Serum potassium and cardiovascular mortality

Potassium status and the risk of type 2 diabetes, cardiovascular diseases, and mortality: a meta-analysis of prospective observational studies

Epidemiological evidence on the association between potassium and cardiometabolic outcomes remains controversial. This study aimed to examine associations of dietary intake and blood and urinary levels of potassium with risk of type 2 diabetes, cardiovascular disease (CVD), and mortality. Relevant prospective studies were retrieved through a comprehensive search of four electronic databases up to July 1, 2023. Random-effects models were used to pool the study-specific relative risks (RRs) and 95% confidence intervals (CIs). Fifty-six studies were included in this meta-analysis. A higher intake of potassium was significantly associated with a 16% lower risk of CVD (RR: 0.84, 95% CI: 0.78-0.90). Similar inverse associations were also observed between potassium intake and mortality. Each 1.0 g/d increment in potassium intake was associated with a decreased risk of CVD (RR: 0.85, 95% CI: 0.80-0.91) and all-cause mortality (RR: 0.93, 95% CI: 0.88-0.99). For blood and urinary potassium levels, higher level of blood potassium increased the risk of all-cause mortality by 23% (RR: 1.23, 95% CI: 1.11-1.36). The association of blood potassium levels with mortality was nonlinear (Pnon-linearit<0.001). However, urinary potassium levels were inversely associated with the risk of all-cause mortality (RR: 0.84, 95% CI: 0.76-0.93). Our findings support the benefits of moderate potassium consumption for primary prevention of chronic diseases and premature death.

Association of Serum Potassium Levels with Mortality and Cardiovascular Events: Findings from the Chinese Multi-provincial Cohort Study

BACKGROUND

Dyskalemia involves critical electrolyte abnormalities and increases mortality risk in patients with acute clinical conditions. However, the association between dyskalemia and adverse outcomes in the general population is less well established.

OBJECTIVE

To investigate the association of serum potassium levels with mortality and cardiovascular events in the general population and to explore the characteristics of individuals at high risk.

DESIGN

A prospective cohort study.

PARTICIPANTS

A total of 5220 participants aged 50-79 years in the Chinese Multi-provincial Cohort Study.

MAIN MEASURES

Serum potassium levels were measured by the ion-selective electrode method. The outcomes were incident cardiovascular disease (CVD), CVD death, non-CVD death, and total death.

KEY RESULTS

Of the 5220 participants, 48.2% were men, and the mean age was 62.3 (SD 7.6) years. Hyperkalemia was found in 8.7% of the participants and was significantly associated with total death (hazard ratio [HR], 1.62; 95% confidence interval [CI], 1.18-2.23) and CVD death (HR, 2.12; 95% CI, 1.25-3.61) after adjustment. Furthermore, the HRs (95% CIs) of hyperkalemia combined with 2 and ≥ 3 risk factors were 2.37 (1.50-3.74) and 4.06 (2.37-6.95) for total death and 3.26 (1.56-6.80) and 8.42 (4.06-17.50) for CVD death, respectively. The 10-year cumulative incidence of total death was 17.4% for participants with 2 or more risk factors.

CONCLUSION

Hyperkalemia is associated with an increased risk of all-cause and CVD death, and this risk is more pronounced in patients with multiple risk factors. Our findings suggest that early identification and management of hyperkalemia in the general population are warranted.

Association of Serum Potassium Derangements with Mortality among Patients Requiring Continuous Renal Replacement Therapy

BACKGROUND

We aimed to assess the association between serum potassium and mortality in patients receiving continuous renal replacement therapy (CRRT).

METHODS

We studied 1,279 acute kidney injury patients receiving CRRT in a tertiary referral hospital in the United States. We used logistic regression to assess the association of serum potassium before CRRT and mean serum potassium during CRRT with 90-day mortality after CRRT initiation, using serum potassium 4.0-4.4 mmol/L as reference group.

RESULTS

Before CRRT, there was a U-shaped association between serum potassium and 90-day mortality. There was a significant increase in mortality when serum potassium before CRRT was ≤3.4 and ≥4.5 mmol/L. During CRRT, progressively increased mortality was noted when mean serum potassium was ≥4.5 mmol/L. The odds ratio of 90-day mortality was significantly higher when mean serum potassium was ≥4.5 mmol/L.

