Lastly, and very importantly emphasizing the importance of NT-proBNP in renal disease, the ICON study has also shown that both NT-proBNP and GFR are independent and additive predictors of prognosis in patients with HF.101 In this sub-study, all 720 patients in ICON diagnosed with HF were dichotomised according to median NT-proBNP concentration (4647 pg/mL) and according to presence or absence of National Kidney Foundation “moderate or more” renal impairment (i.e. GFR<60 ml/min/1.73m2). This evidence concerns the gene NPPB and hydrops fetalis.