GDF15 and heart failure: The secondary end point of death or heart failure was associated with RDW (HR: 1.40; 95% CI: 1.19-1.67), NT-proBNP (HR: 2.97; 95% CI: 2.16-4.06), hs-troponinT (HR: 1.35; 95% CI: 1.09-1.67), and GDF-15 (HR: 1.80; 95% CI: 1.28-2.56).