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

Association of Hypokalemia With Mortality in Patients Undergoing Hemodialysis: A Systematic Review and Meta-Analysis

BACKGROUND

Potassium imbalance, particularly hypokalemia, is a critical risk factor for adverse outcomes in patients undergoing hemodialysis (HD). However, the association between hypokalemia and mortality is unclear.

METHODS

For this systematic review and meta-analysis, we assessed the association between hypokalemia and mortality in patients undergoing HD. We performed a systematic search of electronic databases (PubMed, Embase, Cochrane Library, and Scopus) to identify relevant studies published up to April 2024. Eligible studies were prospective or retrospective cohort studies reporting hazard ratios (HRs) for mortality in association with the presence of hypokalemia among patients undergoing HD. We used the assessed study Newcastle-Ottawa Scale to assess quality of the selected studies.

RESULTS

We carried out both qualitative and quantitative assessments. For the meta-analysis, we pooled the HRs for all-cause and cardiovascular mortalities. The overall pooled HR for all-cause mortality and cardiovascular mortality were 1.34 (95% CI, 1.15, 1.55) and 1.49 (95% CI, 1.12, 1.98), respectively, indicating significant associations between hypokalemia and all-cause mortality and cardiovascular mortality in patients undergoing HD. Additionally, we conducted subgroup analyses based on study design, geographical location, type of dialysis, and serum potassium levels.

CONCLUSION

Our findings provide robust evidence of a significant association between hypokalemia and mortality in patients undergoing HD. Early detection and proactive management of hypokalemia are crucial for improving outcomes and reducing mortality risk in these patients.

Hypokalemia in Peritoneal Dialysis: A Systematic Review and Meta-analysis of Prevalence, Treatment, and Outcomes

Rationale & Objective

Hypokalemia is common and potentially life-threatening in patients undergoing peritoneal dialysis (PD). However, the current literature has produced varying results. This study aimed to evaluate the prevalence and adverse outcomes of hypokalemia and the role of potassium supplementation in patients receiving PD.

Study Design

Systematic review and meta-analysis of randomized controlled trials and observational studies.

Setting & Study Populations

Adults receiving maintenance PD.

Selection Criteria for Studies

Studies that investigated the prevalence and adverse outcomes of hypokalemia and the effect of potassium supplementation.

Data Extraction

Two independent reviewers evaluated studies for eligibility and extracted relevant data.

Analytical Approach

Random effects meta-analysis was conducted to pool hazard ratios (HRs) and 95% CIs for the outcomes of interest. The certainty of findings was rated according to the Grading of Recommendations Assessment, Development and Evaluation criteria.

Results

Of 3,632 reports identified, 24 studies involving 60,313 participants met the inclusion criteria. The prevalence of hypokalemia was 37.9% (95% CI, 27.2%-52.7%), 17.7% (95% CI, 12.0%-25.9%), and 4.4% (95% CI, 1.9%-10.2%) in patients with potassium level <4.0, 3.5, and 3.0 mmol/L, respectively. Hypokalemia, according to the study's definition, was associated with increased risks of all-cause mortality (HR, 1.49; 95% CI, 1.18-1.89), cardiovascular mortality (HR, 1.50; 95% CI, 1.19-1.88), and PD-associated peritonitis (HR, 1.42; 95% CI, 1.17-1.73). These associations were consistent but with low to very low certainty. The effect of correcting hypokalemia with potassium supplementation in patients undergoing PD remains uncertain.

Limitations

Heterogeneity persisted across most of the examined subgroups, and observational studies preclude causation.

Conclusions

Hypokalemia is common and portends poorer survival and a higher risk of peritonitis among patients undergoing PD. Further research into the optimal prevention and treatment strategies for hypokalemia is warranted to improve outcomes.

Registration

Registered at PROSPERO with registration number CRD42022358236.

Association between serum potassium, risk and prognosis of peritonitis in peritoneal dialysis patients - results from the Peritoneal Dialysis Telemedicine-assisted Platform Cohort (PDTAP) Study

BACKGROUND

Hypokalemia has been associated with an increased risk of peritoneal dialysis (PD)-associated peritonitis. However, hypokalemia is commonly associated with malnutrition, inflammation, and severe coexisting comorbidities, which thus are suspected of being potential confounders. This study was aimed at testing whether hypokalemia was independently associated with the occurrence and prognosis of PD-associated peritonitis.

