Association of intravenous digoxin use in acute heart failure with rapid atrial fibrillation and short-term mortality according to patient age, renal function, and serum potassium.

OBJECTIVE/BACKGROUND: Intravenous digoxin is still used in emergency departments (EDs) to treat patients with acute heart failure (AHF), especially in those with rapid atrial fibrillation. We investigated whether intravenous digoxin used to treat rapid atrial fibrillation in patients with AHF may influence mortality. METHODS: A secondary analysis of patients included in the Spanish EAHFE (Epidemiology of Acute Heart Failure in Emergency Departments) cohort, which includes patients diagnosed with AHF in 45 Spanish EDs. The relationships between age, estimated glomerular filtration rate, and potassium with 30-day mortality were investigated using restricted cubic spline models adjusted for relevant patient and episode variables. RESULTS: From the 19 947 patients included, we analyzed 2194 patients with AHF and rapid atrial fibrillation that not receiving digoxin at home, divided according to whether they were or were not treated with intravenous digoxin in the ED. The median age of the patients was 82 years (interquartile range=76-87), 61.4% were women and 65.2% had previous episodes of atrial fibrillation. Digoxin and no digoxin groups were formed by 864 (39.4%) and 1330 (60.6%) patients, respectively. There were 191 deaths within the 30-day follow-up period (8.9%), with no differences between patients receiving or not receiving digoxin (8.5 vs. 9.1%, P = 0.636). Although analysis of restricted cubic spline curves showed that death was associated with advanced age, worse renal function, and hypokalemia and hyperkalemia, the use of intravenous digoxin did not interact with any of these relationships (P = 0.156 for age, P = 0.156 for estimated glomerular filtration rate, P = 0.429 for potassium). CONCLUSION: The use of intravenous digoxin in the ED was not associated with significant changes in 30-day mortality, which was confirmed irrespective of patient age or the existence of renal dysfunction or serum potassium disturbances.