CONCLUSION

Hypokalemia and hyperkalemia before CRRT and hyperkalemia during CRRT predicts 90-day mortality. This article is protected by copyright. All rights reserved.

Fasting serum potassium and long-term mortality in healthy men

Background

Serum potassium levels have been positively associated with cardiovascular mortality, but little is known about the association with cancer mortality and death due to other causes. We examined whether serum levels of potassium were associated with long-term mortality in a healthy cohort.

Methods

Oslo Ischemia Study invited 2341 initially healthy men aged 40–59 years with no use of medication to a comprehensive health survey in 1972. Fasting serum level of potassium (mmol/L) was ascertained at baseline for 1989 men. We have complete follow-up for death throughout 2017. Cox proportional hazard models were used to calculate hazard ratios (HRs) with 95% confidence intervals (CIs) and adjusted for multiple confounders.

Results

After a median follow-up of 30 years (interquartile range 21.2–38.7), 1736 deaths were observed, of which 494 were cancer deaths, 688 cardiovascular deaths, and 536 deaths related to other causes. Restricted cubic spline analysis showed that potassium level was linearly and positively associated with long-term cancer mortality; HR per mmol/L 1.8, 95% CI 1.4–2.4. Compared with low levels of potassium (≤ 4.0 mmol/L), men with high levels (≥4.6 mmol/L) showed a significantly 78% higher risk of cancer death. A positive linear association was found for all-cause mortality (HR per mmol/L 1.6, 95% CI 1.4–1.8), and for cardiovascular (HR per mmol/L 1.4, 95% CI 1.1–1.7) and other cause mortality (HR per mmol/L 1.7, 95% CI 1.3–2.2).

Conclusions

These findings suggest that serum potassium level appears to predict long-term mortality in healthy middle-aged men, and it might imply future surveillance strategies for individuals with high serum potassium levels.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-10738-4.

Serum Sodium and Potassium Distribution and Characteristics in the US Population, National Health and Nutrition Examination Survey 2009-2016

BACKGROUND

Concern has been expressed by some that sodium reduction could lead to increased prevalence of hyponatremia and hyperkalemia for specific population subgroups. Current concentrations of serum sodium and potassium in the US population can help address this concern.

METHODS

We used data from the National Health and Nutrition Examination Survey 2009-2016 to examine mean and selected percentiles of serum sodium and potassium by sex and age group among 25 520 US participants aged 12 years or older. Logistic regression models with predicted residuals were used to examine the age-adjusted prevalence of low serum sodium and high serum potassium among adults aged 20 or older by selected sociodemographic characteristics and by health conditions or medication use.

RESULTS

The distributions of serum sodium and potassium concentrations were within normal reference intervals overall and across Dietary Reference Intake life-stage groups, with a few exceptions. Overall, 2% of US adults had low serum sodium (<135 mmol/L) and 0.6% had high serum potassium (>5 mmol/L). Prevalence of low serum sodium and high serum potassium was higher among adults aged 71 or older (4.7 and 2.0%, respectively) and among adults with chronic kidney disease (3.4 and 1.9%), diabetes (5.0 and 1.1%), or using certain medications (which varied by condition), adjusted for age; whereas, prevalence was <1% among adults without these conditions or medications.

CONCLUSIONS

Most of the US population has normal serum sodium and potassium concentrations; these data describe population subgroups at higher risk of low serum sodium and high serum potassium and can inform clinical care.

Potassium Intake and Blood Pressure: A Dose-Response Meta-Analysis of Randomized Controlled Trials

Background

Epidemiologic studies, including trials, suggest an association between potassium intake and blood pressure (BP). However, the strength and shape of this relationship is uncertain.

