Serum Potassium Levels and Its Variability in Incident Peritoneal Dialysis Patients: Associations with Mortality

Abstract

BackgroundAbnormal serum potassium is associated with an increased risk of mortality in dialysis patients. However, the impacts of serum potassium levels on short- and long-term mortality and association of potassium variability with death in peritoneal dialysis (PD) patients are uncertain.MethodsWe examined mortality-predictability of serum potassium at baseline and its variability in PD patients treated in our center January 2006 through December 2010 with follow-up through December 2012. The hazard ratios (HRs) were used to assess the relationship between baseline potassium levels and short-term (≤1 year) as well as long-term (>1 year) survival. Variability of serum potassium was defined as the coefficient of variation of serum potassium (CVSP) during the first year of PD.ResultsA total of 886 incident PD patients were enrolled, with 248 patients (27.9%) presented hypokalemia (serum potassium <3.5 mEq/L). During a median follow-up of 31 months (range: 0.5–81.0 months), adjusted all-cause mortality hazard ratio (HR) and 95% confidence interval (CI) for baseline serum potassium of <3.0, 3.0 to <3.5, 3.5 to <4.0, 4.5 to <5.0, and ≥5.0 mEq/L, compared with 4.0 to <4.5 (reference), were 1.79 (1.02–3.14), 1.15 (0.72–1.86), 1.31 (0.82–2.08), 1.33 (0.71–2.48), 1.28 (0.53–3.10), respectively. The increased risk of lower potassium with mortality was evident during the first year of follow-up, but vanished thereafter. Adjusted all-cause mortality HR for CVSP increments of 7.5% to <12.0%; 12.0% to <16.7% and ≥16.7%, compared with <7.5% (reference), were 1.35 (0.67–2.71), 2.00 (1.05–3.83) and 2.18 (1.18–4.05), respectively. Similar association was found between serum potassium levels and its variability and cardiovascular mortality.ConclusionsA lower serum potassium level was associated with all-cause and cardiovascular mortality during the first year of follow-up in incident PD patients. In addition, higher variability of serum potassium levels conferred an increased risk of death in this population.

Baseline Serum Magnesium Level and Its Variability in Maintenance Hemodialysis Patients: Associations with Mortality

“…It has been reported that the variability of hemoglobin [29], serum calcium and phosphorus [30], as well as variability of serum potassium levels [9] are closely associated with clinical outcomes. However, few studies have investigated Mg variability in MHD patients.…”

“…CVSM was calculated as the ratio of SD to the mean of serum magnesium [9]. Patients were further divided into three classifications according to each tertile of magnesium CV: high variation group (CV ≥0.149 mmol/L), middle variation group (0.114 mmol/L ≤CV <0.149 mmol/L) and low variation group (CV <0.114 mmol/L).…”

“…Mg plays a role in the active transport of calcium and potassium ions acrossing cell membranes, a process important to nerve impulse conduction, muscle contraction and normal heart rhythm [8]. Higher variability of serum potassium level suggested an increased risk of death [9]. However, few studies could determine whether serum Mg variability is associated with mortality in MHD patients.…”

Hyperkalemia in heart failure patients: current challenges and future prospects

“…In addition, 5.5 mEq/L is the reference worldwide accepted in laboratories, clinical trials, and real practice. [6][7][8] The incidence and prevalence of hyperkalemia, defined as potassium levels .5.5 mEq/L, vary depending on the patient characteristics. Its real prevalence is unknown, although an estimated prevalence in general population is among 2%-3%, and among 1%-10% in hospitalized patients.…”

Serum Potassium Profile and Associated Factors in Incident Peritoneal Dialysis Patients

“…Szeto et al reported no association of residual renal function with hypokalemia in incident PD patients [5]. Moreover, Xu et al reported no association of baseline serum potassium levels with hypokalemia in incident PD patients [7].…”