IL6 and congestive heart failure: Five prospective studies evaluated IL-6 as a prognostic biomarker in heart failure or incident HFpEF: BIOSTAT-CHF [18], ASCEND-HF [30], PREVEND (Chia 2021) [29], LURIC [23], and the DAPA-HF biomarker substudy [22], as in Figure 3.