Abstract

Aims Patients with heart failure (HF) at high risk for hyperkalaemia are underrepresented in prospective HF registries. The CARE‐HK in HF registry sought to characterize prospectively the clinical profile, management, and outcomes for patients with HF at high risk of hyperkalaemia. Methods and results CARE‐HK in HF was a multinational prospective registry of outpatients with HF (regardless of left ventricular ejection fraction [LVEF]) treated with an angiotensin‐converting enzyme inhibitor/angiotensin II receptor blocker/angiotensin receptor–neprilysin inhibitor (ACEI/ARB/ARNI) and either receiving or potential candidate for a mineralocorticoid receptor antagonist (MRA). All patients were at increased risk of hyperkalaemia, defined as hyperkalaemia at baseline, prior hyperkalaemia, or estimated glomerular filtration rate (eGFR) <45 ml/min/1.73 m2. Outcomes included frequency of hyperkalaemic events (defined by clinician report with associated potassium value), achievement of renin–angiotensin system inhibitor (RASi) optimization (defined as ≥50% target doses for ACEI/ARB/ARNI and MRA), medication changes following hyperkalaemic episodes, and clinical events. Overall, 2558 patients from 111 sites across nine countries were included. Median (25th–75th) age was 73 (65–80) years, 32% were women, 61% had LVEF ≤40%, and 40% had prior laboratory evidence of hyperkalaemia. Median baseline eGFR and serum potassium were 44 (33–60) ml/min/1.73 m2 and 5.0 (4.4–5.3) mEq/L, respectively. Over a median follow‐up of 12.3 (9.4–18.1) months, 29% of patients had a hyperkalaemic event, and 7% had multiple events. In characterizing treatment prescribed for most of follow‐up, 29% of patients received optimal RASi/MRA therapy, 69% received suboptimal RASi/MRA therapy, and 3% received no RASi/MRA. In the 30 days following the first hyperkalaemic event, RASi/MRA was down‐titrated or discontinued in 3.6% of cases. Potassium binder use was low (patiromer 9.1%, sodium zirconium cyclosilicate 5.9%). Compared with patients without a hyperkalaemic event, patients experiencing a hyperkalaemic event had similar risk of all‐cause mortality (hazard ratio [HR] 1.22, 95% confidence interval [CI] 0.92–1.62, p = 0.16) and a higher risk of subsequent hospitalization (HR 1.59, 95% CI 1.35–1.86, p < 0.001). Conclusions In this contemporary multinational prospective registry of patients with HF at high risk for hyperkalaemia, hyperkalaemic events were common but infrequently associated with RASi/MRA modification or potassium binder use. Fewer than one in three patients received optimal RASi/MRA therapy for the majority of follow‐up, and hyperkalaemic events were associated with higher risk of adverse clinical outcomes. Clinical Trial Registration: ClinicalTrials.gov NCT04864795.