Dataset Information

Effect of dialysate potassium and lactate on serum potassium and bicarbonate concentrations during daily hemodialysis at low dialysate flow rates.

ABSTRACT:

Background

Observational studies of hemodialysis patients treated thrice weekly have shown that serum and dialysate potassium and bicarbonate concentrations are associated with patient outcomes. The effect of more frequent hemodialysis on serum potassium and bicarbonate concentrations has rarely been studied, especially for treatments at low dialysate flow rate.

Methods

These post-hoc analyses evaluated data from patients who transferred from in-center hemodialysis (HD) to daily HD at low dialysate flow rates during the FREEDOM Study. The primary outcomes were the change in predialysis serum potassium and bicarbonate concentrations after transfer from in-center HD (mean during the last 3?months) to daily HD (mean during the first 3?months).

Results

After transfer from in-center HD to daily HD (data from 345 patients, 51?±?15?years of age, mean?±?standard deviation), predialysis serum potassium decreased (P?ConclusionsControl of serum potassium and bicarbonate concentrations during daily HD at low dialysate flow rates is readily achievable; the choice of dialysate potassium and lactate concentration can be informed when transfer is from in-center HD to daily HD.

SUBMITTER: Leypoldt JK

PROVIDER: S-EPMC6617706 | biostudies-literature | 2019 Jul

REPOSITORIES: biostudies-literature

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Publications

Effect of dialysate potassium and lactate on serum potassium and bicarbonate concentrations during daily hemodialysis at low dialysate flow rates.

Leypoldt John K JK Kraus Michael A MA Jaber Bertrand L BL Weinhandl Eric D ED Collins Allan J AJ

BMC nephrology 20190709 1

<h4>Background</h4>Observational studies of hemodialysis patients treated thrice weekly have shown that serum and dialysate potassium and bicarbonate concentrations are associated with patient outcomes. The effect of more frequent hemodialysis on serum potassium and bicarbonate concentrations has rarely been studied, especially for treatments at low dialysate flow rate.<h4>Methods</h4>These post-hoc analyses evaluated data from patients who transferred from in-center hemodialysis (HD) to daily H ...[more]

PMID: 31288787

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Project description:BACKGROUND:Studies examining the association of dialysate potassium concentration and mortality in hemodialysis patients show conflicting findings. We hypothesized that low dialysate potassium concentrations are associated with higher mortality, particularly in patients with high pre-dialysis serum potassium concentrations. METHODS:We evaluated 624 hemodialysis patients from the prospective Malnutrition, Diet, and Racial Disparities in Kidney Disease study recruited from 16 outpatient dialysis facilities over 2011-2015 who underwent protocolized collection of dialysis treatment characteristics every 6 months. We examined the association of dialysate potassium concentration, categorized as 1, 2, and 3 mEq/L, with all-cause mortality risk in the -overall cohort, and stratified by pre-dialysis serum potassium (< 5 vs. ?5 mEq/L) using case-mix adjusted Cox models. RESULTS:In baseline analyses, dialysate potassium concentrations of 1 mEq/L were associated with higher mortality, whereas concentrations of 3 mEq/L were associated with similar mortality in the overall cohort (reference: 2 mEq/L): adjusted hazard ratios (aHRs; 95% CI) 1.70 (1.01-2.88) and 0.95 (0.64-1.39), respectively. In analyses stratified by serum potassium, baseline dialysate potassium concentrations of 1 mEq/L were associated with higher mortality in patients with serum potassium ?5 mEq/L but not in those with serum potassium < 5 mEq/L: aHRs (95% CI) 2.87 (1.51-5.46) and 0.74 (0.27-2.07), respectively (p interaction = 0.04). These findings were robust with incremental adjustment for serum potassium, potassium-binding resins, and potassium-modifying medications. CONCLUSION:Low (1 mEq/L) dialysate potassium -concentrations were associated with higher mortality, particularly in hemodialysis patients with high pre-dialysis serum potassium. Further studies are needed to identify therapeutic strategies that mitigate inter-dialytic serum potassium accumulation and subsequent high dialysate serum potassium gradients in this population.

