyperkalemia on initial presentation in patients hospitalized for CHF.

DESIGN

A case-control study.

SETTING

Two university-affiliated tertiary-care hospitals.

SUBJECTS

Using ICD-9 code for CHF, CHF admissions with hyperkalemia on presentation (cases) were identified from a population of 938 non-dialysis-dependent CHF patients. CHF admissions with normokalemia on presentation were used as controls. Hyperkalemia was defined as serum K > or = 5.6 mmol/L, and normokalemia as serum K > or = 3.5 and < or =5.5.

METHODS

Data were collected on demographic characteristics, clinical variables, comorbidity and medication use. Factors associated with hyperkalemia on initial presentation were examined.

RESULTS

Mean age did not differ between cases [76 years, standard deviation (SD) = 12] and controls (75 years, SD = 12) (P = 0.824). Mean potassium levels for cases and controls were 6.2 mmol/L (range 5.6 to 8.2) and 4.3 mmol/L respectively (P < 0.001). On multivariate analysis, diabetes mellitus [odds ratio (OR) = 2.42, 95% confidence interval (CI) = 1.04-5.59], creatinine clearance <40 mL/min (OR = 8.36, CI = 2.73-25.56), use of spironolactone (OR = 4.18, CI = 1.27-13.79), and use of ACE inhibitors (OR = 2.55, CI = 1.06-6.13) were independently associated with hyperkalemia.

CONCLUSIONS

In CHF patients, hyperkalemia on presentation is independently associated with diabetes, creatinine clearance <40 mL/min, use of spironolactone, and use of ACE inhibitors. Recommendations for use of spironolactone and ACE inhibitors in CHF, and the intensity of serum K monitoring need to be clarified to account for patients at higher risk for hyperkalemia.

Spironolactone-induced renal insufficiency and hyperkalemia in patients with heart failure

BACKGROUND

A previous randomized controlled trial evaluating the use of spironolactone in heart failure patients reported a low risk of hyperkalemia (2%) and renal insufficiency (0%). Because treatments for heart failure have changed since the benefits of spironolactone were reported, the prevalence of these complications may differ in current clinical practice. We therefore sought to determine the prevalence and clinical associations of hyperkalemia and renal insufficiency in heart failure patients treated with spironolactone.

METHODS

We performed a case control study of heart failure patients treated with spironolactone in our clinical practice. Cases were patients who developed hyperkalemia (K(+) >5.0 mEq/L) or renal insufficiency (Cr >or=2.5 mg/dL), and they were compared to 2 randomly selected controls per case. Clinical characteristics, medications, and serum chemistries at baseline and follow-up time periods were compared.

RESULTS

Sixty-seven of 926 patients (7.2%) required discontinuation of spironolactone due to hyperkalemia (n = 33) or renal failure (n = 34). Patients who developed hyperkalemia were older and more likely to have diabetes, had higher baseline serum potassium levels and lower baseline potassium supplement doses, and were more likely to be treated with beta-blockers than controls (n = 134). Patients who developed renal insufficiency had lower baseline body weight and higher baseline serum creatinine, required higher doses of loop diuretics, and were more likely to be treated with thiazide diuretics than controls.

CONCLUSIONS

Spironolactone-induced hyperkalemia and renal insufficiency are more common in our clinical experience than reported previously. This difference is explained by patient comorbidities and more frequent use of beta-blockers.

Rates of hyperkalemia after publication of the Randomized Aldactone Evaluation Study

BACKGROUND

The Randomized Aldactone Evaluation Study (RALES) demonstrated that spironolactone significantly improves outcomes in patients with severe heart failure. Use of angiotensin-converting-enzyme (ACE) inhibitors is also indicated in these patients. However, life-threatening hyperkalemia can occur when these drugs are used together.

METHODS

We conducted a population-based time-series analysis to examine trends in the rate of spironolactone prescriptions and the rate of hospitalization for hyperkalemia in ambulatory patients before and after the publication of RALES. We linked prescription-claims data and hospital-admission records for more than 1.3 million adults 66 years of age or older in Ontario, Canada, for the period from 1994 through 2001.