Methods and Results

We performed a meta‐analysis to explore the dose‐response relationship between potassium supplementation and BP in randomized‐controlled trials with a duration ≥4 weeks using the recently developed 1‐stage cubic spline regression model. This model allows use of trials with at least 2 exposure categories. We identified 32 eligible trials. Most were conducted in adults with hypertension using a crossover design and potassium supplementation doses that ranged from 30 to 140 mmol/d. We observed a U‐shaped relationship between 24‐hour active and control arm differences in potassium excretion and BP levels, with weakening of the BP reduction effect above differences of 30 mmol/d and a BP increase above differences ≈80 mmol/d. Achieved potassium excretion analysis also identified a U‐shaped relationship. The BP‐lowering effects of potassium supplementation were stronger in participants with hypertension and at higher levels of sodium intake. The BP increase with high potassium excretion was noted in participants with antihypertensive drug‐treated hypertension but not in their untreated counterparts.

Conclusions

We identified a nonlinear relationship between potassium intake and both systolic and diastolic BP, although estimates for BP effects of high potassium intakes should be interpreted with caution because of limited availability of trials. Our findings indicate an adequate intake of potassium is desirable to achieve a lower BP level but suggest excessive potassium supplementation should be avoided, particularly in specific subgroups.

Association of Abnormal Serum Potassium Levels with Arrhythmias and Cardiovascular Mortality: a Systematic Review and Meta-Analysis of Observational Studies

PURPOSE

To provide the first systematic review and meta-analysis of observational studies on the association of abnormal serum potassium and cardiovascular outcomes.

METHODS

Medline and ISI Web of Knowledge were systematically searched from inception until November 24, 2017. Data synthesis of relevant studies was performed using random effects model meta-analyses.

RESULTS

Meta-analyses included 310,825 participants from 24 studies. In the older general population, low serum potassium was associated with a 1.6-fold increased risk of supraventricular arrhythmias (risk ratio [95% confidence interval] 1.62 [1.02-2.55]). Contrarily, high serum potassium was associated with increased cardiovascular mortality (CVM) (1.38 [1.14-1.66]). In patients with acute myocardial infarction, the risk of ventricular arrhythmias was increased for high serum potassium (2.33 [1.60-3.38]). A U-shaped association was observed with a composite cardiovascular outcome in hypertensive patients (2.6-fold increased risk with hypokalemia and 1.7-fold increased risk with hyperkalemia), with CVM in dialysis patients (1.1-fold increased risk with hypokalemia and 1.4-fold increased risk with hyperkalemia) and with CVM in heart failure patients (albeit not statistically significant). Further, only hyperkalemia was associated with an increased risk of a composite cardiovascular outcome in both dialysis (1.12 [1.03-1.23]) and chronic kidney disease (1.34 [1.06-1.71]) patients.

CONCLUSIONS

Controlled clinical trials are needed to determine which populations may profit from more frequent potassium-monitoring and subsequent interventions, e.g., change or withdrawal of potassium-influencing drugs, in order to restore normal values and prevent cardiovascular outcomes.

REGISTRATION DETAILS

Registration in PROSPERO (Centre for Reviews and Dissemination University of York, York, UK): CRD42016048897 ( https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=48897 ).

Prognostic Impact of Mild Hypokalemia in Terms of Death and Stroke in the General Population-A Prospective Population Study

BACKGROUND

Potassium supplementation reduces the risk of cardiovascular mortality and stroke in population studies; however, the prognostic impact of mild hypokalemia in the general population has not been thoroughly investigated. We aimed to investigate associations between mild hypokalemia and endpoints in the general population.

METHODS

Participants (aged 48-76 years) from the general population study "Copenhagen City Heart Study" (n = 5916) were studied. Participants were divided into groups according to baseline values of plasma potassium (potassium): hypokalemia (<3.7 mmol/L, n = 758), normokalemia (3.7-4.5 mmol/L, n = 4973), and high potassium (>4.5 mmol/L, n = 185). Hypokalemia was further divided as potassium <3.4 mmol/L and 3.4-3.6 mmol/L. The primary endpoints were all-cause mortality and nonfatal validated ischemic stroke. The secondary endpoint was acute myocardial infarction (AMI). We adjusted for conventional risk factors, diuretics, and atrial fibrillation at baseline.

