The effect of hyperkalemia and long inter-dialytic interval on morbidity and mortality in patients receiving hemodialysis: a systematic review

Hyperkalaemia prevalence and dialysis patterns in Chinese patients on haemodialysis: an interim analysis of a prospective cohort study (PRECEDE-K)

BACKGROUND

Hyperkalaemia is a known risk factor for cardiac arrhythmia and mortality in patients on haemodialysis. Despite standard adequate haemodialysis, hyperkalaemia is common in patients with end-stage renal disease (ESRD) at interdialytic intervals. Data on hyperkalaemia burden and its effects on dialysis patterns and serum potassium (sK) fluctuations in patients on haemodialysis in China remain limited. The prospective, observational cohort study (PRECEDE-K; NCT04799067) investigated the prevalence, recurrence, and treatment patterns of hyperkalaemia in Chinese patients with ESRD on haemodialysis.

METHODS

Six hundred adult patients were consecutively enrolled from 15 secondary and tertiary hospitals in China. In this interim analysis, we report the baseline characteristics of the cohort, the prevalence of predialysis hyperkalaemia (sK > 5.0 mmol/L), and the trends in serum-dialysate potassium gradient and intradialytic sK shift at Visit 1 (following a long interdialytic interval [LIDI]).

RESULTS

At baseline, most patients (85.6%) received three-times weekly dialysis; mean duration was 4.0 h. Mean urea reduction ratio was 68.0% and Kt/V was 1.45; 60.0% of patients had prior hyperkalaemia (previous 6 months). At Visit 1, mean predialysis sK was 4.83 mmol/L, and 39.6% of patients had hyperkalaemia. Most patients (97.7%) received a dialysate potassium concentration of 2.0 mmol/L. The serum-dialysate potassium gradient was greater than 3 mmol/L for over 40% of the cohort (1- < 2, 2- < 3, 3- < 4, and ≥ 4 mmol/L in 13.6%, 45.1%, 35.7%, and 5.2% of patients, respectively; mean: 2.8 mmol/L). The intradialytic sK reduction was 1- < 3 mmol/L for most patients (0- < 1, 1- < 2, 2- < 3, and ≥ 3 mmol/L in 24.2%, 62.2%, 12.8%, and 0.9% of patients, respectively; mean: 1.4 mmol/L).

CONCLUSIONS

Hyperkalaemia after a LIDI was common in this real-world cohort of Chinese patients despite standard adequate haemodialysis, and led to large serum-dialysate potassium gradients and intradialytic sK shifts. Previous studies have shown hyperkalaemia and sK fluctuations are highly correlated with poor prognosis. Effective potassium-lowering treatments should be evaluated for the improvement of long-term prognosis through the control of hyperkalaemia and sK fluctuations.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT04799067.

DIALIZE China: A Phase IIIb, Randomized, Placebo-Controlled Study to Reduce Predialysis Hyperkalemia With Sodium Zirconium Cyclosilicate in Chinese Patients

PURPOSE

The DIALIZE China study (Reduce Incidence of Pre-Dialysis Hyperkalaemia With Sodium Zirconium Cyclosilicate in Chinese Subjects) (NCT04217590) evaluated sodium zirconium cyclosilicate (SZC) for the management of hyperkalemia in Chinese patients undergoing hemodialysis.

METHODS

In the double-blind, Phase IIIb DIALIZE China study, Chinese adults with kidney failure and predialysis hyperkalemia (predialysis serum potassium [sK+] concentration >5.4 mmol/L after the long interdialytic interval [LIDI] and >5.0 mmol/L after ≥1 short interdialytic interval) who were receiving hemodialysis 3 times weekly were randomized to placebo or SZC 5 g once daily on nondialysis days. Doses were titrated towards maintaining normokalemia for 4 weeks (titration period) in 5-g increments up to 15 g. Primary efficacy was the proportion of responders during the 4-week evaluation period following the titration period (ie, those with a predialysis sK+ of 4.0-5.0 mmol/L for at least 3 of 4 hemodialysis visits following the LIDI) who did not require urgent rescue therapy.

