Race, Serum Potassium, and Associations With ESRD and Mortality

Hypokalaemia in pregnancy - Prevalence, underlying causes, and an approach to investigation

Objective

To investigate the prevalence and aetiology of hypokalaemia in pregnancy.

Methods

This was a five-year retrospective audit of women who received care at a tertiary hospital, who developed hypokalaemia during pregnancy and within three weeks postpartum. Serum potassium and magnesium levels cause(s) of hospitalization and investigations for hypokalaemia were obtained from hospital records.

Results

One hundred and ten women developed hypokalaemia during pregnancy and the immediate postpartum period, representing 0.36% of total births. Ninety-one per cent of patients had mild to moderate hypokalaemia (K 2.6-3.1 mmol/L), while 9% had severe hypokalaemia (K < 2.6 mmol/L). The most common associations of hypokalaemia were infection (38%), vomiting (18%), hypertensive disorders (12%) and postpartum haemorrhage (9%). Twenty-four patients did not have a clear underlying aetiology of hypokalaemia, but only five had further investigations.

Conclusions

There was inadequate investigation and follow-up of hypokalaemia, particularly in women in whom an obvious cause was not apparent.

Sacubitril-Valsartan in Patients Requiring Hemodialysis

Importance

Randomized clinical trials have shown that sacubitril-valsartan reduces the risks of mortality and hospitalization in patients with heart failure with reduced ejection fraction (HFrEF), but patients with kidney failure requiring dialysis were excluded.

Objective

To investigate the comparative effectiveness of sacubitril-valsartan vs angiotensin-converting enzyme inhibitors or angiotensin receptor blockers (ACEIs or ARBs) in patients with HFrEF requiring hemodialysis.

Design, Setting, and Participants

This retrospective, 1:1 propensity score-matched comparative effectiveness study included patients who were 18 years or older with HFrEF, enrolled in Medicare Parts A, B, and D, and survived at least 90 days receiving in-center hemodialysis from July 8, 2015, to December 31, 2020. Patients were excluded for less than 180 days of continuous Medicare Parts A, B, and D primary payer coverage or prior dispensing of sacubitril-valsartan. Data analysis was conducted from September 23, 2023, to June 25, 2024.

Exposures

New use of sacubitril-valsartan vs new or continued use of ACEIs or ARBs.

Main Outcomes and Measures

The associations between initiation of sacubitril-valsartan therapy and all-cause mortality, cardiovascular mortality, all-cause hospitalization, and HF hospitalization were assessed using Cox proportional hazards regression models in a propensity score-matched sample.

Results

Participants included 1:1 matched pairs of 1434 sacubitril-valsartan users and 1434 ACEI or ARB users (mean [SD] age, 64 [13] years). Of the 2868 matched participants, 996 (65%) were male; 987 (34%) were Black or African American and 1677 (58%) were White; and median dialysis vintage was 3.8 (IQR, 1.8-6.3) years. The median follow-up was 0.9 (IQR, 0.4-1.7) years. Sacubitril-valsartan (vs ACEI or ARB) therapy was associated with a reduction in all-cause mortality (hazard ratio [HR], 0.82 [95% CI, 0.73-0.92]) and all-cause hospitalization (HR, 0.86 [95% CI, 0.79-0.93]) but not cardiovascular mortality (HR, 1.01 [95% CI, 0.86-1.19]) or HF hospitalization (HR, 0.91 [95% CI, 0.82-1.02]). There was a decrease in hyperkalemia (HR, 0.71 [95% CI, 0.62-0.81]) and no difference in hypotension (HR, 0.99 [95% CI, 0.83-1.19]). Only 195 participants (14%) ever received the maximum combination dose of sacubitril (97 mg twice daily) and valsartan (103 mg twice daily).

Conclusions and Relevance

In this comparative effectiveness study of patients with HFrEF requiring hemodialysis, sacubitril-valsartan therapy was associated with beneficial effects in all-cause mortality and all-cause hospitalization.

The relationship between potassium levels and 28-day mortality in sepsis patients: Secondary data analysis using the MIMIC-IV database

Objective

The goal of the research is to investigate the link between serum potassium levels and death after 28 days in sepsis patients, utilizing an extensive sample of patients from the multi-center Medical Information Mart for Intensive Care IV (MIMIC-IV) database. Current research on serum potassium levels and 28-day mortality in sepsis patients is questionable. This study adds to the growing body of evidence linking serum potassium levels to the 28-day possibility of death in patients with sepsis.

Methods

We collected 349,08 patients with sepsis from the retrospective cohort MIMIC-IV database, using serum potassium level on the first day of admission to the intensive care unit as the exposure variable and mortality at 28 days as the outcome variable. And controlled for confounding characteristics including gender, age, ethnicity, and vital signs during admission.