Project description:Introduction Atrial fibrillation (AF) disproportionally affects persons on maintenance hemodialysis (HD). Associations of serum and dialysate potassium concentrations [K+] with AF incidence are poorly understood. Methods We conducted a cohort study using Medicare claims merged with clinical data from a dialysis provider to determine whether serum-[K+] and/or dialysate-[K+] independently associated with AF incidence. Persons insured by fee-for-service Medicare aged ≥67 years at dialysis initiation and free from diagnosed AF prior to day 120 of dialysis were eligible. Serum-[K+] and dialysate-[K+] were assessed in 30-day intervals and patients were followed-up with for AF incidence in subsequent 30-day intervals. Results During 2006 to 2011, 15,190 persons (mean age = 76.3 years) initiating HD had no prior AF diagnosis. Mean serum-[K+] was 4.5 mEq/l; dialysate-[K+] was 3 mEq/l in 34% and 2 mEq/l in 52% of patients. Followed-up over 21,907 person-years, 2869 persons had incident AF (incidence/100 person-years, 13.1 [95% confidence interval [CI], 12.6–13.6]). The multivariable-adjusted association of serum-[K+] with incident AF was J-shaped as follows: relative to a serum-[K+] of 4.5 mEq/l, lower serum-[K+] associated with increased AF risk, whereas confidence bands for higher serum-[K+] indicated no association. Dialysis against a dialysate-[K+] of 3 mEq/l versus 2 mEq/l independently associated with a 14% (95% CI, 5%–24%) lower incidence of AF. No effect modification between serum-[K+] and dialysate-[K+] was detected (P = 0.34). Conclusion Lower serum-[K+] was independently associated with incident AF whereas elevated serum-[K+] was not. The findings support adoption of dialysate solutions with a dialysate-[K+] of 3 mEq/l, regardless of patients’ serum-[K+], and elimination of lower dialysate-[K+] solutions from practice. Clinical trials randomizing patients to different dialysate-[K+] are warranted to establish causality. Graphical abstract

Project description:BackgroundSudden death is a leading cause of death in patients on maintenance hemodialysis therapy. During hemodialysis sessions, the gradient between serum and dialysate levels results in rapid electrolyte shifts, which may contribute to arrhythmias and sudden death. Controversies exist about the optimal electrolyte concentration in the dialysate; specifically, it is unclear whether patient outcomes differ among those treated with a dialysate potassium concentration of 3 mEq/L compared to 2 mEq/L.Study designProspective cohort study.Setting & participants55,183 patients from 20 countries in the Dialysis Outcomes and Practice Patterns Study (DOPPS) phases 1 to 5 (1996-2015).PredictorDialysate potassium concentration at study entry.OutcomesCox regression was used to estimate the association between dialysate potassium concentration and both all-cause mortality and an arrhythmia composite outcome (arrhythmia-related hospitalization or sudden death), adjusting for potential confounders.ResultsDuring a median follow-up of 16.5 months, 24% of patients died and 7% had an arrhythmia composite outcome. No meaningful difference in clinical outcomes was observed for patients treated with a dialysate potassium concentration of 3 versus 2 mEq/L (adjusted HRs were 0.96 [95% CI, 0.91-1.01] for mortality and 0.98 [95% CI, 0.88-1.08] for arrhythmia composite). Results were similar across predialysis serum potassium levels. As in prior studies, higher serum potassium level was associated with adverse outcomes. However, dialysate potassium concentration had only minimal impact on serum potassium level measured predialysis (+0.09 [95% CI, 0.05-0.14] mEq/L serum potassium per 1 mEq/L greater dialysate potassium concentration).LimitationsData were not available for delivered (vs prescribed) dialysate potassium concentration and postdialysis serum potassium level; possible unmeasured confounding.ConclusionsIn combination, these results suggest that approaches other than altering dialysate potassium concentration (eg, education on dietary potassium sources and prescription of potassium-binding medications) may merit further attention to reduce risks associated with high serum potassium levels.