FINDINGS

Overall, 134 adults (mean [SD] age, 55 [11.3] years) were randomized to SZC or placebo (n = 67 each). There were significantly more responders with SZC (37.3%) versus placebo (10.4%; estimated odds ratio [OR] = 5.10; 95% CI, 1.90-15.12; P < 0.001). The probability of all predialysis sK+ concentrations being 3.5 to 5.5 mmol/L was significantly higher with SZC versus placebo (estimated OR = 6.41; 95% CI, 2.71-15.12; P < 0.001). A greater proportion of patients achieved an sK+ of 3.5 to 5.5 mmol/L on at least 3 of 4 LIDI visits during evaluation with SZC (73.1%) versus placebo (29.9%). Serious adverse events occurred in 9.1% and 11.9% of patients in the SZC and placebo groups, respectively.

IMPLICATIONS

SZC treatment for predialysis hyperkalemia is effective and well tolerated in Chinese patients with kidney failure receiving hemodialysis.

CLINICALTRIALS

gov identifier: NCT04217590.

Ultrafiltration Rate Levels in Hemodialysis Patients Associated with Weight-Specific Mortality Risks

BACKGROUND

We hypothesized that the association of ultrafiltration rate with mortality in hemodialysis patients was differentially affected by weight and sex and sought to derive a sex- and weight-indexed ultrafiltration rate measure that captures the differential effects of these parameters on the association of ultrafiltration rate with mortality.

METHODS

Data were analyzed from the US Fresenius Kidney Care (FKC) database for 1 year after patient entry into a FKC dialysis unit (baseline) and over 2 years of follow-up for patients receiving thrice-weekly in-center hemodialysis. To investigate the joint effect of baseline-year ultrafiltration rate and postdialysis weight on survival, we fit Cox proportional hazards models using bivariate tensor product spline functions and constructed contour plots of weight-specific mortality hazard ratios over the entire range of ultrafiltration rate values and postdialysis weights (W).

RESULTS

In the studied 396,358 patients, the average ultrafiltration rate in ml/h was related to postdialysis weight (W) in kg: 3W+330. Ultrafiltration rates associated with 20% or 40% higher weight-specific mortality risk were 3W+500 and 3W+630 ml/h, respectively, and were 70 ml/h higher in men than in women. Nineteen percent or 7.5% of patients exceeded ultrafiltration rates associated with a 20% or 40% higher mortality risk, respectively. Low ultrafiltration rates were associated with subsequent weight loss. Ultrafiltration rates associated with a given mortality risk were lower in high-body weight older patients and higher in patients on dialysis for more than 3 years.

CONCLUSIONS

Ultrafiltration rates associated with various levels of higher mortality risk depend on body weight, but not in a 1:1 ratio, and are different in men versus women, in high-body weight older patients, and in high-vintage patients.

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.

A question to the physician from a patient on hemodialysis: Would it be safe to run a marathon? A case report

A patient on maintenance hemodialysis asked his physician if it would be safe for him to run a marathon. For healthy persons, studies show that it is relatively safe. Very few data are available on patients on hemodialysis performing out of center endurance exercise. To address this question, we conducted a clinical study to investigate the electrolyte derangements during different running distances. Our main concern was development of hyperkalemia. We present a case of an anuric hemodialysis patient, who ran eight different runs with a maximum distance of 32.2 km. Blood was analyzed before and after the runs. We did not find severe hyperkalemia at any point. According to this study, we found no signs of increased risk.

A nomogram to predict hyperkalemia in patients with hemodialysis: a retrospective cohort study

BACKGROUND

Hyperkalemia increases the risk of mortality and cardiovascular-related hospitalizations in patients with hemodialysis. Predictors of hyperkalemia are yet to be identified. We aimed at developing a nomogram able to predict hyperkalemia in patients with hemodialysis.