Results

Serum potassium has a U-shaped connection with 28-day mortality in patients suffering from sepsis. The turning point was 4.10 mmol/L (95 % confidence interval: 4.03 to 4.22). Serum potassium and 28-day mortality were negatively linked on the inflection point's left side (OR: 0.72; 95 % CI: 0.63 to 0.83, P < 0.0001); on the opposing side of the point of inflexion, serum potassium was enthusiastically attached to 28-day mortality. (OR: 1.13; 95 % CI: 1.06 to 1.21, P < 0.0001).

Conclusion

The research conducted found that too high or too low potassium levels were linked to a 28-day risk of mortality in humans with sepsis.

Hyperkalemia Recurrence and Its Association With Race and Ethnicity in United States Veterans: A Retrospective Cohort Study

INTRODUCTION

Information on whether race and ethnicity are associated with a greater risk of recurrent hyperkalemia is limited. The aim of this study was to examine the association between race or ethnicity and recurrent hyperkalemia in a population of US veterans.

METHODS

This retrospective study used the US Veterans Affairs database to identify adults (aged ≥18 years) with at least one serum potassium measurement during the study period who ever experienced hyperkalemia (serum potassium > 5.0 mmol/L). The proportion of patients with hyperkalemia recurrence (≥1 subsequent event) within one year was determined for different race and ethnicity groups. The association between patient race and ethnicity and the risk of hyperkalemia recurrence within one year after the index hyperkalemia event was analyzed using competing risk regression.

RESULTS

Among a total of 1,493,539 veterans with incident hyperkalemia (median age (interquartile range): 61.0 years (54.0, 71.0)), recurrence within one year occurred in 19.1% of Black, 16.0% of Native Hawaiian/other Pacific Islander, 15.1% of White, 14.9% of American Indian/Alaska Native, and 13.1% of Asian patient groups. Recurrent hyperkalemia occurred in 18.1% of Hispanic and 15.6% of non-Hispanic patient groups. In a fully-adjusted regression model, recurrent hyperkalemia risk was significantly higher in Black versus White patient groups (subhazard ratio (sHR), 1.17; 95% confidence interval (CI), 1.16-1.19; p< 0.0001) and in Hispanic versus non-Hispanic patient groups (sHR, 1.30; 95% CI, 1.28-1.33; p< 0.0001).

DISCUSSION/CONCLUSION

Among US veterans with incident hyperkalemia, the risk of recurrent hyperkalemia was higher in Black and Hispanic patient groups. This information may be useful for health system screenings to risk stratify patient groups and both guide the frequency of serum potassium monitoring and better understand the root causes of group differences.

Comparing a range of potassium-enriched low sodium salt substitutes to common salt: Results of taste and visual tests in South African adults

BACKGROUND AND AIMS

Potassium-enriched low sodium salt substitutes (LSSS), which replace a proportion of sodium chloride (NaCl) with potassium chloride (KCl), have been shown to reduce blood pressure and offer a potential solution to address the high burden of hypertension in South Africa. However, it is unknown which proportions of KCl in LSSS are acceptable. We compared the taste and visual acceptability of various LSSS in South African adults.

METHODS AND RESULTS

Fifty-six adults underwent double-blind taste and visual tests of four LSSS (35%KCl/65%NaCl; 50%KCl/50%NaCl; 66%KCl/34%NaCl; 100%KCl) in comparison to 100%NaCl (common salt). Participants scored each product by taste ranking, taste perception and likeliness to use. Participants then visually inspected the five products and attempted to identify which was which. Almost half (45 %) of participants ranked the taste of 50%KCl/50 %NaCl as fantastic or really good. Furthermore, 62 % of participants liked and would be happy to use the 50 %KCl/50 %NaCl or felt this tasted like common salt. Only 12 % rated the 100%KCl highly for taste, and over half reported being unlikely to use this. Most participants (57.3 % and 36.4 %) were able to visually identify 100%NaCl and 100%KCl, while identification of other blends was generally poor. Responses were similar for 35%KCl/65%NaCl and 66%KCl/34%NaCl throughout.

CONCLUSION

Our findings suggest that the taste of the 50%KCl salt substitute would be well tolerated by South African adults, most of which could not visually differentiate between this salt substitute and common salt.

Dieta de la Milpa: A Culturally-Concordant Plant-Based Dietary Pattern for Hispanic/Latine People with Chronic Kidney Disease

Chronic kidney disease (CKD) disproportionately affects minorities in the United States, including the Hispanic/Latine population, and is a public health concern in Latin American countries. An emphasis on healthy dietary patterns, including the Mediterranean and the Dietary Approaches to Stop Hypertension (DASH) diets, has been suggested as they are associated with a lower incidence of CKD, slower CKD progression, and lower mortality in kidney failure. However, their applicability may be limited in people from Latin America. The Dieta de la Milpa (Diet of the Cornfield) was recently described as the dietary pattern of choice for people from Mesoamerica (Central Mexico and Central America). This dietary pattern highlights the intake of four plant-based staple foods from this geographical region, corn/maize, common beans, pumpkins/squashes, and chilies, complemented with seasonal and local intake of plant-based foods and a lower intake of animal-based foods, collectively classified into ten food groups. Limited preclinical and clinical studies suggest several health benefits, including cardiometabolic health, but there is currently no data concerning CKD. In this narrative review, we describe and highlight the potential benefits of the Dieta de la Milpa in CKD, including acid-base balance, protein source, potassium and phosphorus management, impact on the gut microbiota, inflammation, and cultural appropriateness. Despite these potential benefits, this dietary pattern has not been tested in people with CKD. Therefore, we suggest key research questions targeting measurement of adherence, feasibility, and effectiveness of the Dieta de la Milpa in people with CKD.

