Lower serum potassium associated with increased mortality in dialysis patients: A nationwide prospective observational cohort study in Korea

Abstract

BackgroundAbnormal serum potassium concentration has been suggested as a risk factor for mortality in patients undergoing dialysis patients. We investigated the impact of serum potassium levels on survival according to dialysis modality.MethodsA nationwide, prospective, observational cohort study for end stage renal disease patients has been ongoing in Korea since August 2008. Our analysis included patients whose records contained data regarding serum potassium levels. The relationship between serum potassium and mortality was analyzed using competing risk regression.ResultsA total of 3,230 patients undergoing hemodialysis (HD, 64.3%) or peritoneal dialysis (PD, 35.7%) were included. The serum potassium level was significantly lower (P < 0.001) in PD (median, 4.5 mmol/L; interquartile range, 4.0–4.9 mmol/L) than in HD patients (median, 4.9 mmol/L; interquartile range, 4.5–5.4 mmol/L). During 4.4 ± 1.7 years of follow-up, 751 patients (23.3%) died, mainly from cardiovascular events (n = 179) and infection (n = 120). In overall, lower serum potassium level less than 4.5 mmol/L was an independent risk factor for mortality after adjusting for age, comorbidities, and nutritional status (sub-distribution hazard ratio, 1.30; 95% confidence interval 1.10–1.53; P = 0.002). HD patients showed a U-shaped survival pattern, suggesting that both lower and higher potassium levels were deleterious, although insignificant. However, in PD patients, only lower serum potassium level (<4.5 mmol/L) was an independent predictor of mortality (sub-distribution hazard ratio, 1.35; 95% confidence interval 1.00–1.80; P = 0.048).ConclusionLower serum potassium levels (<4.5 mmol/L) occur more commonly in PD than in HD patients. It represents an independent predictor of survival in overall dialysis, especially in PD patients. Therefore, management of dialysis patients should focus especially on reducing the risk of hypokalemia, not only that of hyperkalemia.

Association of Low Serum Potassium Levels and Risk for All‐Cause Mortality in Patients With Chronic Kidney Disease: A Systematic Review and Meta‐Analysis

“…Nowadays, no indicator is considered as the gold standard. In our elected studies, almost all results were adjusted for BMI except three studies . Reanalyzing the data after deleting the three HR values, we came to the same conclusion (HR = 1.61, 95% CI: 1.20–2.07; no figure provided).…”

“…We identified 2281 articles from the PubMed database, 3255 articles from the Embase database, 613 articles from Cochrane Library, and 1359 articles from Ovid database. After exclusion of duplicates and papers that did not meet the inclusion criteria, 11 clinical studies including 57 234 subjects were ultimately included in the meta‐analysis . Characteristics of the included studies are provided in Table .…”

“…Ten of the studies included evaluated the association between low SK (including SK <4.0 mEq/L) and risk of all‐cause mortality (Fig. ).…”

“…sudden cardiac death, all‐cause death) . Other studies have reported higher risk of all‐cause death and cardiovascular death among CKD patients with low K levels .…”

Melatonin receptor activation protects against low potassium‐induced ventricular fibrillation by preserving action potentials and connexin‐43 topology in isolated rat hearts

“…Malignant arrhythmias are a significant cause of morbidity and mortality in the world . Electrolyte imbalance due to potassium deficiency increases arrhythmic death . Almost 50% of patients resuscitated by out‐of‐hospital ventricular fibrillation have low potassium levels.…”