In the RELAX study, it was shown that subjects with HFpEF and DM had similar levels of NT-ProBNP compared with nondiabetics, but markedly higher levels of the vasoconstrictor endothelin-1 (ET-1), of markers of inflammation such as uric acid and C-reactive protein, and of profibrotic markers such as valectin-3 and carboxy-terminal telopeptide of collagen type 1 [34]. This evidence concerns the gene EDN1 and diabetes mellitus.