RESULTS

Mean potassium in the hypokalemic group was 3.5 mmol/L (range, 2.6-3.6 mmol/L) and was associated (P < 0.05) with increased systolic blood pressure, higher CHA₂DS₂-VASc score, and increased use of diuretics as compared with normokalemia. Baseline atrial fibrillation was equally frequent across groups. Median follow-up-time was 11.9 years (Q1-Q3: 11.4-12.5 years). Hypokalemia was borderline associated with increased stroke risk in a multivariable Cox model (including adjustment for competing risk) as compared with normokalemia (hazard ratio [HR] 1.40; 95% confidence interval [CI], 1.00-1.98). The subgroup with potassium <3.4 mmol/L had higher stroke risk (HR 2.10; 95% CI, 1.19-3.73) and mortality risk (HR 1.32; 95% CI, 1.01-1.74) as compared with normokalemia. Hypokalemia was not associated with AMI, and no increased risk of mortality was seen with concomitant AMI and hypokalemia. No associations were seen with high potassium.

CONCLUSION

In a general population mild hypokalemia is associated with increased stroke risk and, to a lesser degree, increased mortality risk.

Impact of admission serum potassium on mortality in patients with chronic kidney disease and cardiovascular disease

BACKGROUND

Little is known about the effect of admission potassium (K) on risk of in-hospital mortality in chronic kidney disease (CKD) and cardiovascular disease (CVD) patients.

AIM

The aim of this study was to assess the relationship between admission serum K and in-hospital mortality in all hospitalized patients stratified by CKD and/or CVD status.

DESIGN AND METHODS

All adult hospitalized patients who had admission serum K between years 2011 and 2013 were enrolled. Admission serum K was categorized into seven groups (<3.0, 3.0-3.5, 3.5-4.0, 4.0-4.5, 4.5-5.0, 5.0-5.5 and ≥5.5 mEq/L). The odds ratio (OR) of in-hospital mortality by admission serum K, using K 4.0-4.5 mEq/L as the reference group, was obtained by logistic regression analysis.

RESULTS

73,983 patients were studied. The lowest incidence of in-hospital mortality was associated with serum K within 4.0-4.5 mEq/L. A U-shaped curve emerged demonstrating higher in-hospital mortality associated with both serum K < 4.0 and >4.5 mEq/L. After adjusting for potential confounders, both serum K < 4.0 mEq/L and >5.0 mEq/L were associated with increased in-hospital mortality with ORs of 3.26 (95% CI 2.03-4.98), 2.40 (95% CI 1.89-3.04), 1.38 (95%CI 1.15-1.66), 1.89 (95% CI 1.49-2.38) and 3.62 (95%CI 2.73-4.76) when serum K were within <3.0, 3.0-3.5, 3.5-4.0, 5.0-5.5, and ≥5.5 mEq/L, respectively. In CVD patients, the highest in-hospital mortality was associated with serum K < 3.0 mEq/L (OR 1.70, 95%CI 1.31-2.18). In CKD patients, the highest in-hospital mortality was associated with serum K ≥ 5.5 mEq/L (OR 3.26, 95%CI 2.14-4.90).

CONCLUSION

Admission serum K < 4.0 mEq/L and >5.0 mEq/L were associated with increased in-hospital mortality. The mortality risk among patients with various admission potassium levels was affected by CKD and/or CVD status.

Serum Potassium Is Positively Associated With Stroke and Mortality in the Large, Population-Based Malmö Preventive Project Cohort

BACKGROUND AND PURPOSE

Low serum potassium is associated with stroke in populations with cardiovascular disease, hypertension, and diabetes mellitus but has not been studied in a mainly healthy population. We aimed to study the relation between serum potassium and incident stroke and mortality in the Malmö Preventive Project, a large cohort with screening in early mid-life and follow-up >25 years.

METHODS

Serum potassium measurements and covariates were available in 21 353 individuals (79% men, mean age 44 years). Mean follow-up time was 26.9 years for stroke analyses and 29.3 years for mortality analyses. There were 2061 incident stroke events and 8709 deaths. Cox regression analyses adjusted for multiple stroke risk factors (age, sex, height, weight, systolic blood pressure, fasting blood glucose, serum sodium, current smoking, prevalent diabetes mellitus, prevalent coronary artery disease, and treatment for hypertension) were fitted.

