In addition, the subgroup analysis by types of HF showed that the risk of all-cause death of AHF increased by 79% when the level of BCR increased, while that of other HF patients(non- AHF) increased by 51%, which indicated that compared with other HF patients (non- AHF), the risk of all-cause death increased more obviously in AHF patients when BCR increased. Here, BCR is linked to hydrops fetalis.