Project description:Rationale & objectiveTreatment with certain QT interval-prolonging antibiotics is associated with a higher risk of sudden cardiac death among individuals with hemodialysis-dependent kidney failure. Concurrent exposure to large serum-to-dialysate potassium gradients, which promote large potassium shifts, may augment the proarrhythmic effects of these medications. The primary objective of this study was to examine whether the serum-to-dialysate gradient modifies the cardiac safety of azithromycin, and separately, levofloxacin/moxifloxacin.Study designRetrospective observational cohort study using a new-user study design.Setting & populationAdult in-center hemodialysis patients with Medicare coverage in the US Renal Data System (2007-2017).ExposureInitiation of azithromycin (or levofloxacin/moxifloxacin) as compared to amoxicillin-based antibiotics (exposure). Serum-to-dialysate potassium gradient (effect modifier). Individual patients could contribute multiple study antibiotic treatment episodes to the analyses.OutcomesSudden cardiac death (14 days).Analytical approachInverse probability of treatment-weighted survival models to estimate HRs and robust 95% CIs.ResultsThe azithromycin versus amoxicillin-based antibiotic cohort included 89,379 unique patients with 113,516 azithromycin and 103,493 amoxicillin-based treatment episodes. Azithromycin versus amoxicillin-based antibiotic treatment was associated with a higher risk of sudden cardiac death overall, HR, 1.68; 95% CI, 1.31-2.16. The risk was numerically higher when the baseline serum-to-dialysate potassium gradient was ≥3 mEq/L compared with <3 mEq/L (HR, 2.22; 95% CI, 1.46-3.40 vs HR, 1.43; 95% CI. 1.04-1.96, P interaction = 0.07). Analogous analyses in a respiratory fluoroquinolone (levofloxacin/moxifloxacin) versus amoxicillin-based antibiotic cohort with 79,449 unique patients and 65,959 respiratory fluoroquinolone and 103,776 amoxicillin-based treatment episodes yielded similar results.LimitationsResidual confounding.ConclusionsAlthough treatment with azithromycin and, separately, respiratory fluoroquinolones were each associated with a heightened risk of sudden cardiac death, this risk was augmented in the setting of larger serum-to-dialysate potassium gradients. Minimizing the potassium gradient may be an approach to reduce the cardiac risk of these antibiotics.

Project description:Rationale & Objective Excess morbidity and mortality are associated with both high and low serum bicarbonate levels in epidemiologic studies of patients with end-stage kidney disease (ESKD) receiving hemodialysis. The Kidney Disease Outcomes Quality Initiative (KDOQI) recommends modifying dialysate bicarbonate concentration to achieve a predialysis serum bicarbonate level ? 22 mmol/L, measured as total carbon dioxide (CO2). This practice assumes that total CO2 is an adequate surrogate for acid-base status, yet its surrogacy performance is unknown in ESKD. We determined acid-base status at the beginning and end of hemodialysis using total CO2 and pH and tested whether total CO2 is an appropriate surrogate for acid-base status. Study Design Pilot study. Setting & Participants 25 veterans with ESKD receiving outpatient hemodialysis. Tests Compared pH, calculated bicarbonate level, and total CO2. Outcomes The proportion of paired samples for which total CO2 misclassified acid-base status according to pH was determined. Bias of total CO2 was evaluated using Bland-Altman plots, comparing it to calculated bicarbonate. Results Among 71 samples, mean pH was 7.41 ± 0.03 predialysis and 7.48 ± 0.05 postdialysis. Compared with interpretation of full blood gas profiles, 9 of 25 (36%) participants were misclassified as acidemic using predialysis total CO2 measures alone (total CO2 < 22 mmol/L but pH ? 7.38); 1 (4%) participant was misclassified as alkalemic (total CO2 > 26 mmol/L but pH ? 7.42). Among paired samples in which predialysis total CO2 was < 22 mmol/L, the corresponding pH was acidemic (< 7.38) in just 3 of 13 (23%) instances. Limitations Small, single-center, entirely male cohort. Conclusions A majority of participants became alkalemic during routine hemodialysis despite arriving with normal pH. 10 of 25 (40%) participants’ acid-base status was misclassified using total CO2 measurements alone; the majority of predialysis total CO2 values that would trigger therapeutic modification according to practice guidelines did not have acidemia when assessed using pH. Efforts to improve dialysis prescription require recognition that total CO2 may not be reliable for interpreting acid-base status in hemodialysis patients. Graphical abstract

Dataset Information

Effect of dialysate potassium and lactate on serum potassium and bicarbonate concentrations during daily hemodialysis at low dialysate flow rates.

Background

Methods

Results

Publications

Effect of dialysate potassium and lactate on serum potassium and bicarbonate concentrations during daily hemodialysis at low dialysate flow rates.

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