RESULTS

There was an independent, linear association between serum potassium, per mmol/L increase, and both stroke (hazard ratio, 1.33; 95% confidence interval, 1.17-1.52; P<0.0001) and mortality (hazard ratio, 1.20; 95% confidence interval, 1.13-1.28; P<0.0001). This was significant in subjects both older and younger than the median age (46.5 years), and there was evidence of an interaction with serum sodium. The association was positive and significant for both ischemic stroke and intracerebral hemorrhage and in both hypertensive and normotensive subjects.

CONCLUSIONS

Serum potassium, measured in early mid-life, was linearly associated with both incidence of ischemic stroke and intracerebral hemorrhage and all-cause mortality. An interaction with serum sodium implies that factors related to electrolyte balance and incident hypertension may be mediating factors.

The Relation of Serum Potassium Concentration with Cardiovascular Events and Mortality in Community-Living Individuals

BACKGROUND AND OBJECTIVES

Hyperkalemia is associated with adverse outcomes in patients with CKD and in hospitalized patients with acute medical conditions. Little is known regarding hyperkalemia, cardiovascular disease (CVD), and mortality in community-living populations. In a pooled analysis of two large observational cohorts, we investigated associations between serum potassium concentrations and CVD events and mortality, and whether potassium-altering medications and eGFR<60 ml/min per 1.73 m2 modified these associations.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Among 9651 individuals from the Multi-Ethnic Study of Atherosclerosis (MESA) and the Cardiovascular Health Study (CHS), who were free of CVD at baseline (2000-2002 in the MESA and 1989-1993 in the CHS), we investigated associations between serum potassium categories (<3.5, 3.5-3.9, 4.0-4.4, 4.5-4.9, and ≥5.0 mEq/L) and CVD events, mortality, and mortality subtypes (CVD versus non-CVD) using Cox proportional hazards models, adjusting for demographics, time-varying eGFR, traditional CVD risk factors, and use of potassium-altering medications.

RESULTS

Compared with serum potassium concentrations between 4.0 and 4.4 mEq/L, those with concentrations ≥5.0 mEq/L were at higher risk for all-cause mortality (hazard ratio, 1.41; 95% confidence interval, 1.12 to 1.76), CVD death (hazard ratio, 1.50; 95% confidence interval, 1.00 to 2.26), and non-CVD death (hazard ratio, 1.40; 95% confidence interval, 1.07 to 1.83) in fully adjusted models. Associations of serum potassium with these end points differed among diuretic users (Pinteraction<0.02 for all), such that participants who had serum potassium ≥5.0 mEq/L and were concurrently using diuretics were at higher risk of each end point compared with those not using diuretics.

CONCLUSIONS

Serum potassium concentration ≥5.0 mEq/L was associated with all-cause mortality, CVD death, and non-CVD death in community-living individuals; associations were stronger in diuretic users. Whether maintenance of potassium within the normal range may improve clinical outcomes requires future study.

Serum Potassium, Mortality, and Kidney Outcomes in the Atherosclerosis Risk in Communities Study

OBJECTIVES

To investigate the association between serum potassium, mortality, and kidney outcomes in the general population and whether potassium-altering medications modify these associations.

PATIENTS AND METHODS

We studied 15,539 adults in the Atherosclerosis Risk in Communities Study. Cox proportional hazard regression was used to investigate the association of serum potassium at baseline (1987-1989), evaluated categorically (hypokalemia, <3.5 mmol/L; normokalemia, ≥3.5 and <5.5 mmol/L; hyperkalemia, ≥5.5 mmol/L) and continuously using linear spline terms (knots at 3.5 and 5.5 mmol/L), with mortality, sudden cardiac death, incident chronic kidney disease, and end-stage renal disease. The end date of follow-up for all outcomes was December 31, 2012. We also evaluated whether classes of potassium-altering medications modified the association between serum potassium and adverse outcomes.

RESULTS

Overall, 413 (2.7%) of the participants had hypokalemia and 321 (2.1%) had hyperkalemia. In a fully adjusted model, hyperkalemia was significantly associated with mortality (hazard ratio, 1.24; 95% CI, 1.04-1.49) but not sudden cardiac death, chronic kidney disease, or end-stage renal disease. Hypokalemia as a categorical variable was not associated with any outcome; however, associations of hypokalemia with all-cause mortality and kidney outcomes were observed among those who were not taking potassium-wasting diuretics (all P for interaction, <.001).

