REN and heart failure: BNP: B-type natriuretic peptide, HF: heart failure, IQR: interquartile range, LVSD: left ventricular systolic dysfunction, MRA: mineralocorticoid receptor antagonist, NYHA: New York Heart Association, RASi: renin-angiotensin system inhibitors, SD: standard deviation, UA: uric acid, eGFR: estimated glomerular filtration rate