Machine learning algorithms identify hypokalaemia risk in people with hypertension in the United States National Health and Nutrition Examination Survey 1999-2018

BACKGROUND

Hypokalaemia is a side-effect of diuretics. We aimed to use machine learning to identify features predicting hypokalaemia risk in hypertensive patients.

METHODS

Participants with hypertension in the United States National Health and Nutrition Examination Survey 1999-2018 were included for analysis. To select the most suitable algorithm, we tested and evaluated five machine learning algorithms commonly employed in epidemiological studies: Logistic Regression, k-Nearest Neighbor, Random Forest, Recursive Partitioning and Regression Trees, and eXtreme Gradient Boosting. These algorithms were accessed using a set of 38 screened features. We then selected the key hypokalaemia-associated features in the hypertension group and their cardiovascular diseases (CVD) subgroup using the SHapley Additive exPlanations (SHAP) values. Using SHAP values, the key features and their impact pattern on hypokalaemia risk were determined.

RESULTS

A total of 25,326 hypertensive participants were included for analysis, of whom 4,511 had known CVD. The Random Forest algorithm had the highest AUROC (hypertension dataset: 0.73 [95%CI, 0.71-0.76]; CVD subgroup: 0.72 [95%CI, 0.66-0.78]). Moreover, the nomogram based on the top twelve key features screened by random forest retained good performance: age, sex, race, poverty income ratio, body mass index, systolic and diastolic blood pressure, non-potassium-sparing diuretics use and duration, renin-angiotensin blockers use and duration, and CVD history in hypertension dataset; while in CVD subgroup, the additional key features were comorbid diabetes, education level, smoking status, and use of bronchodilators.

CONCLUSION

Our predictive model based on the random forest algorithm performed best among the tested and evaluated five algorithms. Hypokalaemia-associated key features have been identified in hypertensive patients and the subgroup with CVD. These findings from machine learning facilitate the development of artificial intelligence to highlight hypokalaemia risk in hypertension patients.

Clinical outcomes by serum potassium levels for patients hospitalized for heart failure: Secondary analysis of data from the China National Heart Failure Registry

BACKGROUND

Dyskalemia is a mortality risk factor in patients with heart failure (HF).

HYPOTHESIS

We described the prevalence of dyskalemia, and clinical outcomes by serum potassium (sK) levels, in Chinese patients hospitalized for HF.

METHODS

In this secondary analysis of the prospective China National Heart Failure Registry, adult patients hospitalized between January 1, 2013 and June 30, 2015 who had at least one baseline sK measurement were followed for up to 3 years after discharge. The use of renin-angiotensin-aldosterone system inhibitors at baseline and clinical outcomes during follow-up were compared among sK groups.

RESULTS

Among 6950 patients, 5529 (79.6%) had normokalemia (sK >3.5-5.0 mmol/L), 1113 (16.0%) had hypokalemia (sK 0-3.5 mmol/L), and 308 (4.4%) had hyperkalemia (sK >5.0 mmol/L). Baseline characteristics that were most common in patients with hyperkalemia than those with hypo- and normokalemia included older age, HF with reduced ejection fraction, New York Heart Association Class III/IV status, hypertension, and chronic kidney disease. Use of angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin receptor blockers (ARBs) differed across sK groups (p = .0001); reported in 64.1%, 63.4%, and 54.5% of patients with hypo-, normo-, and hyperkalemia, respectively. Overall, 26.6%, 28.6%, and 36.0% of patients with hypo-, normo-, and hyperkalemia had rehospitalization for worsened HF, or cardiovascular mortality; p = .0057 for between-group comparison.

CONCLUSIONS

Patients with hyperkalemia received ACEIs or ARBs for HF treatment at baseline less frequently than those with hypo- or normokalemia, and had worse prognoses. This warrants further investigation into effective hyperkalemia management in HF.

Hyperkalemia in CKD: an overview of available therapeutic strategies

Hyperkalemia (HK) is a life-threatening condition that often occurs in patients with chronic kidney disease (CKD). High serum potassium (sKsK) is responsible for a higher risk of end-stage renal disease, arrhythmias and mortality. This risk increases in patients that discontinue cardio-nephroprotective renin-angiotensin-aldosterone system inhibitor (RAASi) therapy after developing HK. Hence, the management of HK deserves the attention of the clinician in order to optimize the therapeutic strategies of chronic treatment of HK in the CKD patient. The adoption in clinical practice of the new hypokalaemic agents patiromer and sodium zirconium cyclosilicate (SZC) for the prevention and chronic treatment of HK could allow patients, suffering from heart failure and chronic renal failure, to continue to benefit from RAASi therapy. We have updated a narrative review of the clear variables, correct definition, epidemiology, pathogenesis, etiology and classifications for HK among non-dialysis CKD (ND CKD) patients. Furthermore, by describing the prognostic impact on mortality and on the progression of renal damage, we want to outline the strategies currently available for the control of potassium (K+) plasma levels.