METHODS

A national-level dataset from the Peritoneal Dialysis Telemedicine-assisted Platform Cohort (PDTAP) Study was used to explore the independent association of serum potassium with PD-associated peritonitis. Unmatched and propensity score-adjusted multivariate competing risk models, as well as univariate competing risk models following 1:1 propensity score matching, were conducted to balance potential biases between patients with and without hypokalemia. The association between potassium levels prior to peritonitis and treatment failure due to peritonitis was also investigated.

RESULTS

During a median follow-up of 25.7 months in 7220 PD patients, there was a higher incidence of peritonitis in patients with serum potassium below 4.0 mmol/L compared to those with higher serum levels (677 [0.114/patient-year] vs. 914 [0.096/patient-year], P = 0.001). After adjusting for demographics, laboratory tests, residual renal function, and medication use, baseline potassium levels below 4.0 mmol/L were not linked to an increased risk of peritonitis, with a hazard ratio of 0.983 (95% CI 0.855-1.130, P = 0.810). This result remained consistent in both the propensity score adjusted multivariate competing risk regression (HR = 0.974, 95% CI 0.829-1.145, P = 0.750) and the univariate competing risk regression after 1:1 propensity score matching (Fine-Gray test, P = 0.218). The results were similar when analyzing patients with serum potassium level above or below 3.5 mmol/L. Lastly, hypokalemia before the occurrence of peritonitis was not independently associated with treatment failure.

CONCLUSION

Hypokalemia was not found to be an independent risk factor for PD-associated peritonitis or treatment failure of peritonitis in China.

Effect of banana intake on serum potassium level in patients undergoing maintenance hemodialysis: A randomized controlled trial

Objective

This study aimed to assess the effect of banana intake during hemodialysis on serum potassium levels in maintenance hemodialysis (MHD) patients.

Methods

This study was a single-center, randomized controlled clinical trial conducted from September 15 to December 15, 2021, at a tertiary hospital in southern China. A total of 126 MHD patients were randomly assigned to either the intervention group (n = 64) or the control group (n = 62). Patients in the intervention group consumed approximately 250 g of bananas during hemodialysis, while those in the control group did not consume any food during hemodialysis. Demographic information and hemodialysis-related parameters were collected through case information collection before hemodialysis. Laboratory indicators (such as complete blood count, biochemical indicators, inflammation markers, liver function, kidney function, etc.) were evaluated by collecting pre-hemodialysis blood samples from patients. Serum potassium and blood glucose levels were measured at 2 h and 4 h of hemodialysis, as well as before the next hemodialysis session, and hemodialysis-related complications were recorded. The blood potassium and blood glucose indicators during hemodialysis were compared using repeated measures analysis.

Results

A total of 122 MHD patients completed the study (61 in each group). The results showed that there was no significant interaction between group and time on serum potassium levels. However, serum potassium levels in the intervention group were higher than those in the control group at 2 h (3.9 ± 0.5 mmol/L vs. 3.6 ± 0.3 mmol/L, P < 0.01) and 4 h (3.5 ± 0.4 mmol/L vs. 3.3 ± 0.3 mmol/L, P < 0.01) of hemodialysis. There was no interaction between group and time on blood glucose levels. The incidence of arrhythmias (8.2% vs. 29.5%, P = 0.003) and hypokalemia (52.5% vs. 80.3%, P = 0.002) during hemodialysis was significantly lower in the intervention group compared to the control group.

Conclusion

Consuming approximately 250 g of bananas at the start of hemodialysis does not lead to hyperkalemia. It can effectively reduce the incidence of hypokalemia and arrhythmias, and prevent a rapid decline in serum potassium levels during hemodialysis.

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.

Dietary Potassium and Clinical Outcomes among Patients on Peritoneal Dialysis

BACKGROUND

The association between dietary potassium and clinical prognosis is unclear in patients with chronic kidney disease (CKD). Here, we explored the association between dietary potassium intake and all-cause and cardiovascular (CV) mortality in peritoneal dialysis (PD) patients.

METHODS

Here, we present a retrospective analysis of a prospective study. Patients that began incident PD in our center between 1 October 2002 and 31 August 2014 were screened. We recorded all demographic and clinical data at baseline. Repeated measurements were recorded at regular intervals to calculate time-averaged values. Spline regression analysis and Cox proportional regression models were used to evaluate the relationship between dietary potassium and mortality.

