In stage C HF patients, SGLT2i significantly improved the NT-proBNP level in the HFrEF subgroup (SMD − 0.14, 95% CI − 0.22 to − 0.05, p = 0.001; I2 = 0%) but not in the HFpEF subgroup (SMD − 0.07, 95% CI − 0.29 to 0.14, p = 0.51; I2 = 0%) (Additional file 4: Figure S3). Here, NPPB is linked to hydrops fetalis.