CONCLUSIONS

Higher values of serum potassium were associated with a higher risk of mortality in the general population. Lower levels of potassium were associated with adverse kidney outcomes and mortality among participants not taking potassium-wasting diuretics.

Low-normal serum potassium is associated with an increased risk of cardiovascular and all-cause death in community-based elderly

BACKGROUND/PURPOSE

Several studies have already reported that serum potassium (SK) correlated inversely with adverse events among patients with preexisting cardiovascular disease and impaired renal function; less is known about the prognostic value of SK at the normal range in community-based elderly individuals. This study aimed to examine whether low normal SK value was associated with cardiovascular and all-cause mortalities in elderly people.

METHODS

A prospective study was conducted using two independent elderly Taiwanese community cohorts that included 2065 individuals with relatively normal SK values (2.8-5.6 mmol/L). The participants were grouped as follows: low (2.8-3.4 mmol/L), low-normal SK (3.5-3.8 mmol/L), normal (3.9-4.4 mmol/L), and high-normal SK (4.5-5.6 mmol/L). Proportional hazards model was applied to compare the association between SK concentration groups and mortality.

RESULTS

The relationship between baseline SK and all-cause and cardiovascular mortality was U-shaped, with the lowest mortality rates observed in patients with SK levels of 3.9-4.4 mmol/L. The low-normal SK group had significantly higher risks of all-cause (hazard ratio, 1.3; 95% confidence interval, 1.0-1.6) and cardiovascular mortality (hazard ratio, 1.6; 95% confidence interval, 1.1-2.3) than the normal SK group. The high-normal SK group had higher but nonsignificant risk compared to the normal group.

CONCLUSION

Our findings suggest that low-normal SK may be used as a marker of poor survival for elderly outpatient cares.

Associations between serum potassium and sodium levels and risk of hypertension: a community-based cohort study

Objective

Several studies have examined the relationships between dietary potassium and sodium and hypertension, but few have evaluated the association between serum potassium or sodium and risk of incident hypertension. We therefore investigated the associations between serum potassium and sodium and risk of incident hypertension in a Chinese community-based population.

Methods

A total of 839 normotensive individuals without cardiovascular disease from the Chinese Multi-Provincial Cohort Study who took part in the baseline examination in 2007–2008 and the follow-up survey in 2012–2013 were included in this study. Odds ratios (OR) and 95% confidence intervals (95%CI) for baseline serum potassium and sodium in relation to the risk of new-onset hypertension were evaluated using multivariate logistic regression models.

Results

During five years of follow-up, 218 (26.0%) individuals progressed to hypertension. Logistic regression adjusting for multiple confounders showed that every 1 mEq/L increment in baseline serum potassium level was associated with a 75% increased risk of hypertension (OR: 1.75; 95%CI: 1.01–3.04; P = 0.04). Compared with adults with serum potassium level of 4.20–4.79 mEq/L, adults with level ≥ 4.80 mEq/L had an 84% increased risk of hypertension (OR: 1.84; 95%CI: 1.14–2.96; P = 0.01). There was no significant association between serum sodium and risk of hypertension (OR: 0.96; 95%CI: 0.89–1.04; P = 0.33).

Conclusions

Baseline serum potassium level, but not baseline serum sodium level, was positively related to the risk of incident hypertension in the Chinese population.