Chronic Hyperkaliemia in Chronic Kidney Disease: An Old Concern with New Answers

Increasing potassium intake ameliorates blood pressure (BP) and cardiovascular (CV) prognoses in the general population; therefore the World Health Organization recommends a high-potassium diet (90–120 mEq/day). Hyperkalaemia is a rare condition in healthy individuals due to the ability of the kidneys to effectively excrete dietary potassium load in urine, while an increase in serum K⁺ is prevalent in patients with chronic kidney disease (CKD). Hyperkalaemia prevalence increases in more advanced CKD stages, and is associated with a poor prognosis. This scenario generates controversy on the correct nutritional approach to hyperkalaemia in CKD patients, considering the unproven link between potassium intake and serum K⁺ levels. Another concern is that drug-induced hyperkalaemia leads to the down-titration or withdrawal of renin-angiotensin system inhibitors (RASI) and mineralocorticoids receptors antagonists (MRA) in patients with CKD, depriving these patients of central therapeutic interventions aimed at delaying CKD progression and decreasing CV mortality. The new K⁺-binder drugs (Patiromer and Sodium-Zirconium Cyclosilicate) have proven to be adequate and safe therapeutic options to control serum K⁺ in CKD patients, enabling RASI and MRA therapy, and possibly, a more liberal intake of fruit and vegetables.

Hypokalaemia associated with hydrochlorothiazide used in the treatment of hypertension in NHANES 1999-2018

Hydrochlorothiazide is the most common thiazide diuretic used for hypertension in the US. Yet, hypokalaemia is a well-recognised adverse effect. To evaluate the prevalence and factors associated with hypokalaemia (serum potassium < 3.5 mmol/L) among hydrochlorothiazide users, we included US adults aged ≥20 years in the 1999-2018 National Health and Nutrition Examination Survey. Participants were categorised according to the use of hydrochlorothiazide and other antihypertensive agents. Factors associated with hypokalaemia, including demographics and prescription patterns (monotherapy vs single-pill fixed-dose combination vs polytherapy) were studied using multivariable logistic regression. Hypokalaemia was present in 12.6% of the hydrochlorothiazide users, equivalent to ~2.0 million US adults. Women (adjusted OR, 2.22; 95% CI, 1.74-2.83), non-Hispanic blacks (adjusted OR, 1.65; 95% CI, 1.31-2.08), underweight (adjusted OR, 4.33; 95% CI, 1.34-13.95), and participants taking hydrochlorothiazide for five years or more (adjusted OR, 1.47; 95% CI, 1.06-2.04) had a higher risk of hypokalaemia. Compared to monotherapy, fixed-dose combination therapy (adjusted OR, 0.32; 95% CI, 0.21-0.48) was associated with the lowest risk. Among those taking potassium supplements, hypokalaemia was found in 27.2% of participants on monotherapy and 17.9% on polytherapy. The prevalence of hypokalaemia among hydrochlorothiazide users was considerable, even among participants who also took potassium supplements. Women, ethnic minorities, underweight, monotherapy, and participants with long-term therapy are more likely to have hypokalaemia. Regular monitoring of potassium and combination with potassium-sparing drugs are needed.

Association between serum potassium and risk of all-cause mortality among chronic kidney diseases patients: A systematic review and dose-response meta-analysis of more than one million participants

We aimed to perform a meta-analysis, using prospective cohort studies, to test the association between serum potassium and all-cause mortality among chronic kidney diseases (CKD) patients. A systematic search was performed using PubMed-MEDLINE and Scopus, up to July 2020. Prospective cohort studies which reported risk estimates of all-cause mortality in CKD patients with different serum potassium levels were included in the present meta-analysis. Thirteen studies were included in the analysis. A nonlinear dose-response meta-analysis suggested that there is a J-shaped association between serum potassium levels and the risk of all-cause mortality, with a nadir at serum potassium of 4.5 mmol/L. Subgroup analyses indicated that the strength and shape of the association between serum potassium and all-cause mortality may be influenced by age. Our meta-analysis provides supportive evidence that there is a J-shape association between serum potassium and all-cause mortality among CKD patients.