METHODS

We retrospectively screened patients with end-stage renal disease (ESRD) who had regularly received hemodialysis between Jan 1, 2017, and Aug 31, 2021, at Lishui municipal central hospital in China. The outcome for the nomogram was hyperkalemia, defined as serum potassium [K⁺] ≥ 5.5 mmol/L. Data were collected from hemodialysis management system. Least Absolute Shrinkage Selection Operator (LASSO) analysis selected predictors preliminarily. A prediction model was constructed by multivariate logistic regression and presented as a nomogram. The performance of nomogram was measured by the receiver operating characteristic (ROC) curve, calibration diagram, and decision curve analysis (DCA). This model was validated internally by calculating the performance on a validation cohort.

RESULTS

A total of 401 patients were enrolled in this study. 159 (39.65%) patients were hyperkalemia. All participants were divided into development (n = 256) and validation (n = 145) cohorts randomly. Predictors in this nomogram were the number of hemodialysis session, blood urea nitrogen (BUN), serum sodium, serum calcium, serum phosphorus, and diabetes. The ROC curve of the training set was 0.82 (95%CI 0.77, 0.88). Similar ROC curve was achieved at validation set 0.81 (0.74, 0.88). The calibration curve demonstrated that the prediction outcome was correlated with the observed outcome.

CONCLUSION

This nomogram helps clinicians in predicting the risk of PEW and managing serum potassium in the patients with hemodialysis.

Real-World Management of Hyperkalemia in the Emergency Department: An Electronic Medical Record Analysis

Introduction

Hyperkalemia is often managed in the emergency department (ED) and it is important to understand how ED management and post-discharge outcomes vary by hyperkalemia severity. This study was conducted to characterize ED management and post-discharge outcomes across hyperkalemia severities.

Methods

Adults with an ED visit with hyperkalemia (at least one serum potassium lab measure above 5.0 mEq/L) were selected from US electronic medical record data (2012–2018). Patient characteristics, potassium levels, treatments, and monitoring prior to and during the ED visit were compared by hyperkalemia severity (mild [> 5.0–5.5 mEq/L], moderate [> 5.5–6.0], severe [> 6.0]) using unadjusted analyses. Death, immediate inpatient admission, 30-day hyperkalemia recurrence, and 30-day inpatient admission were also assessed by severity.

Results

Of 6222 patients included, 4432 (71.2%) had mild hyperkalemia, 1085 (17.4%) had moderate, and 705 (11.3%) had severe hyperkalemia. Chronic kidney disease (39.9–50.1%) and heart failure (21.6–24.3%) were common. In the ED, electrocardiograms (mild, 56.5%; moderate, 69.6%; severe, 81.0%) and patients with at least two potassium laboratory values increased with severity (15.0%; 40.4%; 75.5%). Among patients with at least two potassium laboratory values, over half of patients (60.4%) had potassium levels ≤ 5.0 mEq/L prior to discharge. Use of potassium-binding treatments (sodium polystyrene sulfonate: mild = 4.1%; moderate = 17.1%; severe = 27.4%), temporizing agents (5.6%; 15.5%; 31.6%), or dialysis (0.4%; 0.8%; 3.0%) increased with severity; treatment at discharge was not common. Death (1.1%; 3.7%; 10.6%), immediate admission to inpatient care (5.8%; 8.7%; 12.7%), 30-day hyperkalemia recurrence (2.9%; 19.0%; 32.5%), 30-day inpatient admission with hyperkalemia (6.5%; 7.9%; 9.3%) also increased with severity.

Conclusion

Patients with moderate and severe hyperkalemia experienced elevated risk of hyperkalemia recurrence and hyperkalemia-related inpatient readmission following discharge from the ED from a descriptive analysis. Future research to assess strategies to reduce hyperkalemia recurrence and inpatient admission in this patient population would be beneficial.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12325-021-02017-w.