Characterization of structure and function of ZS-9, a K+ selective ion trap

Hyperkalemia, a condition in which serum potassium ions (K+) exceed 5.0 mmol/L, is a common electrolyte disorder associated with substantial morbidity. Current methods of managing hyperkalemia, including organic polymer resins such as sodium polystyrene sulfonate (SPS), are poorly tolerated and/or not effective. Sodium zirconium cyclosilicate (ZS-9) is under clinical development as an orally administered, non-absorbed, novel, inorganic microporous zirconium silicate compound that selectively removes excess K+ in vivo. The development, structure and ion exchange properties of ZS-9 and its hypothesized mechanism of action are described. Based on calculation of the interatomic distances between the atoms forming the ZS-9 micropores, the size of the pore opening was determined to be ∼ 3 Å (∼ diameter of unhydrated K+). Unlike nonspecific organic polymer resins like SPS, the ZS-9 K+ exchange capacity (KEC) was unaffected by the presence of calcium (Ca2+) or magnesium ions (Mg2+) and showed>25-fold selectivity for K+ over either Ca2+ or Mg2+. Conversely, the selectivity of SPS for K+ was only 0.2-0.3 times its selectivity for Ca2+ or Mg2+in mixed ionic media. It is hypothesized that the high K+ specificity of ZS-9 is attributable to the chemical composition and diameter of the micropores, which possibly act in an analogous manner to the selectivity filter utilized by physiologic K+ channels. This hypothesized mechanism of action is supported by the multi-ion exchange studies. The effect of pH on the KEC of ZS-9 was tested in different media buffered to mimic different portions of the human gastrointestinal tract. Rapid K+ uptake was observed within 5 minutes - mainly in the simulated small intestinal and large intestinal fluids, an effect that was sustained for up to 1 hour. If approved, ZS-9 will represent a novel, first-in-class therapy for hyperkalemia with improved capacity, selectivity, and speed for entrapping K+ when compared to currently available options.

Clinical significance of incident hypokalemia and hyperkalemia in treated hypertensive patients in the antihypertensive and lipid-lowering treatment to prevent heart attack trial

Concerns exist that diuretic-induced changes in serum potassium may have adverse effects in hypertensive patients. The Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial, a large practice-based clinical trial, made it possible to examine consequences of observed changes in potassium during care in conventional practice settings. Normokalemic participants randomized to chlorthalidone (C) versus amlodipine or lisinopril as a first-step drug were stratified by year-1 potassium. Postyear-1 outcomes among hypokalemics (potassium, <3.5 mmol/L) and hyperkalemics (potassium, >5.4 mmol/L) were compared with normokalemics (potassium, 3.5-5.4 mmol/L). Year-1 hypokalemia incidence was 6.8%; incidence in C (12.9%) differed from amlodipine (2.1%; P<0.001) and lisinopril (1.0%; P<0.01). Hyperkalemia incidence (2.0%) was greater in lisinopril (3.6%) than in C (1.2%; P<0.01) or amlodipine (1.9%; P<0.01). Coronary heart disease occurred in 8.1% with hypokalemia, 8.0% with normokalemia, and 11.1% with hyperkalemia. Overall, mortality was higher in hypokalemics than in normokalemics (Cox hazard ratio, 1.21 [95% CI, 1.02-1.44]) with statistically significant (interaction, P<0.01) disparity in hazard ratios for the 3 treatment arms (hazard ratios, C=1.21, amlodipine=1.60, lisinopril=3.82). Hyperkalemia was associated with increased risk of combined cardiovascular disease (hazard ratio, 1.58 [95% CI, 1.15-2.18]) without significant treatment interactions. In conventional practice settings, the uncommon appearance of hyperkalemia was associated with increased cardiovascular disease risk. Hypokalemia was associated with increased mortality; however, the statistically significant heterogeneity in hazard ratios across treatment groups strongly suggests that the observed increase in mortality is unrelated to the specific effects of C. Thus, for most patients, concerns about potassium levels should not influence the clinician's decision about initiating hypertension treatment with low-moderate doses of thiazide diuretics (12.5-25.0 mg of C).

A comparative study of the prevalence of hyperkalemia with the use of angiotensin-converting enzyme inhibitors versus angiotensin receptor blockers

Background and objectives

Angiotensin-converting enzyme inhibitors (ACEI) and angiotensin receptor blockers (ARB) are increasingly used in a variety of settings including heart failure, renal failure, arterial hypertension, and diabetic nephropathy. The objective of this study was to investigate the prevalence of hyperkalemia with ACEI and ARB use, in a population of the United States veterans.

Design, settings, material, and measurements

Retrospective observational cohort study of 1163 patients on ACEIs and 1168 patients on ARBs in a single Veterans Affairs Medical Center. Electronic medical records were reviewed over a 12-month period with data collected on various demographic, laboratory, comorbidity, and medication related variables.

