Prevalence, Incidence, and Outcomes of Hyperkalaemia in Patients with Chronic Heart Failure and Reduced Ejection Fraction from a Spanish Multicentre Study: SPANIK-HF Design and Baseline Characteristics

Abstract

Hyperkalaemia is a growing concern in the treatment of patients with heart failure and reduced ejection fraction (HFrEF) as it limits the use of some prognostic-modifying drugs and has a negative impact on prognosis. The objective of the present study was to estimate the prevalence of hyperkalaemia in outpatients with HFrEF and its impact on achieving optimal medical treatment. For this purpose, a multicentre, prospective, and observational study was carried out on consecutive HFrEF patients who were monitored as outpatients in heart failure (HF) units and who, in the opinion of their doctor, received optimal medical treatment. A total of 565 HFrEF patients were included from 16 specialised HF units. The mean age was 66 ± 12 years, 78% were male, 45% had an ischemic cause, 39% had atrial fibrillation, 43% were diabetic, 42% had a glomerular filtration rate < 60 mL/min/1.7 m2, and the mean left ventricular ejection fraction was 31 ± 7%. Treatment at the study entry included: 76% on diuretics, 13% on ivabradine, 7% on digoxin, 18.9% on angiotensin-conversing enzyme inhibitors (ACEi), 11.3% on angiotensin receptors blockers (ARBs), 63.8% on angiotensin-neprilysin inhibitors (ARNi), 78.5% on mineralocorticoid receptor antagonists (MRAs), and 92.9% on beta-blockers. Potassium levels in the baseline analysis were: ≤5 mEq/L = 80.5%, 5.1–5.4 mEq/L = 13.8%, 5.5–5.9 mEq/L = 4.6%, and ≥6 mEq/L = 1.06%. Hyperkalaemia was the reason for not prescribing or reaching the target dose of an MRAs in 34.8% and 12.5% of patients, respectively. The impact of hyperkalaemia on not prescribing or dropping below the target dose in relation to ACEi, ARBs, and ARNi was significantly less. In conclusion, hyperkalaemia is a frequent problem in the management of patients with HFrEF and a limiting factor in the optimisation of medical treatment.

Impact of Hyperkalemia in Heart Failure and Reduced Ejection Fraction: A Retrospective Study

“…First of all, the present study analyzed a sample consisting of a higher proportion of males (76.6%) as compared to females (23.4%). Nevertheless, this gender distribution is consistent with previous studies conducted in similar settings, which have reported comparable figures ranging from 70% to 78% [12,21,48]. It is also important to mention that the present investigation is a retrospective observational study, and it is important to note that our operational definition of hyperkalemia diverges from the definition employed in clinical practice guidelines and the majority of previous research (potassium > 5.0 mEq/L) [20].…”

“…The prevalence of baseline hyperkalemia in our study (2.4%) was lower than in previously published registries (4.3% [12] and 5.7% [21]). Since the baseline characteristics of the patients were similar in all three studies, the main observed differences may be explained by the higher percentage of individuals that received ACEI/ARB/ARNI (92% in the ESC-EORP-HFA Heart Failure Long Term study, 94% in the SPANIK-HF and 79% in our study) and MRA (73% versus 63.8% in the mentioned registries, and 58.4% in our sample), since these patients were under follow-up in specialized units in the drug titration phase [12] or had completed titration [21], while our patients were starting follow-up in such a unit for the first time. The high incidence of hyperkalemia in the first year of follow-up in our population, in comparison to subsequent years, could be explained by the fact that it is in the first months after patient referral when the progressive titration of neurohormonal treatment takes place.…”