In Fig 7, the subgroup (≤ 70 years old) demonstrated that the increase of BCR level was potentially relevant to a lower risk of all-cause mortality in patients with HF (HR = 1.62, 95% CI 1.35–1.94; I2 = 68.3%, P = 0.004) as did the subgroup (> 70 years old) (HR = 1.67, 95% CI 1.19–2.34; I2 = 88.3%, P = 0.000). Here, BCR is linked to hydrops fetalis.