Hyperkalemia with RAAS inhibition: Mechanism, clinical significance, and management

Renin-angiotensin-aldosterone system (RAAS) inhibitors are evidence-based treatments for a number of conditions including hypertension, diabetes mellitus, chronic kidney disease, and congestive heart failure. Among the most common adverse effects of RAAS inhibitors is hyperkalemia which results from either reduced secretion of aldosterone or increased resistance to aldosterone. Many of the conditions for which RAAS inhibitors are recommended further amplify the risk for hyperkalemia in and of themselves. RAAS inhibitor-related hyperkalemia is associated with an increased risk for cardiovascular events, hospitalizations, and death. Yet discontinuation of RAAS inhibitors for patients with chronic kidney disease and congestive heart failure is also associated with an increased risk for cardiovascular events, hospitalizations, and death. Therefore, clinicians are often left to struggle with the dilemma of the best management approach to RAAS inhibitor-related hyperkalemia. The ideal solution involves pharmacotherapies that are safe and effective in mitigating hyperkalemia and allow patients to continue to receive the beneficial effects from RAAS inhibitors. In this regard, modern pharmacologic agents such as patiromer and zirconium cyclosilicate are providing a mechanism whereby physicians are better equipped to maintain their patients on RAAS inhibitors.

Randomized Trial on the Effects of Dietary Potassium on Blood Pressure and Serum Potassium Levels in Adults with Chronic Kidney Disease

In the general population, an increased potassium (K) intake lowers blood pressure (BP). The effects of K have not been well-studied in individuals with chronic kidney disease (CKD). This randomized feeding trial with a 2-period crossover design compared the effects of diets containing 100 and 40 mmol K/day on BP in 29 adults with stage 3 CKD and treated or untreated systolic BP (SBP) 120–159 mmHg and diastolic BP (DBP) <100 mmHg. The primary outcome was 24 h ambulatory systolic BP. The higher-versus lower-K diet had no significant effect on 24 h SBP (−2.12 mm Hg; p = 0.16) and DBP (−0.70 mm Hg; p = 0.44). Corresponding differences in clinic BP were −4.21 mm Hg for SBP (p = 0.054) and −0.08 mm Hg for DBP (p = 0.94). On the higher-K diet, mean serum K increased by 0.21 mmol/L (p = 0.003) compared to the lower-K diet; two participants had confirmed hyperkalemia (serum K ≥ 5.5 mmol/L). In conclusion, a higher dietary intake of K did not lower 24 h SBP, while clinic SBP reduction was of borderline statistical significance. Additional trials are warranted to understand the health effects of increased K intake in individuals with CKD.

Serum potassium variability is associated with increased mortality in a large cohort of hospitalized patients

BACKGROUND

Few studies have examined the role of serum potassium concentrations [K+] variability on clinical outcomes is still poorly investigated. Aim of our study was to analyze the association between serum potassium concentrations ([K+]) disorders, with focus on [K+] variability, and mortality in a large, unselected cohort of hospitalized patients.

METHODS

We performed a retrospective observational cohort study on the inpatient population admitted to Fondazione Policlinico Universitario A. Gemelli IRCCS between January 1, 2010 and December 31, 2014 with inclusion of adult patients with [K+] measurements ≥2. The outcome of interest was in-hospital mortality. The exposures of interest were [K+] fluctuations and hypo-hyperkalemia and mixed dyskalemia during hospital stay. [K+] variability was evaluated using the coefficient of variation (CV). Logistic regression models were fitted to obtain odds ratios (ORs) and 95% confidence intervals (CIs) for the association between the exposures of interest and in-hospital death.

RESULTS

Overall, 64,507 patients met our inclusion criteria. During a median follow-up of 8 days, 965 patients (1.5%) died. Multivariable adjusted logistic models suggested a higher risk for death in patients in the 3rd (OR 1.45, 95% CI 1.13, 1.88, p = 0.003) and 4th (OR 3.30, 95% CI 2.64, 4.16, p < 0.001) highest quartiles of [K+] CV compared with those in the lowest quartile with a significant linear trend across quartiles (p-trend <0.001) Results did not change after restricting the analyses to patients with normokaliemia (NK). All [K+] disorders were independently associated with an increased risk of in-hospital death compared with NK.

CONCLUSIONS

High [K+] variability is an independent risk factor of in-hospital mortality, even within the normal [K+] range.

Race-Specific Comparisons of Antihypertensive and Metabolic Effects of Hydrochlorothiazide and Chlorthalidone

BACKGROUND

Chlorthalidone is recommended over hydrochlorothiazide (HCTZ) as the preferred thiazide, but the supporting evidence is not robust at routinely used doses, or in whites vs blacks, in whom differences in response to thiazides are well known. We compare the efficacy and safety of HCTZ and chlorthalidone as first-line therapies for white and black hypertensive patients.

METHODS

We compared treatment-related outcomes between the HCTZ arm (12.5 mg for 2-3 weeks; 25 mg for additional 6 weeks) of the Pharmacogenomic Evaluation of Antihypertensive Responses (PEAR, n = 376) and chlorthalidone arm (15 mg for 2 weeks; 25 mg for additional 6 weeks) of PEAR-2 (n = 326) clinical trials, in 17-65-year-old mild-moderate uncomplicated hypertensive whites and blacks.

