Serum Potassium and Mortality Risk in Hemodialysis Patients: A Cohort Study

Lower product of magnesium × potassium is associated with higher mortality in chronic hemodialysis patients: a cohort study

This study aimed to investigate the Mg × K product on the mortality risk of hemodialysis patients with concomitant hypokalemia and lower magnesium levels. This was a prospective observational study of patients in a HD center in southern Taiwan. A total of 444 HD patients were divided into 5 groups by the Mg × K product: group 1, bottom quintile, median Mg × K: 7.87, IQR: 7.03-8.12 (n = 89, age: 64 ± 13 years old); group 2, median Mg × K: 9.37, IQR: 8.97-9.86 (n = 89, age:62 ± 13 years old); group 3, median Mg × K: 10.95, IQR: 10.50-11.26 (n = 89, age:64 ± 13 years old); group 4, median Mg × K: 12.30, IQR: 11.87-12.82 (n = 89, 61 ± 12 years old); and group 5, top quintile, median Mg × K: 14.92, IQR:14.07-16.23 (n = 88, 62 ± 11 years old). The patients were followed up for 2 years to determine the risk of all-cause mortality. Patients with a lower Mg × K product had more comorbidities, malnutrition-inflammation status, and a higher mortality risk. Using multivariable Cox regression analysis, a higher Mg × K [HR, 0.89; 95%CI (0.81-0.98)] was found to be an independent predictor of better survival. HD patients with a lower Mg × K product had more comorbidities, a marked malnutrition-inflammation status, and were associated with long-term mortality. A higher Mg × K value is a favorable survival factor.

Association between annual variability of potassium levels and prognosis in patients undergoing hemodialysis

BACKGROUND

Hyperkalemia and hypokalemia are associated with mortality in patients undergoing hemodialysis. However, there are few reports on the association between potassium level fluctuations and mortality. We retrospectively investigated the association between serum potassium level variability and mortality in patients undergoing hemodialysis.

METHODS

This study was conducted at a single center. Variability in serum potassium levels was evaluated using the standard deviation of potassium level from July 2011 to June 2012, and its association with prognosis was examined by following up the patients for 5 years. Serum potassium variability was assessed as the coefficient of variation, and the statistical analysis was performed after log transformation.

RESULTS

Among 302 patients (mean age 64.9 ± 13.3; 57.9% male; and median dialysis vintage 70.5 months [interquartile range, IQR 34-138.3]), 135 died during the observation period (median observation period 5.0 years [2.3-5.0]). Although the mean potassium level was not associated with prognosis, serum potassium level variability was associated with prognosis, even after adjustments for confounding factors such as age and dialysis time (hazard ratio: 6.93, 95% confidence interval [Cl] 1.98-25.00, p = 0.001). After the adjustments, the coefficient of variation of potassium level in the highest tertile (T3) showed a higher relative risk for prognosis than that in T1 (relative risk: 1.98, 95% CI 1.19-3.29, p = 0.01).

CONCLUSIONS

Variability in serum potassium levels was associated with mortality in patients undergoing hemodialysis. Careful monitoring of potassium levels and their fluctuations is necessary for this patient population.

Association of Dietary Potassium Intake With Abdominal Aortic Calcification and Pulse Pressure in US Adults

OBJECTIVES

Arterial calcification contributes to cardiovascular mortality. Based on a recent animal study, we hypothesized that higher dietary potassium intake was associated with less abdominal aortic calcification (AAC) and lower arterial stiffness among adults in the United States.

METHODS

Cross-sectional analyses were performed on participants over 40 years old from the National Health and Nutrition Examination Survey 2013-2014. Dietary potassium intake was categorized into quartiles (Q1: <1911, Q2: 1911-2461, Q3: 2462-3119, and Q4: >3119 mg/d). Primary outcome AAC was quantified using the Kauppila scoring system. AAC scores were categorized into no AAC (AAC = 0, reference group), mild/moderate (AAC >0 to ≤ 6), and severe AAC (AAC >6). Pulse pressure was used as a surrogate for arterial stiffness and examined as a secondary outcome.

RESULTS

Among 2,418 participants, there was not a linear association between dietary potassium intake and AAC. Higher dietary potassium intake was associated with less severe AAC when comparing dietary potassium intake in Q2 with Q1 (odds ratio 0.55; 95% confidence interval: 0.34 to 0.92; P = .03). Higher dietary potassium intake was significantly associated with lower pulse pressure (P = .007): per 1000 mg/d higher dietary potassium intake, pulse pressure was 1.47 mmHg lower in the fully adjusted model. Compared to participants with dietary potassium intake in Q1, pulse pressure was 2.84 mmHg lower in Q4 (P = .04).

CONCLUSIONS

We did not find a linear association between dietary potassium intake and AAC. Dietary potassium intake was negatively associated with pulse pressure.

