NPPB and cardiac arrhythmia: In this study, our findings were consistent with others in terms of the risk factors for ICU admission and in-hospital mortality in patients with AECOPD, including older age [17], cardiovascular complications [18] (arrhythmia, HF), malignancy [16], pneumonia [19–21], anemia [22], and high levels of NT-pro BNP [23].