RESULTS

Mean systolic/diastolic blood pressure (SBP/DBP) reduction with HCTZ vs chlorthalidone: 8 ± 8/4 ± 5 vs 12 ± 9/7 ± 5 mm Hg in whites (P < 10^-6 SBP and DBP); 12 ± 10/7 ± 6 vs 15 ± 10/9 ± 6 in blacks (P = .008 SBP, P = .054 DBP). Treatment with HCTZ vs chlorthalidone in whites resulted in significantly fewer patients achieving target BP (<140/90 mm Hg) (44% vs 57%, P = .018) and clinical response rate (≥10 mm Hg DBP reduction); and significantly higher nonresponse rate (<6 mm Hg DBP reduction); but no significant differences in rates among blacks (eg, target-BP rate: 56% vs 63%, P = .31). HCTZ treatment led to significantly lower rates of hypokalemia and hyperuricemia in whites and blacks, vs chlorthalidone, and significantly lower odds of requiring potassium supplementation among blacks (odds ratio 0.16; 95% confidence interval, 0.07-0.37; P = 3.4e^-7).

CONCLUSION

Compared with HCTZ, chlorthalidone showed greater blood pressure lowering and adverse metabolic effects in whites, but similar blood pressure lowering and greater adverse effects in blacks; suggesting that the recent guideline recommendations to choose chlorthalidone over HCTZ may not be warranted in blacks.

Diuretic-induced hypokalaemia: an updated review

Diuretic-induced hypokalaemia is a common and potentially life-threatening adverse drug reaction in clinical practice. Previous studies revealed a prevalence of 7%-56% of hypokalaemia in patients taking thiazide diuretics. The clinical manifestations of hypokalaemia due to diuretics are non-specific, varying from asymptomatic to fatal arrhythmia. Diagnosis of hypokalaemia is based on the level of serum potassium. ECG is useful in identifying the more severe consequences. A high dosage of diuretics and concomitant use of other drugs that increase the risk of potassium depletion or cardiac arrhythmias can increase the risk of cardiovascular events and mortality. Thiazide-induced potassium depletion may cause dysglycaemia. The risk of thiazide-induced hypokalaemia is higher in women and in black people. Reducing diuretic dose and potassium supplementation are the most direct and effective therapies for hypokalaemia. Combining with a potassium-sparing diuretic or blocker of the renin-angiotensin system also reduces the risk of hypokalaemia. Lowering salt intake and increasing intake of vegetables and fruits help to reduce blood pressure as well as prevent hypokalaemia.

Low Serum Potassium Levels and Clinical Outcomes in Peritoneal Dialysis-International Results from PDOPPS

Introduction

Hypokalemia, including normal range values <4 mEq/l, has been associated with increased peritonitis and mortality in patients with peritoneal dialysis. This study sought to describe international variation in hypokalemia, potential modifiable hypokalemia risk factors, and the covariate-adjusted relationship of hypokalemia with peritonitis and mortality.

Methods

Baseline serum potassium was determined in 7421 patients from 7 countries in the Peritoneal Dialysis Outcomes and Practice Patterns Study (2014-2017). Association of baseline patient and treatment factors with subsequent serum potassium <4 mEq/l was evaluated by logistic regression, whereas baseline serum potassium levels (4-month average and fraction of 4 months having hypokalemia) on clinical outcomes was assessed by Cox regression.

Results

Hypokalemia was more prevalent in Thailand and among black patients in the United States. Characteristics/treatments associated with potassium <4 mEq/l included protein-energy wasting indicators, lower urine volume, lower blood pressure, higher dialysis dose, greater diuretic use, and not being prescribed a renin-angiotensin system inhibitor. Persistent hypokalemia (all 4 months vs. 0 months over the 4-month exposure period) was associated with 80% higher subsequent peritonitis rates (at K <3.5 mEq/l) and 40% higher mortality (at K <4.0 mEq/l) after extensive case mix/potential confounding adjustments. Furthermore, adjusted peritonitis rates were higher if having mean serum K over 4 months <3.5 mEq/l versus 4.0-4.4 mEq/l (hazard ratio, 1.15 [95% confidence interval, 0.96-1.37]), largely because of Gram-positive/culture-negative infections.

Conclusions

Persistent hypokalemia is associated with higher mortality and peritonitis even after extensive adjustment for patient factors. Further studies are needed to elucidate mechanisms of these poorer outcomes and modifiable risk factors for persistent hypokalemia.

Racial and Ethnic Differences in Mortality Associated with Serum Potassium in Incident Peritoneal Dialysis Patients

BACKGROUND

Abnormalities in serum potassium are risk factors for sudden cardiac death and arrhythmias among dialysis patients. Although a previous study in hemodialysis patients has shown that race/ethnicity may impact the relationship between serum potassium and mortality, the relationship remains unclear among peritoneal dialysis (PD) patients where the dynamics of serum potassium is more stable.

METHODS

Among 17,664 patients who started PD between January 1, 2007 and December 31, 2011 in a large US dialysis organization, we evaluated the association of serum potassium levels with all-cause and arrhythmia-related deaths across race/ethnicity using time-dependent Cox models with adjustments for demographics. We also used restricted cubic spline functions for serum potassium levels to explore non-linear associations.

