The importance of developing hyperkalaemia in heart failure during long-term follow-up

Background: Hyperkalaemia is a potentially life-threatening condition. Furthermore, it is one of the main reasons for discontinuation and dose reduction of renin-angiotensin-aldosterone system inhibitors (RAASi) in clinical practice. However, exact data on the prevalence and consequences of occurrence of hyperkalaemia when taking RAASi in a dedicated heart failure care setting are scarce.

Methods: Consecutive patients diagnosed with heart failure from a single tertiary hospital between August 2000 and May 2017 were retrospectively evaluated. Primary endpoint was the development of hyperkalaemia (≥5.5 mmol/L) at any moment during follow-up.

Results: About 396 patients were included in the current analysis (mean follow-up 6.9 years). 26% (n = 104) and 12% (n = 46) of patients developed hyperkalaemia (≥5.5 mmol/L and ≥6.0 mmol/L, respectively). Diabetes mellitus (OR = 1.80, 95% CI = 1.03-3.19) and baseline creatinine (mg/dL) (OR = 2.37, 95% CI = 2.37-3.85) were independent risk factors for hyperkalaemia. Development of hyperkalaemia was associated with 6.5 higher odds for recurrence. Only 10% developed hyperkalaemia during up-titration of RAASi, while 90% developed during later follow-up on stable doses of RAASi. hyperkalaemia was not associated with worse outcome after multivariate adjustment for baseline co-morbidities. However, hyperkalaemia was associated with discontinuation and lower doses of MRAs during follow-up (p = 0.007). Discontinuation of MRA due to hyperkalaemia was associated with an increase in all-cause mortality in HFrEF patients (HR = 1.77, 95% CI = 1.05-2.99).

Conclusions: Approximately, one-fourth of patients developed hyperkalaemia during follow-up which was associated with a lower MRA dose during follow-up. Discontinuation of MRA, but not hyperkalaemia itself, was associated with an increased risk of all-cause mortality and heart failure admission in HFrEF patients.