Compared to placebo, dapagliflozin improved the 6MWT of HFrEF patients [MD = 41.61, CI (27.23–56.00)] and proBNP levels [MD = −402.49, CI (−575.29 to −299.68)], and empagliflozin improved the 6MWT of HF patients [MD = 40.00, CI (2.99–77.01)] and proBNP levels [MD = −547.13, CI (−1,065.35 to −28.91)]. This evidence concerns the gene NPPB and hydrops fetalis.