Serum potassium in chronic kidney disease: prevalence, patient characteristics and clinical outcomes

The burden of hyperkalaemia in chronic kidney disease: a systematic literature review

Background

The global epidemiology and burden of hyperkalaemia in patients with chronic kidney disease (CKD) are unclear due to the inconsistent definitions of hyperkalaemia. The combination of adverse effects and interaction between comorbidity and pharmacotherapies, such as renin-angiotensin-aldosterone system inhibitors (RAASi), justify a systematic understanding of this common complication of CKD.

Methods

This systematic literature review aimed to identify and descriptively summarize the evidence on hyperkalaemia risk factors and associated characteristics in adult CKD patients, including the effects of sub-optimal RAASi. Medline® and Embase® databases were searched from January 2000 to April 2024, with additional hand searching. Publications were screened by two independent reviewers. Data were extracted by one reviewer and verified by another reviewer; study quality assessment was also conducted.

Results

A total of 138 studies described in 145 publications met the eligibility criteria. The published literature revealed varying prevalence of hyperkalaemia amongst inconsistent definitions and a significant increase in the prevalence and incidence of hyperkalaemia among patients with CKD, regardless of RAASi treatment. Hyperkalaemia was associated with adverse outcomes and increased hospital resource use. Additionally, studies pointed to negative health and economic outcomes due to sub-optimal RAASi dosing in CKD patients with hyperkalaemia, as well as in those with CKD and comorbid heart failure.

Conclusions

This review expands on current research, offering a new perspective specifically focused on CKD patients and wider clinical and economic outcomes. Identification of wider clinical and economic consequences of hyperkalaemia in CKD patients, and the interplay between these risks and the risks of sub-optimal RAASi dosing, justify the need for future research. Clinicians should exercise caution when managing this condition in this complex patient group.

Monitoring serum potassium concentration in patients with severe hyperkalemia: the role of bloodless artificial intelligence-enabled electrocardiography

Background

Severe hyperkalemia is a life-threatening emergency requiring prompt management and close surveillance. Although artificial intelligence-enabled electrocardiography (AI-ECG) has been developed to rapidly detect hyperkalemia, its application to monitor potassium (K+) levels remains unassessed. This study aimed to evaluate the effectiveness of AI-ECG for monitoring K+ levels in patients with severe hyperkalemia.

Methods

This retrospective study was performed at an emergency department of a single medical center over 2.5 years. Patients with severe hyperkalemia defined as Lab-K+ ≥6.5 mmol/l with matched ECG-K+ ≥5.5 mmol/l were included. ECG-K+ was quantified by ECG12Net analysis of the AI-ECG system. The following paired ECG-K+ and Lab-K+ were measured at least twice, almost simultaneously, during and after K+-lowering therapy in 1 day. Clinical characteristics, pertinent intervention, and laboratory data were analyzed.

Results

Seventy-six patients fulfilling the inclusion criteria exhibited initial Lab-K+ 7.4 ± 0.7 and ECG-K+ 6.8 ± 0.5 mmol/l. Most of them had chronic kidney disease (CKD) or were on chronic hemodialysis (HD). The followed Lab-K+ and ECG-K+ measured with a mean time difference of 11.4 ± 5.6 minutes significantly declined in parallel both in patients treated medically (n = 39) and with HD (n = 37). However, there was greater decrement in Lab-K⁺ (mean 7.3 to 4.1) than ECG-K⁺ (mean 6.6 to 5.0) shortly after HD. Three patients with persistent ECG-K+ hyperkalemia despite normalized Lab-K+ exhibited concomitant acute cardiovascular comorbidities.

Conclusions

AI-ECG for K+ prediction may help monitor K+ level for severe hyperkalemia and reveal more severe cardiac disorders in the patients with persistent AI-ECG hyperkalemia.

Hyperkalaemia among hospital admissions: prevalence, risk factors, treatment and impact on length of stay

BACKGROUND

Hyperkalaemia is one of the common electrolyte disorders among hospital patients, affected by many risk factors including medications and medical conditions. Prompt treatment is important given its impact on patient mortality and morbidity, which can lead to negative patient outcomes and healthcare resource utilisation. This study aims to describe the prevalence, characteristics, and treatment of patients admitted to hospitals with hyperkalaemia and compare findings between patients with kidney failure on maintenance haemodialysis therapy and patients without kidney failure. It also aims to identify associations between hyperkalaemia and hospital length of stay.

