For example, the BIOSTAT-CHF (A Systems Biology Study to Tailored Treatment in Chronic Heart Failure) trial data demonstrated that suffering from heart failure with preserved ejection fraction (HFpEF) was a strong independent predictor of increased IL6 levels [41], while the PREVEND (Prevention of Renal and Vascular End-Stage Disease) study found IL6 levels significantly associated with the development of HFpEF but not heart failure with reduced ejection fraction (HFrEF) [42]. Here, IL6 is linked to congestive heart failure.