Results

Hyperkalemia (>5 mEq/L) was observed in 20.4% of patients on ACEIs and 31.0% on ARBs. Severe hyperkalemia (6 mEq/L or higher), was observed in 0.8% of ACEI and 2.8% of ARB users. In univariate logistic regression analyses, diabetes mellitus; serum glucose, total carbon dioxide content, creatinine, and estimated glomerular filtration rate (GFR) were significantly associated with hyperkalemia. ARB use, when compared to ACEI, was associated with a 42% increase in odds of hyperkalemia (odds ratio [OR] = 1.42; p = 0.001) in a model including adjustment for GFR and a 56% increase in odds of hyperkalemia (OR = 1.56; p < 0.001) in a model including adjustment for serum creatinine.

Conclusions

Hyperkalemia, associated with the use of ACEIs and ARBs, is usually mild and severe hyperkalemia is rare. Hyperkalemia is more common with ARBs than ACEIs. ARB use, when compared to ACEI use, may significantly and independently be associated with increased odds of hyperkalemia.

Mortalité hospitalière et durée de séjour des patients non programmés en médecine interne: valeur pronostique de paramètres biochimiques usuels à l'admission

PURPOSE

Little is known about prognosis values of biochemical markers in internal medicine patients. We have examined retrospectively the relationship between inhospital mortality or stay duration and several biochemical markers commonly performed on admission in internal medicine patients.

METHODS

Among all stays unplanned in our department during the year 2004, we collected data about 8 blood biochemical markers (sodium, potassium, chloride, bicarbonate, anion gap, urea nitrogen, creatinin, proteins), performed between the day before and the day after admission. Mixed Cox regression models computed hazard ratios for mortality associated with biochemical markers concentration. The relationship between biochemical markers concentration and duration stay was investigated in mixed linear regression models.

RESULTS

In 2004 our department totalized 1199 unplanned stays by 1054 distinct patients (age: 69.9+/-19.2 y, women: 59.2%), among which 59 deceased during stay. Biochemical markers were available for 977 (81.5%) stays (stay duration: 17.5+/-16.0 days). Inhospital mortality was significantly associated with plasma concentration on admission of potassium, proteins, anion gap and with urea nitrogen/creatinin ratio. Among survivors, duration stay was significantly associated with plasma concentration on admission of sodium, chlore, and anion gap.

CONCLUSION

Biochemical markers performed on admission need particular attention as they provide immediate information about short term prognosis of internal medicine patients.

Intake of fruit and vegetables and risk of stroke: an overview

PURPOSE OF REVIEW

This review presents recent scientific advances in understanding the role of fruit and vegetables in lowering stroke risk, based on epidemiological and clinical studies.

RECENT FINDINGS

Recent studies indicate that high dietary intake of fruit and vegetables is associated with reduced risk of stroke and other cardiovascular outcomes. Both observational studies and interventional trials have consistently shown this inverse relationship. Multiple mechanisms may underlie the apparent beneficial effect.

SUMMARY

Public health policy should promote increased dietary intake of fruit and vegetables, as this may have a substantial positive effect on stroke prevention.

Experimental hyperkalaemia in rabbits: effects of salbutamol and norepinephrine treatments on blood biochemistry and electrocardiography

The effects of salbutamol and norepinephrine on the electrocardiogram (ECG), serum potassium level and enzyme activities were studied in rabbits with hyperkalaemia; norepinephrine and salbutamol may be therapeutically useful. For induction of hyperkalaemia, 300 mM KCl solution was used and then isotonic saline solution containing 6 microg salbutamol and 3.9 microg norepinephrine per ml were administered. Norepinephrine and salbutamol decreased the serum potassium from 7.36 +/- 0.26 and 7.21 +/- 0.31 mmol/L to 5.62 +/- 0.27 and 4.35 +/- 0.33 mmol/L, respectively, and caused the ECG changes (flatness of P wave, widening of QRS complex and bradycardia) to return to the control conditions (time 0). Norepinephrine, but not salbutamol, decreased the activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and lactate dehydrogenase (LDH) to the control levels. These results suggest that monitoring of the enzyme activities might be useful as it yields indexes suitable for evaluating the therapeutic approach with norepinephrine in hyperkalaemia.