Serum Potassium and Risk of Death or Kidney Replacement Therapy in Older People With CKD Stages 4-5: Eight-Year Follow-up

RATIONALE & OBJECTIVE

Hypokalemia may accelerate kidney function decline. Both hypo- and hyperkalemia can cause sudden cardiac death. However, little is known about the relationship between serum potassium and death or the occurrence of kidney failure requiring replacement therapy (KRT). We investigated this relationship in older people with chronic kidney disease (CKD) stage 4-5.

STUDY DESIGN

Prospective observational cohort study.

SETTING & PARTICIPANTS

We followed 1,714 patients (≥65 years old) from the European Quality (EQUAL) study for 8 years from their first estimated glomerular filtration rate (eGFR)<20mL/min/1.73m2 measurement.

EXPOSURE

Serum potassium was measured every 3 to 6 months and categorized as≤3.5,>3.5-≤4.0,>4.0-≤4.5,>4.5-≤5.0 (reference),>5.0-≤5.5, >5.5-≤6.0, and>6.0mmol/L.

OUTCOME

The combined outcome death before KRT or start of KRT.

ANALYTICAL APPROACH

The association between categorical and continuous time-varying potassium and death or KRT start was examined using Cox proportional hazards and restricted cubic spline analyses, adjusted for age, sex, diabetes, cardiovascular disease, renin-angiotensin-aldosterone system (RAAS) inhibition, eGFR, and subjective global assessment (SGA).

RESULTS

At baseline, 66% of participants were men, 42% had diabetes, 47% cardiovascular disease, and 54% used RAAS inhibitors. Their mean age was 76±7 (SD) years, mean eGFR was 17±5 (SD) mL/min/1.73m2, and mean SGA was 6.0±1.0 (SD). Over 8 years, 414 (24%) died before starting KRT, and 595 (35%) started KRT. Adjusted hazard ratios for death or KRT according to the potassium categories were 1.6 (95% CI, 1.1-2.3), 1.4 (95% CI, 1.1-1.7), 1.1 (95% CI, 1.0-1.4), 1 (reference), 1.1 (95% CI, 0.9-1.4), 1.8 (95% CI, 1.4-2.3), and 2.2 (95% CI, 1.5-3.3). Hazard ratios were lowest at a potassium of about 4.9mmol/L.

LIMITATIONS

Shorter intervals between potassium measurements would have allowed for more precise estimations.

CONCLUSIONS

We observed a U-shaped relationship between serum potassium and death or KRT start among patients with incident CKD 4-5, with a nadir risk at a potassium level of 4.9mmol/L. These findings underscore the potential importance of preventing both high and low potassium in patients with CKD 4-5.

PLAIN-LANGUAGE SUMMARY

Abnormal potassium blood levels may increase the risk of death or kidney function decline, especially in older people with chronic kidney disease (CKD). We studied 1,714 patients aged≥65 years with advanced CKD from the European Quality (EQUAL) study and followed them for 8 years. We found that both low and high levels of potassium were associated with an increased risk of death or start of kidney replacement therapy, with the lowest risk observed at a potassium level of 4.9 mmol/L. In patients with CKD, the focus is often on preventing high blood potassium. However, this relatively high optimum potassium level stresses the potential importance of also preventing low potassium levels in older patients with advanced CKD.

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.

Digital Healthy Diet Literacy and Fear of COVID-19 as Associated with Treatment Adherence and Its Subscales among Hemodialysis Patients: A Multi-Hospital Study

Treatment adherence (TA) is a critical issue and is under-investigated in hemodialysis patients. A multi-center study was conducted from July 2020 to March 2021 on 972 hemodialysis patients in eight hospitals in Vietnam to explore the factors associated with TA during the COVID-19 pandemic. Data were collected, including socio-demographics, an End-Stage Renal Disease Adherence Questionnaire (ESRD-AQ), 12-item short-form health literacy questionnaire (HLS-SF12), 4-item digital healthy diet literacy scale (DDL), 10-item hemodialysis dietary knowledge scale (HDK), 7-item fear of COVID-19 scale (FCoV-19S), and suspected COVID-19 symptoms (S-COVID19-S). Bivariate and multivariate linear regression models were used to explore the associations. Higher DDL scores were associated with higher TA scores (regression coefficient, B, 1.35; 95% confidence interval, 95%CI, 0.59, 2.12; p = 0.001). Higher FCoV-19S scores were associated with lower TA scores (B, -1.78; 95%CI, -3.33, -0.24; p = 0.023). In addition, patients aged 60-85 (B, 24.85; 95%CI, 6.61, 43.11; p = 0.008) with "very or fairly easy" medication payment ability (B, 27.92; 95%CI, 5.89, 44.95; p = 0.013) had higher TA scores. Patients who underwent hemodialysis for ≥5 years had a lower TA score than those who received <5 years of hemodialysis (B, -52.87; 95%CI, -70.46, -35.28; p < 0.001). These findings suggested that DDL and FCoV-19S, among other factors, should be considered in future interventions to improve TA in hemodialysis patients.

