BCR and hydrops fetalis: In Fig 5, the subgroup (the BCR threshold > 25) demonstrated that the increase of BCR level was potentially relevant to a higher risk of all-cause mortality in patients with HF (HR = 2.08, 95% CI 1.59–2.73; I2 = 0.0%, P = 0.616) as did the subgroup (the BCR threshold between 20 and 25) (HR = 1.42, 95% CI 1.00–2.00; I2 = 85.6%, P = 0.000) and the subgroup (the BCR less than or equal to 20) (HR = 1.52, 95% CI 1.24–1.87; I2 = 78.6%, P = 0.003).