METHODS

We undertook a retrospective cohort study on adult patients admitted to Townsville University Hospital between 1st January 2018 and 31st December 2022 (n = 99,047). Patients were included if they had a serum potassium result of 5.1 mmol/L and above during their admission/s. Statistical analysis was conducted using several methods. A Welch's t test and Chi-square test were employed to assess differences between groups of patients with kidney failure on maintenance haemodialysis therapy and those without kidney failure. For comparison among multiple groups with varying severities of hyperkalaemia, the Kruskal-Wallis test with Mann-Whitney U test and logistic regression were used.

RESULTS

8,775 hyperkalaemic patients were included in the study, with a mean age of 64.7 years. The prevalence of hyperkalaemia was 8.9% of patients. Risk factors for hyperkalaemia were highly prevalent among those who had the condition during their admissions. Patients with kidney failure on haemodialysis who had hyperkalaemia were, on average, 6 years younger, more often Indigenous, and experienced more severe hyperkalaemia compared to other patients without kidney failure. There was a notable difference in hyperkalaemia treatment between groups with varying degrees of hyperkalaemia severity. Hyperkalaemia was not found to be associated with prolonged hospital stay.

CONCLUSION

Hyperkalaemia is common among hospital admissions. Patients with kidney failure on haemodialysis are at higher risk of developing severe hyperkalaemia. Treatment for hyperkalaemia was variable and likely insufficient. Timely detection and treatment of hyperkalaemia is recommended.

Hyperkalemia Incidence in Patients With Non-Dialysis Chronic Kidney Disease: A Large Retrospective Cohort Study From United States Clinical Care

Rationale & Objective

Estimates of the incidence of hyperkalemia in patients with chronic kidney disease (CKD) vary widely. Our objective was to estimate hyperkalemia incidence in patients with CKD from routine clinical care, including by level of kidney damage or function and among important patient subgroups.

Study Design

Retrospective cohort study.

Setting & Participants

1,771,900 patients with stage 1-4 CKD identified from the US Optum De-Identified electronic health records database.

Exposures or Predictors

Impaired kidney damage or function level at baseline based on urinary albumin-creatinine ratio (UACR) and estimated glomerular filtration rate (eGFR), respectively, and selected patient subgroups.

Outcomes

Hyperkalemia: 2 elevated serum potassium values (≥5.5 mmol/L) from the inpatient setting (2-24 hours apart) or outpatient setting (maximum 7 days apart), or 1 elevated serum potassium value plus pharmacotherapy initiation or hyperkalemia diagnosis (maximum 3 days apart).

Analytical Approach

Incidence rates of hyperkalemia were calculated. Estimates were stratified by UACR and eGFR level at baseline and patient subgroups.

Results

Over a mean follow-up of 3.9 years, the incidence of hyperkalemia was 3.37 events/100 person-years (95% confidence intervals, 3.36-3.38). Higher incidence rates were observed with increased UACR and lower eGFR. Highest rates were observed with UACR ≥3,500 (up to 19.1/100 person-years) irrespective of decreased eGFR level. High rates also occurred in patients with type 2 diabetes mellitus (T2DM, 5.43/100 person-years), heart failure (8.7/100 person-years), and those prescribed steroidal mineralocorticoid receptor antagonists (sMRAs, 7.7/100 person-years).

Limitations

Potential misclassification of variables from possible medical coding errors; potential data incompleteness issues if patients received care at institutions not included in Optum.

Conclusions

Hyperkalemia is a frequent occurrence in CKD, particularly in patients with T2DM, heart failure, or prescribed sMRAs, indicating the need for regular serum potassium and UACR monitoring in this patient population to help mitigate risk.