RESULTS

We followed 881 PD patients for 45.0 (21.5, 80.0) months; 467 patients died, of which 189 (40.5%) died of CV death and 93 were still on PD treatment. Compared with those who had baseline dietary potassium ≥1200 mg/d, the majority of patients with lower dietary potassium were female, older, or poorly educated. They were prone to have poorer nutritional status, CV disease, and diabetes mellitus (p < 0.05). In the unadjusted analysis, both baseline and time-averaged dietary potassium <1200 mg/d predicted higher all-cause and CV mortality (p < 0.001~0.01). After adjusting for demographic and laboratory data, the association between potassium intake and all-cause and CV mortality weakened, which even disappeared after additional adjustment for dietary fiber, protein, and energy intake.

CONCLUSIONS

Dietary potassium in PD patients was not independently associated with all-cause and CV mortality.

Hyperkalemia in chronic kidney disease: a focus on potassium lowering pharmacotherapy

INTRODUCTION

Hyperkalemia is one of the most common electrolyte disorders in chronic kidney disease (CKD) and is associated with serious adverse outcomes. Hyperkalemia risk is even greater when CKD patients also have additional predisposing conditions such as diabetes or heart failure. Renin-angiotensin-aldosterone-system blockers are first-line treatments for cardio- and nephroprotection, but their use is often limited due to K+ elevation, resulting in high rates of discontinuation.

AREAS COVERED

This article provides an overview of factors interfering with K+ homeostasis and discusses recent data on newer therapeutic agents used for the treatment of hyperkalemia. A detailed literature search was performed in two major databases (PubMed/MEDLINE and Scopus) up to April 2023.

EXPERT OPINION

Major clinical trials have tested new and promising kidney protective therapies such as sodium/glucose-cotransporter-2 inhibitors and mineralocorticoid-receptor-antagonists, with promising results. Until recently, the only treatment option for hyperkalemia was the cation-exchanging resin sodium-polystyrene-sulfonate. However, despite its common use, the efficacy and safety data of this drug in the long-term management of hyperkalemia are scarce. During the last decade, two novel orally administered K+-exchanging compounds (patiromer and sodium-zirconium-cyclosilicate) have been approved for the treatment of adults with hyperkalemia, as they both effectively reduce elevated serum K+ and maintain chronically K+ balance within the normal range with an excellent tolerability and no serious adverse events.

Hyperkalemia in pediatric chronic kidney disease

BACKGROUND

While hyperkalemia is well described in adult chronic kidney disease (CKD), large studies evaluating potassium trends and risk factors for hyperkalemia in pediatric CKD are lacking. This study aimed to characterize hyperkalemia prevalence and risk factors in pediatric CKD.

METHODS

Cross-sectional analysis of Chronic Kidney Disease in Children (CKiD) study data evaluated median potassium levels and percentage of visits with hyperkalemia (K ≥5.5 mmoL/L) in relation to demographics, CKD stage, etiology, proteinuria, and acid-base status. Multiple logistic regression was used to identify risk factors for hyperkalemia.

RESULTS

One thousand and fifty CKiD participants with 5183 visits were included (mean age 13.1 years, 62.7% male, 32.9% self-identifying as African American or Hispanic). A percentage of 76.6% had non-glomerular disease, 18.7% had CKD stage 4/5, 25.8% had low CO2, and 54.2% were receiving ACEi/ARB therapy. Unadjusted analysis identified a median serum potassium level of 4.5 mmol/L (IQR 4.1-5.0, p <0.001) and hyperkalemia in 6.6% of participants with CKD stage 4/5. Hyperkalemia was present in 14.3% of visits with CKD stage 4/5 and glomerular disease. Hyperkalemia was associated with low CO2 (OR 7.72, 95%CI 3.05-19.54), CKD stage 4/5 (OR 9.17, 95%CI 4.02-20.89), and use of ACEi/ARB therapy (OR 2.14, 95%CI 1.36-3.37). Those with non-glomerular disease were less frequently hyperkalemic (OR 0.52, 95%CI 0.34-0.80). Age, sex, and race/ethnicity were not associated with hyperkalemia.