RESULTS

Baseline serum potassium levels were the highest among Hispanics (4.2 ± 0.7 mEq/L) and lowest among non-Hispanic blacks (4.0 ± 0.7 mEq/L). Among 2,949 deaths during the follow-up of median 2.2 (interquartile ranges 1.3-3.2) years, 683 (23%) were arrhythmia-related deaths. Overall, both hyperkalemia and hypokalemia (i.e., serum potassium levels >5.0 and <3.5 mEq/L, respectively) were associated with higher all-cause and arrhythmia-related mortality. In a stratified analysis according to race/ethnicity, the association of hypokalemia with all-cause and arrhythmia-related mortality was consistent with an attenuation for arrhythmia-related mortality in non-Hispanic blacks. Hyperkalemia was associated with all-cause and arrhythmia-related mortality in non-Hispanic whites and non-Hispanic blacks, but no association was observed in Hispanics.

CONCLUSION

Among incident PD patients, hypokalemia was consistently associated with all-cause and arrhythmia-related deaths irrespective of race/ethnicity. However, while hyperkalemia was associated with both death outcomes in non-Hispanic blacks and whites, it was not associated with either death outcome in Hispanic patients. Further studies are needed to demonstrate whether different strategies should be followed for the management of serum potassium levels according to race/ethnicity.

Dyskalemia, its patterns, and prognosis among patients with incident heart failure: A nationwide study of US veterans

Background

Although hypokalemia has been viewed as a significant concern among patients with heart failure (HF), recent advances in HF management tend to increase the risk of hyperkalemia.

Objective

To characterize contemporary data regarding correlates and prognostic values of dyskalemia in patients with HF.

Design, setting, and participants

In cross-sectional and longitudinal analyses, we studied 142,087 patients with newly diagnosed HF in US nationwide Veterans Administration database from 2005 through 2013.

Exposures

Demographic characteristics, laboratory variables, comorbidities, and medication use for the analysis of correlates of dyskalemia as well as potassium level in the analysis of mortality.

Main Outcomes and Measures

Dyskalemia and mortality.

Results

Hypokalemia (<3.5 mmol/L) at baseline was observed in 3.0% of the population, whereas hyperkalemia (≥5.5 mmol/L) was seen in 0.9%. An additional 20.4% and 5.7% had mild hypokalemia (3.5–3.9 mmol/L) and mild hyperkalemia (5.0–5.4 mmol/L). Key correlates were black race, higher blood pressure, and use of potassium-wasting diuretics for hypokalemia, and lower kidney function for hyperkalemia. Baseline potassium levels showed a U-shaped association with mortality, with the lowest risk between 4.0–4.5 mmol/L. With respect to potassium levels over a year after HF diagnosis, persistent (>50% of measurements), intermittent (>1 occurrence but ≤50%), and transient (1 occurrence) hypo- and hyperkalemia were also related to increased mortality in a graded fashion regardless of the aforementioned thresholds for dyskalemia. These dyskalemic patterns were also related to other clinical actions and demands such as emergency room visit.

Conclusions

Potassium levels below 4 mmol/L and above 5 mmol/L at and after HF diagnosis were associated with poor prognosis and the clinical actions. HF patients (particularly with risk factors for dyskalemia like black race and kidney dysfunction) may require special attention for both hypo- and hyperkalemia.

Effects of Calcium, Magnesium, and Potassium Concentrations on Ventricular Repolarization in Unselected Individuals

BACKGROUND

Subclinical changes on the electrocardiogram are risk factors for cardiovascular mortality. Recognition and knowledge of electrolyte associations in cardiac electrophysiology are based on only in vitro models and observations in patients with severe medical conditions.

OBJECTIVES

This study sought to investigate associations between serum electrolyte concentrations and changes in cardiac electrophysiology in the general population.

METHODS

Summary results collected from 153,014 individuals (54.4% women; mean age 55.1 ± 12.1 years) from 33 studies (of 5 ancestries) were meta-analyzed. Linear regression analyses examining associations between electrolyte concentrations (mmol/l of calcium, potassium, sodium, and magnesium), and electrocardiographic intervals (RR, QT, QRS, JT, and PR intervals) were performed. The study adjusted for potential confounders and also stratified by ancestry, sex, and use of antihypertensive drugs.

RESULTS

Lower calcium was associated with longer QT intervals (-11.5 ms; 99.75% confidence interval [CI]: -13.7 to -9.3) and JT duration, with sex-specific effects. In contrast, higher magnesium was associated with longer QT intervals (7.2 ms; 99.75% CI: 1.3 to 13.1) and JT. Lower potassium was associated with longer QT intervals (-2.8 ms; 99.75% CI: -3.5 to -2.0), JT, QRS, and PR durations, but all potassium associations were driven by use of antihypertensive drugs. No physiologically relevant associations were observed for sodium or RR intervals.