Potential Drug-Nutrient Interactions of 45 Vitamins, Minerals, Trace Elements, and Associated Dietary Compounds with Acetylsalicylic Acid and Warfarin-A Review of the Literature

In cardiology, acetylsalicylic acid (ASA) and warfarin are among the most commonly used prophylactic therapies against thromboembolic events. Drug-drug interactions are generally well-known. Less known are the drug-nutrient interactions (DNIs), impeding drug absorption and altering micronutritional status. ASA and warfarin might influence the micronutritional status of patients through different mechanisms such as binding or modification of binding properties of ligands, absorption, transport, cellular use or concentration, or excretion. Our article reviews the drug-nutrient interactions that alter micronutritional status. Some of these mechanisms could be investigated with the aim to potentiate the drug effects. DNIs are seen occasionally in ASA and warfarin and could be managed through simple strategies such as risk stratification of DNIs on an individual patient basis; micronutritional status assessment as part of the medical history; extensive use of the drug-interaction probability scale to reference little-known interactions, and application of a personal, predictive, and preventive medical model using omics.

Mediation of serum albumin in the association of serum potassium with mortality in Chinese dialysis patients: a prospective cohort study

BACKGROUND

The clinical importance of hypokalemia is likely underrecognized in Chinese dialysis patients, and whether its clinical effect was mediated by serum albumin is not fully elucidated. This study aimed to explore the association between serum potassium and mortality in dialysis patients of a Chinese nationwide multicenter cohort, taking albumin as a consideration.

METHODS

This was a prospective nation-wide multicenter cohort study. Restricted cubic splines were used to test the linearity of serum potassium and relationships with all-cause (AC) and cardiovascular (CV) mortality and a subsequent two-line piecewise linear model was fitted to approach the nadir. A mediation analysis was performed to examine relations of albumin to potassium and mortalities.

RESULTS

A total of 10,027 patients were included, of whom 6605 were peritoneal dialysis and 3422 were hemodialysis patients. In the overall population, the mean age was 51.7 ± 14.8 years, 55.3%(5546/10,027) were male, and the median dialysis vintage was 13.60 (4.70, 39.70) months. Baseline serum potassium was 4.30 ± 0.88 mmol/L. After a median follow-up period of 26.87 (14.77, 41.50) months, a U-shape was found between potassium and mortality, and a marked increase in risk at lower potassium but a moderate elevation in risk at higher potassium were observed. The nadir for AC mortality risk was estimated from piecewise linear models to be a potassium concentration of 4.0 mmol/L. Interestingly, the significance of the association between potassium and mortality was attenuated when albumin was introduced into the extended adjusted model. A subsequent significant mediation by albumin for potassium and AC and CV mortalities were found ( P < 0.001 for both), indicating that hypokalemia led to higher mortality mediated by low serum albumin, which was a surrogate of poor nutritional status and inflammation.

CONCLUSIONS

Associations between potassium and mortalities were U-shaped in the overall population. The nadir for AC mortality risk was at a potassium of 4.0 mmol/L. Serum albumin mediated the association between potassium and AC and CV mortalities.

Elevated serum urea-to-creatinine ratio is associated with adverse inpatient clinical outcomes in non-end stage chronic kidney disease

To better understand the role of the urea-to-creatinine ratio in chronic kidney disease patients, we assessed the epidemiology of the urea-to-creatinine ratio among hospitalised chronic kidney disease patients, and the association between the urea-to-creatinine ratio and inpatient clinical outcomes. This retrospective cohort study (n = 11,156) included patients with at least two eGFR values < 60 mL/min/1.73m² measured greater than 90-days apart and admitted to a tertiary hospital between 2014 and 2019. Dialysis and renal transplant patients were excluded. Adjusted odds ratios for factors associated with an elevated urea-to-creatinine ratio were calculated. Multivariate regression was conducted to identify the relationship between elevated UCR and inpatient mortality, intensive care admission, hospital readmission and hospital length-of-stay. Urea-to-creatinine ratio > 100 was present in 27.67% of hospital admissions. Age ≥ 65 years, female gender, gastrointestinal tract bleeding, heart failure, acute kidney injury and lower serum albumin were associated with elevated urea-to-creatinine ratio. Higher urea-to-creatinine ratio level was associated with greater rates of inpatient mortality, hospital readmission within 30-days and longer hospital length-of-stay. Despite this, there was no statistically significant association between higher urea-to-creatinine ratio and intensive care unit admission. Elevated urea-to-creatinine ratio is associated with poor clinical outcomes in chronic kidney disease inpatients. This warrants further investigation to understand the pathophysiological basis for this relationship and to identify effective interventions.