CONCLUSIONS

Hyperkalemia was observed more frequently in children with advanced stage CKD, glomerular disease, low CO2, and ACEi/ARB use. These data can help clinicians identify high-risk patients who may benefit from earlier initiation of potassium-lowering therapies. A higher resolution version of the Graphical abstract is available as Supplementary information.

Association of serum potassium with decline in residual kidney function in incident hemodialysis patients

BACKGROUND

Hyperkalemia is associated with kidney function decline in patients with non-dialysis dependent chronic kidney disease, but this relationship is unclear for residual kidney function among hemodialysis (HD) patients.

METHODS

We conducted a retrospective cohort study of 6655 patients who started HD from January 2007 to December 2011 and who had data on renal urea clearance (KRU). Serum potassium levels were stratified into four groups (i.e. ≤4.0, >4.0 to ≤ 4.5, >4.5 to ≤ 5.0, >5.0 mEq/L) and 1-year KRU slope for each group was estimated by a linear mixed-effects model.

RESULTS

Higher serum potassium was associated with greater decline in KRU, and the greatest decrease in KRU (-0.20, 95% CI -0.50, -0.06) was observed for baseline potassium > 5.0 mEq/L in the fully adjusted model. Mediation analysis showed that KRU slope mediated 1.78% of the association between serum potassium and mortality.

CONCLUSIONS

In conclusion, hyperkalemia is associated with decline in residual kidney function amongst incident HD patients. These findings may have important clinical implications in the management of hyperkalemia in advanced CKD if confirmed in additional studies including clinical trials.

Hyperkalemia in Chronic Kidney Disease in the New Era of Kidney Protection Therapies

Despite recent therapeutic advances, chronic kidney disease (CKD) is one of the fastest growing global causes of death. This illustrates limitations of current therapeutic approaches and, potentially, unidentified knowledge gaps. For decades, renin-angiotensin-aldosterone system (RAAS) blockers have been the mainstay of therapy for CKD. However, they favor the development of hyperkalemia, which is already common in CKD patients due to the CKD-associated decrease in urinary potassium (K⁺) excretion and metabolic acidosis. Hyperkalemia may itself be life-threatening as it may trigger potentially lethal arrhythmia, and additionally may limit the prescription of RAAS blockers and lead to low-K⁺ diets associated to low dietary fiber intake. Indeed, hyperkalemia is associated with adverse kidney, cardiovascular, and survival outcomes. Recently, novel kidney protective therapies, ranging from sodium/glucose cotransporter 2 (SGLT2) inhibitors to new mineralocorticoid receptor antagonists have shown efficacy in clinical trials. Herein, we review K⁺ pathophysiology and the clinical impact and management of hyperkalemia considering these developments and the availability of the novel K⁺ binders patiromer and sodium zirconium cyclosilicate, recent results from clinical trials targeting metabolic acidosis (sodium bicarbonate, veverimer), and an increasing understanding of the role of the gut microbiota in health and disease.

The quest for cardiovascular disease risk prediction models in patients with nondialysis chronic kidney disease

PURPOSE OF REVIEW

Cardiovascular disease (CVD) is the leading cause of death in patients with chronic kidney disease (CKD). However, traditional CVD risk prediction equations do not work well in patients with CKD, and inclusion of kidney disease metrics such as albuminuria and estimated glomerular filtration rate have a modest to no benefit in improving prediction.

RECENT FINDINGS

As CKD progresses, the strength of traditional CVD risk factors in predicting clinical outcomes weakens. A pooled cohort equation used for CVD risk prediction is a useful tool for guiding clinicians on management of patients with CVD risk, but these equations do not calibrate well in patients with CKD, although a number of studies have developed modifications of the traditional equations to improve risk prediction. The reason for the poor calibration may be related to the fact that as CKD progresses, associations of traditional risk factors such as BMI, lipids and blood pressure with CVD outcomes are attenuated or reverse, and other risk factors may become more important.

SUMMARY

Large national cohorts such as the US Veteran cohort with many patients with evolving CKD may be useful resources for the developing CVD prediction models; however, additional considerations are needed for the unique composition of patients receiving care in these healthcare systems, including those with multiple comorbidities, as well as mental health issues, homelessness, posttraumatic stress disorders, frailty, malnutrition and polypharmacy. Machine learning over conventional risk prediction models may be better suited to handle the complexity needed for these CVD prediction models.