Serum potassium levels provide prognostic information in symptomatic heart failure beyond traditional clinical variables

Abstract

Aims Despite of recent advances in the pharmacological treatment, heart failure (HF) maintains significant morbidity and mortality rates. While serum potassium disorders are common and associated with adverse outcomes, the exact recommended potassium level for patients with HF are not entirely established. We aimed to investigate the prognostic role of potassium levels on a cohort of patients with symptomatic chronic HF. Methods and results Patients with symptomatic chronic HF were identified at the referral to 6 min walking test (6MWT) and were prospectively followed up for cardiovascular events. Clinical and laboratorial data were retrospectively obtained. The primary endpoint was the composite of cardiovascular death, hospitalization due to HF, and heart transplantation. The cohort included 178 patients with HF with the mean age of 51 ± 12.76 years, 39% were female, 85% of non-ischaemic cardiomyopathy, and 38% had New York Heart Association Class III with a relatively high Meta-Analysis Global Group in Chronic Heart Failure (MAGGIC) score (12.91 ± 6.6). The mean left ventricular ejection fraction was 39.98 ± 15.79%, and the mean 6MWT distance was 353 ± 136 m. After a median follow-up of 516 days, there were 22 major cardiovascular events (4 cardiovascular deaths, 13 HF admissions, and 5 heart transplants). Patients were stratified according to cut-point level of serum potassium of 4.7 mmol/L to predict combined cardiac events based on receiver operating characteristic analysis. Individuals with higher potassium levels had worse renal function (glomerular filtration rate, K ≤ 4.7: 102.8 ± 32.2 mL/min/1.73 m 2 vs. K > 4.7: 85.42 ± 36.2 mL/min/1.73 m 2 , P = 0.004), higher proportion of New York Heart Association Class III patients (K ≤ 4.7: 28% vs.

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“…Concerning K levels, hyperkalemia is frequent in patients with heart failure due to different reasons, like neurohormonal alterations implicated in the illness and kidney dysfunction, and is associated with a higher risk of cardiovascular complications (Rakisheva et al 2020 ). Hyperkalemia is also markedly related to poor prognosis in those patients and may influence survival (Toledo et al 2021 ). Other studies, like Jung et al ( 2022 ), reported increased Ca and P levels in heart failure.…”

Six-minute walk test as clinical end point in cardiomyopathy clinical trials, including ATTR-CM: a systematic literature review

“…Two further publications reported the relationship between the 6MWT and mortality in pediatric patients with DCM [ 39 , 47 ], of which one investigated the use of 6MWT as a prognostic marker for death [ 39 ]. Den Boer et al found that after adjusting for factors that may impact the 6MWT distance, such as age, height and weight, the percentage predicted 6MWT distance remained a significant predictor of death (or heart transplant) [ 39 , 67 ].…”

“…One publication identified an association between 6MWT distance and MACE, with the 6MWT distance again demonstrating prognostic value ( Table 2 ) [ 47 ]. Toledo et al reported that 6MWT distance was significantly associated with subsequent cardiac events (including cardiac hospitalization, cardiac-related death or heart transplant) (HR: 0.99; 95% CI: 0.993–0.999; G 2 = 6.30; p = 0.01) in patients with either ischemic CM (ICM) or non-ischemic CM (NICM) [ 47 ]. This publication investigated the prognostic value of serum potassium levels in HF, because they are frequently associated with adverse outcomes in patients with HF.…”

Relationship between Baseline Serum Potassium and 1-Year Readmission in Pediatric Patients with Heart Failure: A Retrospective Cohort Study

“…Our results are consistent with those of recent studies on adult HF populations. Toledo et al found that potassium levels of ≥4.7 mmol/L may facilitate the identification of patients with HF at an increased risk of adverse outcomes [ 14 ]. Aldahl et al reported that the optimal potassium range for patients with chronic HF is 4.1–4.8 mmol/L, and deviations from this range are associated with increased short-term mortality risk [ 9 ].…”