RESULTS

Among patients treated with ACE inhibitors who had recently been hospitalized for heart failure, the spironolactone-prescription rate was 34 per 1000 patients in 1994, and it increased immediately after the publication of RALES, to 149 per 1000 patients by late 2001 (P<0.001). The rate of hospitalization for hyperkalemia rose from 2.4 per 1000 patients in 1994 to 11.0 per 1000 patients in 2001 (P<0.001), and the associated mortality rose from 0.3 per 1000 to 2.0 per 1000 patients (P<0.001). As compared with expected numbers of events, there were 560 (95 percent confidence interval, 285 to 754) additional hyperkalemia-related hospitalizations and 73 (95 percent confidence interval, 27 to 120) additional hospital deaths during 2001 among older patients with heart failure who were treated with ACE inhibitors in Ontario. Publication of RALES was not associated with significant decreases in the rates of readmission for heart failure or death from all causes.

CONCLUSIONS

The publication of RALES was associated with abrupt increases in the rate of prescriptions for spironolactone and in hyperkalemia-associated morbidity and mortality. Closer laboratory monitoring and more judicious use of spironolactone may reduce the occurrence of this complication.

Effect of diabetes on serum potassium concentrations in acute coronary syndromes

OBJECTIVES

To compare serum potassium concentrations in diabetic and non-diabetic patients in the early phase of acute coronary syndromes.

BACKGROUND

Acute phase hypokalaemia occurs in response to adrenergic activation, which stimulates membrane bound sodium-potassium-ATPase and drives potassium into the cells. It is not known whether the hypokalaemia is attenuated in patients with diabetes because of the high prevalence of sympathetic nerve dysfunction.

METHODS

Prospective cohort study of 2428 patients presenting with acute coronary syndromes. Patients were stratified by duration of chest pain, diabetic status, and pretreatment with beta blockers.

RESULTS

The mean (SD) serum potassium concentration was significantly higher in diabetic than in non-diabetic patients (4.3 (0.5) v 4.1 (0.5) mmol/l, p < 0.0001). Multivariate analysis identified diabetes as an independent predictor of a serum potassium concentration in the upper half of the distribution (odds ratio 1.66, 95% confidence interval 1.38 to 2.00). In patients presenting within 6 hours of symptom onset, there was a progressive increase in plasma potassium concentrations from 4.08 (0.46) mmol/l in patients presenting within 2 hours, to 4.20 (0.47) mmol/l in patients presenting between 2-4 hours, to 4.24 (0.52) mmol/l in patients presenting between 4-6 hours (p = 0.0007). This pattern of increasing serum potassium concentration with duration of chest pain was attenuated in patients with diabetes, particularly those with unstable angina. Similar attenuation occurred in patients pretreated with beta blockers.

CONCLUSION

In acute coronary syndromes, patients with diabetes have significantly higher serum potassium concentrations and do not exhibit the early dip seen in non-diabetics. This may reflect sympathetic nerve dysfunction that commonly complicates diabetes.

Life-threatening hyperkalemia during combined therapy with angiotensin-converting enzyme inhibitors and spironolactone: an analysis of 25 cases

PURPOSE

The beneficial effects of spironolactone are additive to those of ACE inhibitors among patients with heart failure and/or hypertension; however, it is essential to identify patients prone to develop serious hyperkalemia during combined treatment and to evaluate the associated morbidity and mortality.

SUBJECTS AND METHODS

We studied 25 patients treated with ACE inhibitors and spironolactone who were admitted to the emergency room with a serum potassium level > 6 mmol/L. Patients were followed up for at least one month after admission.

RESULTS

The mean age of the patients (11 males, 14 females) was 74 +/- 13 years. Five patients were diabetics. On admission, the serum potassium was 7.7 +/- 0.7 mmol/L and the serum creatinine was 3.8 +/- 1.8 mg/dL; these values were significantly higher than the most recent follow-up laboratory measurements (4.6 +/- 0.5 mmol/L and 1.9 +/- 1.2 mg/dL, respectively) obtained at 13 +/- 5 weeks before admission. The arterial pH on admission was 7.3 +/- 0.1 and the plasma bicarbonate was 18 +/- 5 mmol/L. The main causes for acute renal failure were dehydration (n = 12) and worsening heart failure (n = 9). The mean daily dose of spironolactone was 57 +/- 32 mg and 12 patients were concomitantly treated with other drugs that may cause hyperkalemia. Two patients died, and 2 patients were resuscitated but survived. Hemodialysis was necessary in 17 patients; 12 patients were admitted to the intensive care unit. The mean duration of hospitalization was 12 +/- 6 days. Two patients needed to be started on maintenance hemodialysis therapy.

CONCLUSION

A combination of ACE inhibitors and spironolactone should be considered with caution and monitored closely in patients with renal insufficiency, diabetes, older age, worsening heart failure, a risk for dehydration, and in combination with other medications that may cause hyperkalemia. A daily spironolactone dose of 25 mg should not be exceeded.