We previously developed and externally validated a risk prediction model that provides accurate, individualised estimates of the risk of HHF and all-cause mortality in patients at risk of HF or with HF but before first hospitalisation.13 In the current study, we utilised patients from the same cohort in order to (1) identify determinants of GDF-15 and establish whether GDF-15 provides unique information, and (2) investigate whether GDF-15 provides incremental prognostic value beyond known factors. This evidence concerns the gene GDF15 and hydrops fetalis.