Background We recently showed that, in patients with heart failure, lower high-density lipoprotein (HDL) cholesterol concentration was a strong predictor of death or hospitalization for heart failure. In a follow-up study, we suggested that this association could be partly explained by HDL proteome composition. However, whether the emerging concept of HDL function contributes to the prognosis of patients with heart failure has not been addressed. Methods and Results We measured 3 key protective HDL function metrics, namely, cholesterol efflux, antioxidative capacity, and anti-inflammatory capacity, at baseline and after 9 months in 446 randomly selected patients with heart failure from BIOSTAT-CHF (A Systems Biology Study to Tailored Treatm...