C-L Case Conference: Torsades de Pointes in a Patient With Lifelong Medical Trauma, COVID-19, Remdesivir, Citalopram, Quetiapine, and Hemodialysis

We present a case of Torsades de Pointes (TdP) in a patient with COVID-19 infection and multiple TdP risk factors including QT-interval prolongation, hemodialysis, bradycardia, and treatment with remdesivir, citalopram, and quetiapine. The case was complicated by post-resuscitation anxiety superimposed on a history of medical trauma since childhood. Top experts in the field of consultation-liaison psychiatry, trauma informed care, and cardiac electrophysiology provide perspectives on this case with a review of the literature. Key teaching topics include identification of TdP risk factors in patients with a complex illness; the necessity for prompt electrophysiology consultation in clinical scenarios with high risk for TdP; and the approach to patients with medical trauma using a trauma-informed lens. We highlight the contributions of COVID-19, the pharmacokinetics of QT-interval-prolonging psychotropic medications, the risks of hemodialysis, and the role of remdesivir-induced bradycardia in this first reported case of TdP in a patient treated with remdesivir.

Plasma Nitrate and Nitrite Kinetics after Single Intake of Beetroot Juice in Adult Patients on Chronic Hemodialysis and in Healthy Volunteers: A Randomized, Single-Blind, Placebo-Controlled, Crossover Study

Nitric oxide (NO) contributes to maintaining normal cardiovascular and renal function. This bioactive signalling molecule is generally formed enzymatically by NO synthase in the vascular endothelium. NO bioactivity can also be attributed to dietary intake of inorganic nitrate, which is abundant in our diet, especially in green leafy vegetables and beets. Ingested nitrate is reduced to nitrite by oral commensal bacteria and further to NO systemically. Previous studies have shown that dialysis, by means of removing nitrate and nitrite from the body, can reduce NO bioactivity. Hence, dietary intervention approaches aimed to boost the nitrate-nitrite-NO pathway may be of benefit in dialysis patients. The purpose of this study was to examine the kinetics of plasma nitrate and nitrite after a single intake of nitrate-rich concentrated beetroot juice (BJ) in adult hemodialysis (HD) patients and in age-matched healthy volunteers (HV). Eight HD patients and seven HV participated in this single center, randomized, single-blind, placebo-controlled, crossover study. Each participant received a sequential single administration of active BJ (70 mL, 400 mg nitrate) and placebo BJ (70 mL, 0 mg nitrate) in a random order separated by a washout period of seven days. For the kinetic analysis, blood samples were collected at different time-points before and up to 44 h after BJ intake. Compared with placebo, active BJ significantly increased plasma nitrate and nitrite levels both in HD patients and HV. The area under the curve and the maximal concentration of plasma nitrate, but not of nitrite, were significantly higher in HD patients as compared with HV. In both groups, active BJ ingestion did not affect blood pressure or plasma potassium levels. Both BJs were well tolerated in all participants with no adverse events reported. Our data provide useful information in planning dietary nitrate supplementation efficacy studies in patients with reduced NO bioactivity.

Potassium Intake-(Un)Expected Non-Predictor of Higher Serum Potassium Levels in Hemodialysis DASH Diet Consumers

As high serum potassium levels can lead to adverse outcomes in hemodialysis (HD) patients, dietary potassium is frequently restricted in these patients. However, recent studies have questioned whether dietary potassium really affects serum potassium levels. The dietary approaches to stop hypertension (DASH) diet is considered a healthy dietary pattern that has been related to lower risk of developing end-stage kidney disease. The aim of this study was to analyze the association between a dietary pattern with high content of potassium-rich foods and serum potassium levels in HD patients. This was an observational, cross-sectional, multicenter study with 582 HD patients from 37 dialysis centers. Clinical and biochemical data were registered. Dietary intake was obtained using the Food Frequency Questionnaire. Adherence to the DASH dietary pattern was obtained from Fung’s DASH index. All statistical tests were performed using SPSS 26.0 software. A p-value lower than 0.05 was considered statistically significant. Patients’ mean age was 67.8 ± 17.7 years and median HD vintage was 65 (43−104) months. Mean serum potassium was 5.3 ± 0.67 mEq/L, dietary potassium intake was 2465 ± 1005 mg/day and mean Fung´s Dash Index was 23.9 ± 3.9. Compared to the lower adherence to the DASH dietary pattern, patients with a higher adherence to the DASH dietary pattern were older (p < 0.001); presented lower serum potassium (p = 0.021), serum sodium (p = 0.028), total fat intake (p = 0.001) and sodium intake (p < 0.001); and had higher carbohydrate intake (p < 0.001), fiber intake (p < 0.001), potassium intake (p < 0.001), phosphorus intake (p < 0.001) and body mass index (p = 0.002). A higher adherence to this dietary pattern was a predictor of lower serum potassium levels (p = 0.004), even in the adjusted model (p = 0.016). Following the DASH dietary pattern, which is rich in potassium, is not associated with increased serum potassium levels in HD patients. Furthermore, a higher adherence to the DASH dietary pattern predicts lower serum potassium levels. Therefore, generalized dietary potassium restrictions may not be adequate, at least for those with a DASH diet plan.