CONCLUSIONS

The study identified physiologically relevant associations between electrolytes and electrocardiographic intervals in a large-scale analysis combining cohorts from different settings. The results provide insights for further cardiac electrophysiology research and could potentially influence clinical practice, especially the association between calcium and QT duration, by which calcium levels at the bottom 2% of the population distribution led to clinically relevant QT prolongation by >5 ms.

Competing-Risk Analysis of Death and End Stage Kidney Disease by Hyperkalaemia Status in Non-Dialysis Chronic Kidney Disease Patients Receiving Stable Nephrology Care

Hyperkalaemia burden in non-dialysis chronic kidney disease (CKD) under nephrology care is undefined. We prospectively followed 2443 patients with two visits (referral and control with 12-month interval) in 46 nephrology clinics. Patients were stratified in four categories of hyperkalaemia (serum potassium, sK ≥ 5.0 mEq/L) by sK at visit 1 and 2: Absent (no-no), Resolving (yes-no), New Onset (no-yes), Persistent (yes-yes). We assessed competing risks of end stage kidney disease (ESKD) and death after visit 2. Age was 65 ± 15 years, eGFR 35 ± 17 mL/min/1.73 m², proteinuria 0.40 (0.14–1.21) g/24 h. In the two visits sK was 4.8 ± 0.6 and levels ≥6 mEq/L were observed in 4%. Hyperkalaemia was absent in 46%, resolving 17%, new onset 15% and persistent 22%. Renin-angiotensin-system inhibitors (RASI) were prescribed in 79% patients. During 3.6-year follow-up, 567 patients reached ESKD and 349 died. Multivariable competing risk analysis (sub-hazard ratio-sHR, 95% Confidence Interval-CI) evidenced that new onset (sHR 1.34, 95% CI 1.05–1.72) and persistent (sHR 1.27, 95% CI 1.02–1.58) hyperkalaemia predicted higher ESKD risk versus absent, independently from main determinants of outcome including eGFR change. Conversely, no effect on mortality was observed. Results were confirmed by testing sK as continuous variable. Therefore, in CKD under nephrology care, mild-to-moderate hyperkalaemia status is common (37%) and predicts per se higher ESKD risk but not mortality.

[Low protein diet supplemented with ketoanalogues of amino acids in patients with chronic renal insufficiency]

Restricted protein diets in patients with chronic kidney disease have been debated for several decades. In chronic kidney disease as in other chronic diseases, the modulation of the nutritional intake is the object of a certain renewal. It is supported by recent studies that highlight the importance of modulating nutrient intake by diets that are healthier, less rich in animal proteins and richer in plants. The recent reintroduction in France of amino acid supplements and ketoanalogs of amino acids allows the prescription of a very restricted diet. Historical studies have only focused on the relationship between protein intake and renal function degradation. Recent studies on acid loading, bone metabolism or potassium intake allow revisiting the interest of restricted diets. As with any change in eating habits, the selection of patients, information, education and monitoring during the diet are very important and help prevent undernutrition: this is the purpose of this short review.

Revisiting RAAS blockade in CKD with newer potassium-binding drugs

Among patients with proteinuric chronic kidney disease (CKD), current guideline recommendations mandate the use of agents blocking the renin angiotensin aldosterone system (RAAS) as first-line antihypertensive therapy based on randomized trials demonstrating that RAAS inhibitors are superior to other antihypertensive drug classes in slowing nephropathy progression to end-stage renal disease. However, the opportunities for adequate RAAS blockade in CKD are often limited, and an important impediment is the risk of hyperkalemia, especially when RAAS inhibitors are used in maximal doses or are combined. Accordingly, a large proportion of patients with proteinuric CKD may not have the anticipated renoprotective benefits since RAAS blockers are often discontinued due to incident hyperkalemia or are administered at suboptimal doses for fear of the development of hyperkalemia. Two newer potassium binders, patiromer and sodium zirconium cyclosilicate (ZS-9), have been shown to effectively and safely reduce serum potassium levels and maintain long-term normokalemia in CKD patients receiving background therapy with RAAS inhibitors. Whether these novel potassium-lowering therapies can overcome the barrier of hyperkalemia and enhance the tolerability of RAAS inhibitor use in proteinuric CKD awaits randomized trials.

Hyperkalemia and Hypokalemia in CKD: Prevalence, Risk Factors, and Clinical Outcomes

Abnormalities of serum potassium are common in patients with CKD. Although hyperkalemia is a well-recognized complication of CKD, the prevalence rates of hyperkalemia (14%-20%) and hypokalemia (12%-18%) are similar. CKD severity, use of medications such as renin-angiotensin-aldosterone system inhibitors and diuretics, and dietary potassium intake are major determinants of serum potassium concentration in CKD. Demographic factors, acid-base status, blood glucose, and other comorbidities contribute as well. Both hyperkalemia and hypokalemia are associated with similarly increased risks of death, cardiovascular disease, and hospitalization. On the other hand, limited evidence suggests a link between hypokalemia, but not hyperkalemia, and progression of CKD. This article reviews the prevalence rates and risk factors for hyperkalemia and hypokalemia, and their associations with adverse outcomes in CKD.